A Study of Muscle Strengthening for the Fast Twitch Fibers

Abstract

Because most of the activities of daily living are fast speed movements, physical therapists strengthen the patients’ muscle torque usually emphasizing on the reeducation of peak torque at fast speed. The threshold of fast fibers is higher than that of slow fibers. The exercise mode (with high or low resistance) should be different for strengthening fast or slow muscle fibers. The main purpose of this study was to investigate whether the strengthening effect of slow speed, high resistance exercises was better than that of fast speed, low resistance for the fast fibers. Twenty healthy medical college students were divided into two groups evenly. One group was trained using fast speed, low resistance (30, 40, 50 RPM) exercise on the dominant knee and slow speed, high resistance (5, 10, 15 RPM) training on the non-dominant knee. Contrastly, the other group was trained by the same exercise programs in changing leg. All subjects took on the training program for six weeks and trained three times per week. After data analysis, there were the following results: 1. The different length of training period was the main factor to affect the increase of peak extensor torque or average extensor power after exercise training. 2. Both high and low resistance exercises could increase peak extensor torque and average extensor power at fast speed significantly. 3. The effect seems more remarkable for slow speed, high resistance exercise than for fast speed, low resistance exercise in male subjects. 4. The female subjects got greater improvement in peak torque and average power at some speeds. 5. The female subjects appeared more learning effect than male did.