Decrements in stiffness are restored within 10 min

Area of Science:

• Biomechanics
• Sports Medicine
• Physiology

Background:

• Muscle-tendon unit (MTU) stiffness influences joint range of motion and performance.
• Understanding the temporal effects of stretching on MTU properties is crucial for optimizing training and rehabilitation.

Purpose of the Study:

• To investigate the time course of changes in muscle-tendon unit stiffness following static stretching.
• To determine how long the effects of stretching on stiffness and range of motion persist.

Main Methods:

• 11 male participants underwent passive dorsiflexion tests using ultrasonography and an isokinetic dynamometer.
• Measurements were taken before and at intervals (immediately, 5, 10, 15 min) after a 5-minute static stretching protocol.
• Myotendinous junction displacement and passive torque were assessed to quantify stiffness and range of motion.

Main Results:

• Static stretching significantly increased range of motion and passive torque at the end range.
• Muscle-tendon unit stiffness significantly decreased immediately and 5 minutes post-stretching.
• Stiffness returned to baseline levels within 10 minutes, while increased range of motion persisted for over 30 minutes.

Conclusions:

• Static stretching provides a transient decrease in muscle-tendon unit stiffness.
• The observed increase in range of motion is longer-lasting than the reduction in stiffness.
• These findings have implications for the timing of stretching in athletic and therapeutic contexts.