How to Prevent a Pulled Hamstring

Avoid hamstring injuries with two simple tests.

You're sprinting like you normally do in a game, practice or workout. You reach your top speed, and suddenly you feel like someone stabbed you in the back of your thigh.

And you immediately know what's wrong: A dreaded pull hamstring.

A pulled hamstring is one of the most common muscular injuries in sports. The injury often occurs when sprinting at full speed. The hamstring is responsible for decelerating the lower leg as it swings forward during your stride, and sometimes the muscle can't handle that stress and is injured—there are other mechanisms of injury as well.

Usually, an injury occurs because the hamstring is weak, lacks flexibility or is overused, which can be caused by simply doing too much or if the hamstring muscle is compensating for another dysfunctional area in the body. According to Dr. Matt Stevens, physical therapist and owner of Pure Physio (Strongsville, Ohio), an injury is particularly common when there's either a strength or flexibility imbalance between the left and right hamstring.

"Often, with some of our athletes I'm more concerned about asymmetry from right to leg than overall flexibility," explains Stevens. "Flexibility requirements are going to vary depending on sport and activity. So a runner may require less flexibility than a gymnast."

So before doing anything to prevent a dreaded hamstring injury, you need to assess your current hamstring health. Stevens provides the two tests below to accomplish just that.

Leg Raise Test

This tests flexibility asymmetries between your left and right hamstring.

how to prevent a pulled hamstring

How to: Flex the quad or your left leg, straighten your knee and pull your toes toward your ankles. Keeping your right leg straight and on the ground, lift your left leg up as high as flexibility allows. Measure the distance from the heel to the ground, but you can also do an eye test if you don't have a measuring stick or tape measure. Repeat with your opposite leg and compare the results.

You fail if there's a 20-percent difference in flexibility between your legs.

The Fix: You need to prioritize hamstring flexibility exercises in your workouts.

Single-Leg Bridge

This tests for strength asymmetries between your left and right hamstrings.

how to prevent a pulled hamstring

How to: Lie down, bend your knees and plant your heels on the ground hip-width apart and about a foot away from your butt so your shins are at a 45-degree angle. Lift your right leg into the air and keep your knee straight. Drive your hips up until you form a straight line with your body from your shoulders to your knees. Lower with control and repeat, continuing until you can't perform any more reps. Note the number of reps and repeat on the other side.

You fail if you there's a 20-percent strength difference between your legs, but any strength difference should be addressed.

The fix: Prioritize hamstring strength exercises, especially single-leg exercises that target the hamstrings. Here are some of the best moves to choose from.

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