Responses to static stretching are dependent on stretch intensity and duration

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Limited research exists on how static stretching intensity impacts joint torque-angle responses.
• Understanding these effects is crucial for optimizing stretching protocols for flexibility and performance.

Purpose of the Study:

• To investigate the effects of different static stretching intensities and durations on the passive knee extension torque-angle response.
• To compare outcomes such as joint angle, passive torque, stress relaxation, and perceived intensity across various stretching protocols.

Main Methods:

• Seventeen male participants underwent three static stretching protocols (P50, P75, P100) based on maximal tolerable torque.
• Protocols varied in intensity and duration (90-180s per stretch, 30s rest).
• Measurements included passive torque, joint angle, electromyography, and visual analogue scale scores.

Main Results:

• Only the highest intensity protocol (P100) significantly increased knee extension angle and peak passive torque.
• Lower intensities (P50, P75) did not improve these outcomes despite longer durations.
• Higher intensity stretching (P100) was more effective for increasing range of motion, while longer duration (P50) led to greater passive torque decrease.

Conclusions:

• Higher static stretching intensity is key for maximizing joint range of motion.
• Increased stretch duration is more effective for reducing passive torque and improving flexibility.
• Stretching intensity perception is primarily linked to joint angle changes rather than passive torque.