Your lower back has been aching for weeks now, but no matter how much you massage or stretch those muscles along your spine, the pain won’t go away. This might be because the problem isn’t actually your back at all: While there are a number of things that can cause back pain, one that’s easy to overlook is tight hamstrings.

Yes, your legs could be the guilty party. To find out how to tell if this is the case, and how to stretch hamstrings effectively if it is, we spoke with Katya Campbell, a certified movement and mobility specialist, yoga teacher, CrossFit coach, and the fitness director at Mountain Trek Health Reset Retreat in British Columbia.

How do you know if your hamstrings are tight enough to cause back pain?

Low back pain can crop up when your hamstrings are so tight that they pull your pelvis out of alignment, which can strain the deep back muscles. But before blaming your hammies outright, it’s helpful to determine if they’re tight enough to be the culprit. There are a few basic tests you can do to test your range of motion, says Campbell.

The simplest is probably the passive forward fold. To do this, stand upright with your feet together (preferably with no shoes on) then hinge from your hips and reach down to touch your toes or as close to your toes as possible.

If you are within two inches from reaching the floor, Campbell says that you have “moderate flexibility,” but anything higher up could indicate excessive tightness in your hamstrings.

However, this assessment has some limitations. Namely, if you have long arms, it will naturally make it easier to reach the ground (and those with shorter arms will have a harder time). Also, Campbell points out that this doesn’t test each leg individually. That’s why she also recommends the active straight leg raise test.

To do this one, lie on the floor with both legs straight out on the ground. Keep one leg flat on the floor and raise the opposite leg into the air, keeping both knees as straight as possible. As you lift your leg, look at how far the heel is coming up towards the ceiling. Campbell says that ideally, your heel should be able to come in line with or beyond the opposite knee. “This is a great indicator of hamstring flexibility, and we can see if one leg has greater limitations than the other, which is fairly common,” she says.

What causes very tight hamstrings?

Sometimes, chronically tight hamstrings are simply something you’re born with. “Genetics do play a role in hamstring length and we can’t argue our way out of that one, but there are other factors as well,” suggests Campbell. “Prolonged sitting, insufficient stretching after exercise, injury, and limited movement can all contribute to shortened hamstrings.”

Campbell points out that there is a difference between short, stiff, and tight muscles, even though we tend to colloquially describe all of these as feeling “tight.” The nuanced distinctions between each of these situations can affect what’s going on in your body to create this sensation.

If your hamstrings are short

“Short muscles (the least common) are often due to an injury that has caused a significant lack of movement at end range for a prolonged period of time,” says Campbell. “For example, a person is in a cast or a brace. This has caused the muscle to progressively adapt to this new shortened position.”

If your hamstrings are stiff

Campbell says that a stiff muscle results from lack of movement, often from sitting in a car or at a desk, or from overuse due to hard workouts with eccentric exercises or repetitive movements.

If your hamstrings are tight

“A tight muscle can often feel more like bone than muscle. They are those thick, ropey muscles that you can stretch repeatedly but are continually tight,” describes Campbell. “These often accompany an injury or a poor recruitment pattern where the body has essentially overused the muscle (causing it to be more hypertonic and thus ropey and bony feeling) rather than using a more functional movement pattern.”

What are the risks of not stretching your hamstrings?

Ultimately, whether your hamstrings are stiff, short, or tight, Campbell says that one of the biggest concerns is potential injury. After all, we have ideal ranges of motion for the hamstrings, which we have evolved over time for safe movements. When something compromises this range of motion, injuries can occur.

“If our muscles lack those abilities, it can take something small, like tripping over our kids’ Lego, to potentially tear a muscle due to its inability to extend and contract,” warns Campbell.

But it doesn’t necessarily take a Lego incident to cause problems. Overly tight hamstrings “can also add undue strain on other parts of our body that need to compensate for this lack of movement,” she says. “A perfect example of this is lower back pain, which is often seen as a result of tight hamstrings.”

How to stretch hamstrings effectively

The key to releasing tight hamstrings is to incorporate a variety of stretching exercises into your regular routine, says Campbell. Even a dedicated 10-minute stretch session can make a major difference if you choose the right mix of moves and know how to stretch hamstrings the right way.

“I like to blend active (dynamic) and passive stretching, so that the muscle has the ability to be in a lengthened position in all scenarios,” says Campbell. “Often, we might have moderate passive flexibility (such as the standing forward fold), but when we make it more active, we see greater limitations.”

Campbell shares a few of the best hamstring stretches:

Reclined single-leg hamstring stretch

1. 1.
   Lie on your back with a strap or belt beside you.
2. 2.
   Bend both knees and plant your feet on the floor hip-width apart.
3. 3.
   Extend one leg up above the hip and hook the strap/belt over your midfoot. Try to maintain a neutral spine.
4. 4.
   Gently straighten the leg.
5. 5.
   On an exhale, slowly straighten the opposite leg onto the floor. If this is too much, keep it bent.
6. 6.
   Breath deeply and maintain this for five deep breaths.
7. 7.
   Repeat on the other side.

Swinging leg touches

1. 1.
   Stand upright with one hand on a chair for balance, if needed.
2. 2.
   Shift your weight onto one leg and allow the opposite leg to swing as if it’s a pendulum, back and forth from in front of you, to behind you. Make sure to keep your chest tall as you do this.
3. 3.
   As the leg loosens up, slowly increase the range of motion of your swing.
4. 4.
   If possible and you have the balance, as you swing the leg out in front, take the hand on the opposite side and reach it to touch towards your toes of the leg that’s swinging as it comes up in front of your body. Avoid rounding your back to make the touch.
5. 5.
   Keep swinging and kicking to the hand 10 times, then switch sides.

Box hang

1. 1.
   Step up onto a stable box or stair.
2. 2.
   Place your toes at the front edge with your feet hip-width apart.
3. 3.
   Hinge at your hips (not rounding your back) and allow your body to hang so that your arms drape down to the toes. If you are flexible or want to challenge your flexibility more, hold light dumbbells in your hands to deepen the stretch.
4. 4.
   Hold for 20 to 30 seconds.
5. 5.
   Engage your core and glutes to slowly stand back up.

Counteracting tight hamstrings isn’t just about doing leg stretches, however. When your hamstrings are chronically tight, other muscles—like those deep back muscles—can tighten up as well.

“Often, the lower back becomes tight, as the hamstrings pull the pelvis back,” explains Campbell. “Working on lengthening the erectors (the long muscles alongside the spinal column) can be really helpful, as can foam rolling this area.”

Here’s how to stretch hamstrings for back pain and hit those spinal muscles in the process with this seated hamstring stretch:

Seated supported forward folds

1. 1.
   Sit on a folded blanket or firm pillow with the legs stretched out in front.
2. 2.
   Place a firm pillow under the knees.
3. 3.
   Hinge from the hips, thinking of rolling forward onto the edge of the sitting bones as you reach the hands along the legs towards the feet.
4. 4.
   Hold for one minute, breathing deeply. Then release.

Looking for more leg stretches? Try this lower body mobility routine: 

Is there anything you can do besides stretching to help loosen up tight hamstrings?

Stretching isn’t the end-all-be-all when it comes to loosening up tight hamstrings. You might wonder, Will massage loosen hamstrings? Certainly. “Massage is a wonderful way to increase blood flow, soften connective tissue, and restore healthy range of motion,” says Campbell, who particularly recommends Thai massage for this purpose.

Self-myofascial release methods like foam rolling and ball rolling can also be highly effective, she adds. Campbell says she loves an exercise she calls the “hammy smash roll” with a lacrosse ball or similar small, firm ball:

1. 1.
   Sit on a firm surface with legs overhanging, like a chair.
2. 2.
   Place the ball behind one thigh, nestled into the tissue of the hamstrings.
3. 3.
   Rest the weight of the leg onto the ball if you can handle it.
4. 4.
   Slowly extend the leg out, mashing the ball into the tissue as you elongate the muscle along that pressure point.
5. 5.
   Do that several times, and keep relocating the ball to different areas to find out where the gnarly spots are. Make sure to breathe throughout the entire process to help relax your tissues.
6. 6.
   Switch legs.

How long does it take to loosen tight hamstrings?

Ultimately, the cause of your tight hamstrings will affect how much time it takes to resolve the issue.

“If it is due to injury, the key is slow and steady, and it can take several months to restore full range of motion,” says Campbell. “If the tissue is stiff due to exercise (post-workout soreness and tension), usually a day or two and getting blood flow will loosen things up. If the muscles are tight and rigid, it can be something that will require regular maintenance to keep things agile.”

So, be patient. With consistent practice, you can work your way to feeling limber and agile—and pain-free—again.