Chronic Effects of a Static Stretching Program on Hamstring Strength.

Area of Science:

• Sports Medicine
• Exercise Physiology
• Biomechanics

Background:

• Hamstring injuries are common in athletes.
• Understanding the effects of stretching on hamstring function is crucial for injury prevention and rehabilitation.
• Static stretching is a widely used method to improve flexibility.

Purpose of the Study:

• To investigate the chronic effects of a 4-week static stretching program on hamstring isokinetic and isometric strength.
• To assess changes in passive stiffness and range of motion after a static stretching intervention.
• To determine the impact of static stretching on the angle of peak torque in knee flexors.

Main Methods:

• Thirty healthy men were randomized into a static stretching (SS) intervention group (n=15) or a control group (n=15).
• The SS group performed a 4-week hamstring stretching program.
• Measurements included passive stiffness, maximum pain-free knee angle, isometric and isokinetic (60°/s and 180°/s) peak torque, and angle of peak torque before and after the intervention.

Main Results:

• Passive stiffness of the hamstrings significantly decreased in the SS intervention group.
• No significant changes were observed in isometric or isokinetic peak torque at either speed.
• A significant increase in the peak extension angle at 60°/s was noted in the SS group.

Conclusions:

• Static stretching is effective in reducing musculotendinous unit stiffness of the hamstrings.
• Static stretching influences the angle of peak torque, which may be relevant for hamstring strain injury prevention.
• Static stretching does not appear to significantly alter peak torque production in healthy individuals.