Validation of a commercially available inertial measurement unit for recording jump load in youth basketball players

A high incidence of overuse knee injuries among youth basketball players may be attributed to number of jumps. Wearable technology may be an effective tool for measuring jump load compared to traditional counting methods. The purpose of this study was to validate a commercially available jump counter (VERT® Classic) in youth basketball practices and games, and to identify the characteristics (i.e., height, direction, takeoff) of jumps recorded by the VERT® Classic. 46 (19F, 27M) youth basketball players wore a VERT® Classic and were recorded on video during games and practices. The number of jumps recorded by the VERT® Classic and evaluated by video raters were compared for each jump characteristic using intraclass correlation coefficient (ICC(3,k)), mean offset, and limits of agreement. The number and percent of VERT® Classic jumps and corresponding video jumps according to timestamp were reported. VERT® Classic jumps had excellent reliability with video-counted jumps over 15 cm (ICC(3,k) = 0.958), with a mean offset of −2.4 jumps (fewer VERT® Classic) and limits of agreement −12.6 to 7.8 jumps. Pairs of corresponding jumps represented 68.0% of total video jumps and 92.0% of VERT® Classic jumps. The VERT® Classic can provide an estimate of jump load in youth basketball.