The Reliability and Consistency of Instrumented Shoes During Vertical Jumping

Abstract

Vertical jump height is an important measure of lower extremity power. Collection of this information during athletic practices can be difficult. As a result high technology solutions have been developed to allow for real-time data collection and feedback. However, the reliability and validity of these testing solutions need to be established. PURPOSE: To compare the between day reliability of single leg vertical jump (SLVJ) and bilateral vertical jump (BVJ) heights when measured using motion capture and instrumented shoes, and to determine the correlation between these two measures. METHODS: 20 physically active adults performed both unilateral and bilateral jumps. During the jumps each subject wore a pair of instrumented shoes that synced with a Training application to determine jump height. Two sacral markers were tracked with an 8 camera motion capture system to determine jump height. This assessment was repeated within 2-4 days. An average of 7 BVJ trials and 5 SLVJ trials were analyzed. Intraclass correlation coefficients (ICC) were calculated to examine consistency of the BVJ and SLVJ values across days for the different systems (instrumented shoes, motion capture). Correlation coefficients were calculated to compare the values between systems during the BVJ and SLVJ trials. Finally, the consistency of data collection was examined for the instrumented shoe system. RESULTS: The instrumented shoes had high between day reliability for all jump types (BVJ = 0.97, Right SLVJ = 0.93, Left SLVJ = 0.97) as did the motion capture assessment (BVJ = 0.91, Right SLVJ = 0.91, and Left SLVJ = 0.93). Correlation coefficients between the instrumented shoe and motion capture were also high, with the bilateral jump (r = 0.89-0.95) being more highly correlated when compared with the unilateral jumps (r = 0.74-0.89). The instrumented shoe consistently collected the BVJ trials (99%), however the consistency was noticeably lower during the SLVJ trials (46-51%). CONCLUSIONS: The findings from this study provide evidence that SLVJ and BVJ measures as collected with instrumented shoes are reliable across days and are correlated with motion capture jump height. Therefore, the shoes can provide a reliable and valid measure of field based vertical jump testing however data was only consistently captured during the bilateral jumping tasks.