(56) NOVEL TRANSLATION OF COUNTERMOVEMENT JUMP FORCE-TIME CHARACTERISTICS: DYNAMIC FORCE, POWER, AND VELOCITY RATIOS

Purpose: The purpose of this study was to develop and examine the relationship between a novel method for evaluating SSC efficiency during the CMJ and IR. Methods: 78 NCAA Division-II athletes participated in this study as part of normal performance testing. Athletes from the university’s American football (n=15, wt. = 97.9±21.4), men’s basketball (n=13, wt.= 90.5±8.0), women’s basketball (n=12, wt.= 78.1±10.7), women’s golf (n=8, wt.= 66.6±8.8), women’s soccer (n=7, wt.= 65.4±7.0), and women’s volleyball (n=14, wt.=69.6±11.1) CMJ data were analyzed. Following a standardized dynamic warm-up, athletes performed 2-4 CMJ on a dual force plate system (1000 Hz sampling rate). The vertical ground reaction force of each CMJ was recorded. Descriptive statistics and Pearson’s r correlation coefficients were calculated to determine the relationship between dynamic force (avg. braking force/avg. propulsive force; Newtons), power (avg. braking power/avg. propulsive power; watts), and velocity (avg. braking velocity/avg. propulsive velocity; watts/kg) ratios, CMJ kinematic and kinetic variables, as well as the impulse ratio. The a priori alpha level was set at 0.05 for all analyses. Results: Moderate to strong significant correlations were observed between DFR and IR (r=0.374, p< 0.001), DPR and IR (r=-0.956, p< 0.001), and DVR and IR (r=-0.943, p< 0.001). Further significant relationships were observed between DFR (r=-0.395-0.506, p< 0.001), DPR (r=-0.643-0.485, p< 0.001), and DVR and CMJ kinematic variables (r=-0.665-0.809, p< 0.001). However, no significant relationships were observed between DFR, DPR, DVR, or IR and CMJ height (r= -0.183 – 0.133, p = 0.435-0.250). Additionally, averages for each ratio observed were as follows; DFR = -1:1.09 N, DPR = -1:2.00 W, and DVR = -1:1.72 m/s. Conclusions: Findings from this study provide evidence of a potential alternative to the IR that can be utilized to measure SSC efficiency, and translated into appropriate units for measures of force, power, and velocity. Practical Applications: When athletic performance is considered, understanding how one portion of a movement directly transfers to another can provide practitioners with insight into movement efficiency and can support training approaches to optimize athletic preparation and performance. Acknowledgements: This research investigation was funded by the Clara Wu and Joseph Tsai Foundation.