Interlimb asymmetry in persons with and without an anterior cruciate ligament deficiency during stationary cycling

OBJECTIVE: To investigate the power output generation from anterior cruciate ligament (ACL)-injured and noninjured limbs during stationary cycling. DESIGN: Repeated measures. SETTING: Research laboratory. PARTICIPANTS: Ten people with unilateral ACL deficiency and 10 uninjured controls matched for age and sex. INTERVENTIONS: Participants performed 6 randomized bouts of stationary cycling at intensities of 2 cadences (60, 90 rpm) and 3 power outputs (75, 125, 175 W) for approximately 2 minutes for each bout during a single laboratory visit. MAIN OUTCOME MEASURES: The effective component of force (perpendicular to the crank) was measured and used to calculate the power output contribution from each limb to the total power output. RESULTS: Subjects with ACL injury generated significantly more power from uninjured limbs compared with that from injured limbs and the limbs of control subjects. CONCLUSIONS: Results suggest that people with ACL injury have a reduced total output from the injured limb and rely on the uninjured limb for most of the power output. This may compromise the ability to restore lower-limb muscle strength after injury.