Surface Electromyography Analysis Of The Effect Of Different Depth Jump Exercises On Lower Limb Muscles Of Male Volleyball Players In Colleges And Universities

Research object: Volleyball has become a popular sport all over the world.To get good results in the competition,players should have good jumping ability to guarantee their superiority into full play in the air.To ensure the exercise of the jumping ability,the deep leap method was adopted to enhance the explosive force of legs.The research on the key points of volleyball showed that the main jump manner was longitudinal take-off.Therefore,the downward jump and upward jump were put together to exercise and test.The choose of height is very important for players.It should not only guarantee the improvement of the explosive force but also should avoid the sport injury.The main objective of this work was the effect of jump height on the myoelectricity of the lower limb muscle groups.By comparing different myoelectricities,we tried to investigate the relation between the jump height and myoelectricity,optimizing the exercise height.Research methods: A wireless portable surface myoelectric tester with 16 passes and a high-speed camera were used to test and record the exercise process of twelve players.Then,the kinematics characteristics of the players were characterized based on these data.Research results:(1)Both the buffer time at the landing process and the pedal extension time increased with increasing the jump height.The ratio of the pedal extension time and the buffer time firstly increased and then decreased.The maximum value was 1.326,which was attained at the jump height of 60 cm.This proved the best of the transformation of resilience kept in the muscle to the mechanical energy at such height.(2)The second jump height varied with the first jump height.The maximum second jump height in this research was among these 12 players was 0.4 m,which was attained at the jump height of 60 cm.(3)At the landing stage,the MS values of surface electromyography at most of the muscles at the buffer period were higher than those at the pedal extension period for the same jump height.The RMS value firstly increased and then decreased at both the pedal extension periods and buffer periods.(4)Most of the RMS values decreased because the longer landing time for tired players.Conclusions:(1)There existed an optimum jump height.In this research,the optimum jump height for the player who owned the similar physical quality was 40 – 60 cm.(2)For the most of the jumping training,the surface electromyography of the most of the muscles increased with increasing the jump height and then decreased after reaching the maximum value.(3)The training effect could be influenced by the physical state of the players.The training of explosive force could play a negative role if the player were tired.