Wilson v Nilepac Pty Ltd t/as Vision Personal Training

Judgment 1BEAZLEY JA : I have had the advantage of reading in draft the reasons of Tobias JA and Whealy JA in this matter. I agree with Tobias JA that the appeal should be allowed and the matter remitted to the trial judge for the assessment of damages. 2The issue upon which Whealy JA departs from the reasoning of Tobias JA, namely whether the trial judge erred in rejecting the whole of the evidence of the expert witness, Mr Tzarimas. As both their Honours indicate, the appeal succeeds regardless whether the trial judge did err in rejecting that evidence. Both their Honours advance cogent reasons for their respective views. Given that the appeal succeeds, it is not necessary for me to express any view on the issue. I would only intimate that during the course of the appeal, it seemed to me that there were aspects of Mr Tzarimas' evidence that should have been accepted, notwithstanding her Honour's demeanor finding. The evidence to which I refer was his evidence relating to Mr Draffin's incorporation of the medicine ball exercise into the appellant's exercise program. 3TOBIAS JA : On 5 April 2008 the appellant sustained a right-sided prolapse of his L4/5 intervertebral disc with associated nerve compression which he alleged was caused when he undertook two particular exercises at the behest of his personal trainer at a gym operated by the respondent at Crows Nest. He instituted proceedings in both tort and contract against the respondent alleging breach of its duty of care which the respondent accepted was owed. The claim was brought against the respondent in its own right and as the employer of the personal trainer allocated to the appellant for whose negligence, if any, it was vicariously liable. 4On 30 April 2009 an order was made that the issue of liability be determined separately from, and in advance of, the question of damages. 5McCallum J determined the issue of liability on 10 December 2009. Her Honour found in favour of the respondent upon the ground that there had been no breach of any contractual or tortious duty of care either directly by the respondent or by the personal trainer. She accordingly ordered that there be a verdict and judgment for the respondent and that the appellant pay the respondent's costs of the proceedings. The appellant appeals to this Court from those orders.

The background facts 6The appellant is a barrister and was aged 40 as at April 2008. In March 2008 he decided to lose weight and get fit. For this purpose he contracted with the respondent for reward to undertake a programme developed specifically for him and which was to be implemented under the supervision of a personal trainer. In early March 2008 he underwent a pre-exercise screening and assessment conducted by Ms Jenni Webb (Ms Webb), a staff member of the respondent. 7The appellant informed Ms Webb that he felt overweight and unfit. He stated that his goals were to lose weight and "tone" himself to a leaner physique. 8Ms Webb's assessment of the appellant took about two hours. She asked him a series of questions and completed a number of forms on a computer. She asked him to perform a number of basic exercises such as sit-ups and push-ups. She provided him with a " nutrition strategy " (a diet) and formulated a training plan during the initial assessment. The programme was based on four sessions with a personal trainer each week extending over 12 weeks and consisting of three cardio sessions and one weights session per week. 9The personal trainer allocated by the respondent to the appellant was Mr Alec Draffin. At the time he was 20 years old, having recently completed his qualifications as a Fitness Instructor and Fitness Trainer. He commenced employment with the respondent shortly after obtaining those qualifications. It was common ground that Mr Draffin was an inexperienced personal trainer - his evidence was that the appellant was one of his first ten clients. 10As I have noted, the appellant's training programme was divided into three phases of four weeks each. Within each phase, and with each new phase, the programme contemplated gradual progression to more difficult exercises. According to the primary judge (at [10]), the four sessions per week consisted of three cardio sessions and one weights session. She observed that in his evidence the appellant had stated that he changed the programme because he wanted to do more of the weights sessions. It was submitted on the appeal that the second phase of the programme was brought forward or escalated by the appellant so as to include a weights programme. However, it was ultimately conceded that no evidence of the appellant could be identified to support either her Honour's finding or the submission based on it. 11Nevertheless, although the appellant's attendance had been irregular, within three week and a half weeks of commencing training at the gym the respondent's records established that he had completed nine cardio sessions and five weights sessions. This was the total number of sessions contemplated at the outset but with more weight sessions than originally proposed by Ms Webb. 12The respondent supplied standard forms on which the trainer was required to record the exercises carried out during each session. The form for weights sessions was referred to within the gym as a "red weights card". It was designed to record four weeks to a page and two sessions per week. Relevantly to the issues on the appeal, the red weights card in evidence set out the particular exercises that the appellant was to undertake. In the first phase referred to on the card as "Starter", some five different exercises were identified including " Leg Press" and "Supine Floor Holds". In the second phase, a further six exercises were identified of which the last was identified as Supine Floor Crunches. 13This last-mentioned exercise is of particular relevance as an unprogrammed variation of it was the exercise ultimately found to have caused the appellant's injuries. That unprogrammed variation of the exercise departed from that which Ms Webb had devised for the appellant after assessing his fitness or lack thereof but which he was directed to undertake by Mr Draffin in order to accelerate the strength of the appellant's abs (shorthand in the fitness industry for abdominal muscles) and so help him to meet his fitness objective more quickly. It will be necessary to return in detail to this aspect of the matter below. 14The primary judge found (at [15]) that it was clear from the appellant's evidence and the contemporaneous records of the respondent, that on Friday 4 April 2008 Mr Draffin started the appellant on the second phase of his programme a few days earlier than initially planned. She also accepted that the appellant's injury was sustained during a weights session conducted by Mr Draffin on Saturday 5 April 2008.

The nature of the appellant's case 15The appellant's case before the primary judge was that the injury to his lumbar spine was caused by either or one both of two " dangerous " exercises performed during a weights session on 5 April 2008. The first was an exercise known as a " horizontal leg press ". The second was described in the pleadings as an exercise which required the appellant " to twist from side to side whilst sitting up from a prostrate position and catching a heavy medicine ball ". 16The primary judge ultimately found (at [134]) that she was not satisfied of any breach of duty in relation to the leg press exercise. There is no challenge to that finding. Further, she held (at [166] and [167]) that she was not satisfied or persuaded on the balance of probabilities that the leg press exercise was a cause of the appellant's injury. Again, the last-mentioned finding was not challenged but it became relevant to the issue of causation with respect to what was referred to by the primary judge as the " medicine ball exercise " and to which I shall return when dealing with that issue. 17The pleadings alleged some 15 contractual and tortious breaches of duty by the respondent itself such as devising an unsafe and unsuitable training programme; failing to train and/or supervise Mr Draffin, and failure to provide appropriate risk management with respect to the appellant's programme - allegations together with variations thereof which the primary judge rejected and in respect of which there is no challenge. The only challenge is to the primary judge's finding that there was no breach of duty on the part of Mr Draffin in requiring the appellant to undertake the medicine ball exercise. 18An issue arose as to whether the appellant undertook a weights session on 5 April 2008. In this context, the primary judge at [18] of her reasons noted that at the outset of the session on that day, Mr Draffin asked the appellant how many drinks he had had since their last session, presumably because one of the appellant's training goals was to confine himself to 14 standard alcoholic drinks per week. The appellant told Mr Draffin that he had drunk more than he should have the previous night and said " so go easy on me ". 19According to the appellant, Mr Draffin responded " there is nothing better for a hangover than exercise. We'll have to smash you ". That term is one used within the fitness industry to describe an intense level of exercise, meaning to give someone a " pretty tough " workout. Mr Draffin denied that he used that expression but the primary judge found (at [20]) that he did but that the remark was made in a jovial sense. She did not accept that Mr Draffin had pushed the appellant any harder than he otherwise might have because he had drunk more than he should have the night before. There is no challenge to that finding but equally it would appear that although the appellant denied he was hung-over, nonetheless he did not deny that he requested Mr Draffin to " go easy " on him. 20As to the issue as to whether the appellant undertook a weights session as distinct from a cardio session on 5 April, the appellant insisted that he had, but the incomplete entries on his red weights card led Mr Draffin to conclude that the appellant had not. Notwithstanding extensive cross-examination on the subject, Mr Draffin maintained that the appellant did not do weights that day. The primary judge rejected Mr Draffin's evidence on that issue. 21Her Honour said at [26] that she was satisfied that the appellant had undertaken at least part of a weights session on 5 April 2008. In this respect she had no difficulty in accepting the appellant as a truthful witness and that his recollection as to this aspect of his evidence was reliable. In particular, her Honour found at [29] that the appellant's recollection of doing an abdominal exercise with a medicine ball on that day was correct. That finding is of some importance as Mr Draffin denied that a medicine ball was used on that day although, as will appear, his evidence as to its previous use was inconsistent.

The witnesses called at the trial 22Both the appellant and Mr Draffin gave evidence. Each was extensively cross-examined. Apart from the evidence of a number of specialised medical practitioners, the only expert evidence called on the issue of liability was a Mr Christopher Tzarimas, an Accredited Exercise Physiologist and, since 2005, Director of the Lifestyle Clinic in the Faculty of Medicine at the University of New South Wales. His expertise in the field of fitness physiology was not questioned. He holds, amongst other qualifications, a Certificate IV as a Dual Accredited Personal Fitness Trainer and Specialist Fitness Trainer. His areas of expertise and special interests included, according to his Curriculum Vitae, "Fitness Industry Standards". He had had much to do with Fitness Australia as well as Fitness NSW Personal Trainers Council as well as Fitness NSW Training and Registration Council. 23In cross-examination Mr Tzarimas stated that he knew the fitness industry well and was aware in general of the qualifications of those who operated commercial gyms in the Sydney area and the lower North Shore. He stated that he had expertise not only as a personal trainer but also an intimate knowledge of the fitness industry and its standards. According to his CV (at Blue 118) and his evidence (at Black 161Q-X) he was the owner/manager of his own gym at Ultimo from 1996 or 1997 until 2004. His duties included health assessments and exercise consultations as well as management of staff. It was not suggested to him that standards had changed between 2004 and 2008. 24I mention Mr Tzarimas' expertise and background because he was subjected to a lengthy and at times unnecessarily aggressive cross-examination in respect of which her Honour was forced to intervene. He was challenged as to his knowledge of the practices and standards of commercial gyms, it being submitted that Mr Tzarimas was really only an academic so that by not calling any evidence from a hands-on operator of a gym as at 2008, the appellant had failed to establish what was a reasonable standard of care to be adopted by such a gym against which Mr Draffin's conduct in requiring the appellant to undertake the medicine ball exercise could be measured. 25The respondent called no evidence on this issue. It did not call the proprietor of the gym, its manager or Ms Webb - all of whom were apparently available to give evidence. The appellant sought to persuade her Honour that a Jones v Dunkel [1959] HCA 8; (1959) 101 CLR 298 inference should be drawn as a consequence of those potential witnesses not being called by the respondent. It was submitted that it could be inferred that those witnesses would not have corroborated Mr Draffin's evidence relating to the operations and practices of the respondent's gym. Her Honour (at [81]) remarked that the principal factual context appeared to be the way in which the exercises were undertaken which only Mr Draffin could address. She was therefore not satisfied that any adverse inference should be drawn against the respondent on account of its decision not to call any of the witnesses referred to. 26The primary judge also declined (at [84]) to draw any adverse inference from the fact that the respondent did not call any expert evidence to establish the appropriate " normative " standard of care applicable to a personal trainer such as Mr Draffin as the onus of proving the relevant standard was on the appellant. As a consequence, the only source of evidence as to the appropriate standard of care was Mr Tzarimas. 27I have some doubt as to whether her Honour was correct in her findings at [84] at least so far as it related to Ms Webb who devised the appellant's programme of exercises after carefully assessing his condition of fitness. However, there is no challenge by the appellant to those findings so that it need not be further considered.

The primary judge's findings as to the credit of the appellant and Mr Draffin 28In relation to whether part of a weights session took place on 5 April, the primary judge had no difficulty in accepting the appellant as a truthful and reliable witness. In relation to Mr Draffin, the primary judge rejected his evidence on this issue, as she found (at [25]) that his evidence was derived from reconstruction: although she did not mean to suggest that he was in any way untruthful. She formed the clear impression that Mr Draffin was endeavouring to give an honest account of events. 29With respect to the medicine ball exercise, the primary judge (at [55]) concluded that Mr Draffin presented as an earnest witness who expressed himself in simple terms without guile. In contrast, at [58], she doubted the reliability of the appellant's evidence as to whether the appellant had been asked to do a sit-up rather than a crunch with respect to the medicine ball exercise. Thus at [65] her Honour said that although she accepted without hesitation that the appellant was an honest witness, she regarded his attention to detail in matters of exercise as poor at the time of the events in question and, in her view, that had impaired his ability to give a reliable account. She therefore accepted (at [66]) Mr Draffin's evidence that the exercise he required the appellant to perform on 5 April was a crunch with a medicine ball in which he was required to move from side to side at the top of the crunch.

Sit-up or crunch? 30The issue of whether the medicine ball exercise was a sit-up or a crunch seemed to assume a deal of significance in the primary judge's reasons notwithstanding that the respondent appeared to have conducted its case at all times upon the basis that Mr Draffin had required the appellant to perform a sit-up exercise rather than a crunch exercise. The difference between the two was described in the evidence of Mr Tzarimas. In each case the person undergoing the exercise commences in a supine position with their back flat on the floor and knees bent. A sit-up involves flexion of the hip joint so that the lumbar vertebrae are no longer in contact with the floor and the torso is off the ground. The effect of this is that lower back is no longer held in a neutral or straight position but is bent, thus placing some degree of pressure upon the lumbar spine. In other words, performing a sit-up with full flexion of the spine produces low back compression as the lumbar spine then operates as a fulcrum holding the weight of the torso. A crunch involves raising the upper body in a straight line to a position approximately 30 from the horizontal as distinct from 90 for a sit-up. As the lumbar spine is kept straight and not bent, there is less compression on the lower lumbar vertebrae. The crunch is solely focussed on lumbar flexion; the hips are not flexed so there that is no movement in the hip joint. 31In his evidence, the appellant said that he raised his upper body to a point that, by reference to the photographs in Exhibit M (at Blue 8-9), would appear to indicate that he was at 30 -40 to the horizontal. The respondent asserted that the difference between the two exercises was merely semantic but this notwithstanding, a deal of time was spent on the issue and, as I have indicated, the primary judge ultimately found that the exercise in question was a crunch with a medicine ball with the appellant required to move from side to side at the top of the crunch. Be it a sit-up or a crunch, it seems to me that the critical factor was that the appellant's upper body was, in effect, suspended. Moreover, it was not the fact that he was being requested to do a sit-up or crunch which, on the medical evidence as well as that of Mr Tzarimas, was the cause of the injury. The injury was caused by Mr Draffin throwing a medicine ball weighing 5.4kg to the appellant which he was then required to hold with his arms outstretched and also to move or rotate from side to side in a twisting movement and, according to the appellant, to touch the floor with the ball and then return it to Mr Draffin. 32Although the appellant submitted that the primary judge's finding that the exercise was a crunch rather than a sit-up should be overturned, it was also contended that even if it was a crunch, the appellant was still entitled to succeed. This was particularly so given that the only critical aspect upon which the appellant's evidence was not accepted, was whether the exercise involved " sit-ups " or " crunches ". 33In my view one of the reasons why the question of the appellant being requested to sit-ups or crunches is only of academic interest, is that on the issue of causation the primary judge found (at [173]) that she was satisfied "to a point of actual persuasion that the pressure on the lumbar spine when the medicine ball was caught, combined with the flexion of the spine created by the twisting part of the exercise, probably enabled the disc to protrude in the manner described by Dr Hopcroft." 34The evidence of Dr Hopcroft (at Black 199) to which the primary judge referred arose from a question put to him by her Honour to the effect that she understood his evidence to be that he regarded the relevant exercise as one which was highly dangerous and imposed a risk to the integrity of the lumbar spine. In this respect Dr Hopcroft had described the exercise in the following terms (at Blue 186 D-G): "Also in the session on 5 April, the patient did supine floor crunches. Those crunches involved the patient lying on his back on the floor with his feet flat on the floor and knees elevated. As he sat up from the floor, the patient would then be thrown a medicine ball from the Trainer, Mr Draffin, (who incidentally had his feet placed on the patient's shoes a stabilising mechanism). The patient would then sit up with the medicine ball at chest level and twist from left to right with each repetition. With each twist the patient would be required to touch ball on the floor on each side." 35The primary judge then referred to the impact of the medicine ball both as a consequence of its momentum and its weight to which Dr Hopcroft responded as follows: "The classic law of physics. So we don't know which was one thrown [i.e. the 2 kilogram ball or the 5.4 kilogram ball]. We can assume that the momentum was significantly higher than 4 pounds per metre. And what happens on impact with the patient flexed like this, is that (indicating) all the core musculature and the abdominal muscles brace on impact. So at that moment the pressure is suddenly increasing on the front of the disc, the soft mucoid centre of the disc can find its way right through to the posterior part of the disc, and then you have the evolution of disc protrusion. That seemed to be the confusion to the Court. And that is that most disc protrusions don't suddenly occur and are static and that's what you see in the X-ray 6 months later. It's an evolving process. It can start as a disc bulge and go into a focal protrusion, and that can happen at any speed."

The medicine ball exercise 36The appellant's evidence was that he was aware that there was an exercise described (on the red weights card) as a "Supine Floor Crunch". He said that it required him to lie on the floor and lift the upper part of his body off the floor approximately six inches in order to develop stomach strength. However, he did not believe that he did floor crunches on 5 April. On that day his evidence (at Black 44-45) was that Mr Draffin pulled over a mat, placed it on the floor and told him to lie on the floor and bend his knees, which he did. Mr Draffin then went over to a rack and picked up a medicine ball, returned to where the appellant was lying and stood on his shoes and told him to do sits-ups. Mr Draffin then explained that during the sit-ups he would throw the medicine ball to the appellant who was to then twist from side to side and touch the floor with the ball. The following exchange then took place: "Q. This is what, after you caught [the medicine ball]? A. After I caught it, touched the floor with the ball before throwing the ball back to him once I reached the upright position and then I would recline and that exercise would be repeated. Q. Up until that time at the gymnasium, had you ever done any full sit ups at all? A. Not that I recall. Q. Had a medicine ball every appeared in any of your exercises? A. No I hadn't - no." 37Shortly after giving this evidence, the appellant was asked when he first felt the weight of the ball. He responded that it was when the ball was thrown to him and he was about a third of the way off the floor. He said that Mr Draffin held the ball at about chest height then, with his palms facing outwards and extending his arms, threw or pushed the ball at the appellant. The appellant then caught the ball and twisted to each side with it, attempting to touch the floor on both sides. He said that he found it quite difficult to touch the floor. He then threw the ball back to Mr Draffin when he reached the full 90 sit-up position. 38In cross-examination the appellant was referred to the photographs in Exhibit M and in particular to what was previously MFI 2 at Blue 9, stating that when he caught the ball he was at some point between the positions as shown on the photographs in that exhibit. He was then shown MFI3 (at Blue 10) after which the following exchange occurred (at Black 85-86): " Q. Well, did you have the ball in outstretched arms in the way Mr Draffin is demonstrating or in some other way? A. Oh no. In that fashion. Q. Did you, first of all, twist to one side? A. Yes. Q. Then to the other? A. Correct. Q. It's correct, isn't it, that you have no recollection of that ball touching the carpet whilst you were in the position that you have just described? A. I recall the intention of the exercise as directed was to touch the floor, but I also recall that I was unable to do it more than a couple of times. Q. But I want to be precise about this, is your recollection that at any time the ball actually made contact with the carpet? A. I, I believe it did. Q. You could be entirely wrong about that, you would concede, would you not? A. Oh no. Look, I'm I'm reasonably certain that on at least several occasions it touched the floor. However, as I was beginning to fail in the exercise the twisting became less vigorous. Q. There was a set of ten or 12 so far as you could remember? A. Correct. Q. Did you manage to touch the ball to the ground early in those set of ten or 12, halfway through, or at the end? A. Oh, only at the beginning. Q. Mr Wilson, I may be mistaken. My recollection is that you evidence before lunch is you didn't finish a full set of 12? A. No, I didn't. I think I, I think I said, your Honour, that I didn't, could not do any more than one set. I can't be precise, but I would be surprised if it was ten or 12. It could have been less." (Emphasis added) It needs to be emphasised that the above answers (and particularly that which I have emphasised) were elicited in cross-examination. 39The appellant said that the two photographs at Blue 10 best represented the exercise he did on 5 April. It was then put to him that those photographs not only best depicted the exercise but did so accurately. The respondent replied (at Black 86W): "Well, subject to the qualification I mentioned earlier as to twisting further to the floor, I agree." 40Of particular significance in my view was the primary judge's finding at [45] that the exercise prescribed in the appellant's training plan did not include the medicine ball exercise. Each weights session, she said, included an abdominal exercise but not with a medicine ball or a twist. 41I have already referred to the difference, explained by Mr Tzarimas in his evidence, between a sit-up and a crunch. The primary judge summarised that evidence in the following terms (at [46]): "Mr Tzarimas explained, and demonstrated (at T137) that a stomach crunch involves lifting the torso off the floor only so far as is permitted by flexion of the lumbar spine, with no flexion of the hip joint. In that exercise, the lumbar spine curves but does not act as a fulcrum for the lifting of the torso. A sit-up is a different exercise, involving flexion of the hip joint so that the torso is lifted higher off the floor. In that exercise, the lumbar spine acts as a fulcrum, holding the weight of the torso, and so comes under more strain." 42At [47] her Honour stated that she was satisfied that Mr Draffin had required the appellant to perform an abdominal exercise using a medicine ball on 5 April 2008. This was notwithstanding the fact that Mr Draffin in his evidence at one point denied that this was so. His recollection, such as it was, was that at the very least he was not sure when he asked the appellant to undertake the Supine Floor Crunch, nor as to whether he used a medicine ball or not. 43Mr Draffin acknowledged that at some stage he had required the appellant to do sit-ups but because the appellant found them to be too challenging, he went back to crunches. The problem was that he did not know on which day that occurred. It was put to him that it was after he had received a letter from a Mr La Scala, a physiotherapist consulted by the appellant, and dated 7 April 2008 in which it was suggested that the appellant, having presented with right side sciatica, should avoid any activity that placed him in lumbar flexion, especially with his leg outstretched in hip flexion. 44Mr Draffin's evidence (at Black 332W) was that sit-ups only occurred on one occasion but he was not sure whether he used the medicine ball or not. That does not sit well with his evidence (at Black 325V-X) that he could not remember whether he had the appellant perform the exercise with the medicine ball on only one occasion. He accepted that he had not recorded the use of a medicine ball on any of the documentation he was required to complete. The following exchange then relevantly occurred (at Black 325Y-326M): "Q. Bearing in mind what you have said about the red documents setting out the exercises to be undertaken, what Vision's own directions to you were, that you have agreed were to follow the programme exactly, where did you come up with this medicine ball exercise from ? A. Well, when I was at the AIF, we had almost half a day going through all the different types of exercises you can do and how you can make the easier for clients and harder for clients, and one of those, although it is not written down, was doing crunches with a weight, and I just thought doing crunches holding a medicine ball is a lot easier than holding a dumbbell. So it was just to - it's the next logical step up, in terms of making the exercise a bit more challenging. ... Q. So, when you say the next step up, do you mean the next sep up from a supine floor crunch with your hands on your chest? A. No. Well, crunches and sit ups are two different exercises, and we were using the medicine ball doing sit ups. Q. Do you agree with me that sit ups don't appear in any of the documents that we have referred to in the last few moments? A. Yes. Q. Either on the Vision documents, or the AIS training documents, or the Vision manual, or the DVDs? A. Yes." 45Earlier in his evidence (at Black 288) when referred to the photographs at Blue 8-10, Mr Draffin agreed that he had required the appellant to do the exercise seen in those photographs using the medicine ball and, to the best of his recollection, the exercise was performed at least two or three times. Further down at Black 288T-Y he said the exercises involving the medicine ball were only floor crunches and that the appellant was doing them with the ball in his hands, moving it from left to right. At Black 289P-S Mr Draffin denied that he threw the ball to the appellant whilst he was doing those exercises. He maintained that the appellant held the ball continuously. The following exchange then occurred: "Q. Did you observe at any time during the crunch exercises that ball touching the carpeted floor? A. Yes. Q. Ho many times did you observe that happen? A. Two or three times. Q. Was that something involving a twisting motion? A. Yes. Q. Did that twisting motion involve Mr Wilson? A. Yes. Q. When, in terms of your time with him, just to give it a point in time, did you see that happen? A. It was during the crunches when it happened." 46When it was suggested to him that he had previously accepted that the appellant was doing twists with the ball, Mr Draffin responded (at Black 350): "I wouldn't call them twists. What he was doing was he would have the ball and he would crunch up to the left and he would crunch up to the right as opposed to twisting the body." It was then put to him that he had said in chief that the appellant used the ball in a way where he twisted and touched the carpet on either side. Mr Draffin responded that the whole idea of the exercise was not to touch the carpet and that he had not intended the appellant to touch the carpet whilst doing the 30 off the floor supine crunch. Although Mr Draffin accepted that the appellant did touch the carpet, he maintained that he would have corrected him and told him not to do so as " we are looking for the ball not to touch the ground ". It was never suggested to the appellant in cross-examination that Mr Draffin corrected the medicine ball exercise when the appellant undertook it incorrectly by touching the floor with the ball. 47Following the primary judge's finding at [47] (see [42] above), her Honour considered that that three factual issues remained to be determined: whether the appellant was required to do a sit-up or a crunch - the primary judge finding the latter; whether the medicine ball was thrown to the appellant whilst he did the exercise; and the weight of the medicine ball used. 48The primary judge found (at [67]) that contrary to Mr Draffin's evidence, the ball was thrown by him to the appellant throughout the exercise and (at [68]) that the medicine ball in question weighed 5.4kgs. 49Although the primary judge's finding (at [66]) was that the appellant was required to move the medicine ball from side to side at the top of the crunch, notwithstanding the appellant's evidence to which I have referred at [38] above, she made no specific finding as to whether he was required to twist with the medicine ball in his outstretched arms and touch the ball to the floor. Given her finding on the issue of causation, namely, that the injury was caused by the pressure on the lumbar spine when the medicine ball was caught combined with the flexion of the spine created by the twisting part of the exercise, it is apparent that she accepted the appellant's evidence that he was required to proceed with a twisting or rotational movement with the medicine ball in his hands irrespective of whether he was able or required to touch the floor with it. At the end of the day it is probable that a finding on this last-mentioned issue was not required given the medical evidence as to the cause of the appellant's prolapsed disc, which her Honour accepted.

The evidence of Mr Tzarimas 50The evidence upon which the appellant relied at trial and which it submitted the primary judge should have accepted, was that of Mr Tzarimas at paragraph 62-70 of his report of 27 November 2008 (Exhibit C). Paragraphs 63-66 were concerned with the effect of a sit-up on the lumbar spine. Mr Tzarimas opined that performing a sit-up caused spine-loading conditions that greatly elevated the risk of injury due to the fact that each sit-up produced low back compression. At paragraph 65 he quoted from a popular text for fitness industry professionals that stated that lumbar discs are more easily injured during a combination of flexion and rotation and should be avoided when prescribing exercises to " susceptible clients ". 51At paragraphs 67-69 Mr Tzarimas said: "67. When an individual bends forward and twists to one side, a certain amount of torque would be generated on the lumbar spine. Such awkward testing movements are closely related to disc prolapse and back pain. 68. Generating high rotational torque or high torque (as when moving a medicine ball with outstretched arms from side to side) while the spine is twisted is an activity that poses a very high injury-risk to the L4-L5 joint. Furthermore, the additional compressive burden on the spine during trunk flexion is substantial for even a low amount of axial torque production. 69. A high rotational torque coupled with the additional compression on the lumbar spine performed during this exercise would be (sic) place it amongst the highest risk movements for acute injury to the lower back." 52He concluded that the medicine ball exercise was, for the reasons indicated, an inappropriate exercise for a person of the appellant's age and physical condition. Furthermore, it was not referred to at all in the National Fitness Industry Training Package which set out the requirements for attaining Certificate III in Fitness and Certificate IV in Fitness being the qualifications which Mr Draffin had achieved. 53As I have observed, Mr Tzarimas was exposed to a lengthy and at times aggressive cross-examination intended to attack his credit. Mr Tzarimas' thesis was that the most significant factor which rendered the medicine ball exercise inappropriate for the appellant to undertake was the requirement that, with medicine ball in hand, he was to twist to the end of his range of rotation and to place the ball in contact with the floor. It was the degree of rotation that was the significant factor. 54Mr Tzarimas accepted (at Black 215W-217O) that many movements in the fitness industry involved rotating the spine and that in that sense spinal rotation could be described as conventional in a gym. But what the appellant was required to do was not conventional. It involved an extreme twist with the added stress of catching and holding a 5.4kg medicine ball in outstretched arms. Mr Tzarimas accepted that such an exercise was performed in gyms in Sydney even though not recommended within the fitness industry, but he later made it plain that it was an exercise that ought to be, and was, confined to persons who exhibited an athlete's fitness. 55So much was, in effect, also accepted by Mr Draffin in the following critical exchange (at Black 368): "Q. I want to suggest to you that you did throw a medicine ball to Mr Wilson at some stage of your exercise programme with him? A. No, I didn't throw it at him. Q. You do throw medicine balls at clients, don't you? A. I pass it to clients, and as a challenge to my really advanced clients, that I know can handle it. Q. So, if the client is really advanced, you throw them the ball when they are doing a crunch or when they are standing or what? A. There would be the top part of the crunch. I would not throw when they were halfway down. I would throw when they would catch up at the top. Then they do the crunch. They, they come back up and I throw it again. Q. So, you do have exercises with some of your clients that involves you throwing a ball at them whilst they are doing a crunch, is that right? A. I have done that, yes." (Emphasis added) 56Such a rotational manoeuvre or "axial torque" as Mr Tzarimas labelled it (at Black 135F-O) posed a major impact to the compression of the lumbar vertebra, which placed it at the risk of disc herniation. Twisting rotation and lumbar flexion, he opined, was a dangerous combination especially when there was the added stress caused by the impact of a medicine ball being thrown and caught. As the appellant submitted, this evidence was consistent with the appellant's medical evidence which was unchallenged (except by Dr Matheson whose opinion on causation was not accepted). 57When pressed on what was conventional, the following exchange occurred (at Black 217) between her Honour and the witness: "Q. You are now addressing the training the trainers have. What basis do you have for saying that exercise isn't regularly - I understood you to mean not conventional in the sense that nobody does it in gyms in Sydney at the moment. A. It's performed but it's not a recommendation within the fitness industry. There is no mention of the sit-up in the National Fitness Industry Training Package. The most challenging abdominal exercise that is mentioned in the NFITP is the crunch. Q. So you're referring to what is recommended in the training? A. That is correct." 58It was suggested to Mr Tzarimas that the standards he asserted were those of a university qualified academic holding, as he did, a Masters degree rather than a realistic person who might run a gym in the CBD or lower North Shore of Sydney. His response was (at Black 268 O-U): "A. No they are not, they are the standards that are defined by the National Fitness Institute Training Package in various modules that pass occupational health and safety risk analysis, injury prevention and so forth that are expected to be implemented in the industry. Q. To the extent you have mentioned those umbrella bodies, you are not seized or of sufficient knowledge to know whether or not Vision Gym complied with those standards, are you? A. I have the expertise to know what the industry standards are, the experience and the background for the fitness industry and given the information I have been provided, determined against that background as to whether those standards are appropriate." It should be remembered in this context that Mr Tzarimas operated and managed his own gym at Ultimo from 1996/1997 to 2004: see [ 23 ] above. 59Again, in re-examination (at Black 272) Mr Tzarimas was asked whether the use of a medicine ball being thrown to someone doing a sit-up was an " innovative use " of the ball. He responded that it was not considered a conventional exercise by fitness industry standards. Given the exchange referred to at [57] above and that which is recorded in the following paragraph, it is apparent that the witness was using the word " conventional " in the sense of an exercise used in the fitness industry (meaning thereby fitness studios or gyms such as that of the respondent) for ordinary clients such as the appellant as distinct from those used for specific sports athletes. 60The further exchange to which I refer in the preceding paragraph took place between the witness and her Honour in the following terms: "HER HONOUR Q. Is it your opinion that that exercise is not appropriate for any person or are you only giving your opinion in relation to the plaintiff? A. Certainly not, there is a sport training package which provides qualification for officials and it includes coaches and in sports specific circumstances it is an exercise that may be appropriate. Q. Depending on the preparation of a particular person ? A. Correct your Honour . Q. You don't have to go any further." (Emphasis added) 61The primary judge did not accept Mr Tzarimas' evidence although she accepted (at [84]) that it was the only source of evidence as to the appropriate normative standard of care to be applied. In this respect the appellant acknowledged that that standard was one of a reasonable personal trainer and a reasonable personal training gym. The primary judge agreed that that was the correct standard to apply at [87], [103] and [126] of her reasons. In particular the critical question was whether Mr Draffin failed to act in accordance with the legal standard of care whether due to his inexperience or otherwise: see Imbree v McNeilly [2008] HCA 40; (2008) 236 CLR 510 at [72]. 62The primary judge rejected Mr Tzarimas' evidence on a number of grounds. First, at [121] she stated that the principal difficulty she had with his opinion with respect to the importance of performing adequate warm-up activities before a weights session was that he failed to expose the reasoning by which he reached that conclusion. However, at the end of the day this was not the fundamental basis upon which Mr Tzarimas expressed his view as to the inappropriateness of the medicine ball exercise that Mr Draffin had required the appellant to undertake. Rather, it was because that particular exercise was not one recommended within the fitness industry as an appropriate conventional fitness training exercise. Significantly, the most challenging abdominal exercise referred to in the National Fitness Industry Training Package was a floor crunch but not, as I understand his evidence, a crunch associated with the twisting or rotation required of the appellant by Mr Draffin with the added weight of a 5.4kg medicine ball. That this was so was confirmed by the respondent's own red weights card which, for the week in question, only identified the Supine Floor Crunch as the appropriate exercise for the appellant at that stage of his training programme. 63Second, at [122] the primary judge observed that she had reservations regarding Mr Tzarimas' evidence in that she was not satisfied that he brought a completely independent mind to the task. Rather, he presented as having assumed the role of the appellant's advocate in the case. Her Honour then referred to Mr Tzarimas' oral evidence at Black 162W-163C in which he stated that after discussion with the appellant's counsel he had volunteered to speak to the manufacturer of the leg press machine for the purpose of preparing his third report and which related to the adjustments that could be made to the machine to accommodate a person such as the appellant. With respect, this example seems to be a thin reed upon which to justify the rejection of the whole of Mr Tzarimas' evidence on every issue (of which there were many). 64It is important to note that her Honour's rejection of parts of the appellant's evidence was not based on any credibility finding but rather on an unreliability finding: cf Fox v Percy [2003] HCA 22; (2003) 214 CLR 118 at [28]-[29]. In particular, her rejection of Mr Tzarimas' evidence because she was not satisfied that he brought a completely independent mind to his task but presented as having assumed the role of the appellant's advocate and had thus approached his task looking for fault in the respondent's studio according to his exacting standards was not, in my view, a credibility finding but more a reliability finding. But Mr Tzarimas' evidence on the issue under discussion must, in my opinion, be viewed in the context first, that it was unchallenged; second, that what her Honour considered was advocacy was, I respectfully suggest, the expression of opinions strongly held; and third, although some of his evidence exhibited a degree of arrogance (such as the unfortunate response to her Honour's question at Black 216Q-R recorded in her reasons at [141]), and at times a degree of frustration on his part, this was in no small measure due to the nature and extent of his cross-examination which her Honour was forced to interrupt on occasions to ask where the cross-examiner was headed. 65At [125] the primary judge's conclusions with respect to Mr Tzarimas' evidence were as follows: "Those considerations lead me to the conclusion that Mr Tzarimas approached his task looking for fault in the defendant's studio according to Mr Tzarimas' exacting standards. Outside his role as an expert in these proceedings, I make no criticism of him on that account. It was clear that Mr Tzarimas is passionately concerned to see the highest standards of professional responsibility practiced in the fitness industry, but my task is not governed by those standards but by what is reasonable in the circumstances." 66I agree with the primary judge's observation that Mr Tzarimas was passionately concerned to see the highest standards of professional responsibility practised in the fitness industry and I acknowledge that the her statement of the relevant standard of care is that which was reasonable in the circumstances. I also agree that one could describe Mr Tzarimas' standards as " exacting " with respect to what he asserted were numerous failings in its risk management procedures and professional responsibilities. These related to such matters as inadequate risk management procedures relating to staff competence; inadequate pre-exercise screening process by failing to identify the appellant as a person with increased risk; not providing the appellant with an opportunity to provide informed consent; inappropriate exercise instruction and supervision; inappropriate prescription of exercises and absence of provision of education to the appellant regarding the principles of exercising and self-monitoring. 67A fair reading of Mr Tzarimas' evidence, reveals an expert witness who was indeed an expert in his subject and who gave his evidence in a forthright and honest manner. Of course, whether he set the bar too high is another matter. But, as I understand his evidence, his thesis which is of relevance to the present appeal was that the particular exercise which the appellant was required to undertake, even if it was a crunch but coupled with the requirement to rotate or twist with the medicine ball in the appellant's outstretched hands to the extent that it touched the floor, was simply one which was not recommended in the manuals of the Australian Institute of Fitness (from whom Mr Draffin received his certificates qualifying him as a fitness trainer), and was inappropriate for the appellant given his age and poor physical condition. 68In my respectful opinion, the primary judge's grounds for rejecting Mr Tzarimas' evidence that it was unreasonable for Mr Draffin to introduce the additional challenge of the medicine ball and the side-to-side movement to the supine floor crunch were flawed. I agree that in the circumstances it may well be that there is no breach of duty on the part of the respondent itself with respect to that matter, but that does not answer the question as to whether Mr Draffin, as a reasonably competent professional personal trainer, was in breach of his (as distinct from the respondent's) duty of care which he, as well as the respondent, owed to the appellant. 69The primary judge at [141] did not accept Mr Tzarimas' evidence that for Mr Draffin to require the appellant to undertake a sit-up with the medicine ball would be negligent in the sense of breaching the standard of care of a reasonably competent professional personal trainer. It is as that point that I respectfully part company with the primary judge's conclusion. It is therefore necessary to examine Mr Draffin's evidence in some detail and to that I now turn.

Mr Draffin's evidence 70In the evidence which followed from the critical exchange which I have recorded at [ 55 ] above, Mr Draffin (at Black 368) said that only once had he thrown a medicine ball to a client whilst he was doing a sit-up and that the ball that he had used was the green one weighing, so the evidence established, 2kg. The following exchange then occurred: "Q. And when you perform that exercise with that client, is that something which you also get them to catch and twist with? A. No, that is a different exercise. Q. So, your sit-ups, throwing the ball at a client, does not include a twist? A. No. Q. But if it is a crunch, it does? A. Yes. Well, there are numerous different exercises." 71What appears out of these answers of Mr Draffin is, first, that he denied that he ever threw the medicine ball at the appellant at any stage, a denial the primary judge rejected; second, that he only passed (or possibly threw) a medicine ball to " my very advanced clients that I know can handle it " (and there was no doubt that the appellant did not fall into that category); third, although he would throw the ball to such a client at the top of a crunch when he would catch the ball, do the crunch and then return it to the trainer, there was no suggestion of requiring the client to catch the ball and then twist from side to side; fourth, he only used the 2kg ball whereas in the present case the medicine ball found to have been thrown to the appellant was a 5.4kg ball; fifth, when he threw a ball to a client who was doing a sit-up, the exercise did not include a twist although it would appear that if the exercise was only a crunch, a twist was apparently included. Why this was so for a crunch and not for a sit-up was not explained. 72The most significant aspect of the foregoing is that the medicine ball exercise was one which Mr Draffin maintained was confined to his really advanced clients and, as I have indicated, it was never suggested by him that the appellant fell within that category. Indeed, at Black 319-320, Mr Draffin agreed that the appellant was an absolute beginner when he commenced his fitness training and that he remained at that level. He was referred to a page in MFI 6 that has not been reproduced in the appeal books. It apparently sets out how to train persons at various levels in a safe manner. The levels went from 1 to 10, 1 being the lowest level of fitness. 73Mr Draffin agreed at Black 307J that the appellant was at Level 1 or 2 at the commencement of his training which meant that he was an absolute beginner and that his abdominal strength was very poor. At Black 320B-C he accepted that he had agreed, in effect, that throughout the period that he was involved with the appellant, he characterised him as such. Levels 1 to 3 apparently involved a beginner who found the exercises easy and could keep going for a while. Level 4 was one at which the client felt a slight effort in his muscles. Mr Draffin agreed that whilst under his supervision, the appellant did not rise above Level 4. Having read the document to which he was referred, he agreed that he had in fact trained the appellant to a level higher than Level 4 even though it was apparent to him that he was only just at that level. The following exchange then occurred at Black 320S-V: "Q. Despite earlier conceding that he was an absolute beginner? A. When he started he was an absolute beginner. Q. I think you said earlier that at all stages of his training with you, that is the level he remained at; you agree you said that earlier? A. Yes." 74At Black 309 Mr Draffin acknowledged that the programme set for the appellant changed every four weeks and the exercises identified in that programme were ones to which he was required to adhere. He acknowledged at Black 324 that the only exercises involving a crunch that was set for the appellant as at 5 April were Supine Floor Crunches as per the red weights card. He further acknowledged that the respondent's own Personal Trainer Manual provided that the trainer must follow each programme exactly unless a client had a specific limitation. He agreed that the respondent was particular in relation to a trainer adhering to the set exercises being, in effect, those tailored to a particular individual. At Black 325E he agreed that in neither the Australian Institute of Fitness document nor in the respondent's documents nor in its training DVD was there any depiction of a person doing a crunch or a sit-up using a medicine ball. 75Mr Draffin was then asked to explain why he departed from the exercises the respondent had set for the appellant when he knew that he was required to follow the programme exactly. The following exchanges relevant to that issue and to Mr Draffin's reasons for requiring the appellant to perform the medicine ball exercise are revealing. Thus at Black 325Y-326F the following exchange occurred: "Q. Bearing in mind what you have said about the red documents setting out the exercises to be undertaken, what Vision's own directions to you were, that you have agreed were to follow the programme exactly, where did you come up with this medicine ball exercise from? A. Well, when I was at the AIF, we had almost half a day going through all the different types of exercises you can do and how you can make them easier for clients and harder for clients, and one of those, although it is not written down, was doing crunches with a weight, and I just thought doing crunches holding a medicine ball is a lot easier than holding a dumbbell. So it was just to - it's the next logical step up, in terms of making the exercise a bit more challenging." 76T he cross-examiner returned to this point at Black 338T-339C in the following exchange: "Q. Can I ask you why you moved away from the programme and did an exercise which is not on the chart? A. Adding a ball is just another way of adding a weight to the exercise. It's a little bit of extra resistance. It makes it a little bit more challenging, but it also means that your abs get stronger and you can go through the levels a bit faster. It was common knowledge to me that that's a way you can add a bit of resistance and a lot of other people in the studio were also doing it, so I thought that it would have been ok to do it . Q. So you copied other trainers who were showing people how to do it, or other people who were just doing it? A. I was just making observations from other trainers that were doing their sessions, because I was still learning a lot ." (Emphasis added) 77Again, at Black 322B-G, after agreeing with the primary judge that he added the medicine ball in order to add an extra level of difficulty, the following exchange occurred: "Q. 'In weight training we often use the terms beginner/intermediate/advanced lifter to describe the person's training age'? A. Yes. Q. Page 141. Do you see that? A. Yes. Q. And it says: 'If we relate to the graph on the previous page, the beginner lifters would be in the first stage of two to three months, where they experience great neurological development'? A. Yes." 78At Black 350 Mr Draffin agreed that no part of the supine floor crunches involved any twisting of the torso from side to side. When asked whether the appellant was doing twists with the medicine ball, he responded "I wouldn't call them twists. What he was doing was he would have the ball and he would crunch up to the left and he would crunch up to the right as opposed to twisting the body." As I have indicated, the primary judge did not accept this evidence. 79The cross-examiner then proceeded with the following exchange at Black 350-351: "Q. I may be mistaken, and you can tell me if I am, but didn't you tell Mr Gracie yesterday that he used the ball in a way where he twisted and touched the carpet on either side? A. The whole idea of the exercise is you don't touch the carpet. Q. That wasn't my question. Didn't you tell Mr Gracie yesterday in your evidence-in-chief that Mr Wilson did touch the ball on either side? A. He did touch the ball on either side, but that wasn't the objective of the exercise. Q. The exact question is at 289, line 50: 'Q. Did you observe at any time during the crunch exercises that the ball touched the carpet of the floor? A. Yes. ... Q.Did that twisting motion involve Mr Wilson? A. Yes' Q. Does that mean that, if you were only doing four crunches with the ball which you added, you also added to the supine floor crunch a twist to either side? A. Yeah, he was moving from side to side, yes. Q. Where did you get that exercise from? A. It is just another progression that I had observed in my course and in the studio. Q. You agreed with me yesterday that the Vision manual told you to stick strictly to the exercises on the chart? A. Yes. Q. Why didn't you? A. Well, I had seen it being done in the studio. As I saw it being done in the studio, I just thought it would be okay to do . Q. On the videos we have just watched or the DVDs we just watched, the supine floor crunches the person gets 30 degrees off the ground? A. Yes. Q. Do you say that Mr Wilson had a ball and could do supine floor crunch[es] to 30 degrees off the ground but whilst in that position, 30 degrees off the ground, could twist from side to side and touch the ground with the ball? A. Well, the whole idea of the exercise is that the ball doesn't touch the ground, so if it did touch the ground I would have corrected him and said 'The ball is to stay in the air'. " Q. You didn't say that yesterday, did you? You were asked whether it touched the carpet. You just said 'Yes'. You didn't say, 'but I told him not to do that'. A. He asked if the ball touched the carpet and it did touch the carpet, but it wasn't supposed to." (Emphasis added) 80As I noted at [46] above, it was never suggested to the appellant that he was instructed by Mr Draffin when moving the medicine ball from side to side, not to touch the carpet with it or, that if he did, that he was then told not to do so. As I have also indicated, the primary judge made no finding in respect to this issue although there would seem to be no reason for rejecting the appellant's evidence on this topic. 81The appellant said in examination in chief (at Black 47F-G) that he could not guarantee that he touched the floor on both sides, but that he certainly moved in that direction in an attempt to do so but found it quite difficult. In cross-examination recorded at [38] above, the appellant when challenged as to his recollection of whether the ball actually made contact with the carpet, stated that he was reasonably certain that at least on several occasions it did. But as he was beginning to fail in the exercise his twisting became less vigorous: see also Black 110G-J. The important point is that the cross-examiner never put to the appellant that he was instructed by Mr Draffin not to touch the ground with the ball or that if he did that he should desist from trying to do so. 82Returning to Mr Draffin's evidence regarding his instructions to the appellant to undertake the medicine ball exercise, the following further exchange took place at Black 352P-353B: "Q. Why didn't you stick to the program? A. Well, as I said, I'd seen other people in the studio do it and his abs weren't the strongest and I was just looking at ways that would help him accelerate through the levels and build strength. ... Q. You thought that was better than going through the programme on the red sheets? A. Well adding a weight, adding a ball is just like adding resistance to a weights exercise, it is going to accelerate the way in which your abs grow and develop. So adding a ball to any level of the crunches is just another way of accelerating the growth of the abs. ... Q. Do you use that exercise on beginners still, do you? A. After they have done the starter abs, the holds, I do. I still believe that it is a good way to increase the strength of the abs." 83The last exchange referred to above is also inconsistent with that which I have recorded at [55] above in which Mr Draffin stated that he passed medicine balls as a challenge to his really advanced clients whom he knew could handle it. At Black 356 Mr Draffin was asked whether he apparently inserted the medicine ball into the exercises when he judged it to be appropriate or only after the client had completed the supine floor crunches. His response was that he made a decision when or if a ball should be added judging on the ab strength of the client. He agreed that whether he did so would depend on the individual client. The following exchange then occurred at Black 356Q-T: "Q. In relation to Mr Wilson, does that mean you finished the first four weeks, you regarded as within your discretion as to what to do in relation to following it for the next four weeks? A. I believe that after the first four weeks adding that extra bit of weight would accelerate his abs in a way that meant that the results would come quicker." It is noteworthy that Mr Draffin never suggested, let alone said directly, that he considered that the appellant's ab strength was sufficiently robust or advanced to justify his undertaking the medicine ball exercise on 5 April. 84Finally, with respect to Mr Draffin's evidence as to why he departed from the set exercises on the red weights card, he was cross-examined as follows (at Black 365H-O): "Q. Just before morning tea I think you said, and this is my summary of what you said, you believe that you could add weight to exercises by your discretion? A. Yes. Q. And who told you that you could that within Vision, anybody? A. It was just common practice when you are going through a weights programme to add weight, to make it more changing. Q. It is not something that is in the Vision manual at all? A. It would be covered, yes. It is adding weight to a weights exercise which is the whole point of doing the exercise. Q. What about adding exercises to the programme, that is not something which was up to you, was it? A. No." (Emphasis added) The last question and answer is of significance for Mr Draffin was not only adding weight to the supine floor crunch exercise but was adding, in effect, a totally new exercise to the appellant's programme which involved the throwing of 5.4kg medicine ball to him when he was at the top of his crunch and then requiring him to rotate or twist from side to side with the ball held with arms extended and with or without the requirement to touch the ball to the floor on each rotation. 85Finally, the cross-examiner put a number of propositions to Mr Draffin which, in my view, tends to effectively summarise his evidence and which bears repeating (at Black 366-368): "Q. Can I just put a couple of matters to you. I suggest to you in fact that Mr Wilson only did sit-ups, and I think you have agreed with this, on one occasion? A. Yes. Q. I suggest to you that, and I think you have agreed with this, he couldn't complete the number that you set for him? A. For the sit-ups, yes. Q. He did something like eight, 10, something like that? A. I am not sure as to the number, but it was enough to make it apparent that sit-ups were not the exercise that were correct at that time. Q. I suggest to you that was very close in time to when Mr Wilson turned up with a letter from his physiotherapist? A. Timing wise, I am not too sure. Q. It could well have been? A. It could have, yes. Q. I am going to suggest a couple of things which I don't think you are going to agree with. I suggest to you the day you did sit-ups with him you also used in that exercise a medicine ball? A. No. Q. I suggest that it was the blue/black medicine ball that you were shown earlier/ A. No. Q. I suggest to you that the sit-ups also involved a twist? A. No. Q. But I understand you to accept that around this time yo did supine floor crunches with him with a medicine ball which did involve a twist? A. I did that exercise with him but in regards to the timing, I am not too sure. Q. It could well have been very much around the time he failed to your satisfaction a sit-up? A. It would have been in the next few sessions, so that would have been over the next week or so, I believe. Q. I want to suggest you did them all at once, you did sit-ups with a medicine ball and with twists? A. No. Q. Of course, you would accept, wouldn't you, doing sit-ups with a medicine ball, even the green one, at Mr Wilson's level of fitness, was something that was not a good idea? A. His ab strength was not strong enough to do that, no. Q. If he did it, I think you have agreed, if he did it, being sit-ups with a medicine ball, at his level of ab fitness, that was too much for him and would have been too much for him? A. If he did it, it would have been, yes. Q. And more so if those exercises involved a twist? A. Yes. Q. And I assume you would accept that throwing even a green ball at someone doing a sit-up was something which would have been dangerous? A. Depending on their hand/eye co-ordination, possibly. Q. But apart from not being able to catch the ball, if they had poor abdominal fitness, throwing them a medicine ball as they did a sit-up would be dangerous? A. It would only be done on someone that had strong abs. Q. Because otherwise it could hurt them in relation to somewhere in their spine? A. I have got not idea, I am not a doctor ." (Emphasis added) 86The last two questions and answers are, in my opinion, revealing. They give the impression that as Mr Draffin was not a doctor, he never put his mind as to whether throwing a 5.4kg ball to the appellant with his poor abdominal fitness and then requiring him to twist or rotate with the ball in his outstretched arms from side to side was likely to impact upon his lumbar spine. Mr Draffin simply did not know. Whether this was because of lack of knowledge or lack of experience, one can only speculate. The consequence of either or both of these possibilities may be that a newly qualified but inexperienced fitness trainer, as was Mr Draffin, should be required to follow exactly the exercise programme which had been set by his employer for a particular client and not deviate from it without consulting with a more experienced staff member that it was safe to do so. This was in fact what the respondent required of Mr Draffin as he readily acknowledged. 87The danger associated with the medicine ball exercise that Mr Draffin required the appellant to undertake was made clear in the medical evidence, which the primary judge accepted.

The primary judge accepts Mr Draffin's evidence 88At [107] of her reasons the primary judge referred to the appellant's submission that the respondent had breached its duty of care by failing to ensure that Mr Draffin followed the prescribed programme, noting that that was not pleaded as a particular of negligence. She continued: "Even if that allegation had been pleaded against [the respondent], it is doubtful whether failure to ensure strict adherence to the programme would be negligent in itself. It would be necessary to consider all of the circumstances, including the extent of the departure and whether there was any reason for it ." (Emphasis added) 89I agree with the primary judge's foregoing comment, which is why I have set out the relevant evidence of Mr Draffin as to the extent of, and the reasons for, his departure from the programme. This is because the alleged breach of duty relevant to the appeal is not that of the respondent but that of Mr Draffin for which, if it occurred, the respondent is vicariously liable. However, as will appear, there were important parts of Mr Draffin's evidence which her Honour seemed to ignore. 90The respondent submitted that it was not open to the appellant to contend on the appeal that Mr Draffin had breached the standard of care owed by a personal trainer to his client where he had departed from the programme of exercises set for his client by his employer by adding variations to set exercises, the implementation of which caused the relevant harm. It was submitted there was no particular of negligence pleaded by the appellant that would permit such a contention to be advanced. 91This submission should be rejected. It overlooks four matters. The first is that no objection was taken to the cross-examination of Mr Draffin on this subject. The second is that it overlooks paragraph 7 of the Amended Statement of Claim which pleads not only that the appellant's injuries were caused by the respondent's breach of contract or negligence but also that those injuries were caused by the respondent's servant's negligence - that is, Mr Draffin's negligence. Third, the appellant's contention is within the terms of particulars (d), (f), (g). In my view, particular (d) is sufficient in its terms to cover the appellant's contention. Fourth, the submission is contrary to what was said by Dixon CJ, Webb, Fullager and Taylor JJ in Mummary v Irvings Pty Ltd (1956) 96 CLR 99 at 110-112 92At [136] the primary judge noted the submission of the appellant that even if the exercise was not a sit-up but a crunch, it was nonetheless inappropriate due to the introduction of the medicine ball and the twist. She remarked that the principal basis for this contention was that those variations were not recognised or recommended either by the Australian Institute of Fitness or within the respondent itself. 93Her Honour then acknowledge at [137] that neither of the variations introduced by Mr Draffin to the supine floor crunch exercise was expressly described in the appellant's written training plan prepared by Ms Webb. She then referred to Mr Draffin's evidence at Black 326 which I have recorded at [75], observing that one of the ways of making an exercise harder was to do crunches with a weight which Mr Draffin considered to be the next logical step up in terms of making the exercise a " bit more challenging ". 94Her Honour then referred (at [138]) to Mr Draffin's evidence at Black 338 to the effect that a medicine ball was his way of adding a weight to the exercise. Significantly she referred only to Mr Draffin's answer to the first question in the exchange recorded by me at [ 76 ] but not the second where he said that he was, in effect, copying what other trainers were doing in their sessions " because I was still learning a lot ". The primary judge also referred in the same paragraph of her reasons to Mr Draffin's statement that he still used that exercise with beginners once they had completed the " starter abs " (the Supine Floor Hold). 95Mr Draffin's statement appears to have been extracted by the primary judge from the following exchange at Black 356H-P in answer to the question (at Black 353J-K) as to whether he currently introduced the medicine ball after the client had completed four sets of supine floor holds and then the supine floor crunches: "A. There are a few different exercises that get prescribed in the first programme and I stick to them, and then judging their strength over the period after, I do the exercise that I see fit. Q. So, does that mean, currently, you insert the medicine ball when you judge it to be appropriate or is it only after you do the supine floor hold progression and supine floor crunches? GRACIE: Might we have the answer to that, then I may ask for it to be struck out. A. The system that produces that programme goes over lots and lots of different ab exercises. So, it is not very often that the programme, the ab programme, is the same every time. So, judging on their ab strength, I make a decision when or if a ball is needed to be added. So, what I am saying is that not always are the holds followed on by the crunches. Whatever the system tells me to do for the first four weeks, I do. Then, after that, I see what needs to be done, to get the best results in regards to the abs. HER HONOUR Q. Depending on the individual client? A. Yes." These answers of Mr Draffin need to be contrasted with his evidence that I have recorded at [55] in which he stated that he would only throw a medicine ball to a " really advanced " client. It cannot be the case that simply because Mr Draffin had seen the exercise performed by other trainers, that it followed that it was an appropriate exercise for the appellant to undertake. 96At [142] the primary judge again referred to Mr Draffin's reasons for requiring the appellant to undertake the medicine ball exercise and concluded that Mr Draffin was not negligent. She said: "Even accepting that a sit-up with a twist is not 'a recommendation within the fitness industry', I am not satisfied that it would have been negligent for Mr Draffin to see whether Mr Wilson could undertake that exercise at the stage that he had reached. Mr Draffin explained that he had identified abdominal strength as a weakness in Mr Wilson and he was looking for ways to improve his fitness in that area. He said that the exercise was tried once, but that Mr Wilson couldn't do it, so they went back to doing crunches. I am not satisfied that, in taking that approach, Mr Draffin took a risk that a reasonable personal trainer in his position would not have taken. As noted by Mr Gracie in his submissions, intense physical exertion was the object of Mr Wilson's training. Mr Tzarimas' opinion on that issue is, in my view, a counsel of perfection that does not reflect the normative standard of care imposed on personal trainers in that context." 97Her Honour's conclusion in the foregoing paragraph is consistent with that at [140] where she said: "Assuming that the exercise Mr Wilson was requested to do was a crunch, Mr Tzarimas' evidence has not satisfied me that it was unreasonable, by reference to the normative standard of care in a personal training studio, to introduce the additional challenge of the medicine ball and the side to side movement. They were progressions that Mr Draffin had been taught during his course to become a personal trainer. He had also seen them used by other trainers in the gym at [the respondent]."

Did the primary judge err in finding that Mr Draffin was not negligent? 98At [89] the primary judge acknowledged that the appellant's claim was governed by the provisions of Part 1A of the Civil Liability Act 2002 (NSW) ('the Act'). The general principles of the Act are set out in s 5B in the following terms: "(1) A person is not negligent in failing to take precautions against a risk of harm unless: (a) the risk was foreseeable (that is, it is a risk of which the person knew or ought to have known), and (b)the risk was not insignificant, and (c) in the circumstances, a reasonable person in the person's position would have taken those precautions. (2)In determining whether a reasonable person would have taken precautions against a risk of harm, the court is to consider the following (amongst other relevant things): (a) the probability that the harm would occur if care were not taken, (b)the likely seriousness of the harm, (c)the burden of taking precautions to avoid the risk of harm, (d) the social utility of the activity that creates the risk of harm." 99Her Honour found at [90] that the provisions of s 5B(1)(a) and (b) were satisfied and there is no challenge to that finding. At [91] she found that the risk of back injury in a gym was not improbable with the result that it was a probability that harm would occur to the appellant if care was not taken with respect to the exercises which he was required by Mr Draffin to undertake. Equally, there could be no doubt, as the medical evidence established, that any such harm would be serious. So far as s 5B(2)(c) is concerned, not requiring the appellant to undertake the medicine ball exercise would have avoided that risk of harm. 100Thus the relevant negligence, if it existed, was that of failing to take the precaution of not requiring a person of the appellant's age and physical condition with limited ability, to undergo challenging weights exercises. 101Her Honour's observed at [107] of her reasons (which I noted at [86] above) that the failure of Mr Draffin to strictly adhere to the programme of particular exercises set for the appellant would not of itself bespeak negligence without considering all of the circumstances, including the extent of the departure and the reasons for it. At [137] and [138] she considered Mr Draffin's evidence that he had seen " all different exercises " performed during his qualifying course for the purpose of making it harder and more challenging for clients and with a view to accelerating the strengthening of the client's abs. 102At [141] the primary judge expressed the view that she was not satisfied that requiring the appellant to undertake the medicine ball exercise even as a sit-up was negligent in that she did not accept that Mr Tzarimas' evidence on this issue reflected the standard of care of a reasonable personal trainer. She said: "His conclusion rested on the fact that, following a review of standards in the fitness training industry conducted in 2000, sit-ups were not specifically included in the range of recommended abdominal exercises. I do not think that is a sufficient foundation for a conclusion that it is negligent to ask a person like Mr Wilson to try to do one at all.' 103The primary judge then referred to Mr Tzarimas' evidence (at Black 217E-J) which I have recorded at [54]. At [142] she expressed the view that even accepting that a sit-up with a twist was not a " recommendation within the fitness industry ", she was not satisfied that it would have been negligent for Mr Draffin to see whether the appellant could undertake that exercise at the stage that he had reached. 104With respect, what her Honour did not refer to were the following critical aspects of Mr Draffin's evidence:

• that he had seen the exercise as varied by him performed in the respondent's studio and " just thought it would be okay to do ";
• that he had copied what other trainers in the studio were doing " because I was still learning a lot ";
• that he did not throw the medicine ball to clients but passed it to them and then only as a challenge to his " really advanced clients that I know can handle it ";
• that when it was suggested that it would be dangerous to throw a medicine ball to a client with poor abdominal fitness, he responded that " it would only be done on someone that had strong abs ";
• that when it was suggested that his last answer was because he would appreciate that to do otherwise would hurt a client who did not have strong abs somewhere in their spine, he responded that he had no idea as " I am not a doctor ". 105In my opinion, therefore, the primary judge's process of fact finding was flawed as a consequence of her failure to examine and factor into her findings the evidence of Mr Draffin which I have summarised in the preceding paragraph and which I regard as not only materially relevant to, but also determinative of, the issue of whether Mr Draffin departed from the standard of care required of a reasonably competent professional personal fitness trainer: cf Waterways Authority v Fitzgibbon [2005] HCA 57; (2005) 79 ALJR 1816 at [130] per Hayne J; Goodrich Aerospace Pty Ltd v Arsic [2006] NSWCA 187; (2006) 66 NSWLR 186 at [30] per Ipp JA (with whom Mason P and myself agreed). 106Mr Draffin's evidence established that the medicine ball exercise was not only a variation or exercise not referred to in the written material of the Australian Institute of Fitness (from whom Mr Draffin had gained his qualifications) but also was one he had introduced merely because he had seen other trainers utilising it but with no knowledge, so far as his evidence went, as to the ability or capacity of the particular clients of those trainers to cope with the added challenge. His evidence went no further than establishing that as he had seen it being done by others, he " just thought it would be okay to do ". This is hardly the standard of care expected of a reasonably competent professional personal fitness trainer in what was clearly a field of endeavour calling for the application of appropriate expertise. 107Mr Draffin acknowledged (as the primary judge recorded at [137] and [142] of her reasons) that he did not strongly adhere to the programme devised and tailored expressly for the appellant because although the appellant's abs were not the strongest, he was looking for ways that would help the appellant accelerate through the relevant levels in order to building up his strength and had seen other people in the studio doing the subject exercise. But there was no evidence from Mr Draffin that he believed, let alone on reasonable grounds, or considered whether the appellant had reached a level of fitness which would enable him to meet the challenge he had set him without risk of injury to his lumber spine. He just did not give this possibility any thought. 108It was nevertheless submitted by the respondent that one would infer that Mr Draffin thought the exercise was appropriate for the appellant. However, Mr Draffin's own reasons for requiring the undertaking of the exercise requires the contrary inference to be drawn or, at the very least, that he simply did not know one way or the other. In my respectful opinion, that was not an appropriate response of a reasonably competent professional fitness trainer. 109In the foregoing context in my view, the primary judge should have accepted Mr Tzarimas' evidence on this specific issue. Essentially his evidence was that such an exercise was inappropriate for a person such as the appellant given his age and lack of physical fitness. The particular exercise created an unacceptable risk of injury to the appellant' spine for that reason. Furthermore, this was so irrespective of Mr Tzarimas' evidence on the point. It was established by Mr Draffin's own evidence. In my view Mr Draffin, no doubt due to his inexperience, failed to discharge his duty of care by requiring the appellant to undertake the medicine ball exercise. 110The respondent further submitted that Mr Draffin's testimony was that the medicine ball exercise was not unusual and, indeed, he had observed it " apparently without incident ". That he had observed it may be correct. Whether it was " without incident " is another matter. In the present case the exercise was undertaken " without incident " in the sense that there was no immediate reaction by the appellant to the exercise except to the extent that he said (at Black 85T) that although he was reasonably certain that on at least several occasions he touched the floor with the medicine ball, he was beginning to fail in the exercise and therefore his twisting became less vigorous. Further, he said that he did not finish the full set of 12 repetitions. Given the nature of his injury according to the medical evidence accepted by the primary judge, it is apparent that such an injury would not necessarily reveal itself during the course of undertaking the exercise. To therefore submit that Mr Draffin had observed other trainers requiring their clients to undertake the exercise " apparently without incident " is somewhat disingenuous. 111Furthermore, the respondent submitted (at Orange 23 [17]) that " absent evidence that the activity of which complaint is now made was not normal for a gymnasium or a personal trainer to undertake " the appellant was forced to rely on the medical evidence that the exercise was inappropriate for this particular appellant. In my view the assertion is too general. Mr Draffin did not give evidence that the medicine ball exercise was one that was " normal' for a personal trainer to undertake: only that he had seen it undertaken. He was not, naturally enough, able to assert that it was an exercise that he had seen undertaken by a client of the same age and physical condition as the appellant. What the evidence does establish, in my view, is that the appellant performed the exercise under Mr Draffin's direction without any consideration by the latter as to whether the appellant had the capacity to undertake it safely. 112The respondent then submitted (at Orange 23 [18]) that the appellant's submission that the appellant should not have been invited by Mr Draffin to undertake the medicine ball exercise, would effectively require the respondent to have known of the medical and physiological expert opinions expressed by the appellant's witnesses and to have discharged his duty of care according to the standards advocated by them. 113Reliance was placed by the respondent on the first two sentences of the following passage from the reasons of McHugh J in Dovuro Pty Ltd v Wilkins [2003] HCA 51; (2003) 215 CLR 317 at [34]: "If negligence law is to serve any useful social purpose, it must ordinarily reflect the foresight, reactions and conduct of ordinary members of the community or, in cases of expertise, of the experts in that particular community. To hold defendants to standards of conduct that do not reflect the common experience of the relevant community can only bring the law of negligence, and with it the administration of justice, into disrepute. That is not to say that a defendant will always escape liability by proving that his or her conduct was in accord with common practice. From time to time cases will arise where, despite the common practice in a field of endeavour, a reasonable person in the defendant's position would have foreseen and taken steps to eliminate or reduce the risk that caused harm to the plaintiff. But before holding a defendant negligent even though that person has complied with common practice, the tribunal of fact had better first make certain that it has not used hindsight to find negligence. Compliance with common practice is powerful, but not decisive, evidence that the defendant did not act negligently. And the evidentiary presumption that arises from complying with common practice should be displaced only where there is a persuasive reason for concluding that the common practice of the field of activity fell short of what reasonable care required." The whole of what his Honour said is relevant to what follows. 114In my view the appellant's case did not require Mr Draffin to have known of the expert opinions expressed by the appellant's witnesses. But the standard of care of a reasonably competent professional personal trainer would surely require him or her to be aware of the risks of injury associated with different exercises and of the physical condition of the persons for whom they are appropriate, and have some knowledge of the physiological consequences of requiring a client whose abs had not advanced to the point where such an exercise could be undertaken without risk of injury, to undertake that exercise. 115Mr Draffin must have had some appreciation of the risks associated with the medicine ball exercise given that his evidence was that he would only pass or throw the ball to his really advanced clients and that to do so to someone who did not have " strong abs " would be dangerous: see [85] above. The fact that Mr Draffin took it upon himself to exercise a discretion to deviate from appellant training programme devised by Ms Webb especially for the appellant, a discretion Mr Draffin knew he did not have, in my view, is indicative of a departure from the standard of care expected of a professional fitness trainer. 116It is true that Dr Hopcroft expressed the view that the medicine ball exercise was highly threatening to the integrity of the appellant's lumbar discs given that he had not undertaken that type of exercise previously and had not undergone any strengthening programme for his abs before the exercise was performed. In essence, this was Mr Tzarimas' evidence and it was, in effect, conceded by Mr Draffin when (at Black 368L, recorded at [55] above) he expressed the view that he would only require a client to exercise with a medicine ball passed (as distinct from thrown) to him if the client was " really advanced " and he knew that they could handle it. Nowhere in his evidence did Mr Draffin suggest that he considered the appellant within that category. In fact his evidence was to the contrary. If, as he stated (at Black 367R-T) the appellant's level of fitness and in particular the strength of his abs, was not sufficient to undertake sit-ups with the 2kg medicine ball and certainly not a sit-up exercise involving a twist, then it is difficult to conclude in the absence of reasoned explanation from Mr Draffin, that he considered that the appellant had sufficient ab strength to undertake a floor crunch involving a 5.4kg medicine ball being thrown to him which he was then required to twist from side to side while holding the ball at arm's length. 117The evidence of Dr Hopcroft was that such an exercise should only be considered suitable for persons with a top level of fitness and who had " notch[ed] up their levels of abdominal and back muscle fitness ". Furthermore, Dr Conrad regarded the medicine ball exercise as inappropriate for a man of 41 years as it would put some strain on his back although at [163] of her reasons, her Honour did not attach much weight to Dr Conrad's opinion that the medicine ball exercise was responsible for the disc disruption although, based on Dr Hopcroft's evidence, she ultimately accepted that it was. 118It should be noted that the primary judge did not refer to the medical evidence other than in the context of causation. An issue arose on the appeal as to whether the medical reports tendered early in the trial, were tendered both on the issue of liability and causation or only with respect to the latter. The transcript (at Black 24-25) would seem to indicate that the reports of Drs Hopcroft and Conrad were tendered on behalf of the appellant but on the issue of causation. It was therefore submitted by the respondent that the appellant could not rely upon them on the issue of liability. 119In the appellant's written submissions to the primary judge reference was made (at Black 430) to Dr Hopcroft's reports, it being submitted that his evidence was not challenged as to two important aspects, namely, the plausible mechanism for the appellant's injury and the onset pattern. There is no reference in the written submissions to Dr Hopcroft's opinion that the exercise was inappropriate for the appellant to undertake. On the other hand (at Black 433) when dealing with Dr Conrad's evidence, it was submitted that he had expressed opinions on three central matters of which the first was that the exercise was dangerous for the appellant. The second was that the sudden impact in a semi-sitting position of catching a heavy ball and twisting from side to side, in particular, with that load, was a " totally inappropriate exercise for a man of 41 years " and, in his view, was responsible for the appellant's disc rupture. I have been unable to find any assertion in the respondent's written submissions that it was not open to her Honour to take into account on the issue of liability Dr Conrad's expression of opinion as to the appropriateness of the exercise for a person such as the appellant. However, I think the better view is that the case was conducted on the basis that the medical evidence was confined to the issue of causation. 120Whether or not it was open to the primary judge to consider the opinions expressed by Drs Hopcroft and Conrad on the issue of the appropriate standard of care matters not at the end of the day given that their evidence was practically identical to that of Mr Tzarimas who was clearly an expert called on the issue of breach of duty. Although, as I have already observed, her Honour considered that Mr Tzarimas' evidence lacked objectivity and that the standards that he was evoking were those of a counsel of perfection, in my opinion there was no reason to reject his evidence insofar as it was confined to the issue of whether, in the fitness industry in which the respondent was operating and in which Mr Tzarimas had had many years of hands-on experience, it was appropriate to require the appellant to undertake the medicine ball exercise given his age and physical condition (or lack thereof). In this respect, I have already observed that the respondent called no evidence on this issue so that the only evidence was that of Mr Tzarimas and Mr Draffin. But even if one ignores Mr Tzarimas' evidence, that of Mr Draffin is sufficient of itself to establish that he was in breach of his duty of care to the appellant. 121Thus in my opinion Mr Draffin's reasons for requiring the medicine ball exercise to be undertaken not only neglected any consideration of what impact the exercise might have upon the appellant's spine but were also contrary to his own evidence that a client using a medicine ball when doing a crunch was an exercise which he would only ask " really advanced clients that I know can handle it " to undertake. 122Finally, I would reject the respondent's submission that the foregoing would involve a substantial element of reasoning in hindsight. I see no answer to the proposition that it was reasonably foreseeable that the medicine ball exercise would involve a risk of harm to the appellant's spine unless his physical condition, and in particular his abdominal strength, was such as to satisfy Mr Draffin that he could undertake the exercise safely. There was no evidence that he was so satisfied: only that having seen it performed in the respondent's studio, he thought it to be okay. Reasonable care required more than that. No hindsight is involved in that proposition which, at least to me, is no more than common sense. 123For convenience I would summarise my reasons for rejecting the respondent's submissions in the following propositions: The respondent held itself out as having expertise in the field of personal fitness; It provided a service within the fitness industry to those members of the public seeking to improve their fitness; It did so for reward; It provided its services to the appellant by assessing his standard or condition of fitness and then tailoring a personalised training programme for him to extend over 12 weeks; It did not countenance an inexperienced trainer such as Mr Draffin to use his discretion to vary or change the particular exercises identified in the red weights card as being appropriate for the appellant's fitness condition at any particular point of his training; It should be inferred that the respondent omitted the medicine ball exercise from the red weights card because, given in its own knowledge and experience in the fitness industry, it considered that such an exercise was inappropriate for a person of the appellant's standard of fitness as its use would expose the appellant to a foreseeable and unreasonable risk of injury; There was no evidence that the medicine ball exercise was "normal" or "common practice" for a professional personal trainer to undertake with a client irrespective of that client's ability to cope with that exercise without risk of injury; On the contrary, in what was clearly a field of expertise - a professional fitness studio - the only expert called, who was highly experienced in that field, opined that the medicine ball exercise was fraught with danger if undertaken by a person who had not reached the necessary level of fitness to enable the exercise to be undertaken without risk of injury; The standard of care of a reasonably competent professional personal trainer would surely require him or her to have some knowledge of the physiological consequences of requiring a client whose abdominal muscles were not advanced to the point where such an exercise could be undertaken without risk of injury, to undertake that exercise; No element of hindsight is involved in the foregoing propositions which are consistent with McHugh J's statement of principle in Dovuro. 124It follows from the foregoing that I would agree with paragraph 18 of the appellant's written submissions on the appeal where the following is stated: "The respondent is in the business of providing safe and effective personal training services to individual consumers, for reward. A reasonable person in such a business must be aware of the risks of different exercises, and the persons for whom they are appropriate. [The respondent's] case does not involve the proposition that this exercise was, for all persons and in all circumstances, dangerous. But it was plainly dangerous for a person with [the respondent's] level of fitness, and lack of core-strengthening experience." 125Accordingly, in my opinion the appellant has established that a reasonably competent professional fitness trainer in the position of Mr Draffin would not have engaged the appellant in the medicine ball exercise for the purpose of s 5B(1)(c) of the Act. The precautions that such a reasonable person or trainer would have taken would have been to desist from requiring the appellant to undertake the medicine ball exercise unless and until he had satisfied himself that the appellant was sufficiently advanced in terms of the strength of his abdominal muscles as to have the capacity to undertake the exercise without risk of harm to his lumbar spine. 126This brings me to the respondent's submissions based on s 5B(2)(d) that requires the Court to consider the " social utility of the activity that creates the risk of harm ". 127At [93] of her reasons, the primary judge recorded a submission on behalf of the respondent evoking s 5B(2)(d) to the effect that the operation of personal training studios was an activity of high social utility. She then recorded the submission that gyms were meeting places, progenitors of community health, designed to keep burgeoning health costs down and similar general statements as to their general social utility. 128At [94] of her reasons, her Honour remarked that those considerations were relevant to the present case. She continued: "The legislation appears to assume that it might be reasonable to take fewer precautions against the risk of harm created by an activity of high social utility. I accept that physical exercise is such an activity." 129In my respectful opinion, the Act makes no such assumption. Although it might be said that as a general proposition physical activity is of social utility, what the subsection requires to be taken into consideration is the social utility of " the activity that creates the risk of harm ". In the present case that activity was the medicine ball exercise. Of itself it had no relevant social utility let alone a high social utility - quite the contrary, unless Mr Draffin was satisfied on reasonable grounds that the appellant had the physical strength and capacity to undertake it safely. 130In any event the social utility of the relevant activity is but one factor which s 5B(2) requires to be taken into account in determining whether a reasonable person would have taken the necessary precautions against the relevant risk of harm. As the chapeau to the subsection makes clear, each of the four subparagraphs is to be considered " amongst other relevant things ". There is nothing in the Ipp Report or in the text of the legislation which recommended s 5B which suggests that the standard of reasonable care requires the taking of fewer precautions against an acknowledged risk of harm simply because the activity which creates that risk has some social utility. There may be cases where the social utility of the activity is sufficiently high as to justify, notwithstanding other factors, a finding that a reasonable person would not have taken the necessary precautions against the identified risk of harm. Rescuing people from the impact of floods, cyclones and earthquakes were said to be examples that might attract such a finding. But in my view the present case does not fall into that or any similar category.

Causation 131The issue of causation was to be determined in accordance with s 5D(1) of the Act which provides as follows: "(1) A determination that negligence caused particular harm comprises the following elements: (a) that the negligence was a necessary condition of the occurrence of the harm ( factual causation ), and (b) that it is appropriate for the scope of the negligent person's liability to extend to the harm so caused ( scope of liability )." (Emphasis in original) 132As a result of the decision of the High Court in Adeels Palace Pty Ltd v Mourbarak [2009] HCA 48; (2009) 239 CLR 420 at [55], it is now established that factual causation is to be determined by the " but for " test in all but the undefined group of exceptional cases contemplated by s 5B(2): see also Zanner v Zanner [2010] NSWCA 343 at [11]. 133The respondent submitted that pursuant to s 5E of the Act, the appellant bore the onus of proving, on the balance of probabilities, any fact relevant to the issue of causation. Accordingly, it bore the onus of establishing, to the relevant standard, that " but for " the appellant being required by Mr Draffin to undertake the medicine ball exercise, he would not have sustained a prolapsed disc. 134The medical evidence contemplated two possible causes of the appellant's injury. The first was the leg press exercise and the second was the medicine ball exercise. At [166] of her reasons, the primary judge stated that she was not satisfied on the balance of probabilities that the leg press exercise was a cause of the appellant's injury. She referred to the concurrent evidence of Drs Hopcroft and Matheson in which the former acknowledged that the medicine ball exercise was the " much more likely cause " of that injury. She considered at the conclusion of this evidence that Dr Hopcroft put the matter no higher than to say that the leg press exercise " may " have made a contribution to the injury but that the medicine ball exercise " was " a significant cause. 135The primary judge then concluded this issue at [167] in the following terms: "Dr Matheson gave a compelling explanation as to why he did not accept that the leg press exercise caused the injury (at T177). In light of that evidence, together with Dr Hopcroft's equivocation on that issue, I am not persuaded that the leg press exercise was a cause of the injury." 136It is clear from Dr Matheson's evidence on which her Honour relied, that he did not consider that the leg press exercise made any contribution to the injury which the appellant sustained; hence her Honour's finding that she was not persuaded that that exercise " was the cause of the injury ". 137The respondent submitted that as the onus of proof imposed upon the appellant by s 5E required him to affirmatively establish that but for the medicine ball exercise the appellant would not have sustained the injury in question, it was necessary for her Honour to find that, upon the assumption that the medicine ball exercise was the only negligent cause of the appellant's injury, the non-negligent leg press exercise was not a cause of that injury. It was submitted that her Honour's negative findings at [166]-[167] of her reasons to the effect that she was not satisfied or persuaded that the leg press exercise was the cause of the injury was not sufficient: what was required was a positive finding that that exercise was not such a cause. 138In my opinion, the respondent's submissions should be rejected. The fact that the primary judge expressed her finding in the negative in the paragraphs referred to does not mean that she regarded the leg press exercise as a possible cause of the injury but that she was not persuaded that that possibility reached the necessary level of probability. To put the matter another way, in my view given that her Honour accepted the evidence of Dr Matheson that the leg press exercise was not a cause of the injury, it follows that she was satisfied that that was so. 139Significantly, however, at [173] the primary judge said: "... measured on the balance of probabilities, I am satisfied to a point of actual persuasion that the pressure on the lumbar spine when the medicine ball was caught, combined with the flexion of the spine created by the twisting part of the exercise, probably enabled the disc to protrude in the manner described by Dr Hopcroft." Further, at [175] she said: "For those reasons I am satisfied that the injury was caused or materially contributed to by the medicine ball exercise." 140The respondent relied on these positive findings to contrast the negative findings at [166] and [167]. In my view there is no merit in that submission. 141In my opinion, each of her Honour's findings at [173] and [175] constituted positive findings that the cause of the appellant's injury was the medicine ball exercise and that but for that exercise the injury would not have been sustained. For the foregoing reasons the respondent's submissions to the effect that the appellant had not satisfied the onus imposed upon him by s 5E of establishing any fact relevant to the issue of causation should be rejected.

Conclusion 142In my opinion the primary judge erred in failing to find that Mr Draffin was in breach of his duty of care to the appellant when he required him to undertake the medicine ball exercise and that the respondent is vicariously responsible for that breach. 143I would therefore propose the following orders: (a)Appeal allowed. (b)Set aside the orders made by McCallum J on 10 December 2009 and in lieu thereof that there be a verdict and judgment for the appellant. (c)Remit the proceedings to McCallum J for the purpose of assessing damages. (d)The respondent to pay the appellant's costs of the proceedings to date before McCallum J. (e)The respondent to pay the appellant's costs of the appeal and to have a certificate under the Suitor's Fund Act 1951, if otherwise qualified. 144WHEALY JA: I have had the advantage of reading the draft decision of Tobias JA. I have ultimately concluded that the primary judge erred in relation to the finding on breach of duty and, for that reason, I agree with the order proposed by Tobias JA. I also agree with Tobias JA in relation to the causation issue argument arising from the decision of the High Court in Adeels Palace Pty Ltd v Moubarak (2009) 239 CLR 420. I would like, however, to make some observations of my own in relation to the evidence on the breach of duty issue. 145The principal issue on appeal was a narrow one. The primary judge found that the appellant's injury was caused as follows:- The pressure on the lumbar spine when the medicine ball was caught, combined with the flexion of the spine created by the twisting part of the exercise, probably enabled the disc to protrude in the manner described by Dr Hopcroft (at T.199) (Red Book, 68 at 173). 146There was no dispute about this causation finding on appeal. What was critically in issue, however, was whether Mr Draffin, the personal trainer employed by the respondent gymnasium, had been negligent in requiring the appellant to do the crunch exercise with the medicine ball and twist. The appellant's case was that the respondent had breached its duty of care (or its contract) because it required or permitted the appellant to carry out the medicine ball exercises when he was not fit enough, or well-conditioned enough, to do so. The plaintiff had also contended at trial that the injury had been caused or contributed to by a second exercise (leg press). The primary judge rejected this contention. This aspect of the trial, however, was not raised by the appellant in this appeal, either in relation to causation or breach. 147The primary judge had little difficulty in finding that Mr Draffin and the respondent owed a duty of care to the appellant. That duty was, as her Honour found, the need to observe the standard of care of a reasonable personal trainer, and that of a reasonable personal training studio. If the trainer were found to have breached his duty of care in setting and implementing the medicine ball exercise, there was no dispute that, as a consequence, the respondent would have been vicariously liable. 148There were, of course, many other issues at trial that travelled well beyond the principal matter that emerged on the hearing of the appeal. The trial, as it transpired, was a most complicated affair. There is little point in my identifying all of these features. Principal among them, however, was the complication that arose from the fact that there were, as I have mentioned, two exercises alleged to have been involved in the breach of duty of care. The combination of a number of factors resulted in the claim being made initially that the appellant had been required to do a two hundred kilogram leg press, when in fact, as it later transpired, it was two hundred pounds. This considerable misconception resulted in an error of approach which ran through many aspects of the appellant's case, including the reports prepared by his experts. In the end, it became a matter of no real importance, in the sense that the leg press exercise was found not to have been causative of the injury in any way at all. The second major confusion in the trial was the confusion as to whether the movement involved in the medicine ball exercise was a crunch rather than a sit-up. This distinction had not perhaps been raised squarely with the appellant during his evidence. This confusion in nomenclature led to difficulties in the identification and resolution of the issues. In the end, the primary judge concluded that the medicine ball exercise had been conducted with a crunch rather than a sit-up, and, in that regard, she did not accept the reliability of the appellant's evidence. 149I will not pause to list all of the problems that arose throughout the trial. It is sufficient to say that the primary judge was faced with a considerable number of difficulties in evaluating the reliability and, for that matter, the substance of much of the evidence before her. This flowed through to an evaluation of the expert evidence, both from Mr Tzarimas and the doctors, especially those called on the appellant's behalf. 150There were three areas of evidence which the primary judge addressed in her examination of the breach of duty question in relation to the medicine ball exercise. There was first the evidence from Mr Tzarimas, the expert called on the appellant's behalf. This, of course, had to be examined in the light of the appellant's evidence. Secondly, there was the evidence of the doctors, and finally there was the evidence of Mr Draffin. 151On the hearing of the appeal, Mr Jackson QC submitted that the evidence of the doctors could and should have been relied on by the primary judge to satisfy her that the medicine ball exercise was a dangerous exercise, requiring a finding of breach of duty. In my opinion, that argument was not available to the appellant upon appeal. The trial was plainly conducted on the basis that the medical reports were to be used only on the basis of causation. The four reports by Mr Tzarimas represented the expert evidence on liability. This court must be particularly astute not to permit parties to depart from the manner in which the case has been presented below ( Suttor v Gundowda Pty Ltd (1950) 81 CLR 418; Coulton v Holcombe (1986) 162 CLR 1; Metwally [No 2] v University of Wollongong (1985) 60 ALR 68). The plaintiff's case on breach of duty could only succeed having regard to the evidence of the plaintiff, Mr Tzarimas and Mr Draffin. 152This brings me to the primary judge's treatment of Mr Tzarimas. Her Honour's analysis of Mr Tzarimas' evidence was extremely comprehensive. More than fifty paragraphs of a fifty-five page judgment were devoted to matters involved in the rejection of Mr Tzarimas as a reliable and credible expert. First, there was the confusion about the facts relating to the events at the gymnasium on the day of the injury. Mr Tzarimas had relied on a history derived from his oral conversations with the appellant, and the appellant simply subsequently adopted this history, with some minor qualifications. This unorthodox approach created significant problems for comprehending the basis of Mr Tzarimas' conclusions. It created problems indeed for understanding the nature of the appellant's case. Secondly, the primary judge noted that Mr Tzarimas' instructions from the appellant (as he repeated them in his reports) were at variance, often in significant ways, with the appellant's evidence on the same issues (for example, Red Book 39, where instances are given). Thirdly, given the absence of precise instructions in a number of areas, the primary judge was simply unable, on a number of important matters, to understand how Mr Tzarimas reached the conclusions he did. This led to difficulties in examining those conclusions so as to test their validity. Fourthly, the major error Mr Tzarimas made, in relation to the leg press exercise, permeated to a very considerable degree the reliability of the later conclusions he reached. He had, it seems, been labouring under three misapprehensions. Two of them related to the leg press, namely, the weight involved in the exercise, and the proposition that the weight exercise had been done prior to the cardio session on 5 th April 2008. The third misconception was that the appellant had done three sets of ten repetitions in respect of the abdominal medicine ball exercises. Her Honour pointed out that she was simply unable to evaluate the reasoning by which Tzarimas had been able to conclude that Mr Draffin had ignored fundamental principles in relation to setting the exercises. 153Fifthly, there was Mr Tzarimas' assumption that Mr Draffin had set a number of the exercises at a very high level of intensity, when the appellant's evidence made it clear that this was not so. Moreover, there was the fact that none of the misapprehensions, when corrected, led to Mr Tzarimas toning down his opinions, or revising them in any substantial way. It can sometimes be regarded as a significant failure on the part of an expert if he maintains unreasonably an intransigent approach to the questions involved in the litigation, especially when, as an expert, he is required to show independent detachment and to make concessions when appropriate. So it was here. Finally, the primary judge concluded that Mr Tzarimas had assumed the role of Mr Wilson's advocate in the case. This was a trenchant criticism, and not one that was undertaken lightly by her Honour (Red, 51 at 122). Her Honour gave considerable attention to the reasons that led her to this conclusion. 154The major criticism directed at Mr Tzarimas at trial, quite apart from his lack of detachment and his assumption of the role of an advocate, was that he had placed reliance on a number of scientific and training manuals for the opinions he expressed. His views, it was said, did not relate to the contemporary practices of gyms and health studios in Sydney. Mr Tzarimas nevertheless conceded in cross-examination that the medicine ball exercise, or variants of it, occurred in gymnasiums in the central business district of Sydney, although he insisted it was not a conventional fitness training exercise. In other words, he agreed that the exercise was being performed, but he maintained that it was not recommended within the National Fitness training package. He also accepted that there were other sources outside the training manuals upon which he had placed reliance, which may have allowed for the particular exercise. 155On the hearing of the appeal, Mr Jackson QC argued that her Honour did not mention, and therefore did not consider or reject, certain opinions expressed by Mr Tzarimas regarding the cautions that had to be taken before the medicine ball exercise was given to the appellant. It was on the basis of those opinions (Blue Book, 106-109) that Mr Tzarimas had concluded that the medicine ball exercise was inappropriate. 156In my opinion, it is a less than fair reading of her Honour's reasons to suggest that, merely because she failed to refer specifically to one brief section in Mr Tzarimas' report, that she must be taken to have accepted it, or that the failure to mention it means that her overall finding concerning the expert evidence was flawed. A fair reading of her Honour's decision shows that she did, in general terms, reject the expert for not adequately exposing and justifying the whole of his reasoning. There is no basis for restricting that finding to any particular segment of Mr Tzarimas' reasoning process. Her Honour saw the witness giving evidence. She listened to his responses to cross-examination and indeed to a number of questions she herself had asked. The primary judge was in a perfect position to assess whether, and to what extent, weight should be given to the expert's evidence. She was in a perfect position to determine whether she could rely on that evidence or not. She gave considered reasons as to why she thought Mr Tzarimas' evidence was unhelpful on the central issue, namely whether there had been a breach of duty by the personal trainer. It should not be overlooked that there were many other categories of negligence which were vehemently propounded by Mr Tzarimas (eg: lack of proper training and supervision of personal trainer), but these too were all rejected. There was no satisfactory basis, the primary judge said, for those opinions as well. 157Tobias JA, in his draft reasons, suggests that a fair reading of Mr Tzarimas' evidence revealed an expert witness who was "indeed an expert in his subject" and who gave his evidence "in a forthright and honest manner". This observation, it seems to me, is, with respect, apt to fall foul of the well-known constraints on the extent of permissible appellate intervention. I shall return to that issue shortly. Before doing so, it is necessary to briefly touch again on the nature and extent of the criticism levelled by the primary judge at the reliability of Mr Tzarimas' evidence. 158The primary judge, as I have said, was highly critical of Mr Tzarimas as an expert. Her careful and comprehensive analysis occupied, as I have noted, nearly one-third of her lengthy reasons. The analysis included criticism of the method of recording the information given to him by the appellant, his failure in many instances to state the factual assumptions on which he based his conclusions, and his lack of explanation for those conclusions. It included criticism of a number of factual assumptions where they were actually stated in the reports, but were later shown to be at variance with the evidence given by the appellant upon those very matters. The analysis was critical of his lack of detachment and independence, and of his assumption of the role of an advocate, both in his written and oral evidence. The specific example of this that was given by her Honour - and there were, no doubt, others available to her - was a particularly telling one. This was that Mr Tzarimas described that he, on his own initiative, had gone to the manufacturer of the leg press machine "to support my case" (Red Book, 52 at H - M). No clearer example could be given of an expert stepping outside the proper confines of his professional detachment to argue a case. 159There were many other areas of criticism. It is not necessary to repeat them all. Significantly, however, this critical analysis was made throughout the lengthy section of the primary judge's reasons, where her Honour dealt with "breaches of duty alleged by Mr Wilson" (Red Book, 43 at Z). Her Honour said:- The allegations fall into four broad categories: the systems under which Mr Wilson's training plan was established (including the allocation of Mr Draffin as his trainer); general allegations in relation to the exercise programme delivered; specific allegations in relation to the leg press exercise and specific allegations in relation to the medicine ball exercise. 160In my opinion, it cannot be said that the primary judge's criticisms of Mr Tzarimas were isolated from, or had nothing to do with, the opinions the expert expressed in relation to the medicine ball exercise. A fair reading of her Honour's decision, with respect, is, in my opinion, inimical to any suggestion that her criticisms were confined to the expert's views about the respondent's risk management procedures and professional responsibilities. Nor were they confined to the allegations concerning the leg press exercise, to the exclusion of a full consideration of the issue concerning the cause of the injury, namely the medicine ball exercise. Indeed, her Honour said (Red Book, 57 at K - M):- Assuming that the exercise Mr Wilson was requested to do was a crunch, Mr Tzarimas' evidence has not satisfied me that it was unreasonable, by reference to the normative standard of care in a personal training studio, to introduce the additional challenge of a medicine ball and the side-to-side movement. And again (Red Book, 57 at R - T) (postulating a sit-up, as opposed to a crunch):- I do not accept Mr Tzarimas' evidence on this issue reflects a standard of care of a reasonable personal trainer. His conclusion rested on the fact that, following a review of standards in the fitness training industry conducted in 2000, sit-ups were not specifically included in the range of recommended abdominal exercises. I do not think that this is a sufficient foundation for a conclusion that it is negligent to ask a person like Mr Wilson to try to do one at all. It is clear that each of these statements were directed expressly to the medicine ball exercise. 161Finally, it might be noted that (Red Book 59 at K - M) the primary judge, referring to the medicine ball exercise, said:- Mr Tzarimas' opinion on that issue is, in my view, a counsel of perfection that does not reflect the normative standard of care imposed on personal trainers in that context. 162Tobias JA considers that the primary judge rejected the evidence of Mr Tzarimas upon the basis that he had not satisfied her that it was unreasonable, by reference to the normative standard of care in a personal training studio, to introduce the additional challenge of a medical ball and the side-to-side movement. Tobias JA referred to her Honour's statement, that Mr Tzarimas' opinion on the issue was "a counsel of perfection". Tobias JA disagreed with this for several reasons. First, that her Honour's rejection of the appellant's evidence, to the extent that she did, was based upon an unreliability finding. Secondly, her Honour's rejection of Mr Tzarimas' evidence was not a credibility finding, but more in the nature of a reliability finding ( Fox v Percy (2003) 214 CLR 118; [2003] HCA 22). Thirdly, Tobias JA considered that Mr Tzarimas' evidence was unchallenged and, further, it was no more than the expression of a strongly held opinion. Tobias JA thought that a number of the responses of the expert witness might properly be traced back to his frustration at the nature and extent of his cross-examination. 163In relation to each of these matters, I wish to make the following comments. First, while it is true that Mr Tzarimas' opinions expressed at Blue Book, 108 - 109 (in his report of 27 th November 2008) were not directly challenged, there was clearly a challenge to the nature of the exercise the appellant had performed with the medicine ball. Certainly, there were challenges to Mr Tzarimas' understanding of the actual nature of the exercises performed by the appellant. That was critical to the opinions the expert expressed. Brought into issue by the cross-examination were, amongst others, the following matters: whether the exercise was properly described as a crunch or a sit-up; whether the medicine ball was thrown to the appellant or simply held by him; whether the medicine ball was the two kilogram ball or the 5.4 kilogram ball; whether the number of sets and their repetitions was as recorded in Mr Tzarimas' report, or at the lower level suggested by the appellant; whether the medicine ball was moved to the side, and if so, to what extent; whether the medicine ball was placed on the floor with each twist; whether the twist was correctly described in that way, or whether it was more aptly described as a crunch to the left and then to the right. The appellant's version was ultimately accepted on a number of these matters but they were certainly in dispute. Each of these contested issues, in turn, had a capacity to impact on the relevant opinions expressed by Mr Tzarimas. 164Secondly, I do not consider that the findings of the trial judge in relation to her rejection of Mr Tzarimas' evidence should be disturbed for the other reasons referred to by Tobias JA. In Fox v Percy , it was held by Gleeson CJ, Gummow and Kirby JJ that a finding of fact by a trial judge, based on the credibility of the witness, may only be set aside upon appeal where "incontrovertible facts or uncontested testimony demonstrate that the judge's conclusion was erroneous", or where it is concluded that "the decision of the trial judge was glaringly improbable or contrary to compelling inferences in the case". McHugh J held that an appellate court is entitled to set aside a trial judge's finding based expressly or inferentially on demeanour, if there is something that points decisively, and not merely persuasively, to error on the part of the judge in acting on his or her impressions of a witness or witnesses. 165In his decision, at 139-140, McHugh J referred to "a valuable passage" in the judgment of Isaacs J in Dearman v Dearman (1908) 7 CLR 549:- So that the position is clearly laid down by the very highest authority that the primary duty, and in fact the whole duty, of every Court of Appeal is to give the judgment which in its opinion ought to have been given in the first instance. But there are natural limitations, that is to say, in some cases, where the evidence below is solely upon written documents, if for instance it is upon affidavit as it used to be in the old Court of Chancery, the appellate Court is in as good a position as the primary Judge to say what ought to have been the decision; but where viva voce evidence is taken there is a large amount of material upon which the primary Judge acts that is altogether outside the reach of the appellate tribunal . The mere words used by the witnesses when they appear in cold type may have a very different meaning and effect from that which they have when spoken in the witness box. A look, a gesture, a tone or emphasis, a hesitation or an undue or unusual alacrity in giving evidence, will often lead a Judge to find a signification in words actually used by a witness that cannot be attributed to them as they appear in the mere reproduction in type. And therefore some of the material, and it may be, according to the nature of the particular case, some of the most important material, unrecorded material but yet most valuable in helping the Judge very materially in coming to his decision, is utterly beyond the reach of the Court of Appeal. So far as their judgment may depend upon these circumstances they are not in a position to reverse the conclusion which has been arrived at by the primary tribunal. Now it may be that in some cases the effect of what I call the unrecorded material is very small, indeed insignificant, and utterly outweighed by other circumstances. It may be, on the other hand, that it guides, and necessarily guides, the tribunal to the proper conclusion. If that is the case, as I have said before , the Court of Appeal cannot say that the conclusion is wrong without disregarding the material which it knows must have been existent before the tribunal below , and is necessary to a just conclusion." 166It is true that the rejection of aspects of the appellant's case was in the nature of a finding based on unreliability rather than credibility, but it was nevertheless based on demeanour. It is also true that the rejection of Mr Tzarimas' evidence was more in the nature of a finding based on unreliability rather than on credibility. But that is to be expected in relation to the rejection of an expert witness. Such a witness does not attest to the facts of a case, as does a participant, bystander or victim, in, for example, accident litigation. Where a trial judge has made a careful appraisal of the evidence of an expert, as had happened here, and forms a reasoned and concluded opinion that the evidence cannot be relied upon, the principles in Fox v Percy are plainly called into play. This is especially so where, as here, the expert has given extensive oral evidence, and has been tested in cross-examination before the primary judge. In particular, it is not appropriate, in my view, for this court on appeal to rely on its impressions, taken from a reading of the transcript, that the witness "gave his evidence in a forthright and honest manner". Nor is it appropriate to speculate as to why the witness gave evidence in the way he did. This court has not had the benefit of seeing and hearing the evidence of the witness and must, within the confines of the reasoning in Fox v Percy , yield to the findings of the trial judge, based as they were on a close appraisal of the witness. These principles apply to the evidence of an expert in the same way they apply to the evidence of a lay person: Dobler v Halverson and Others; Dobler v Halverson (By His Tutor Kenneth Halverson ) [2007] NSWCA 335; 70 NSWLR 151 per Giles JA at [49] - [52] (with whom Ipp and Basten JJA agreed). 167Indeed, it is often the case that an expert witness who has assumed the role of an advocate, and who has apparently stepped outside the confines of his proper role in the litigation, may well be inclined to give his evidence "in a forthright manner". Whether he is honestly and reliably doing so will then, ordinarily, be a matter for the trial judge. In the present matter, there were no "incontrovertible facts or uncontested testimony" that could demonstrate that her Honour was wrong in taking the view that she did of Mr Tzarimas and his evidence. 168Insofar as Mr Tzarimas had conducted a gymnasium himself (until 2004), this was not a matter he relied on in any of his reports or in his evidence-in-chief to justify his opinions. It was brought out in cross-examination to show he had no (or very little) contemporary understanding of the usual practices in CBD training centres in relation to the exercises he criticised. 169The critical evidence that remained for consideration at trial on the breach issue was the evidence of Mr Draffin. Tobias JA has conducted a thorough and compelling analysis of the evidence of Mr Draffin. Following upon this examination, Tobias JA concluded that the appellant had established that a reasonably competent professional fitness trainer in the position of Mr Draffin would not have engaged the appellant in the medicine ball exercise. Tobias JA also concluded that precautions that such a reasonable personal trainer might have taken would have been to desist from requiring the appellant to undertake the medicine ball exercise, unless and until he had satisfied himself that the appellant was sufficiently advanced in terms of the strength of his abdominal muscles as to have the capacity to undertake the exercise without risk of harm to his back. These findings, if accepted, must flow through vicariously as against the respondent. 170Upon careful consideration of Tobias JA's analysis and reasoning, I have concluded that I should agree with his conclusions in relation to Mr Draffin's evidence. It may be accepted that Mr Draffin, though no doubt well meaning, was not an experienced trainer. His intention was no doubt to push the appellant reasonably hard, in an endeavour to strengthen his abdominal muscles more rapidly. Mr Draffin's evidence shows, however, that while he realised that the full import of the medicine ball exercise, with its additions, might be too much for an inexperienced client, he nonetheless encouraged the appellant to perform it. On the findings made by the primary judge, the exercise was carried out with the heavier ball, and it was thrown to the appellant to catch. He was required to catch the ball with his spine off the ground, and then rotate from side-to-side, holding the ball as he did so. The respondent argued that the setting of this exercise was in response to a general request from the appellant that he be worked hard during his training programme. There is, however, no evidence to suggest that the appellant made that specific request in relation to this particular exercise. Mr Draffin should have realised that more care should have been taken, and caution exercised, in acclimatising the appellant to the basic medicine ball exercise before considering whether additions should be made to it. There is no doubt, as the primary judge found, the medicine ball exercise, with its variations, was the cause of the injury. 171It must follow that the appellant is entitled to succeed on this basis and, for that reason, but no other, I am prepared to agree with the orders proposed by his Honour. For my part, I would prefer to express no opinion on the matters raised by Tobias JA in relation to the applicability and interpretation of s 5B(2)(d) of the Civil Liability Act 2002 . That matter was not fully argued before us and, in any event, the particular matters tentatively reflected upon by the primary judge do not appear to have played any major part in her ultimate reasoning and conclusion. In my opinion, the issue is a difficult one, and should be left for resolution in an appropriate case, where full argument and attention is given to the question.

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