(40) VALIDITY AND RELIABILITY OF A NOVEL INERTIAL MEASUREMENT UNIT FOR ASSESSING VERTICAL JUMP PERFORMANCE

Purpose: This study aimed to evaluate the validity and reliability of a novel inertial measurement unit (IMU) device for assessing countermovement jump (CMJ) performance metrics, using a force plate as the criterion measure. Methods: Fifty NCAA Division-III collegiate athletes (178.64±13.21 cm; 75.79±15.03 kg) from basketball, golf, acrobatics and tumbling teams volunteered to participate in this study. Before testing, all athletes completed a warm-up protocol consisting of dynamic stretching exercises. The IMU (Model V2.0, V2.27.0; Output Sports, Dublin, Ireland) sampling at 500 Hz, was secured over the midfoot using a Velcro strap to minimize movement. Each athlete performed two CMJs on a uni-axial force plate system (M1531; Hawkin Dynamics, MA, USA) sampling at 1000 Hz, with a 30-second rest interval between trials. Athletes were instructed to descend to approximately 90° knee flexion and "jump as high as possible" while keeping their hands on their hips during the entire movement. The second jump trial was used for analysis. Jump height (JH), flight time (FT), and take-off velocity (TOV) were selected as variables of interest. Independent samples t-tests with Cohen’s d effect sizes were used to assess between-device differences, while Pearson correlation coefficients (r) and intraclass correlation coefficients (ICC) determined the measurement agreement between the IMU device and force plates (p< 0.05). Results: No significant differences were found between the IMU and force plates for JH (p=0.810, d=0.041), FT (p=0.465, d=0.148), or TOV (p=0.815, d=0.048), while strong ICC and correlation (r) values were observed (Table 1). Conclusions: The IMU device demonstrated high validity and reliability for measuring JH, FT, and TOV in during CMJ in this specific cohort of athletes. Practical Applications: Considering that the CMJ is a widely used assessment tool in strength and conditioning, these findings support the use of this IMU device as a low-cost, portable, user-friendly alternatives to force plates for field-based jump performance monitoring. Acknowledgements: None