(35) RELATIONSHIPS BETWEEN MODIFIED REACTIVE STRENGTH INDEX AND SPRINT PERFORMANCE IN MALE NCAA DIVISION III SOCCER PLAYERS

Purpose: The purpose of this study was to examine the relationships between countermovement jump (CMJ) modified reactive strength index (RSImod) and sprint performance in National Collegiate Athletic Association (NCAA) Division III collegiate male soccer players.

Methods: 41 NCAA Division III male soccer players (age: 19.0 ± 1.1 years, height: 178.4 ± 6.7 cm, weight: 72.7 ± 8.7 kg) completed CMJ and sprint testing as part of a long-term athlete monitoring program. Following a standardized warm-up, athletes performed two maximal effort CMJ on force plates. Force-time data were used to determine jump height (JH) and time to takeoff (TTT). RSImod was then calculated as the ratio between JH and TTT. Following CMJ testing, the subjects performed two maximal effort 20m sprints on an indoor track from a staggered start. Sprint times were recorded at 10- and 20m using laser timing gates. The average CMJ and sprint performances were used for correlational analyses. Pearson correlation coefficients (r) and coefficients of determination (R²) were used to examine the relationships between RSImod, JH, TTT, and sprint performance. Results: The relationships between the CMJ variables and sprint times are shown in Table 1. Mean and standard deviations are as follows: RSImod = 0.46 ± 0.11, JH = 0.36 ± 0.05 m, TTT = 0.80 ± 0.14 s, 0-10m time = 1.73 ± 0.07 s, 10-20m time = 1.28 ± 0.07 s. All relationships were statistically significant (p < 0.05) except for the relationships between TTT and both sprint times (p > 0.05). There were moderate relationships between RSImod and JH with 0-10m sprint time with 13.7% and 22.8% of the variance being explained, respectively. In contrast, there was a trivial relationship between TTT and 0-10m time with only 2.9% of the variance being explained. In addition, there were small, moderate, and trivial relationships between RSImod, JH, and TTT and 10-20m sprint time, respectively. In addition, RSImod, JH, and TTT explained 6.6%, 13.5%, and 0.2% of the variance in 10-20m time, respectively. Conclusions: Small to moderate relationships were found between RSImod and JH and the 0-10m and 10-20 m sprint times in NCAA Division III male soccer players. JH explained the largest portion of the sprint time variance, although only a small portion was explained. Practical Applications: It is known that both jumping and sprinting are key performance indicators to soccer players, suggesting that these characteristics should be monitored. However, the current results suggest that the performances of each may not largely related to each other. Therefore, it is important that strength and conditioning practitioners continue to develop both the jumping and sprinting abilities of soccer players to maximize the performance of each. Future research may consider examining the relationships between the current variables with other performance characteristics in collegiate soccer players.
 

 

Acknowledgements: None