(10) CHANGES IN COUNTERMOVEMENT JUMP FORCE-TIME CURVE CHARACTERISTICS IN DIVISION III MALE BASKETBALL PLAYERS: A SEASONAL MONITORING STUDY

Purpose: This study investigated the impact of the training season on countermovement jump (CMJ) force-time characteristics. Methods: 12 NCAA Division III male basketball players (age: 20.8 ± 1.1 years, height: 185.1 ± 6.1 cm, weight: 84.5 ± 7.4 kg) completed CMJ testing during the offseason, pre-season, and competitive season (non-conference and conference) as part of a long-term athlete monitoring program. The subjects followed a standard warm-up procedure throughout the study and performed two maximal effort CMJ trials. Each CMJ was performed with a PVC pipe on their shoulders to remove the influence of an arm swing movement during the jumps. Jump trials were separated by 30-second rest intervals and the subjects were cued to perform each jump as fast and high as possible. CMJ testing was performed using a wireless uniaxial dual force plate system and the force-time data were used to calculate jump height (JH), modified reactive strength index (RSImod), relative peak power (PP), average rate of force development during the braking phase (B-RFD), braking peak force (B-PF), propulsion mean force (P-MF), propulsion duration (P-D), time to take-off (TTT), and countermovement (CM) depth. Testing was separated into four phases and included the following number of testing sessions within the analysis: off-season (n=4), pre-season (n=5), non-conference season (n=2), and conference season (n=1). A series of one-way repeated measures ANOVA with Bonferroni post hoc tests were utilized to compare the differences in CMJ performance variables between different phases. In addition, Hedge’s g effect sizes were calculated to examine the magnitude of the differences between phases. Results: There was a significant difference across seasons for JH (p=0.002), PP (p< 0.001), B-PF (p< 0.001), P-MF (p< 0.001), P-D (p< 0.001), and CM depth (p< 0.001), but not for RSImod (p=0.455), B-RFD (p=0.077), or TTT (p=0.098). Descriptive data of each performance variable and post hoc analyses are displayed in Table 1. Conclusions: Although there was a significant increase in JH from the off-season to pre-season, these values returned to baseline during the non-conference season. In addition, there was a significant decrease in PP, B-PF, and P-MF from the off-season and pre-season to non-conference season. Further, there were small and small-moderate increases in P-D and CM depth during the phases following the off-season, respectively. However, there were no significant or meaningful changes in RSImod, B-RFD, or TTT across different phases of the year. Practical Applications: JH, PP, B-PF, and P-MF may be utilized to evaluate fatigue or adaptation across of Division III male basketball players across different phases across the training year; however, it is important that strength and conditioning practitioners consider the individual magnitude of changes in performance as well. Acknowledgements: None