Accuracy of force measurement via motion analysis system in artistic gymnastics

BACKGROUND: The aim of this study was to validate the accuracy of ground-reaction force measurement using inverse body dynamic analysis via video motion analysis system versus portable force-plate direct measurement system (i.e., gold standard model). METHODS: Six elite-level male gymnasts (age =23.70±1.94 years; height =1.66±0.06 m; body mass =58.67±8.24 kg) participated in this study. The concurrent kinematic and dynamic analysis of the ground-reaction forces during snap-down take-off to back somersault were performed in the acrobatic series (i.e., round-off flic-flac back somersault). RESULTS: The finding of the present study showed very good relative and absolute reliability of the motion analysis system outcomes (intraclass correlation coefficient [ICC] =0.953, typical error of measurement [TEM] =85.31 N, and TEM_(%) =1.17%). Further, the motion analysis device demonstrated good ability to detect small and meaningful performance change (TEM< smallest worthwhile change [SWC]). No statistically significant differences were observed when comparing the ground-reaction force outcome between repetitions and devices (P>0.05; d=0.048). Additionally, results showed a nearly perfect association between the two methods (r=0.965 and R²=93%). The mean (bias)±95% limits of agreement between the two measurement devices was 341.0±508.8 N. CONCLUSIONS: In conclusion, inverse body dynamic analysis could be a good alternative to force-plate device for coaches to evaluate ground-reaction force in male artistic gymnastics.