THE STUDY OF BIOMECHANICS PROPERTY OF RAT SKELETAL MUSCLE IN TENSION

INTRODUCTION One of the most important biotic material motive system of people is muscle. It is the basis of human body motion. Studying mechanical property of muscle has been one of the main subjects in sport biomechanics. Muscle cannot only contract actively to make a variety of action but be tensioned to take over the load as well. To study the mechanical property of muscle, we should consider either the active contraction or the passive tension. However this paper belongs to the latter. It is hoped that it provides a better understanding of the relation of the structure and the function of muscle. Maybe it will provide some reliable experimental data for preventing injury from sports and some reference material of sport biomechanics. METHODS The objects of research were Wistar male rats. We divided 35 rats into 4 groups. Experiment instruments: Tensile machine which the velocity can be changed, Model GZB-2 resistance strain sensor. Model Y6D-3A dynamic strainer, Model SC-16 record oscilloscope. Model JJC-2 physiological poly-usage tester. RESULTS AND CONCLUSIONS 1. When muscle is tensioned, the ability of anti-tension is correlated closely with the extent of excitation. The limiting strength of the stimulated muscle which produces the tetanic contraction is larger than the relaxed muscle. So it is able to reduce the probability of injury. As a result, the athlete should pay attention to avoid injury of muscle, as the nervous system works badly to make the anti-tensioned ability decreased. 2. The stimulation may change sticky elasticity of muscle. The rigidity of stimulated muscle will be reduced when it is in tetanic contraction. The maximum strain value and the maximum deformed energy will be increased. So the anti-tensioned ability of muscle is improved. 3. The limiting strength of muscle correlates with tensioned velocity: The slower the tensioned velocity, the smaller the limiting strength. 4. The limiting strength of fatigued muscle would be reduced significantly. The maximum strain value and the maximum deformed energy will be decreased. Therefore it is easily damaged than unfatigued muscle. When the anti-tensioned ability of fatigued muscle was reduced, athletes must avoid overloading the fatigued muscle in the sport training. REFERENCES Y.C. Fung, Biomechanics mechanical properties of living tissues. A.C. Giese Cell Physiology 5th Ed. W.B. Saunders company, 1979. Makku Jarvinen (1976) Healing of a crush injury in rat striated muscle. Effect of early mobilization and immobilization on the tensile properties of gastrocnemius muscle. Acta. Chir. Scand. 142:47-56