Sex-dependent differences in the volleyball spike jump performance and specific technique training for female athletes

Despite the importance of the spike jump in volleyball and the high number of female athletes at high level, movement analyses of the volleyball spike jump were mainly conducted in male players. Potential sex-dependent differences were marginally considered in the scientific literature and practical training. The few studies that tackled this problem can, due to limitations, only hint on the existence of sex differences in essential movement characteristics. Investigations on factors that determine performance in females are also lacking; frequently, performance determinants found in males were assumed to be identical in female players. Consequently, sex-specific training measures to improve technical movement characteristics in the volleyball spike jump are not common. The purpose of this dissertation was 1) to investigate sex-specific differences in movement characteristics, 2) to identify performance determinants in females, and 3) to implement and assess a specific technical training to enhance volleyball spike jump performance in female players. One female and one male team (n1=15, n2=15) competing in the highest Austrian division were recorded via 12 Vicon MX-13 (250 Hz) cameras, two AMTI force plates (2000 Hz), and surface electromyography (2000 Hz) in 5 lower limb muscles. They performed volleyball spike jumps striking a stationary ball and the data was assessed to identify sex differences and performance determinants in females. Based on these findings, a specific six-week training intervention was derived and implemented for female players (n=12). Kinematic and kinetic data were obtained during three measurement sessions with six weeks between the sessions to allow for a comparison between control and intervention phase. Significant (p<.05) sex differences were documented in approach, arm and torso usage, neuromuscular activation pattern, range of motion and acceleration distances, and the strategy to convert horizontal into vertical velocity. Correlation and regression analyses revealed that a majority of these variables affected jump height in females. A subsequent technical-coordinative training intervention that specifically focused on the relevant movement characteristics improved jump height by 11.9% during the competitive season. The intervention resulted in beneficial adaptations in all measured movement characteristics that were not strictly related to strength and power abilities. The sex differences corroborated that technical patterns identified on the basis of a sample that consists of males only cannot be assumed to be identical in females without any further investigation. The second study showed that several characteristics where differences have been found affected spike jump performance in female players. Therefore, they should not be ignored and, instead, addressed in specific training measures. The training intervention study reported positive effects of such approach. The training measure applied in this study showed to effectively enhance female spike jump performance at high level in a short amount of time. However, this training approach requires biomechanical understanding of performance determinants from the coach and specific adaptations to the target group.