Single versus multiple joint isokinetic testing with ACL reconstructed patients

The purpose of this study was to compare lower extremity strength using a traditional isokinetic single joint (open kinetic chain) knee extension/flexion test and a multiple joint (closed chain) isokinetic leg press test in patients following an anterior cruciate ligament (ACL) reconstruction. Twenty three subjects underwent both isokinetic single and multiple joint testing at 180, 240, and 300 degrees/s using a calibrated Biodex dynamometer. Testing was performed following (x = 15) weeks of accelerated knee rehabilitation with a predominantly closed chain rehabilitation protocol. Peak torque (PT) and single repetition work (SRW) were analyzed and compared bilaterally in both the single and multiple joint tests. Single joint isokinetic knee extension testing measured strength of the injured limb relative to the uninjured limb at 74-77% for (PT) with multiple joint isokinetic extension testing at 91-93% for (PT). Significant (P < 0.001) differences were identified between the bilateral comparisons measured in the single and multiple joint isokinetic testing conditions for both PT and SRW. Results from this study demonstrate significant differences between single and multiple joint isokinetic testing in the lower extremity. This information is of vital importance to clinicians interpreting results of muscle function in patients following ACL reconstruction. Copyright (C) 1996 Elsevier Science Ireland Ltd.