Analysis Of Kinematic And Surface Electromyogram(EMG) Features Of Volleyballsetters' Jumping-Set Movements

Setters are the ones who always act a dominant role in organizing offense during a volleyball game.Therefore,reasonable and well-performed jumping-set techniques have been one of the essential topics in volleyball training and competing.Applying to the methodologies of documents,interviewing,statistics and testing,the study conducted a survey of 6 male volleyball players' jumping-set movements with kinematics and EMG analysis.The purpose of the study lies in finding out the biomechanical principles of setters' jumping-set movements in a standing position.The research came to the following conclusions:Firstly,the testers have to modify specific physical joints coordination in order to finish jumping-set movements during the different phases of jumping.The kinematics pattern of the movements shows that testers modify body position as well as joints range in the series of jumpingset.Secondly,the analysis displays that the time duration of pre-squatting and taking-off are obviously related to the movement range of hip and knee joints.Whereas,stretching time duration is closely related to hip joints movement range only.Thirdly,the height of body gravity in pre-squatting differs simultaneously with the hip joints movements and in stretching period both hip and knee joints could obviously influence the height of body gravity.Moreover,the ankle joints have no relations to the height of body gravity neither in pre-squatting nor stretching.Fourthly,correct and reasonable bending in hip and knee joints could not only decrease the height of body gravity when landing,but effectively prevent lower limbs from injuring.Finally,rectus femoris and gastrocnemius are properly activated by the testers in pre-squatting and stretching period when they perform jumping-set in a standing position,but the muscles of upper limbs are not much motivated relatively.