5.3 Whether claim 1 requires both legs to be secured
93 A central issue in this case is whether claim 1 requires that both legs be secured in the securing members (KangaTech's construction) or whether claim 1 requires that either one or both legs be so secured (Vald's construction).
94 Claim 1 refers to two securing members, each securing member being configured to secure a respective lower leg of the subject in a position that, in use, is substantially fixed relative to a support when the subject lowers the subject's upper body from a kneeling position to perform an eccentric contraction of the at least one knee flexor muscle of the subject (integers 1.2 and 1.3).
95 In support of its construction, Vald submits, and I accept, that the word "configured" in claim 1 is not a word which has a technical meaning and nor is it a word to which the specification ascribes a special meaning. The ordinary meaning of the word "configured" means "designed or adapted to form a desired configuration".
96 Vald also contrasts the words of claim 1 to that of claim 18, which is a method claim and which it submits requires a performative action, that is, "securing the lower legs of the subject, using the respective securing members" (emphasis added).
97 Finally, Vald cites s 116 of the Patents Act and observes that the reference to "securing" was contained in the original version of claim 1 but that this was amended as follows (with the mark up showing the amendments):
two securing members, each securing member securing being configured to secure a respective lower leg of the subject in a position that, in use, is substantially fixed relative to the support when the subject lowers the subject's upper body from a kneeling position to perform an eccentric contraction of the at least one knee flexor muscle of the subject.
98 However, notwithstanding these matters, the proper construction of claim 1, when read in the context of the specification as a whole (rather than selected parts of it), is that both legs must be secured in the securing members.
99 That is for the following reasons.
100 The "Background of the Invention" describes the invention as being an apparatus for use in assessing the strength of at least one knee flexor muscle of a subject. The reference to at least one knee flexor muscle being tested, even if that muscle is only tested in one but not both legs, does not have the consequence that only one leg is secured for the purpose of testing that knee flexor muscle. That is made plain by, for example, [0038] and [0039] of the specification.
101 The "Background of the Invention" then states to the effect that, in one example, the invention relates to an apparatus for use in assessing at least the hamstring strength in at least one leg of the subject while the subject performs an eccentric knee flexor contraction. While the superficial impression of these words is that only one leg is secured (the hamstring strength of which is being tested), it will be seen that the Patent contemplates the testing of only one leg using one sensor, with the other leg being secured but not tested.
102 As observed above, the specification refers to existing devices, including the "gold standard" isokinetic dynamometer, which device assesses the strength in each leg independently (one leg at a time), with the specification stating that this requires "significant time": [0005].
103 At [0012], the specification reiterates that a disadvantage of existing devices is "significant assessment times" and further states that, "previous methods and apparatus have failed to provide simultaneous assessment of hamstring strength in both legs, independently, during a bilateral exercise, or a combined assessment of hamstring strength in both legs during a bilateral exercise" (emphasis added). No mention is made of deficiencies in existing devices by reference to unilateral exercises.
104 Further, taking into account the emphasis in [0005] and [0012] upon the undue length of assessment times where each leg is tested one at a time (particularly through use of the isokinetic dynamometer), the solution which is proffered by the Patent is an apparatus which permits the hamstring strength in both legs to be tested at the same time, either independently or on a combined basis, thereby reducing the assessment time. If the apparatus was one which tested the hamstring strength of one leg at a time (which would be the case if only one leg was secured), this would not reduce the assessment time, and would not be regarded as overcoming the perceived disadvantage of existing devices.
105 In the "Summary of the Present Invention", the specification reveals that the invention seeks to ameliorate "one or more" of the abovementioned problems. It goes on to describe the invention in three broad forms at [0014], [0040] and [0041]. Each of these broad forms or consistory clauses contains wording which indicates that both legs are secured by the securing members, namely:
(1) "two securing members, each securing member securing a respective lower leg of the subject…": [0014];
(2) "two securing members, each securing member constraining movement of a respective lower leg of the subject…": [0040];
(3) "securing two lower legs of a subject using the respective securing members…": [0041].
106 There is nothing in the part of the specification described as the "Summary of the Present Invention" which contemplates that only one leg is secured by a securing member. If this was contemplated, one would expect to see at least some reference to it here.
107 Each of the consistory clauses also refers to the apparatus having "at least one sensor" which is then described as, in effect, sensing a force indicative of the strength of at least one knee flexor muscle in at least one leg. However, the reference to and use of only one sensor does not mean that only one leg is secured; it simply means that a knee flexor muscle of one of the two secured legs is being assessed by that one sensor when the bilateral Nordic curl is performed using the apparatus.
108 This construction is supported by [0015] (for example), where reference is made to at least one sensor being coupled to at least one of the two securing members. It is also supported by the words used in the consistory clauses such as [0014] which provides:
at least one sensor, which in use senses a force indicative of the strength of the at least one knee flexor muscle in at least one leg of the subject while the subject performs an eccentric contraction of the at least one knee flexor muscle.
109 Further support for this construction is found at (for example) [0044] which provides that: "Typically the method includes sensing the force indicative of the hamstring strength in at least one leg of the subject while the subject performs a Nordic hamstring exercise". This paragraph is connected with the third broad form which is in turn the consistory clause of claim 18 (the method claim) which Vald accepts requires both legs to be secured. Yet [0044] refers to sensing the force indicative of the hamstring strength in at least one leg of the subject. Although only one leg is referred to in [0044] as being tested, both legs are secured using the method described in [0041].
110 An example of the invention is then described with reference to the drawings. Figures 1D, 1E and 1F are shown above. At [0050], these drawings are described as schematic drawings of a first example of a subject performing an eccentric contraction of at least a knee flexor using the apparatus.
111 The Detailed Description of the Preferred Embodiments provides an example of the apparatus by reference to Figures 1A to 1F.
112 As already identified above, the specification then states:
[0072] In this example, the apparatus 100 includes a support 110, and two securing members 121, 122, that in use secure a respective lower leg of the subject S in a position that is substantially fixed relative to the support 110.
[0073] The apparatus 100 further includes two sensors 130.1, 130.2 that, in use, sense a force indicative of the strength of at least one knee flexor muscle in one or both legs of the subject S while the subject S performs an eccentric contraction of the at least one knee flexor muscle.
113 Pausing there, although the words refer to an eccentric contraction of the at least one knee flexor muscle, the description refers to an example shown in drawings which depict the apparatus being used with both legs secured by the securing members.
114 At [0075], it is stated that:
Figures 1D to 1F show a subject S performing an eccentric contraction of at least a hamstring using the apparatus 100. In this respect, Figure 1D shows the subject S in an initial kneeling position prior to commencing the contraction, in which the subject's lower legs are secured using the respective securing members 121, 122 in a position that in use is substantially fixed relative to the support. The subject S subsequently proceeds to lower their upper body toward the support 110 in a controlled manner, while substantially maintaining alignment of the upper legs or thighs and torso, as shown in Figure 1E. Figure 1F shows a final position, with the subject S laying substantially prone on the support 110. It will be appreciated that the abovementioned eccentric contraction is typically called the 'Nordic hamstring exercise', 'Nordic curl', or the like.
(Emphasis added.)
115 There is no drawing which depicts, and nor does the specification identify, how the subject S lowers their upper body toward the support 110 in a controlled manner, while substantially maintaining alignment of the upper legs or thighs and torso, if only one leg is secured in a securing member.
116 At [0076], it is stated that:
Accordingly, the above-described arrangement provides apparatus 100 for use in assessing hamstring strength of a subject S, in which the force exerted at the lower leg of the subject S while they perform an eccentric contraction of at least the hamstring is indicative of hamstring strength. …
117 Again, the advantage of the apparatus over the existing methods is emphasised at [0079] by reference to the fact that each leg may be tested at the same time, as follows:
It will also be appreciated that the apparatus 100 including two sensors 130.1, 130.2 allows the assessment of the hamstring strength of both hamstrings of a subject S, at the same time. Accordingly the sensors 130.1, 130.2 may sense the force indicative of at least the hamstring strength in each leg of the subject S simultaneously. In this regard, the assessment may be performed in significantly less time than existing methods, for example isokinetic dynamometry, which is limited to assessing hamstrings of opposing legs at different times. …
118 At [0083], it is stated that a number of further features will now be described. At [0084] and [0085], the following is then stated:
[0084] In another example, each sensor 130.1, 130.2 is coupled to a respective securing member 121, 122 that secures the ankles of a subject S relative to the support 110 and accordingly the force sensed at the ankles is indicative of hamstring strength. However, this feature is not essential and it will be appreciated that the sensors 130.1, 130.2 may sense a force exerted at any part of the lower leg, for example under the knees of the subject S.
[0085] Furthermore, the assessment of hamstring strength may occur during a unilateral or bilateral contraction/s of the hamstring/s. For example, during a bilateral contraction, two sensors 130.1, 130.2 may be used to sense the force in each leg of the subject simultaneously or at different times, or alternatively a single sensor 130.1, 130.2 may be used to sense the force in either or both legs. During a unilateral contraction, the apparatus may include one sensor 130.1, 130.2 which is interchangeable between the lower legs of the subject, by repositioning the sensor 130.1, 130.2 and/or the securing members 121, 122 and/or the subject S relative to the support 110, such that the hamstring strength in both legs can be assessed sequentially. However, this feature is not essential.
(Emphasis added.)
119 Dr Pizzari's evidence (both affidavit and oral evidence) concerning the construction of the Patent (which favoured Vald) was centred upon [0085] of the specification in particular.
120 In reliance upon Dr Pizzari's evidence, Vald points to the emphasised words in [0085] to contend that claim 1 should not be construed as requiring both legs to be secured by the securing members on the basis that a person skilled in the art as at the priority date would know that, in order to perform a unilateral contraction of the hamstring, one leg must be unsecured.
121 However, I do not accept this submission having regard to my finding as to the common general knowledge as at the priority date.
122 My view as to the proper construction of claim 1 aligns with that of Dr Lovell, whose evidence I prefer to that of Dr Pizzari for the reasons already stated. Dr Lovell gave the following evidence in his first affidavit (which evidence I accept):
111. In my opinion, none of the claims of the Patent encompass a subject performing an NHE with only one lower leg secured. While there are references to testing 'at least one knee flexor', I read this as meaning the force generated by only a single leg may be measured but that both the subject's lower legs are both secured in their respective securing members.
112. My understanding of the apparatus described and claimed in the Patent is that it encompasses:
• an apparatus where the subject has both their legs secured (i.e., fixed relative to the support (platform);
• An NHE is performed to cause an eccentric contraction of at least one hamstring (knee flexor) - that eccentric contraction being necessary to resist the subject's upper body falling forward; and
• The force which the subject leaning forward - and the resultant eccentric contraction generates - being measured in one or both legs - via a sensor (or sensors) connected to the securing member(s).
…
114. While there is no specific reference to the contralateral leg (being the leg for which force is not being measured) being secured, in my opinion that leg must also be secured for stability purposes.
115. In my opinion, the stability required to perform an NHE in a way which would produce any useful form of measurement in one leg, would require that the other 'contralateral' lower limb - being the leg for which no force measurement was being taken - was supported and/or restrained or otherwise stabilised by some form of support, platform or restraint.
…
121. While, at paragraph 173, the Patent refers to the performance of "unilateral contractions" and NHEs being performed "unilaterally", it is unclear to me whether this is referring to unilateral measurements (i.e. measuring the force exerted in one leg whilst the other leg remains secured) or that it contemplates a one-legged Nordic curl being performed. To the extent that it is the latter, the Patent does not explain how this is done and the drawings do not depict this activity. Accordingly, while the Patent refers to both bilateral and unilateral NHE's, it does not explain how a unilateral NHE is performed and measured in any meaningful way.
122. …Furthermore, any force results obtained in carrying out [a one-legged NHE] would, in my view be of very limited value.
(Emphasis original.)
123 An additional reason in support of my construction rests upon my finding that claim 1 requires the apparatus to assess strength in a reliable and accurate way to provide clinically relevant information. That is because, based upon Dr Lovell's evidence as follows (which evidence I accept), such an assessment is not achieved when a unilateral NHE is performed on the apparatus disclosed in claim 1. Dr Lovell explained in his first affidavit that:
[P]erforming an NHE in the way outlined above, with one leg restrained and the other stabilised, supported or held in a different manner, would compromise the accuracy of the assessment as the contralateral limb (i.e., the limb not restrained in the same way) would inevitably be absorbing a proportion of the force generated in performing an NHE but that force would not be measured in any way.
124 Returning then to the Patent itself, there are many strong indicators within it that Vald's construction is not the correct one. Some of these have already been addressed above. Others will now be considered.
125 Use of the apparatus with only one leg secured by a securing member is not depicted in any of the drawings, and [0085] does not state in express terms that only one ankle or one leg of the subject is secured (unlike other paragraphs in the specification which refer expressly to the ankles or legs of the subject being secured, such as [0075], [0081] and [0084]). Nor does the specification (whether through any drawing or otherwise) describe where the unsecured leg is to be placed (for example) or, as already observed, how the subject S lowers their upper body toward the support 110 in a controlled manner, while substantially maintaining alignment of the upper legs or thighs and torso, if only one leg is secured in a securing member.
126 The specification is detailed in its description of the different means of using the apparatus with both legs secured, including by reference to numerous drawings, but is silent as to how this is to be achieved with only one leg secured. These matters tell against a construction of claim 1 which does not require both legs to be secured. If it was a simple matter of informing the person skilled in the art to perform a bilateral Nordic curl on the apparatus and leaving it to them to understand how to undertake that process, these details and drawings would not be required. Having regard to the evidence of Dr Lovell, a unilateral Nordic curl is more difficult for a person to perform, and there are impediments to obtaining a reliable force measurement from such an exercise without the use of a support. This makes it more, not less, likely that there would be an explanation in the specification about the manner of performing a strength assessment on the apparatus with only one leg secured if claim 1 encompassed that.
127 This is especially as one of the advantages which the Patent holds the apparatus out as having is better reliability and repeatability of measurements of between limb strength imbalances. It is to the issue of reliability that I now turn.
128 At [0012] of the specification, after addressing existing methods and devices for testing hamstring strength, the specification identifies that existing techniques have questionable reliability and repeatability of measurements of between limb strength imbalances.
129 In the Detailed Description of the Preferred Embodiments at [0079], it is stated that the apparatus also appears to provide enhanced sensitivity and reliability for the assessment of between limb strength imbalances compared to existing techniques.
130 At [0170], it is stated that, "A number of experiments were performed in order to demonstrate the effectiveness of the abovementioned apparatus 100…".
131 The section which follows is entitled "Reliability and Validity Experiments" and appears at [0171]-[0182] of the specification.
132 These experiments involved 30 subjects (initially 31, but one was excluded). One session involved the determination of eccentric knee flexor strength via isokinetic dynamometry and the apparatus, and another session involved the assessment of eccentric knee flexor force via the apparatus only, to allow for test-retest reliability to be determined. Participants were asked to perform two sets of "three maximal NHEs bilaterally (with both legs) and unilaterally (using only one leg)".
133 The specification identified at [0177] that:
(1) on the whole absolute force measurements taken during bilateral contractions were more reliable than the unilateral contractions;
(2) with respect to between limb imbalances in force, only the bilateral average peak force condition displayed acceptable reliability.
134 The specification then continued as follows:
[0179] From the data presented, the apparatus 100 displays acceptable levels of test-retest reliability when measuring peak or average peak knee flexor force during a bilateral NHE and approaches an acceptable level of reliability for average peak force during unilateral contractions. For the measurement of between limb strength differences, only when the NHE was completed bilaterally, and peak force was average across six contractions, did the measure display acceptable reliability. Hence, the findings from the current study suggests that the single most reliable method to acquire eccentric knee flexor force and between limb force ratios from the apparatus 100 is via a bilateral NHE with peak force averaged across six contractions. There is also the capability to assess eccentric knee flexor strength during a bilateral contraction but using a single peak measure instead of an average of peak forces, or during unilateral contraction, however the between limb strength comparisons, and in some cases the absolute force measures, do not appear to be reliable for these methods. Therefore, it appears that a bilateral NHE performed with multiple repetitions across a number of sets to determine average eccentric peak knee flexor force produces optimal reliability. For the purposes of maximal strength assessment it is important to minimise the number of repetitions per set to reduce the impact of fatigue throughout a set because this will have a significant impact on average peak force. In the current study two sets of three repetitions were performed, but similar set and repetition formats (i.e. three sets of two repetitions) are also feasible. It is also recommend [sic] that measures of eccentric knee flexor strength and between limb strength imbalances be used to compare within but not between athletes. This is due to the varying factors which influence the performance of the NHE, such as lever lengths and upper body mass that would differ markedly between athletes, but would be expected to remain mostly similar within an athlete.
…
[0181] It might also be expected that the difference in laterality between the bilateral NHE and the unilateral dynamometry testing would contribute to some of the variability, however on the whole, the unilateral NHE displayed weaker correlations than the bilateral contractions. This may be due in part to the difficulty participants experienced in becoming comfortable with the unilateral condition, as exemplified by the greater amount of familiarisation time that was required to be devoted to the unilateral contractions.
[0182] Aside from the bilateral NHE condition displaying the highest level of test-retest reliability, the ability to assess unilateral eccentric knee flexor strength during bilateral contractions may have additional benefits. It is well known that there are complexities in the neural control of bilateral and unilateral contractions, with the bilateral deficit a primary example of such a phenomenon. It would appear feasible that under bilateral conditions, in a task with a known but ever increasing load such as the NHE, the nervous system may elect to protect a weaker or more vulnerable muscle/limb and consequently chose to 'load' the more capable muscle or limb more aggressively. As such bilateral testing may be better able to detect between limb strength imbalances, if they exist, compared with unilateral strength assessments which have already shown some predictive ability. This is particularly pertinent for the monitoring of HSI risk in athletes, given between limb strength difference have been reported to increase the risk of injury in athletes. Indeed, unpublished observations show that in elite athletes with a previous unilateral HSI history, the apparatus 100 has been able to better predict the previously injured limb compared to the isokinetic dynamometer, based on between limb eccentric strength deficits.
(Emphasis added.)
135 The specification next addresses the results of what is described as an "Intervention Experiment" which was performed using the apparatus, with the participants' eccentric knee flexor strength measured using the apparatus by performing two sets of two bilateral NHEs on the apparatus both prior to and following the completion of the intervention. At [0185], it is stated that the apparatus can reliably detect improvements in hamstring strength over a period of training.
136 The specification then addresses what are described as "Injured Cross-sectional Experiments" which involved participants with clinically diagnosed unilateral hamstring strain injury. The participants performed two sets of two bilateral NHEs on the apparatus to determine eccentric knee flexor strength for both the injured and uninjured limb, and then further tests were performed. At [0187], the results are stated as being that the previously injured limb was significantly weaker than the uninjured limb.
137 At [0189], it is stated that, in view of these experiments, it will be appreciated that the apparatus is capable of effectively assessing the hamstring strength of a subject, and in particular displays acceptable levels of test-retest reliability and correlation with gold standard, i.e. isokinetic dynamometry assessments. It also states that the apparatus displays promising results in intervention and cross-sectional injury investigations.
138 Having regard to the earlier sections of the specification which precede the conclusions at [0189], as set out above, these conclusions relate only to the performance of bilateral NHEs on the apparatus. As it was common ground between the experts that a unilateral NHE could not be performed on the apparatus if both legs were secured by the securing members, which evidence I accept, it follows that these conclusions are directed to use of the apparatus in which both legs are secured by the securing members.
139 There are no similar conclusions which are referable to the performance of unilateral NHEs on the apparatus (being with only one leg secured). Rather, the results of the testing demonstrate that either the performance of unilateral NHEs on the apparatus did not display acceptable reliability with respect to limb imbalances in average peak force condition ([0177]), only approached (but I interpret, did not achieve) an acceptable level of test-retest reliability for average peak force ([0179]) and displayed weaker correlations with isokinetic dynamometry assessments ([0181]).
140 The conclusions at [0189] are an echo of the identified issues with the prior art at [0012] being "questionable reliability and repeatability of measurements of between limb strength imbalances". Having commenced with identification of the problems with existing devices and methods, the specification then seeks to demonstrate that the performance of bilateral NHEs on the apparatus has overcome these problems through the experiments conducted on the apparatus.
141 At [0190], the specification again highlights the decreased assessment times as compared to the isokinetic dynamometer, being something which is achieved by assessing the hamstring strength of each leg simultaneously (through a bilateral Nordic curl), rather than one leg at a time such as occurs when using the isokinetic dynamometer.
142 For these reasons, the Patent teaches away from unilateral Nordic curls being performed on the apparatus, being the use of the apparatus with only one leg secured by a securing member.