Isokinetic Training, Isotonic Training And Strength Development

Abstract

Strength training is a valuable component of rehabilitation and a variety of exercise settings. Strength training is used to enhance exercise performance and reduce sports related injuries. In addition strength training is also used in rehabilitation to reestablish strength that has been lost to injury or illness. I have seen the differences in using both modes in my clinical experience. Strength training can be performed in three different modes: isometric, isotonic and isokinetic. PURPOSE The purpose of this study is to determine if isokinetic training or isotonic training is more effective in developing strength. METHODS Twenty-six subjects were assigned to either a control(group 1) group, an isotonic (group 2) group, or an isokinetic group(group 3). Each was pre- and post-tested utilizing a Cybex 600 isokinetic dynanometer. Group 2 and group 3 trained 2 sessions per week for 3 weeks. Group 2 used the Daily Adjustable Progressive Resistance (DAPRE) protocol with all repetitions limited to 120 deg/sec. Group 3 performed 4 sets of 10 repetitions at 120 deg/sec. RESULTS Both exercise groups made significant increases in force, power and total work in the mode of exercise in which they were not trained, but greater improvements were seen in the mode of exercise in which the individual had trained. However, isokinetic power and total work for right knee flexion and total isokinetic work for left knee flexion was significantly greater (p < 0.05) for group 2 when compared to group 3. CONCLUSION This study has demonstrated that isotonic exercise is more effective than isokinetic exercise in improving knee flexion strength. Further research is needed to determine the efficacy of these modalities for individuals involved in rehabilitation and fitness taining.