Activity of upper limb muscles during human walking

Area of Science:

• Biomechanics
• Human locomotion
• Neuroscience

Background:

• Electromyography (EMG) studies of upper limb muscles during human gait are infrequent.
• Understanding arm swing's role in gait is crucial for biomechanical analysis.

Purpose of the Study:

• To investigate upper limb muscle EMG activity during different arm swing conditions in normal gait.
• To differentiate between passive and active components of arm swing.

Main Methods:

• EMG activity of upper limb muscles was recorded in 20 volunteers.
• Four walking conditions were tested: natural arm swing (Normal), holding arms still (Held), arms immobilized (Bound), and anti-normal arm swing (Anti-Normal).

Main Results:

• Normal arm swing showed weak, rhythmical contractions in arm and shoulder muscles.
• Holding arms still (Held) required phasic muscle activity, indicating a passive component.
• Even with immobilized arms (Bound), EMG signals persisted, suggesting an active, possibly centrally programmed, component.
• Anti-Normal gait exhibited greater EMG activity and was less economical than normal walking.

Conclusions:

• Normal human arm swing during gait comprises both passive and active muscular components.
• The active component of arm swing may be centrally programmed.
• Altered arm swing patterns (Anti-Normal) are more energetically costly.