Adaptation to peripheral muscle training.

Abstract

Ten healthy subjects underwent a 6-week dynamic exercise program designed to put a high relative load on individual muscle groups while maintaining low central circulatory stress levels. This was done to test the hypothesis that such "peripheral" training could produce skeletal muscle adaptation at low levels of myocardial work. Such a program may be useful in rehabilitating patients whose myocardial disease prevents adequate levels of participation in the traditional types of large muscle training. Strength testing, muscle biopsies and both submaximal and maximal bicycle ergometry were done to assess the effects of "peripheral" training. Heart rate during the training sessions decreased progressively over the 6 weeks (p less than 0.001). Quadriceps strength increased (p less than 0.02) with training as did both quadriceps (p less than 0.03) and gastrocnemius (p less than 0.008) fiber areas. Fiber composition was unchanged. Succinic dehydrogenase concentrations were unchanged while phosphorylase activity decreased in both muscle groups (p less than 0.03). Submaximum and maximum bicycle ergometry results were unchanged with training. The data show that dynamic training of small groups of muscles sequentially can produce significant skeletal muscle adaptation with little central circulatory stress. The effects of "peripheral" training in cardiac patients remain to be determined.