Passive stretching decreases muscle efficiency in balance tasks

Area of Science:

• Biomechanics
• Exercise Physiology
• Neuromuscular Control

Background:

• Passive static stretching is commonly used to increase flexibility.
• Its effects on balance control and muscle efficiency remain debated.
• Understanding these effects is crucial for optimizing training and rehabilitation protocols.

Purpose of the Study:

• To investigate the impact of passive static stretching on balance control.
• To assess changes in muscle activation and efficiency following stretching.
• To determine the duration of these effects.

Main Methods:

• Thirty-eight participants underwent passive static stretching or a control session.
• Balance control was evaluated using center of pressure (CoP) measures under various conditions.
• Muscle activation (sEMG RMS) and range of motion (ROM) were recorded.

Main Results:

• Passive static stretching increased ROM but decreased maximum voluntary contraction (MVC) and sEMG RMS during MVC.
• CoP sway speed decreased, but sway area and perimeter remained unchanged.
• sEMG RMS during balance tests increased, indicating reduced muscle efficiency.
• Effects returned to baseline within 30 minutes.

Conclusions:

• Passive static stretching does not impair overall balance control ability.
• It may reduce muscle efficiency, necessitating increased muscle activation to maintain balance.
• These effects are transient, recovering within 30 minutes post-stretching.