Muscle activity during maximal isometric forearm rotation using a power grip

Area of Science:

• Biomechanics
• Human anatomy
• Exercise physiology

Background:

• Forearm rotation is crucial for daily activities.
• Understanding muscle activation patterns during forearm rotation is essential for diagnosing and treating injuries.

Purpose of the Study:

• To quantify the electromyographic (EMG) activation of 15 forearm muscles during pronation and supination with a power grip.
• To identify muscles with significant activation during specific forearm rotation efforts.

Main Methods:

• EMG data collected from 15 forearm muscles in 11 subjects.
• Subjects performed maximal isometric pronation and supination efforts.
• Data gathered across nine forearm rotation positions.

Main Results:

• Biceps brachii showed significantly higher activation during supination (52.1%) than pronation (5.1%).
• Brachioradialis, flexor carpi radialis, palmaris longus, pronator quadratus, and pronator teres were more active during pronation.
• Abductor pollicis longus was more active during supination.

Conclusions:

• Forearm rotation involves significant activation of multiple muscles beyond primary rotators.
• Accurate biomechanical models of forearm rotation require considering a broader range of muscles.
• This data can improve treatments for forearm fractures, muscle dysfunction, and joint replacements.