For access to all of our training, gear, and race coverage, plus exclusive training plans, FinisherPix photos, event discounts, and GPS apps, sign up for Outside+.
Go to any search engine and type, “How to stretch your hamstrings.” How many different answers pop up? How many stretches have you tried? You might even see a few search results telling you to stop stretching your hamstrings altogether — so what are you supposed to believe?
Why you should stretch your hamstrings
Hamstrings attach to your pelvis; your pelvis is the base of support for your spine. Hamstrings that are too tight will tilt your pelvis and create tension through all of the ligaments, fascia and muscles that connect to your low back. This added tension alters your motion, putting you at a higher risk for lower back injuries — particularly with lifting, jumping or running.
Tight hamstrings also love to take over other muscles’ jobs, especially the glutes. When hamstrings are working in place of the glutes (both in daily life and in your workouts), the glutes become inhibited and don’t contract well. Some call this dead butt syndrome. When this happens, your glute-strengthening efforts like squats, lunges, hip thrusts and step-ups can end up overworking the hamstrings. What’s more, overworking the hamstrings can lead to repetitive muscle strains and, eventually, scar tissue. Scar tissue is not stretchable, nor can you strengthen it, so the injury cycle continues to repeat itself. This cycle limits your workout options more and more over time.
We don’t have to feed into this cycle of limited workout options. Instead, we can make hamstring stretching part of our daily post-workout routine. But when it comes to safety and effectiveness, some hamstring stretches are better than others.
Hamstring stretches to avoid
Two of the most popular hamstring stretch variations you might see in your Google search are:
- Seated forward bend (also known as a pike stretch)
- Standing forward bend
Unless you are naturally very flexible or well-trained in the details of yoga technique, copying these motions may actually elevate your risk of back injury. Your hamstrings not only attach to your pelvis, but also your knees. Fully stretching them in the forward bend or pike stretch requires lengthening the hamstrings across both the back of the pelvis and the back of the knees. When you straighten your knees to lengthen the hamstrings and then bend forward, the ligaments, fascia and discs in your back take up the slack. Ligaments, facia and discs are not designed to stretch, so these structures will limit how far you can go before you even achieve an effective hamstring stretch.
Many people try to bypass this limit by bouncing, having other people assist the stretch or adding weight. This can create micro tears and overstretching in your ligaments, fascia and even parts of your discs. While micro tearing muscles with progressive weight lifting is a good thing in terms of strength-building goals, the opposite is true for all of these back structures. Over time, with repetition, your low back will become less stable. This opens a window of opportunity for not just one back injury, but repetitive injuries over time.
The standing forward bend version presents further risk factor, as it also stretches the sciatic nerve. If you’ve ever heard of sciatica, or pain that shoots from your back down your entire leg, over-stretching the sciatic nerve is a common cause.
With both versions, many fitness instructors encourage you to bend your knees to protect your back. But while this modification works to mimic the position, it does not fully lengthen and stretch your hamstrings.
So if we should stretch our hamstrings, but these popular stretches present low back injury risks for people who are not naturally flexible, what should we do?
RELATED: Injury Guide for Triathletes
How to stretch your hamstrings without hurting your back
Instead of performing the forward bend or seated pike stretch, grab a stretch strap, yoga strap or bath towel and lie on your back.
The best hamstring stretch:
- Lying on your back, bend one knee and place the center of your stretch strap around the arch of your foot. This will be the leg that you stretch.
- Use the stretch strap to support your leg as you straighten your knee to extend your leg up toward the ceiling.
- Your foot does not need to point all the way up to the ceiling for an effective stretch. Instead, focus on straightening the knee on the side you are stretching. Note: You will likely need to lower the height of the leg to accomplish this goal.
- Hold the stretch for 30 seconds as you relax and breathe into it. Stretches should feel like a gentle line of pull that you would rate as an intensity of 5 to 7 out of 10.
- Repeat on each side for 3 to 4 sets.
Pro tips & key takeaways for hamstring stretches
- For the leg you’re not stretching, your knee may be bent or straight. Do what feels comfortable for your back.
- Try to keep your ankles relaxed. Fully flexing your toes toward your nose may pull on the sciatic nerve instead of creating an effective hamstring stretch.
- Focus on a straight knee instead of how high your leg is on the stretching side. Proper technique repeated over time will improve your flexibility.
- Avoid bouncing. Bouncing can make the muscle contract, and when a muscle tries to contract and stretch at the same time, injury can occur.
For people with tight hamstrings, daily post-workout hamstring stretching can be effective in improving your flexibility, enhancing how well your glutes activate during your workouts and contributing to your lower back health. However, effective hamstring stretching is better done while lying on your back than sitting up or standing, since common forward bending variations may stress structures in your back that can contribute to injury. Let’s celebrate fitness longevity by putting safety first!