Forearm extensor and flexor muscle exertion during simulated gripping work -- an electromyographic study

Area of Science:

• Occupational Health
• Biomechanics
• Ergonomics

Background:

• Gripping tasks activate both forearm flexor and extensor muscles.
• Previous research lacks systematic quantitative assessment of muscular exertion during gripping.
• Understanding forearm muscle fatigue is crucial for preventing work-related disorders.

Purpose of the Study:

• To investigate forearm muscular exertion during intermittent gripping at varying work/rest cycles.
• To quantitatively assess forearm muscle fatigue in vocational gripping scenarios.
• To compare fatigue development between forearm extensors and flexors.

Main Methods:

• Electromyography (EMG) was used to measure activity in five forearm muscles (three extensors, two flexors).
• Intermittent gripping tasks were performed at 25% maximal voluntary contraction (MVC).
• Work/rest cycles of 10/10s, 20/10s, and 30/10s were analyzed using zero crossing rate for fatigue detection.

Main Results:

• Significant fatigue signs were observed in at least two extensor muscles across all tested regimes (P < 0.05).
• Significant flexor muscle fatigue was only evident at the 30/10s work/rest regime.
• Fatigue effects were consistently more pronounced in the extensor muscles.

Conclusions:

• Forearm extensor muscles exhibit greater susceptibility to fatigue during intermittent gripping compared to flexors.
• The tested work/rest regimes (10/10s, 20/10s, 30/10s) are not ergonomically acceptable due to significant EMG-detected fatigue.
• Systematic assessment of forearm extensor fatigue is vital for understanding and mitigating forearm disorders related to muscular exertion.