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Published on: February 20, 2020
Shoulder muscle activation and fatigue during a controlled forceful hand grip task
O Alizadehkhaiyat1, A C Fisher, G J Kemp
1Musculoskeletal Science Research Group, Institute of Translational Medicine, University of Liverpool, Liverpool, UK. omid@liv.ac.uk
Summary
A novel hand grip task effectively activates rotator cuff muscles, offering a reliable method for shoulder muscle assessment. This technique bypasses movement limitations, aiding in the evaluation and rehabilitation of shoulder conditions.
Area of Science:
- Biomedical Engineering
- Kinesiology
- Orthopedics
Background:
- Shoulder electromyography is challenging due to pain and limited movement.
- Accurate assessment of rotator cuff muscles is crucial for diagnosing and managing shoulder conditions.
Purpose of the Study:
- To investigate a hand grip task for assessing shoulder muscle activation.
- To evaluate the reliability of this task in healthy individuals.
Main Methods:
- Electromyography (EMG) of supraspinatus and infraspinatus muscles in 16 healthy adults.
- Fine-wire electrodes used during a standardized hand grip task at 50% maximum voluntary contraction.
- Analysis of muscle activity and fatigue using root mean square amplitude and median frequency slopes.
Main Results:
- Significant increase in muscle activity (positive amplitude slope) for both supraspinatus and infraspinatus muscles (p<0.01).
- No significant signs of muscle fatigue were detected during the task (median frequency slope).
Conclusions:
- A standardized hand grip task in a neutral position successfully activates key rotator cuff muscles.
- This method may overcome challenges associated with pain-limited shoulder movement in EMG assessments.
- Potential application in developing and monitoring shoulder rehabilitation strategies.
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