Intra- and inter-session reliability of countermovement jump and gait analysis in collegiate athletes measured using an inertial measurement unit (BTS G-Walk)

This study assessed the intra- and inter-session reliability of the inertial measurement unit (IMU) in measuring countermovement jump (CMJ) and 10m-walking gait-related outcomes. Thirty collegiate-level athletes (15 males age: 21.0 ± 2.5 years and 15 females age: 21.5 ± 2.1 years) were recruited to perform CMJs and 10m-walking test that were simultaneously recorded using the commercially available body-worn IMU – BTS G-walk. The coefficient of variation (CV), the analysis of variance with repeated measures (ANOVA), and the interclass correlation coefficient (ICC) were used for intra-session reliability. While the Pearson’s correlation coefficient (r) and the ICC were used to analyze inter-session reliability. Measurement of CMJ and 10m-walking test gait variables using the IMU resulted in moderate to excellent intra-session reliability for CMJ (ICC = 0.881 to 0.988) and gait analysis (ICC = 0.807 to 0.978) with acceptable CV (≤10%). Inter-session reliability for CMJ variables ranged from poor to excellent (ICC = 0.134 to 0.963), and 10-m walking test gait analysis variables were moderate to excellent (ICC = 0.683 to 0.931). The IMU (BTS G-walk) provides reliable data for most CMJ and gait variables. Future studies may determine the accuracy of the equipment to monitor changes over time (e.g., after a training intervention).