Slow Expiration Reduces External Oblique Muscle Activity during Maximum Trunk Flexion

Area of Science:

• Biomechanics
• Exercise Physiology
• Human Movement Science

Background:

• Abdominal muscle activation is crucial for trunk stability and movement.
• Understanding how breathing patterns influence muscle activity during exercise is important for optimizing training and rehabilitation.

Purpose of the Study:

• To investigate the impact of slow expiration on abdominal muscle activity.
• To compare muscle activation during trunk flexion with and without breath holding.

Main Methods:

• Electromyography (EMG) was used to measure the activity of rectus abdominis, external oblique, and internal oblique muscles.
• Twenty-one healthy university students participated in maximal trunk flexion tests under two conditions: breath holding and slow expiration.
• Paired t-tests were employed to analyze the differences in muscle activity.

Main Results:

• A significant reduction in electromyography (EMG) activity was observed in the external oblique muscle during maximal trunk flexion with slow expiration compared to breath holding.
• No significant differences were found in the rectus abdominis or internal oblique muscles between the two conditions.

Conclusions:

• Slow expiration effectively decreases external oblique muscle activity during maximal trunk flexion in healthy young adults.
• These findings suggest that controlled exhalation can modulate core muscle recruitment during dynamic movements.