Hamstrings

Back of the thigh

Your hamstrings are a group of three muscles on the back of your thigh. They run from the bottom of your pelvis, across the back of your knee, to the top of your lower leg.

What they do

They bend your knee and pull your leg back. When you sprint, they work hard while they're stretched and loaded, as your back leg pushes off.

What is a strain?

A strain, or pulled muscle, is when muscle fibers get stretched too far or torn. It can be mild or serious.

Sprinting is the big one

Hamstring strains happen a lot in sports with sprinting, like track, soccer, football, and basketball. They usually happen during a fast sprint.

Myth or fact?

• Hamstring strains happen more often late in a game, when players are tired. Fact. Tired muscles can't absorb as much force. Studies of soccer players find more hamstring strains near the end of each half.
• Jumping straight into full-speed sprints without warming up is fine if you're young. Myth. Cold muscles are more likely to get hurt, and teens who are still growing are actually at higher risk for hamstring strains. Warm up and build up to full speed.

Nordic hamstring curls

Kneel with a partner holding your ankles. Keep your body straight and lower yourself forward as slowly as you can, then catch yourself with your hands.

Studies of soccer players show this exercise can cut hamstring injuries by about half or more. Learn it from a coach first.

More ways to build them

Hip bridges, hamstring curls, and lying-down leg lifts also train your hamstrings. Building up your sprinting in practice may help too.

Myth or fact?

• Nordic hamstring curls have been shown to lower hamstring injuries. Fact. In studies of soccer players, teams that did them had 50 to 70% fewer hamstring injuries.

What it feels like

A pulled hamstring usually feels like a sudden sharp pain in the back of the thigh while sprinting. Some people feel a pop. A bruise can show up over the next few days.

Myth or fact?

• Once a pulled hamstring stops hurting when you walk, you're ready to sprint in a game. Myth. Most repeat hamstring strains happen within two months of the first one, so finishing rehab matters. Wait for your doctor's OK and build back up step by step.