Effects of Static and Dynamic Stretching on Hamstring Strength and Stiffness

What’s This Research About?

This study looked at how combining static (holding a stretch) and dynamic (moving through a stretch) stretching for 30 seconds affects the stiffness and strength of hamstring muscles. The researchers tested stretches of different intensities and speeds on 13 healthy people. 

Before sports or exercise, people often do short stretches, either holding a position (static) for 20 to 30 seconds or moving through stretches (dynamic), hoping to make their muscles and tendons (the muscle-tendon unit or MTU) less stiff and stronger. 

Studies have found that if the MTU is too stiff, it can lead to injuries because the muscles and tendons don’t absorb shock well. Yet, short stretches of about 20 or 30 seconds don’t help make the hamstrings less stiff. More intense or longer static stretches are needed. However, stretching too long can make muscles weaker, mostly because it makes them less active, rather than changing the stiffness. 

To improve warm-ups, researchers are looking at combining static, and dynamic stretches to both reduce MTU stiffness and increase muscle strength. These researchers thought that doing intense static stretches followed by fast dynamic stretches might be a good way to achieve both goals.