Effects of resistive exercise and stretching on the soleus muscle of ovariectomized rats

ABSTRACT This study analyzed the effects of resistive exercise and/or stretching in the muscle morphology of ovariectomized rats. Seventy-five female Wistar rats (218±22g) were divided into 8 groups: Control (CONTROL, n=5); Ovariectomy/Hysterectomy (OH, n=10): ovariectomized/hysterectomized and then waited 8 weeks for the onset of osteopenia. Stretching (STRET, n=10): manual stretching of the soleus muscle (10 repetitions of 60s), twice weekly; Ovariectomy/Hysterectomy and Stretching (OH+STRET, n=10); Progressive Loading (PL, n=10): 4 sets of 10 repetitions, initial load 50% of body weight, increasing weekly until 70%, three times a week. Progressive Loading and Stretching (PL+STRET, n=10); Ovariectomy/Hysterectomy and Progressive loading exercise (OH+PL, n=10); Ovariectomy/Hysterectomy, Progressive Loading and Stretching (OH+PL+STRET, n=10). Stretching and/or progressive loading were performed for 6 weeks. After 14 weeks, the female rats were euthanized to remove the soleus muscle. The following variables were assessed: body weight; muscle weight and length; number and length of sarcomeres and the muscle fiber cross-sectional area (MFCSA). Comparisons between the groups were performed with ANOVA one-way post hoc Tukey or Kruskall-Wallis (p