Medicine and Health Sciences Commons^™

The Relationship Between Vertical Jump Scores And Peak Force Measurements Of An Isokinetic Leg Press, David M. Silkey

Physical Therapy Scholarly Projects

This study evaluated potential correlations between related closed kinematic chain strength measurements on a Kin-Com isokinetic machine and a functional strength test. The correlation between standing vertical jump height and isokinetic leg press measurements were statistically analyzed. The following measurements were obtained from 22 subjects (mean age of 24.4 years): a body weight measurement, a vertical jump score, and the force measurements of an isokinetic leg press at 90°/second on each leg. Pearson correlation coefficients were significant (p < .001) when power quotient scores (vertical jump height multiplied by body weight) were compared to leg press results. However, second-order partial correlation coefficients did not find a significance (p > .005) between vertical jump scores and isokinetic leg press results when weight and gender were considered. A significant difference (p < .001) existed between left leg press and right leg press measures. Although isokinetics are useful for lower extremity assessment, this study found that the isokinetic leg press may not be appropriate in determining functional ability.