Brachialis muscle activity can be assessed with surface electromyography
Didier Staudenmann1, Wolfgang Taube1
1Movement and Sport Science, Department of Medicine, Faculty of Science, University of Fribourg, 1700 Fribourg, Switzerland.
Summary
Surface electromyography (EMG) can effectively measure brachialis muscle (BR) activity. This method distinguishes BR from biceps brachii (BB) during combined elbow flexion and forearm supination, enabling independent assessment.
Area of Science:
- Biomechanics
- Neuroscience
- Sports Medicine
Background:
- The brachialis muscle (BR) is a key elbow flexor.
- Intramuscular electromyography (EMG) is the primary method for measuring BR activity.
- Assessing BR activity non-invasively with surface EMG is desirable.
Purpose of the Study:
- To investigate if surface EMG can measure brachialis muscle (BR) activity independently of the biceps brachii (BB).
- To differentiate the contributions of BR and BB during specific isometric contractions.
Main Methods:
- Eight subjects performed isometric elbow flexion and elbow flexion with forearm supination.
- Surface EMG was recorded from the brachialis (BR), biceps brachii (BB), and brachioradialis (BRR).
- Correlation coefficients between EMG amplitudes and force/torque were analyzed.
Main Results:
- During pure elbow flexion, BR, BB, and BRR activities correlated similarly with flexion force (r = 0.96 ± 0.02).
- During flexion with supination, BR activity showed a distinct pattern from BB.
- BR activity correlated better with flexion force (14% higher) and less with supination torque (40-64% lower) compared to BB.
Conclusions:
- Surface EMG can assess brachialis muscle (BR) activity distinctly from the biceps brachii (BB).
- This non-invasive method is viable for measuring BR contributions during specific movements like combined elbow flexion and supination.
