Abstract
The purpose of this study was to investigate the effects of exhaustive exercise and muscle fiber type on superoxide dismutase (SOD). Fifty male rats were randomly divided into the following two groups: 1) exhaustive exercise, and 2) control group (n=25). The strenuous exercise was performed on a rodent treadmill at a speed of 2 Km/h up a 15% grade until exhaustive. The soleus, plantaris, and red and white gastrocnemius muscles of the rat right hindlimb were removed following exhaustive exercise. Control rats were sacrificed at the same time as the exhaustive exercise group. The SOD activity was determined using the method of McCord & Fridovich. Two way repeated measure ANOVA was performed to examine the effects of exhaustive exercise and muscle fiber type on SOD. The finding showed that exhaustive exercise resulted in a singificant increase in SOD activity of rat skeletal muscle. There was no identical alteration among 4 kinds of fiber types on SOD activities in response to exhaustive exercise. Moreover, the activity of SOD induced by exhaustive exercise on red fiber (soleus and red gastrocnemius) was significantly higher than control group, while SOD activity on white fiber (plantaris and white gastrocnemius) was not significant different between exhaustive exercise and control group. It was concluded that exhaustive exercise could result in oxygen free radical stress. The higher SOD activity in red fiber during exercise may be due to fiber type difference, biochemical property, and fiber pattern recruited.