Reproducibility of isokinetic peak torque assessments of the hip flexor and extensor muscles.

OBJECTIVES: Isokinetic assessment is currently the reference method for measuring dynamic muscle strength. We have sought to evaluate the reproducibility over time of isokinetic testing of the hip flexor (FI) and extensor (Ext) muscles and to establish whether there is a significant difference in peak torque (PT) between the left and right hips. PATIENTS AND METHODS: Ten adults were tested once a week for 3 weeks by the same investigator and according to the same protocol, with two velocities (60 degrees /s and 180 degrees /s) for the hip FI and Ext in concentric tests and one velocity (30 degrees /s) for the Ext only in eccentric tests. The reproducibility of the measured PT was analyzed by using the intraclass correlation coefficient (ICC) and a Bland and Altman plot. The difference in PT between the right and left hips was tested using Student's T test. RESULTS: The ICC for the observed PT values revealed very good reproducibility (with a value of between 0.75 and 0.96) for the hip FI and Ext measurements (regardless of the body side, test velocity or contraction mode). We did not observe any significant PT differences between the right and left hips. CONCLUSION: The isokinetic assessment of the concentric and eccentric PT values generated by the hip FI and Ext is highly reproducible. There is no difference between dominant and nondominant body sides, which enables the use of the contralateral limb as a reference.

[Isokinetic evaluation of the knee flexor muscles after anterior cruciate ligament reconstruction using gracilis and semitendinous tendon grafts]. / Evaluation isocinétique des muscles fléchisseurs du genou après greffe du ligament croisé antérieur (LCA) utilisant le droit interne et le demi-tendineux (DIDT).

PURPOSE OF THE STUDY: The purpose of this study was to evaluate recovery of hamstring force after anterior cruciate ligament reconstruction using gracilis and semitendinous tendon grafts. MATERIAL AND METHODS: Isokinetic evaluation of the knee flexor muscles was performed with the system 3 Biodex isokinetic dynameter in twelve patients (mean age 26 years) 12 to 24 months after ligamentoplasty. Concentric (60 degrees /s, 180 degrees /s, 300 degrees /s) and excentric forces were measured. We retained for analysis: 1) moment of maximal force, 2) moment of force at 75 degrees knee flexion, and 3) work. RESULTS: The knee flexor muscles of the operated limb exhibited greater deficit when considering force at 75 degrees knee flexion (24%, 15%, and 18% concentric deficit at 60 degrees /s, 180 degrees /s, and 300 degrees /s respectively, and 20% excentric deficit) than when considering maximal force (14%, 7%, 5% concentric deficit at 60 degrees /s, 180 degrees /s, and 300 degrees /s respectively and 9% excentric deficit). DISCUSSION: This study demonstrates persistent deficit of knee flexor muscle force 12 to 24 months after anterior cruciate ligament repair with hamstring muscle tendons. The deficit reaches 15% to 24% at 75 degrees of knee flexion. The protective role of the hamstring muscles for the cruciate graft submitted to important stress may be compromised by the lack of recovery of knee flexor force more than one year after ligamentoplasty.