Relationship between isokinetic and isometric knee extension muscle strengths and performance test

Abstract

Objective: This study was conducted to examine the relationship between muscle strength, measured using an isokinetic dynamometer (ID) and a hand-held dynamometer (HHD), and the single leg hop (SLH) distance.

Methods: This study included 40 healthy male volunteers (age: 22.0 ± 1.2 years). Maximal knee extension force at 90° flexion was measured using HHD. Peak torque values were measured using ID at two speeds (60°/s and 180°/s) and during isometric contraction at 90° knee flexion. Additionally, the SLH distance was measured. A single regression analysis was performed with each peak torque at ID as the objective variable and HHD strength and SLH distance, respectively, as the explanatory variables. Then, multiple regression analysis was also performed to predict ID peak torque using HHD strength and SLH distance as explanatory variables simultaneously.

Results: HHD strength contributed most significantly to 60°/s peak torque (β＝0.524; p＜0.001), and SLH distance contributed most significantly to 180°/s peak torque (β＝0.611; p<0.001). Furthermore, the results of multiple regression analysis with both factors as explanatory variables showed that the coefficient of determination for predicting ID peak torque was greater than that of single regression analysis.

Conclusion: It was suggested that HHD strength and SLH distance can be applied to predict ID peak torque, which is used as an index of return to sports.