EFFECT OF TRAINING ON SOME ISOMETRIC CONTRACTION CHARACTERISTICS OF A FAST MUSCLE

1. In a group of female rats the fast m. plantaris was overexerted by denervating the m. gastrocnemius and m. soleus. Part of these rats were trained systematically on a motor-driven endless belt set at an inclination. 2. Isometric contraction characteristics were studied in these and in control rats. 3. Muscle weight and tetanic muscle force of the experimental group both increased to about 130% of that of control rats of the same age. 4. Training had no additional effect on the mechanical characteristics studied in the muscles of the denervated rats. 5. The results indicated that, in the m. plantaris of the denervated group, no changes occurred in the twitch contraction time nor in the tetanic force per unit of weight. 6. A comparison is made with the findings on slow muscles as reported in the literature. © 1969 Springer-Verlag.