Anterior Cruciate Ligament Rehabilitation Adolescent Female Athletes Exhibit Relative Muscle Dysfunction After Return to Sport

We sought to examine the relationship between upper-leg compartmental lean mass, muscle-specific strength, and explosive strength following anterior cruciate ligament reconstruction. Twleve adolescent female athletes with prior anterior cruciate ligament reconstruction were individually-matched by age (16.4 +/- 0.9 vs. 16.4 +/- 1.0yrs.), body mass index (23.2 +/- 2.1 vs. 23.2 +/- 2.7kg/m(2)), and sport to 12 female athlete controls. One total-body and 2 lateral-leg dual X-ray absorptiometry scans measured total/segmental body composition. Isokinetic dynamometry measured knee extensor/flexor peak torque. Squat jumps on force platforms measured bilateral peak vertical ground reaction force. Paired t-tests assessed lean mass, peak torque, and force between previously-injured athletes' legs and between previously-injured and control athletes' legs. Previously-injured athletes' involved vs. non-involved leg demonstrated lower total (7.13 +/- 0.75 vs. 7.43 +/- 0.99kg; p<0.01) and anterior (1.49 +/- 0.27 vs. 1.61 +/- 0.23kg; p<0.01) and posterior (1.90 +/- 0.19 vs. 2.02 +/- 0.21kg; p=0.04) upper-leg lean mass. Involved leg peak torque (1.36 +/- 0.31; 1.06 +/- 0.27; 0.97 +/- 0.19Nm/kg) was lower vs. non-involved leg (1.71 +/- 0.36; 1.24 +/- 0.33; 1.04 +/- 0.15Nm/kg; p<0.01-0.02) for extension at 60 and 120 degrees/sec and flexion at 60 degrees/sec and vs. controls' 'matched' leg (1.77 +/- 0.40Nm/kg; p=0.01) for extension at 60 degrees/sec. Involved leg force (296 +/- 45N) was lower vs. non-involved leg (375 +/- 55N; p<0.01) and vs. controls' 'matched' leg (372 +/- 88N; p=0.02). One-year post-anterior cruciate ligament reconstruction, adolescent female athletes' involved leg demonstrated relative muscle dysfunction.