Correlation of isokinetic, isometric, isotonic strength measurements with a one-leg vertical jump

The purpose of this study was to determine the degree of correlation between isokinetic, isometric, and isotonic knee extension strength measurements and a one-leg vertical jump ground reaction force. Fifty-one volunteer students were put into three different groups (sedentary, partially trained, trained) depending upon their training level. All subjects performed an isokinetic, isometric, isotonic, and jump test as determined by a balanced latin square. One-leg vertical jump peak force was moderately correlated with isokinetic (r = 0.57), isometric (r = 0.54) and isotonic (r = 0.68) peak force measurements. Partially trained subjects had the lowest correlations (r = 0.26 to 0.56) to one-leg vertical jump peak force while trained subjects had the highest correlations (r = 0.81 to 0.85). Correlations among strength measurements were moderate (r = 0.70 to 0.75). It is concluded that isokinetic, isometric, and isotonic peak force measurements are only moderately correlated to one-leg vertical jump, therefore they cannot be used independently to predict vertical jump ability.