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Get to Know Your Hamstrings: Why Both Strength & Length Are Essential

Flexible and strong, hamstrings are key to a healthy, happy yoga practice. Here's what you need to know in order to lengthen and strengthen these muscles.

hamstring anatomy

When I was in my early 20s, I had a vigorous Ashtanga Yoga practice, and I loved that my hypermobile body could easily contort into even the most advanced postures. Yet my drive to feel a deep stretch, particularly in all of the forward folds in the Ashtanga series, caused microtears in my hamstrings, which led to knee and hip pain—plus so much soreness that when I got out of bed each morning, I wasn’t able to straighten my legs for at least an hour.

Like me, many yoga practitioners learn lessons about their hamstrings the hard way. After all, having the ability to achieve all kinds of complex yoga poses due to hypermobile hamstrings is a common, if unspoken, goal. On the flip side, a lack of flexibility is often associated with not being able to practice yoga at all. How many times have you heard someone say, “Yoga isn’t for me; I can’t even touch my toes!”?

In fact, optimal hamstring health lies somewhere between the two ends of this spectrum. If your hamstrings don’t have a lot of motion, gaining flexibility can help keep your knees, hips, and legs healthy. If your hamstrings are hyperlax, controlling their range of motion will also help you stay injury free. It took me two solid years of avoiding forward bends in order to heal my hamstrings and learn the importance of both stretching and strengthening this muscle group. Here’s how you can create strong, pliable hamstrings, wherever your starting point.

See also Anatomy 101: Understand + Prevent Hamstring Injury

Strengthen to lengthen

It seems paradoxical that if your hamstrings are tight, you should strengthen them. However, hamstrings are healthiest when all of their fibers are able to fully lengthen and contract, which is what prevents muscle tears and promotes optimal muscle health. The following exercise is like medicine for both hypermobile and restricted hamstrings. It’s a concentric exercise (read: it shortens the hamstrings). If you dislike this move as much as I do, take it as a sign that you’ve got some hamstring-strengthening work to do.

The Move: Hamstring Slides

Step One

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Place a yoga blanket on a slippery surface, like a hardwood or tile floor. Lie down to rest your bottom, torso, and head on the blanket with your legs outstretched in front of you, hips parallel to each other.

See also Standing Forward Bend

Step Two

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Drive your heels into the floor, and pull your bottom toward your heels by exclusively using your hamstrings. When you’re halfway there, stop and make sure your knees are pointing to the sky and still parallel to one another.

See also Legs-Up-the-Wall Pose

Step Three

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Complete the move by pulling your heels all the way to your bottom, then straighten your legs to return to the starting position. Repeat until you feel tired.

See also Explore Your Hamstrings: Yoga Poses for All Three Muscles

Why Touching Your Toes Is Overrated

Remember the toe-touch test in grade school, where your teacher gauged your flexibility based on how far you could reach your fingers toward your feet? This “test” has been used as a measure of musculoskeletal health for decades. However, hamstring limberness without strength shouldn’t be anyone’s goal. Placing too much focus on stretching your hamstrings can shorten your hip flexors, creating a muscle imbalance that can contribute to an anterior (forward) pelvic tilt—and back pain as a result. 

Body of Knowledge: Anatomy of the Hamstrings

Your hamstrings are a collection of four muscle bellies (with only three names) on the posterior (back) thigh. They originate (attach) on the ischial tuberosities (sit bones) and run down the backs of your thighs. There are two hamstrings in each medial thigh (the inner back side) and one in each lateral (outer) thigh. All three attach by long tendons crossing the back of the knee to the lower leg—and they’re all bi-articular, meaning they connect and affect the function of two joints: the hip and knee. Your hamstrings work to flex (bend) your knees, extend (straighten) your hips, and posteriorly tilt your pelvis.

Biceps Femoris 

This two-headed muscle is in the outer portion of your thigh. The long head begins on the ischial tuberosity (bottom of the pelvis), and the short head is nestled against the lower half of your femur. Both converge at a tendon on your outer knee (at your fibula). This muscle externally rotates your hip. It also externally rotates your bent (flexed) knee.

Semimembranosus

This muscle begins as a thick membranous tendon (hence its name) on your ischial tuberosity (sit bone) and attaches just behind your inner knee. It also serves as
a fascial anchor for the largest of your inner thigh muscles: the adductor magnus.
The semimembranosus muscle internally rotates your hip. It also internally rotates your lower leg at the flexed knee.

Semitendinosus

This muscle begins on your ischial tuberosity and tapers into a long tendon that attaches on the innermost portion of the front of your knee. This muscle internally rotates your hip, and when your knee is bent, it internally rotates your lower leg.

See also Not ALL Hips Need Opening: 3 Moves for Hip Stability

3 Poses to Keep Your Hamstrings Healthy

Supta Padangusthasana (Reclining Hand-to-Big-Toe Pose, variation)

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This classic pose reveals the truth behind your current hamstring length. By lying on the floor with one foot against a wall, you can keep both your pelvic bones and spine in neutral positions as you explore the range of motion in your raised leg (which is permitted by the length of your hamstrings).

How to Wrap a strap around the middle of your right foot. Lie on the ground with the bottom of your left foot against a wall and your left toes pointed toward the ceiling. Engage your core, maintaining a neutral spine. Note the position of both pelvic (ilia) bones as you begin; your ilia should never tilt or shift. Grasp the strap and bring your right hip into flexion without changing the position of your pelvis or spine. As soon as you feel a stretch on the back of your right thigh, stop pulling and breathe deeply. Once the stretching sensation dissipates (30–60 seconds), switch sides.

Strengthen-to-Lengthen Challenge Harness the strap firmly around your heel, and try to push your right thigh back toward the ground without allowing your thigh to move. Hold for 10–20 seconds.

See also Anatomy 101: A Hip-Opening + Balancing Sequence

Uttanasana (Standing Forward Bend, variation)

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This Uttanasana asymmetrical variation favors a stretch in your outer hamstrings, the biceps femoris. The pose is great for practitioners who have a limited range of motion in their hamstrings.

How to Begin in Uttanasana with both knees bent, feet hip-width apart. Place one block under your right foot and one next to the outside of your left foot. Lean your weight forward as you try to straighten both knees. Walk your hands to the left to place them on the block, and lean your hips to the right to emphasize the stretch on your right hip and right hamstrings. Breathe deeply for 30–60 seconds, then switch sides.

Strengthen-to-Lengthen Challenge Put pressure on the block under your foot and simultaneously try to slide it to the right without actually moving it. Do this for 10–20 seconds, then repeat on the other side.

See also Achieve Uttanasana the Safe Way

Purvottanasana (Upward Plank Pose)

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This is one of the few classic yoga poses that requires concentric contraction (shortening) of the hamstrings along with the whole posterior chain of muscles—the calves, glutes, and back muscles. Thanks to our increasingly sedentary lifestyles, we tend to be weaker in the back of our bodies than in the front. This back-body strengthener is an excellent antidote to this common problem.

How to Sit in Dandasana (Staff Pose) with your torso upright and legs outstretched in front of you. Slide your palms backward approximately 9–12 inches, with your fingers pointing toward your feet. (In the full expression of the final pose, your shoulders should stack above your wrists.) Point your toes so that the soles of your feet plant into the ground, then engage all of your back-body muscles to lift off the floor into a reverse-incline plank. Internally rotate your hips by squeezing your thighs toward one another. Hold the pose until you can no longer sustain all of these actions.

Strengthen-to-Lengthen Challenge Try pulling your heels toward your bottom without allowing your knees to bend. Even though your heels won’t move very far, you should feel your hamstrings engage, which will build strength.

See also Dolphin Plank Pose

About Our Pros
Writer Jill Miller is the creator of Yoga Tune Up and The Roll Model Method, and author of The Roll Model: A Step-by-Step Guide to Erase Pain, Improve Mobility, and Live Better in Your Body. She has presented case studies at the Fascia Research Congress and the International Association of Yoga Therapists Symposium on Yoga Therapy and Research, and she teaches at yoga conferences worldwide. Learn more at yogatuneup.com. 

Model Colleen Saidman Yee is a yoga instructor with more than 30 years of practicing experience. She is the owner of Yoga Shanti studios in New York City and author of Yoga for Life.