Upper limb biomechanical differences in volleyball spikes among young female players

The performance assessment of relevant biomechanical factors is essential for appropriate age-related training progression in volleyball spike (VS). This study aimed to investigate the differences in upper limbs' (a) range of motion (ROM), (b) angular velocities, and (c) muscular activity during VS among under 16- (U-16), under 18- (U-18), and under 20- (U-20) year-old female volleyball players. The kinematic variables of the spike performances were recorded using six optoelectronic cameras (Vicon Motion system, UK). Additionally, the wireless Trigno system (Delsys, USA) was used to record the electromyographic signals. The one-way ANOVA (1d SPM analysis) exhibited a significantly greater wrist internal rotation (p < .001), wrist adduction velocity (p < .001), and palmaris longus activity (p < .001) in the acceleration phase in U-20, compared to the U-16 group. Additionally, the U-20 and the U-18 players portrayed a significantly greater shoulder external rotation (p < .001) and internal angular velocity (p = .035) relative to the U-16 group. A significantly greater pectoralis major (p < .001), biceps brachii (p < .001), and anterior deltoid (p < .001) activity was observed in the U-20 group, compared to younger groups. This study suggests that older players employ more upper limb muscular activities during spike with the presence of blocks, which enables them to hit the ball with greater velocities and direct the ball in their desired direction through increased wrist ROMs.