Influence of Sex on the Recovery Response Following Isometric Exercise Performed at Long Muscle Length

Area of Science:

• Sports Science
• Exercise Physiology
• Muscle Physiology

Background:

• Understanding sex-based differences in muscle recovery is crucial for optimizing training and rehabilitation protocols.
• Isometric exercise at long muscle length (LML) is a common training modality, but its differential effects on men and women require further investigation.

Purpose of the Study:

• To compare the recovery responses of the pectoralis major muscle between men and women after high-intensity isometric exercise at LML.
• To investigate potential sex differences in muscle strength, architecture, soreness, and power output post-exercise.

Main Methods:

• Twelve men and 10 women performed intermittent isometric exercise targeting the pectoralis major at LML.
• Measurements included peak force, muscle thickness, echo intensity, muscle soreness, and average power via the bench throw power test.
• Assessments were conducted pre-exercise and at 15 minutes, 24 hours, and 48 hours post-exercise.

Main Results:

• Men were significantly stronger than women, but no sex differences were found in recovery of peak force, muscle architecture, soreness, or perceived exertion.
• A significantly greater drop in average power was observed in men compared to women 15 minutes post-exercise (p < 0.001, d = 2.36).
• Similar recovery patterns were noted for most variables, indicating comparable muscle healing processes.

Conclusions:

• While muscle strength and recovery patterns are similar, men may experience more acute fatigue and power reduction after isometric exercise at LML.
• These findings suggest sex-related differences in the immediate impact of isometric exercise on power exertion, highlighting potential sensitivity to acute fatigue in men.