How Tight Hamstrings Affect Your Knees, Plus Tips From Physical Therapists

If your knee starts aching a day or two after you were particularly active, any number of potential causes might run through your mind. Did I twist it? Maybe I squatted too heavily. Am I just getting old? But there may be a culprit you didn’t consider: tight or weak hamstring muscles. 

A number of studies have linked weak, inflexible hamstrings to different types of knee pain, including patellofemoral pain syndrome (runner’s knee) and osteoarthritis (OA) of the knee. That’s not to say tight hamstrings give you knee OA — it’s more complicated than that and a lot of factors come into play. But the strength and flexibility of your hamstrings can certainly be a piece of the puzzle. 

That’s because the hamstrings are one of many structures that stabilize the knee and help it bend and straighten. “The hamstrings help control the knee’s dynamic movement,” says Cody Anderson, PT, DPT, a physical therapist at Hinge Health. “If you have tight hamstrings, they pull on the whole system, so that everything isn’t moving quite as it needs to.” 

Here, learn about how tight, weak hamstrings can contribute to knee pain and the lifestyle changes and remedies that bring your body back into balance — including at-home exercises that strengthen and lengthen the hamstring muscles.

What is a Hamstring, Anyway? 

The hamstrings start at the hips, run down the back of the thighs, cross the knee joints (spanning either side of the knee), and attach to the shin bones. Most people tend to feel a tight hamstring in the middle of the back thigh, but it’s possible to feel it all the way down to the knee, says Dr. Anderson. These muscles play a vital role in helping you perform a lot of everyday activities, including walking, running, bending your knees to pick something up off the ground, and extending your legs to stand up. 

Tight Hamstrings and Knee Pain

Below are some of the most common reasons hamstrings tighten up and may play a role in knee pain. But first, it’s important to remember that knee pain is always due to a combination of factors. And while it’s unlikely that tight hamstrings are the sole cause of knee pain, addressing tight or weak hamstring muscles is a very effective way to turn the volume down on your knee pain and prevent it from flaring up in the future. 

You were more active than usual. “Most of the time, you get tight hamstrings because you changed the type or intensity of activity,” says Dr. Anderson. (Think: running instead of walking, using heavier weights during a strength workout, or doing any type of activity after a long period of rest.) This doesn’t mean you should avoid any particular activities. If you experience hamstring tightness after exercise, releasing the tension with remedies like foam rolling or massage (more information below) can help. 

Your hamstrings could benefit from some strengthening exercises. People assume that tight hamstrings are a sign of inflexibility, but they could actually indicate that the muscles themselves are weak or underutilized. “Your body tenses its muscles if they’re not quite strong enough for a task because that tension gives them extra strength,” says Dr. Anderson. Think of it this way: You don’t really have to flex your muscles to lift a pencil, but you definitely have to if you want to lift a heavy dumbbell. When your hamstrings are faced with a challenging task, they need to tense up and they may stay tight and sore after the activity. 

You may also compensate for weak hamstrings by relying on the quadricep muscles in the front thigh. This muscular imbalance can pull on the knee and lead to pain in the front of the knee (patellofemoral pain syndrome). 

You sit a lot. Let’s be honest — this is a problem for many of us. If your knees are bent, like when you sit, this puts the muscles in a shorter position over a longer period of time. This can lead to both inflexibility and weakness if you don’t incorporate some variety and movement into your day. Sitting a lot can also cause the pelvis to tilt forward for some people. While that’s not necessarily a bad thing, over time it can contribute to tightness in the hamstrings for some people. 

You need to check your running stride. An analysis of runners who suffer knee pain found that inflexible hamstrings were a major risk factor. In fact, runners who don’t stretch their hamstrings past 70 degrees when lying on their backs are more likely to experience hamstring pain after a half marathon.

Try This Hamstring Tightness Test

Maybe you have a sense that your hamstrings are tight or weak. But how can you really know for sure? Here’s a quick way to test how flexible your hamstrings are (or aren’t): 

• Lie on your back and lift one leg with your knee bent. 

• Use your hands to support the back of your thigh and pull until your thigh is perpendicular (at a 90-degree angle) to the ground. 

• Continuing to support your thigh with your hands, try to fully straighten your leg in the air so it forms a 90-degree angle to the ground. 

If you can straighten your leg or get pretty close, that’s a sign of healthy flexibility. If you struggle to straighten your leg or can’t get close to a 90-degree angle, that’s probably a good indication you have tight hamstrings, says Dr. Anderson.

How to Treat and Prevent Knee Pain Due to Tight Hamstrings

In most cases, tight hamstrings are not serious and can be treated with stretching and strengthening exercises, as well as a few lifestyle adjustments, such as: 

• Warm up with dynamic stretches. In 46 volunteers who had knee pain (patellofemoral pain) and inflexible hamstrings, dynamic hamstring stretches before exercise were more effective at improving pain than static stretches held for 15 seconds. “Dynamic stretches lengthen the muscles while preparing them for movement, so I recommend doing them as a warm-up before an activity,” says Dr. Anderson. Start with 10 minutes of high knees or straight-leg marching before your workout and see if that helps. 

• Cool down with static stretches. While dynamic stretches get you loose and warm muscles up, static stretches, which involve holding a pose for 15 to 30 seconds, encourage your muscles to get longer and more flexible. “When you hold a stretch, you’re telling your body you want a particular muscle to be longer, so you challenge your flexibility,” says Dr. Anderson. 

• Do physical therapy. A physical therapist will help identify the different causes of your knee pain and design a customized exercise routine to correct any musculoskeletal imbalances. When tight hamstrings cause knee pain, people are often surprised by how much strengthening the routine might involve, says Dr. Anderson. “They are expecting someone to stretch them out, or give them specific stretches to do. And while that can bring short-term relief, if hamstring weakness is the root cause, and you don’t address that, the pain will keep returning.” You can see a physical therapist in person or use a program like Hinge Health to access a PT via telehealth/video visit.  

• Use a foam roller. Foam rolling is a form of self-massage, that helps to relax and stretch a muscle. Studies suggest foam rolling also relieves muscle soreness by reducing pain perception. To foam roll your hamstrings, sit on the ground with the foam roller under your thighs. Prop yourself up on your hands, and roll yourself back and forth for a minute or two. If that feels too difficult, do one leg at a time, keeping the other leg bent, suggests Dr. Anderson. 

• Try yoga or Pilates. Yoga and Pilates both involve strengthening and stretching and can help prevent and treat tight hamstrings. “Yoga is helpful because you put your body through motions you wouldn’t normally do and you often get into the end range of the motion,” says Dr. Anderson. “Pilates is similar, where you use resistance and do these very long motions that also work on core control.” In a study of adults with knee osteoarthritis, two weeks of yoga helped improve pain, morning stiffness, and anxiety associated with arthritis. In another study, Pilates reduced pain associated with knee osteoarthritis (as well as back and osteoporosis pain) and improved functioning in middle-aged adults. 

• Take frequent breaks from sitting. “If a sedentary lifestyle is contributing to tight hamstrings, you’ll want to address that as best as you can,” says Dr. Anderson. The American College of Sports Medicine recommends two days of strength training per week plus 30 minutes of moderate-intensity aerobic exercises five days per week or 20 minutes of vigorous-intensity activity three times per week. Another simple solution: Stand up every hour and stretch for a minute. You can even do a seated hamstring stretch (see below) to lengthen the hamstring muscles and break up your work day. 

• Massage therapy. “If you did a hard workout and your muscles are tight because they are overworked, then things like massage, foam rolling, and static stretching will help,” says Dr. Anderson. “When the root cause of pain is a workout that causes tension, the best treatment is to relieve that tension.” 

Your hamstrings are involved in so many daily activities that stretching and strengthening exercises are incredibly important — regardless of whether your hamstrings play a role in knee pain or not. The given exercises recommended by Hinge Health physical therapists are a great starting point. Begin doing the strengthening exercises three times per week and build up to doing them daily. You can do the stretching exercises two to three times per day.

The information contained in these videos is intended to be used for educational purposes only and does not constitute medical advice or treatment for any specific condition. Hinge Health is not your healthcare provider and is not responsible for any injury sustained or exacerbated by your use of or participation in these exercises. Please consult with your healthcare provider with any questions you may have about your medical condition or treatment.

When Knee Pain is More Complicated 

Knee pain, especially when related to tight hamstrings, can usually be managed independently and does not require a doctor’s visit. However, the knee is a complex joint, and there are many causes of pain other than tight or weak hamstrings. Some symptoms that may indicate you should reach out to your doctor include: 

• You have high levels of persistent pain. This could indicate a more serious injury like a muscle or ligament tear.

• You also have back pain. A sore or tense back along with tight hamstrings could indicate a more complex issue. For example, a herniated disc in the spine could cause pain that travels down the back of the thigh to the knee (called sciatica). In other cases, weak or tight hamstrings lead to back pain as the back compensates for underperforming muscles. Bottom line: Get evaluated to make sure you are treating the right problem. 

• The pain doesn’t go away or keeps recurring despite consistent at-home treatment. This could mean that you haven't identified the correct root cause or that your situation requires a different intervention. 

• You have signs of nerve pain. “Sometimes tightness behind the knee or high into the calf occurs because the nerves are irritated, but it will feel similar to muscle tension,” says Dr. Anderson. In that case, a physical therapist might recommend movement to increase mobility around the nerves rather than a hamstring stretch. Signs that nerves are affected include pain radiating from the back to the knee, numbness, or a pins-and-needles sensation. 

• Your pain began after a trauma or impact. This increases the chances that a structural injury is the cause of your pain.

• Your knee feels unstable or you have trouble bearing weight or doing daily activities. If your pain is that severe or causes that level of dysfunction, get a medical evaluation as soon as possible.

PT Tip: Bust This Toe-Touching Myth 

You may have heard that one way to test your hamstring flexibility is simply to bend forward and see if you can touch your toes. “But this may not tell you as much about your hamstrings as you think,” says Dr. Anderson. If you have good mobility in your lower back, then that will help you bend a lot farther forward, even if your hamstrings are super tight. (And many of us do have good lower back mobility because we sit with rounded backs all day). 

If you want to only stretch the hamstring while doing a forward bend, keep your chest upright and your back straight, and only hinge forward at your hips. If you’re doing a full forward bend and your back is rounded, you’re probably stretching both the hamstrings and the lower back muscles (though that’s not a bad thing!). 

How Hinge Health Can Help You

If you have joint or muscle pain that makes it hard to move, you can get the relief you’ve been looking for with Hinge Health’s online exercise therapy program.

The best part: You don’t have to leave your home because our program is digital. That means you can easily get the care you need through our app, when and where it works for you.

Through our program, you’ll have access to therapeutic exercises and stretches for your condition. Additionally, you’ll have a personal care team to guide, support, and tailor our program to you.

See if you qualify for Hinge Health and confirm free coverage through your employer or benefit plan here.

This article and its contents are provided for educational and informational purposes only and do not constitute medical advice or professional services specific to you or your medical condition.

References 

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