Effects of Static Hamstring Stretching on Maximal Sprint Speed and Relationship With Nordic Hamstring Strength

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Static stretching is commonly used by athletes before exercise.
• The acute effects of static stretching on sprint performance and injury risk are debated.
• Understanding hamstring muscle behavior during sprinting is crucial for injury prevention.

Purpose of the Study:

• To investigate the acute effects of static hamstring stretching on maximal sprint speed.
• To analyze changes in spatiotemporal variables and lower-limb kinematics during the late swing phase of sprinting.
• To examine the relationship between these effects and Nordic hamstring strength.

Main Methods:

• Within-participant experimental design with 16 male college sprinters.
• Counterbalanced sprint trials: with and without 4x30s static hamstring stretching per leg.
• Measurement of maximal sprint speed, spatiotemporal variables, lower-limb kinematics, and Nordic hamstring peak torque.

Main Results:

• Static stretching significantly increased touchdown distance (p = .036).
• Maximal sprint speed showed a non-significant decrease (p = .086) post-stretching.
• Theoretical hamstring length at touchdown increased (p = .069) post-stretching.
• Lower Nordic hamstring strength correlated with a greater decrease in sprint speed.

Conclusions:

• Pre-sprint static hamstring stretching may increase hamstring strain injury risk by altering late swing phase kinematics.
• Athletes with lower hamstring strength may experience more pronounced negative effects on sprint speed.
• Enhancing Nordic hamstring strength could potentially reduce the adverse impacts of static stretching on sprint performance.