Wheelchair propulsion fatigue thresholds in electromyographic and ventilatory testing

Area of Science:

• Biomechanics and Exercise Physiology
• Rehabilitation Engineering

Background:

• Understanding physiological responses during manual wheelchair propulsion is crucial for optimizing performance and preventing fatigue.
• Muscular fatigue significantly impacts the efficiency and sustainability of wheelchair use.

Purpose of the Study:

• To detect electromyographic (EMG) and ventilatory fatigue thresholds during a single wheelchair incremental test.
• To examine the relationship between EMG threshold (EMGT) and ventilatory threshold (VT).
• To identify differences in EMGT between propulsive and recovery muscle synergies.

Main Methods:

• A qualitative study involving ten wheelchair users (seven males, three females) in a biomechanics laboratory.
• Recorded oxygen uptake and EMG signals during an incremental wheelchair ergometer test.
• Utilized the V-slope method for VT identification and bisegmental linear regression for EMGT determination in eight key upper limb muscles.

Main Results:

• Successfully determined EMGT and VT from a single incremental test for all participants.
• Demonstrated good agreement between EMGT and VT.
• Observed high similarity (ICC=0.91) in EMGT between propulsive and recovery muscles.

Conclusions:

• The EMG fatigue threshold method is a valid and reliable tool for detecting muscle fatigue during wheelchair propulsion.
• This method can form the basis for automated muscle fatigue detection and prediction in wearable technologies for wheelchair users.