A novel use of unilateral leg press power during a bilateral leg press task to detect quadriceps weakness and limb symmetry index in acl-reconstructed individuals

Quadriceps weakness is a common clinical sign following anterior cruciate ligament reconstruction surgery (ACLR). We examined quadriceps strength and limb symmetry index (LSI) from different types of functional tests: isokinetic dynamometry, hop tests, and leg press. A total of 26 subjects with ACLR participated in the study. Knee extension torque at speeds of 60/180/300°/s, single/triple hop distance, and unilateral peak leg power during a bilateral leg press were measured on each leg; LSI was calculated as the percent of the involved leg over the uninvolved limb values. Bivariate correlations were used to examine the relationships among those variables. One-way ANOVA and post-hoc analyses were used to assess the magnitude of LSI differences. Peak knee extension torque values were positively associated with hop distance and leg power. LSIs during hop tests were significantly higher than the LSIs from peak knee extension torque at 60°/s.