Sex Differences In Relative Force And Power Development During A Countermovement Jump

Abstract

Research has shown that the measurement of countermovement jumps may relate to sport performance and injury. Certain measurements of force production and power output can additionally inform the athlete and coaches of deficiencies in strength and velocity. These measurements can help inform players and coaches of specific training modalities that may lead to improvements in these measurements. Among elite level athletes, biological males often produce more force and power during a counter movement jump, than biological females due to differences in lean body mass and overall body fat percentage. PURPOSE: The purpose of this study was to compare normalization methods of force and power production during a counter movement jump in college basketball players. METHODS: 15 Division 1 basketball players participated in the study (7 females, 20.8 ± 2.2 yrs, 1.79 ± 0.09 m., 84.7 ± 12.9 kg; 8 males, 21.5 ± 1.2 yrs, 1.94 ± 0.09 m., 91.5 ± 11.3 kg). Participants performed a warmup consisting of 5 minutes of stationary cycling and dynamic stretching. Participants then performed three countermovement jumps on two force plates (Bertec Inc.) while data was collected and analyzed using Noraxon MR:16 software. Body composition was assessed using air displacement plethysmography (Bod Pod, Cosmed). RESULTS: Biological males (11.5 ± 4.4 %) had reduced body fat percentage compared to biological females (25.6 ± 4.4%, p < 0.001). Biological males jumped 11.8 cm higher (46.2 ± 4.1 cm) than biological females (34.3 ± 71 cm, p = 0.001). When normalized to body mass, concentric power (33%, p < 0.001) and concentric force (11%, p = 0.03) were higher in biological males compared to biological females. When normalized to lean body mass, there were no significant differences in concentric power or concentric force between males and females. When concentric peak force was normalized to only lean body mass, biological females showed a nonsignificant increase of 6% (p = 0.19) compared to biological males. CONCLUSION: Jumping power and force differences were reduced between biological males and females when normalized to lean body mass, likely due to the increase in body fat percentage in biological females. These data suggest that care should be taken when considering methods of normalization for gender comparisons of jumping power and force.