ASSESSMENT OF HAMSTRING INJURY

Abstract

A device and associated method for measuring hamstring function, determining previous hamstring injury, predicting the risk for future injury, and controlling the return to sports play following such an injury.

Claims

1. A device for the measurement of hamstring function comprising: a base adapted to sit on the ground; a frame extending vertically from the base; a thigh support element having an inclined surface adjustably mounted on the frame; and at least one hook shaped element mounted adjacent the base of the device, the hook shaped element comprising at least one force sensor which senses the force applied either by one or both of the hamstrings of a user pushing their thighs against the thigh support element, and which transmits the force which is sensed to a device which records and measures the force.

2. The device of claim 1, wherein the frame comprises a planar element mounted substantially vertically on the frame.

3. The device of claim 2, wherein the planar element has a front face and a rear face, the thigh support element being adjustably mounted on the front face of the planar element.

4. The device of claim 1, wherein the thigh support element is adjustably mounted on the frame.

5. The device of claim 1, wherein the inclined surface of the thigh support element is inclined at 27 to 33 to the horizontal.

6. The device of claim 5, wherein the inclined surface of the thigh support element is inclined at 29 to 31 to the horizontal.

7. The device of claim 5, wherein the inclined surface of the thigh support element is inclined at 30 to the horizontal.

8. The device of claim 1, wherein the force sensor is a loadcell.

9. The device of claim 1, wherein the device is provided with two hook shaped elements, one for each ankle of the user.

10. The device of claim 1, wherein the device is provided with a handle that the user grasps during use of the device.

11. The device of claim 1, further comprising a seat.

12. The device of claim 11, wherein the height of the seat is adjustable.

13. A method of measuring bilateral hamstring function, the method comprising: sensing and measuring the force applied by a user pushing their thighs against a thigh support element having an inclined surface inclined at 27 to 33 to the horizontal.

14. A method of measuring unilateral hamstring function with the tested leg, the method comprising: sensing and measuring the force applied by a user pushing their thighs against a thigh support element having an inclined surface inclined at 27 to 33 to the horizontal with the non-tested leg in 10-30 of hip extension.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows the hamstring anatomy,

[0027] FIG. 2 shows Late Swing and Early Stance phases of human movement,

[0028] FIG. 3 is a perspective view of the device of the invention from the front,

[0029] FIG. 4 is an end view from above of the device of the invention,

[0030] FIG. 5, shows the device of the invention set up in the bilateral test position,

[0031] FIG. 6, shows the device of the invention set up in the unilateral test position,

[0032] FIG. 7 is an end view of the device of the invention from one side,

[0033] FIG. 8 is a perspective view from the rear of the device of the invention, and

[0034] FIG. 9 is a perspective view of a second embodiment of the device of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0035] As shown in FIGS. 3 and 4 the device for the measurement of hamstring function comprises a base (1) adapted to sit on the ground, a frame (2) which extends vertically from the base, a thigh support element (3) having an inclined surface (4) which is adjustably mounted on the frame (2) and two hook shaped elements (5) mounted adjacent the base (1) of the device. The hook shaped elements (5) which wrap around the ankles of the user when the device is being used. The hook shaped elements (5) comprise at least one force sensor which is not visible in the figure. The device is connectable with a means of recording and analysing the force which is sensed. The frame (2) comprises two upright members (6) which extend from the base (1). A planar element (7) is mounted substantially vertically on the frame. The planar element (7) has a front face (8) and a rear face (9), the front face being the face which faces the user when the device is in use. The element (3) is adjustably mounted on the front face (8) of the planar element (7). The element (3) can slide up and down on the frame (2) within two slots (16) and can be locked in position via the two lock wheels (15) as illustrated in the FIGS. 7 and 8. Suitably the inclined surface (4) of the element (3) is inclined at a 30 angle to the horizontal such that its slopes away from the user towards the base (1) of the device. The inclined surface (4) may be provided with padded material. The upper in use surface of the element (3) is provided with a handle (10) which can be used to move the element up and down in relation to the frame, thus adjusting the height of the element on the planar element (7).

[0036] The two hook shaped elements (5) are attached to a bar (11) located at the base (2) of the device and fixed between the two upright members (6). Each hook shaped element (5) is provided with a force sensor which is a loadcell(s). Typically there is one loadcell in each hook, but that could be varied. The loadcell can convert the force applied by the ankles of the user into a measurable electrical output. The electrical output is transmitted to a software platform by Wi-Fi and the software platform can record and analyse that output.

[0037] The hook shaped elements (5) are shaped so that they can be fastened around the ankle of the user. This may be achieved by means of a strap (not shown), or different sizes of hook shaped elements (5) can be provided with the device. The hook shaped element may be made of a plastics material so it is easy to wipe clean sterilise. Suitable hook shaped elements are commercially available at least from VALD Performance, Australia.

[0038] The device is provided with a handle (12) that the user can grasp during use of the device. The handle (12) is in the form of a bar positioned along the upper, in use position, of the device. The handle (12) is fixed at either end to one of the upright members (2). Other handle structures are possible, such as two handgrips, one positioned on either side of the device, towards the upper in use position.

[0039] The base (2) is generally U-shaped with two elongate elements (13) which are connected by another elongate element (14) adjacent their ends. The upright members (2) extend upwardly from the elongate elements (13). However, other suitable base configurations are possible.

[0040] Generally, the base (2) and the upright members (3) are made from a heavy, durable material such as metal, so that the device cannot be easily knocked over when it is being used.

[0041] A second embodiment of the invention is shown in FIG. 9. It also a base (1) adapted to sit on the ground, a frame (2) which extends vertically from the base, a thigh support element (3) having an inclined surface (4) which is adjustably mounted on the frame (2) and two hook shaped elements (5) mounted adjacent the base (1) of the device.

[0042] The frame (2) comprises two upright members (14) which extend from the base (1). A planar element (7) is mounted substantially vertically on the frame. The element (3) is adjustably mounted on the frame (2). The element (3) can slide up and down on the frame (2) and can be locked in position. Suitably the inclined surface (4) of the element (3) is inclined at a 30 angle to the horizontal such that its slopes away from the user towards the base (1) of the device. The inclined surface (4) may be provided with padded material.

[0043] The two hook shaped elements (5) are attached to a bar (11) located at the base (2) of the device and fixed between the two upright members (14). Each hook shaped element (5) is provided with a force sensor which is a loadcell(s).

[0044] The device is provided with an adjustable seat (15) with the figure showing suitable alternative heights for the seat depending on which measurement is being made.

[0045] The method of using the device and analysing hamstring function will now be described using the H-rig which is the device of the invention.

EXAMPLE

1. Testing Procedures

Bi-Lateral H-Rig Test-Iso.SUB.BI .0.89, ICC-0.79-0.94

[0046] The participant's knees should rest comfortably against the pad while the ankles (malleoli) are positioned directly in line vertically with the knee. [0047] The participant should be placed in a seated position. [0048] The participant's feet should rest on the floor at the start position. [0049] Once the participant achieves a comfortable position, they should be seated 30 cm away from the pad. [0050] The participant should be seated at a height that helps to achieve 30 degrees of knee flexion, by adjusting the seat height and feet positioned on the ground. [0051] 30 degrees of knee flexion is achieved by sliding the 30 degree thigh support element into place and locking it to hold the knee in 30 degrees of knee flexion. [0052] The participant's trunk should remain upright with both arms crossed in front of their chest. [0053] The participant should be queued to drive their knees into the thigh support element while each ankle should drive posteriorly into the ankle hooks. [0054] Three maximal repetitions should be carried out with the maximal force output being recorded.

Uni-Lateral H-Rig Test-Iso.SUB.UNI .(0.9, ICC=0.8-0.95)

[0055] The participant should ensure that their trunk is in an upright position throughout test. [0056] Both arms should remain fully locked out and should be placed on the horizontal grip bar of the H-Rig. [0057] A 50 cm high bench should be placed 60 cm away from the face of the H-Rig. [0058] 20 degrees of hip extension in the contralateral (non-tested limb) should be measured using a goniometer. [0059] If this angle needs to be adjusted to find 20 degrees of extension, the bench can be moved towards or away from the rig to do so.

[0060] The un-involved knee should be positioned on the bench or seat, with the patella resting at its nearest point. [0061] The contralateral limb is then positioned with the patella placed against the H-Rig. [0062] A 30 degree thigh support element is then placed between the anterior thigh and the rig in order to form a 30 degree angle of knee flexion. [0063] Three sets of two maximal reps should take place, with the involved limb alternating between sets. [0064] Repetitions should last for five seconds. [0065] Five minutes of recovery should be allowed before carrying out the eccentric strength test.

2. Clinical Research

[0066] A total of 70 amateur Gaelic Football players with 18 previous HSI were tested in the preseason period (January to March).

TABLE-US-00001 Iso.sub.BI Non- Effect Involved Involved size Absolute Force (N) 281 66 332 72 0.738 Relative force (N .Math. kg) 3.48 0.89 4.11 0.92 0.696 Absolute Torque (Nm) 120 29 142 31 0.72 Relative Torque (Nm .Math. kg) 1.49 .39 1.76 .40 0.683 Scaled Force 5.2 1.22 6.14 1.33 0.736 Previously injured isometric hamstring variables (P > 0.05)

[0067] Iso.sub.BI force and torque all differed significantly with a moderate effect size (p<0.01, d=0.68-0.74) between the injured and uninjured sides in players with previous hamstring injury with bilateral deficits of +15% which also included players who suffered HSI in the previous season. This indicates that strength deficits still exist and it may be that Iso.sub.BI testing is more sensitive to detecting residual or underlying weaknesses as it assesses muscle function in a long lever 150 position. A total of 49 amateur Gaelic Football (26.5+/2.4 yrs; 81.6+/9.1 kgs) were tested in the preseason period (June) of whom sustained a previous hamstring strain in the past 12 months with mean time lost per HSI to training or matches 20.17.1 days. The major mechanism was high speed running and kicking, accounting for 89% and 11% of hamstring strains, respectively. In Iso.sub.UNI there were significant differences between the injured and non-injured group for absolute force, relative force, scaled force, absolute torque, scaled torque and relative torque measures (p>0.05).

TABLE-US-00002 Injured Non-injured ES Ab Force (N) 363 62 417 72 0.80 Relative force (N .Math. kg) 4.48 0.85 5.19 0.86 0.92 Scaled force 6.68 1.26 7.75 1.28 0.92 Ab Torque (Nm) 156 28 185 34 0.93 Relative Torque (Nm .Math. kg) 1.92 0.38 2.33 0.39 1.06 Scaled Torque 1.88 0.37 2.28 0.38 1.06 Comparison of Iso.sub.UNI variables from those with previous HSI injured versus non-injured players (mean of L + R) (P > 0.01)

[0068] As we have indicated Iso.sub.BI strength better identifies those with residual strength deficits following HSI in the previous season and in this current cohort there is trend towards a Iso.sub.UNI underlying weakness in previously injured players. Iso.sub.UNI may be more sensitive to underlying residual deficits as this long lever position may more closely simulate the mechanism of injury seen in late swing phase/early stance in which the contralateral limb is also in extension. The test is unilateral preventing any neural crossover isolating any potential weaknesss. Also in Iso.sub.UNI the opposite hip is placed into extension and subjective feedback from participants indicates this places a counter stretch on the limb been tests and perhaps even encourages a cocking mechanism prior to MVIC.

[0069] Fascicle length in the injured group was moderately correlated with Iso.sub.BI (r=0.442, P<0.086), Iso.sub.UNI (r=0.389, P<0.136). 62.5% of all previous hamstring injuries scored below the averages of the group for both fascicle length (9.9 cm) and unilateral isometric strength (420N). Our results suggest that Iso.sub.UNI and Iso.sub.BI is related to BFlh L.sub.f in previously injured Gaelic footballers. The main advantages of these isometric tests is 1) the Iso.sub.BI assesses muscle function in a long lever 1500 position 2) The Iso.sub.UNI may isolate the affected muscle group and preclude any crossover between limbs which occurs in bilateral testing, secondly the placement of the contralateral hip into extension may simulate the mechanism of injury in which the contralateral hip is in extension during late swing phase/early stance as running is the main mechanism of injury. The isometric testing may expose the vulnerability for injury by testing in a position in which the hamstrings are in their position of greatest risk and may help explain the disparity between eccentric and isometric testing and provide an insight to the greater relationship to BFlh L.sub.f.

[0070] A total of 30 HSI were tested 0-7 days following acute hamstring injury. 30 club footballers who presented following an acute onset of posterior thigh pain in either training or competition were invited to participate in the study. These players were unable to train or participate in Gaelic football at the time of their injury. The initial hamstring injury diagnosis was made by a lead clinician and verified by a clinical colleague. Hamstring injury was defined as a posterior thigh injury, to the hamstring muscle group and were indirect muscle disorders of the musculotendinous complex of biceps femoris, semitendinosus and semimembranosus. Injuries were graded according to the signs and symptoms as described by (Pollock et al., 2014). The myofascial/musculotendinous/intratendinous component of the classification system was omitted and injuries referred to as Grade 0, I, II, III and IV, as MRI is used to determine the extent or component of HSI. Inspection and palpation, active knee extension, passive straight leg raise, manual muscle testing and VAS were all used to corroborate the diagnosis.

[0071] In the bilateral isometric test there was no difference (p>0.05) between the involved and uninvolved sides for Grade 0 (22442v24659N), Grade I (20467v 24049N), and II (13756v 16336N), respectively. The ratios were 0.940.19, 0.860.26 and 0.840.25 for Grade 0, I and II. In the unilateral isometric test there were significant differences (p<0.05) between the involved and uninvolved sides for Grade 0 (35199v 40274N), II (252101v 38099N), and III (18762v32758N), receptively. The involved limb ratios were 0.870.17, 0.660.18 and 0.590.20 for Grade 0, I and II.

TABLE-US-00003 Involved side Un-Involved side Ratio P-Value Grade 0 351 99 402 74 0.87 0.17 0.043 Grade I 252 101 380 99 0.66 0.18 0.003 Grade II 187 62 327 58 0.59 0.20 0.016 Unilateral isometric strength for involved versus uninvolved side (p < 0.05)

TABLE-US-00004 Bilateral Isometrics Uni-lateral Isometrics Total Total N % N % Positive 27 57 Positive 24 80 Negative 13 43 Negative 6 20 Total 30 100 Total 30 100 Clinical assessment and <10% bilateral deficit in isometrics strength and hamstring strain injury

[0072] Level of agreement between clinical hamstring assessment and <10% bilateral deficit in isometric strength with regard to the presence of injury. In 27 cases (57%) there was a greater than 10% deficit in bilateral isometric strength with associated hamstring injury. In 24 (80%) of the cases there was a greater than 10% deficit in unilateral isometric strength with associated hamstring injury.

TABLE-US-00005 Grade r.sup.a P Unilateral Iso Test 0.553 <0.01 Bilateral Iso Test 0.350 <0.06 Bilateral Ratios 0.163 <0.04 Unilateral ratios 0.587 <0.01 Correlation between clinical assessment of hamstring injury and isometric strength .sup.aSpearman rank correlation

[0073] The isometric strength during the clinical assessment injury was highly correlated with unilateral isometric strength and the grade of hamstring injury (r=0.002, P<0.01) and moderate correlations for the bilateral test was (r=0.058, P<0.06). The bilateral ratio during the clinical assessment injury was highly correlated with unilateral isometric ratio and the grade of hamstring injury (r=0.587, P<0.01) and low correlations for the bilateral test (r=0.163, P<0.04).

TABLE-US-00006 Bilateral Unilateral Grade 0 0.94 0.17 0.88 0.18 Grade I 0.86 0.26 0.66 0.18 Grade II 0.84 0.25 0.59 0.20 Bilateral Ratio and grading of hamstring injury

[0074] The ISO.sub.uni of the involved side was significantly weaker in comparison to the uninjured limb for grade 0, I and II HSI classification, and a high level of agreement and correlation between ISO.sub.uni ratios and clinical assessment in the classification of HSI. Iso.sub.UNI ratios (0-7 days post injury) can provide an indication of HSI grade and classification and we suggest Iso.sub.UNI ratios of 0.9, 0.7, 0.6 to corroborate clinical diagnosis and grading of 0, I and II hamstring injuries respectively.

3. Normative Data and Recommendations

TABLE-US-00007 ISO.sub.BI ISO.sub.uni Previous Injury <15% deficit We recommend a 15% deficit in screening can be indicative of previous HSI in the past season. Future Injury 150 Nm 185 Nm We recommend cut off points of 150 Nm for the bilateral test and 185 Nm for unilateral test to protect from future injury. Classification ratio Grade 0 0.95 0.87 We recommend from our Grade I 0.86 0.66 research that opposite limb Grade II 0.84 0.59 ratios in the unilateral test, where possible be widely used to assist in the classification of HSI. Strength Classification Good 320+ 505+ Green represents a good score which reduces the risk of hamstring injury, athlete should continue to work on increasing hamstring strength Average 250-319 435-505 Orange represents a score around the average strength of squad of players and the Athletes should work on increasing strength into the green category Poor 250 435 Red represents any score below this average threshold or a 10% bilateral difference from left to right. Athlete needs to work to increase the hamstring strength in this category

4. Return to Play Programming and Recommendations

Return to Play Timelines for Grade 0, Grade I & Grade II Hamstring Injuries.

Grade 0: Recovery Time; 1710 days.

TABLE-US-00008 Assessments Uni- Bi- Lateral Lateral Rehabilitation Running Strength Strength Days Session Description Ready to Return to Running Stage 0.87 0.17 0.94 0.17 4 1 RTR 1 2,000 m*Zone 4 (approx. 100 m in 20-22 seconds) 0.88 0.17 0.94 0.17 10 5 RTR 2 2,700 mZone 4 (approx. 100 m in 18-20 seconds) RTR 3 2,000 mZone 4 1,000 m*Zone 5 0.90 0.95 RTR 4 2,000 mZone 4 1,000 mZone 5 500 MD (Zone 4/5) RTR 5 2,000 mZone 4 1,250 mZone 5 750 m MD (Zone 4/5) Ready for Modified Training 13 5 RTP 1 Warm up + 1,500 mZone 4 1,500 mZone 5 150 m*Zone 6 0.92 0.96 RTP 2 Warm up + 20 mins + 1,000 mZone 4 500 mZone 5 150 mZone 6 RTP 3 Warm up + 40 mins + 500 mZone 4 500 mZone 5 150 mZone 6 Game Ready 0.95 0.97 17 10 RTR 4 Full training (*HMLD >15 m/min). Zones Zone Description *HMLD High metabolic Load Distance (High speed meters (Zone 5 + 6), acceleration meters >2.0 m/s.sup.2 & deceleration meters >2.0 m/s.sup.2 combined). *Zone 4 4.0-5.5 m/s 14.4-19.8 (e.g 100 m in 18-25 seconds km/hr [1:1 to 1:2]) *Zone 5 5.5-7.0 m/s 19.8-25.2 (e.g 70 m in 10-13 seconds km/hr [1:2 to 1:3 work to rest])

[0075] The words comprises/comprising and the words having/including when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0076] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.