Experimental research on the changes of skeletal muscle ultrastructural after repetitive exercise

Objective:Research on the changes of skeletal muscle ultrastructural after repetitive exercise.Method:72 male Wistar rats,randomly divided into control group,one time econcentric exercise group,one week repeat exercise group.Let one time econcentric exercise group do down hill run exercise once.Keep the same intensity on one week repeat exercise group,but repeat the exercise for 7 days.Take quadriceps femoris separately right after the econcentric exercise,24 h,48 h,72 h,120 h,168 h and right after the last repeating exercise of the seventh day,24 h,48 h,72 h,120 h.168 h.Result:The damage of quadriceps muscle ultrastructure presented evolutionarily aggravating right after the one time econcentric exercise and 24 h.48 h.It recovered to the pre-exercise level 168h after the exercise;The damage of quadriceps muscle ultrastructure presented the same tendency right after seven times econcentric exercise and 24 h.However,it didn't completely recover to the pre-exercise level 168h after the exercise;The damage of quadriceps muscle ultrastructure of one week repeat exercise group was more seriously than the one time econcentric exercise group during every time interval.Conclusion:There was a delay phenomenon on the skeletal muscle damage caused by repetitive motion,the skeletal muscle damage wasn't serious right after the one time econcentric exercise,but the damage became apparently 24 h after the motion and reached the peak at 48 h.The damage could recover seven days after exercise.The continuous repetitive exercise may lead to a cumulative effect on the damage of skeletal muscle fibre.