As a runner, you’ve probably thought about your hamstrings before—or at least felt them during or after a run.

Technically, the hamstrings consist of three muscles—the biceps femoris, semimembranosus, and the semitendinosus—which sit at the back of the upper leg. They originate at the ischial tuberosity (also known as your sit bones or the part of the pelvis you feel when you sit down) and run along the back of the leg until they connect with bone just below the knee.

When you run, your hamstrings work to extend your hips and flex your knees. Picture your gait as you push off the ground and the strength and power you need for that hip extension and knee bend during the leg swing—that’s why you need healthy hamstrings. In fact, a systematic review published in BMC Musculoskeletal Disorders, says running hamstring injuries (which typically occur at high speeds) likely happen in the late swing phase of your gait as your hamstring takes on the load.

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If you’ve experienced aches on the back of the legs postrun, you might wonder whether it’s something serious or your typical soreness. Because hamstring strains are common in runners, and chronic hamstring tightness can easily arise in people who spend a lot of time in their chairs, we break down everything you need to know about sore hamstrings after running and whether you can still run if you have a hamstring strain.

Common Causes of Hamstring Strains

The repetitive motion of running can cause hamstrings to tighten over the course of a run, especially on runs with little variation in terrain or incline, such as a treadmill or flat bike path.

Hamstring pulls, when there’s a sudden tear in the belly of the muscle, are rare in distance runners but more common in sprinters. For distance runners, hamstring strains are more typical and result from microtears that subsequently develop scar tissue, leading to chronic stiffness and discomfort. Runners most often get hamstring strains higher in the muscles, near the sit bones.

These hamstring strains can be difficult to manage because they’re usually not bad enough to stop you from running. In fact, most runners with hamstring strains find that complete rest doesn’t help the problem go away, and that gentle running can ease symptoms because of the increased blood flow.

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Putting too much load on your hamstring causes the muscle injury, says Jordan Metzl, M.D., a sports medicine physician at the Hospital for Special Surgery in New York City and creator of Runner’s World’s IronStrength Workout for Runners. Runners who overstride—or step way out in front of their center of mass—commonly experience hamstring strains because the longer your stride, the higher your feet are off the ground, and the more impact you experience upon landing.

Hamstrings can also become troublesome if your hips and glutes are tight or weak, as well. This shifts some of their work to the hamstrings, which can lead to overuse issues.

Identifying Symptoms of Hamstring Strains

A hamstring strain is typically the result of pushing too hard and, most importantly, not paying enough attention to pain cues, Metzl says. So rule one for identifying a possible strain is to simply pay attention to how your body feels—if you feel pain in the back of the leg that doesn’t go away after about 24 hours, then it’s smart to see a doctor.

Proximal hamstring strains (or the section at the top near the glutes)—the common type for runners— will hurt when running, especially if you’re running uphill or doing speedwork. The pain doesn’t tend to radiate to other areas of your leg, though.

Running With a Hamstring Strain

So can you still run if you have a grade 1 hamstring strain? According to Dr. Metzel the answer depends on where the strain is and if it’s affecting your stride and gait.

“In general, the high hamstring ‘pain in the butt’ injury has a slower healing time due to the lack of blood supply at the hamstring origin. I tell my patients to see how they’re feeling,” he says. If it’s a faint ache and you can run without serious pain, then it’s likely okay. But if the pain gets worse as you run, or changes the way you run, hold off and get checked out.

Preventing Hamstring Strains

A regular flexibility routine for your hamstrings will reduce your chances of developing a hamstring injury, according to the same systematic review mentioned above and published in the BMC Musculoskeletal Disorders. According to the research, the Nordic hamstring exercise—in which you start from a kneeling position, feet anchored or held by a partner and slowly lower your torso toward the floor—can also help you sidestep injury. This move works the eccentric strength of the hamstring, or its lengthening phase.

The number one thing Metzl recommends to prevent hamstring injuries is strength training to make your glutes stronger. The stronger your glutes are, the more they’ll protect the hamstring and help you avoid injury. Try exercises such as deadlifts, jump squats, or lunges.

Treating Hamstring Strains

As soon as you can, Metzl recommends icing the area four to six times a day for 15 minutes within the first two days. After that window, stretch the muscle very gently a few times a day, but avoid stretching the hamstrings when they’re cold. (A couple dynamic stretches can help you get warm before you focus solely on the hamstrings.)

It’s important to note that it’s better to stretch your hamstrings by lying on your back and not by standing up and trying to touch your toes, according to Susan Paul, running coach and exercise physiologist. This is because a prone or lying stretch is not as harsh on the muscle. To do that, lie on your back and lift your leg up in the air, keeping your knee slightly bent until you feel the stretch in your hamstring. If possible, gently pull the leg toward you. But don’t push it if you’re feeling pain and make sure to get the okay from your doctor before doing this if you do have a strain.

Hamstring strains respond best to reduced mileage and intensity until you get things under control. Depending on the severity of the strain, expect a healing time of anywhere from two to eight weeks, says Metzl. Long term, strengthening your hamstrings should allow a return to normal training.

If your hamstring strain doesn’t go away after months, newer treatments like platelet-rich plasma (PRP) therapy can be used to speed up the recovery process. Dr. Metzl says. “PRP is a good step to consider if you’re dealing with a hamstring injury that’s isn’t getting better. These can be effective when the injury lasts more than several months, appears to be stagnating, and is a high hamstring injury (just off of the sit bone),” he says. This process takes blood from your arm, removes the platelets, and injects them into your hamstring to get blood flowing into the area. (Keep in mind, it’s not necessary in most cases.)

Hamstring surgery is also rare but not unheard of, and it is used only to repair significant tears or ruptures. If that’s your problem, trust us, you’ll know it.