CALORIE RESTRICTION AS A MEANS TO CONTROL SKELETAL MUSCLE STIFFNESS IN AGED RATS

It has been shown that elderly skeletal muscle does not respond as effectively to exercise as young muscle. This impairment not only limits the effectiveness of interventions in an elderly population but may also be a cause of sarcopenia. One possible explanation for diminished response to exercise is that stiffening of muscle tissue, as a result of glycation, changes the mechanical environment around the muscle cells and that the cells therefore experience less force for any given stimulus. To examine this possibility, it is necessary to manipulate muscle material properties. The purpose of this study is to examine the possibility of using caloric restriction to accomplish this. It was found that calorie-restricted rats were less sarcopenic than ad libitum (AL) fed rats and that there was a significant negative relationship between muscle stiffness and muscle size in all rats. While the caloric-restricted rats' muscles were not statistically less stiff than the AL-fed rats, the majority of them were less stiff and the use of this group broadened the range of muscle stiffness. In conclusion, caloric restriction appears to be a promising method to manipulate muscle stiffness to study the effects of stiffness on diminished response to exercise.