PURPOSE: The Paralympic Research and Sport Science Consortium (PRSSC) has identified electromyography (EMG) analysis of wheelchair sport performance to be a major research need. EMG analysis can be used to design evidence-based training programs through the understanding of sport-specific fatigue.The purpose of the current study was to document fatigue and associated compensation among push and recovery muscles during a Paralympic Rugby training camp.
METHODS: Wheelchair rugby players were recruited from a Paralympic training facility (Lakeshore Foundation, Birmingham, AL, USA). Three national team wheelchair rugby players completed 5 training sessions (3 hours each) over 2 training days. A 16-channel Noraxon EMG system 1400A (Scottsdale, AZ) with telemetry (Telemyo DTS) was used to assess EMG data of the pectoralis major (PM), anterior deltoid (AD), posterior deltoid (PD), upper trapezius (UT), biceps (B), triceps (T), and latissimus dorsi (LD). To assess fatigue, changes in EMG median frequency and mean amplitude across each training session and each training day were examined. IRB approval and informed consent were obtained prior to the study.
RESULTS: Fatigue of the PM was most substantial, approaching 30% within an hour of training activity. A 25% fatigue of the AD was also present during the first training session. Some fatigue was demonstrated in BB and T during the first training session (<8%) but these muscles recovered over a training day and generated greater force production over additional training sessions. Increased force production was demonstrated in the UT throughout a training day to compensate for shoulder flexor fatigue. Function of the PD and LD were varied across participants.
CONCLUSIONS: In the current study, Paralympic rugby athletes demonstrated fatigue in shoulder flexors, namely pectoralis major and anterior deltoid. Fatigue was demonstrated within the first training session of a prolonged training camp and was typically present across a training day. Whereas shoulder joint muscles fatigued, the elbow joint muscles demonstrated recovery and ultimately increased force output across a training day to compensate. This finding is typical in wheelchair users as force production moves from the shoulder joint to elbow and wrist joints when the prime movers become fatigued.