ABSTRACT:
Background/Objectives: Patients with anterior cruciate ligament injury are known to develop muscular weakness in the quadriceps. Also, ligament injures contribute to loss of stability and function. To assess the correlations between single-leg balance ability and isokinetic extensor muscle strength measurements in subjects after partial (ACL) injury. Methods/Statistical analysis: We examined38men (mean age, 26.3 ± 7.0 years) with partial ACL tear. The isokinetic strength of extensor muscles was evaluated by using the CSMI isokinetic testing device. The peak torque was determined at speeds of 60°/s and 180°/s. The balance ability was measured with single-leg by using the Biodex stability system. The correlations between the ability of single-leg balance and knee extensor muscle strength were determined. Findings: The knee extensor strength deficit of 22.5±18.9.% was found in the injured side that compared to the uninjured side at 60°/s. and extensor strength deficit was 18.8±17.2% at 180°/s. Single-leg balance ability at 22.1±15.8%was required the level of improvement of balance stability. Significant correlations were found between deficient of each extensor muscles in injured knees at 60°/s, 180°/s and single-leg balance stability (r=.61and r=.58, respectively). Improvements/Applications: The ability of single-leg balance with injured knees appeared to be influenced by knee extensor muscle strength. The results contribute to the evidence indicating the importance of knee strength for dynamic balance ability for partial ACL injury.