Long-term static stretching can decrease muscle stiffness: A systematic review and meta-analysis.

Area of Science:

• Biomechanics
• Exercise Physiology

Background:

• Stretch training enhances joint range of motion, but underlying mechanisms remain unclear.
• Previous research indicated no change in passive muscle properties (stiffness) after long-term stretching.
• Recent studies suggest long-term static stretching may influence muscle stiffness.

Approach:

• A meta-analysis synthesized data from 10 studies published before December 28, 2022.
• Included studies focused on the long-term (≥2 weeks) effects of static stretching on muscle stiffness.
• Mixed-effect models, subgroup analyses (sex, stiffness assessment type), and meta-regression (stretching duration) were employed.

Key Points:

• Static stretching training for 3-12 weeks resulted in a moderate decrease in muscle stiffness.
• No significant differences in stiffness reduction were observed between sexes or stiffness assessment methods.
• Total stretching duration did not correlate significantly with changes in muscle stiffness.

Conclusions:

• Long-term static stretching effectively reduces muscle stiffness, contributing to increased joint range of motion.
• The findings provide evidence for a physiological adaptation mechanism underlying the benefits of static stretching.
• This meta-analysis clarifies the impact of static stretching on muscle passive properties.