The U.S. Paralympics Research and Sport Science Consortium (PRSSC) identified electromyography (EMG) analysis of wheelchair sport performance to be a major research need. The reasoning is that EMG analysis can be used to design evidence-based training programs through the understanding of sport-specific fatigue; however, the equipment may not always be feasible in sport-specific settings. Accelerometry is an alternative for examining fatigue in wheelchair sport that may be more practical in sport-specific settings.
PURPOSE: The purpose of this study was to compare the relationship between EMG fatigue measures and accelerometry counts among wheelchair push and recovery muscles during wheelchair rugby training.
METHODS: Wheelchair rugby players were recruited from a U.S. Olympic & Paralympic Training Site (Lakeshore Foundation, AL). Three national team wheelchair rugby players completed 5 training sessions (3 hours each) over 2 days. A 16-channel EMG system was used to assess EMG data of the pectoralis major (PM), anterior deltoid (AD), and posterior deltoid (PD). In addition, an accelerometer monitor was placed on each player’s dominant forearm. To assess fatigue, changes in EMG median frequency and mean amplitude across each training session and each training day were examined and correlated with the sum vectors of acceleration.
RESULTS: EMG data indicated general fatigue, upwards of 20%, was seen in all muscle groups, and there was a significant decrease of acceleration during this time. There was a strong correlation (p<0.05) between acceleration and fatigue in both the AD and PM (r = 0.63 and 0.64, respectively) but not in PD (r = 0.40).
CONCLUSIONS: There was a strong, positive relationship between EMG-detected fatigue and accelerometer scores in shoulder flexor muscles, namely pectoralis major and anterior deltoid. These findings lend support that accelerometer data is an alternative to investigating sport-specific fatigue in this athletic group and is less intrusive than EMG.