Hamstrings and Yoga: Anatomy, Stretches and Strength Poses

The hamstrings are the three muscles on the back of the thigh: biceps femoris, semitendinosus and semimembranosus. They run from the sitting bones to the top of the lower leg bones, so they extend the hip and bend the knee. In yoga you stretch them in forward folds such as Uttanasana and Paschimottanasana, and you strengthen them in poses that lift the hips or a leg behind you, such as Bridge, Upward Plank and Locust.

Hamstring anatomy

All three hamstrings start on the ischial tuberosity, the sitting bone you feel under you on a hard chair. From there they run down the back of the thigh and cross the back of the knee. Because they cross two joints, the hip and the knee, how far you can fold forward depends on what the knees are doing. Bend the knees and the hamstrings go slack. Straighten them and the stretch arrives.

The tibial part of the sciatic nerve supplies them, with one exception noted below.

Biceps femoris

The outer hamstring. It has two heads. The long head starts on the sitting bone. The short head starts on the back of the femur (the linea aspera), so it crosses only the knee. Both heads join and end on the head of the fibula, the thin bone on the outside of the lower leg. You can feel its tendon on the outer back of the knee when you bend it against resistance.

It extends the hip (long head), bends the knee, and turns the lower leg outward when the knee is bent. The short head is supplied by the common fibular part of the sciatic nerve. Since it does not cross the hip, some anatomists do not count it as a true hamstring.

Semitendinosus

One of the two inner hamstrings. It starts on the sitting bone and turns into a long, thin tendon halfway down the thigh, which gives it its name ("half tendon"). It ends on the inner side of the upper tibia, in the pes anserinus, where it shares an attachment with the sartorius and gracilis. It extends the hip, bends the knee and turns the lower leg inward when the knee is bent.

Semimembranosus

The deepest of the inner hamstrings. It starts on the sitting bone with a broad, flat tendon ("half membrane") and ends on the back of the inner tibial condyle, with fibres that spread into the capsule at the back of the knee. It does the same work as the semitendinosus.

The fourth hamstring

The back part of the adductor magnus, the largest inner thigh muscle, also starts on the sitting bone and extends the hip. It is supplied by the same nerve as the hamstrings, and many anatomy teachers call it the fourth hamstring. You feel it in wide-legged folds, where the inner thigh and the back of the leg stretch together.

What the hamstrings do in yoga

• Lengthen in forward folds. When you hinge at the hip with straight legs, the sitting bones move up and back and the hamstrings are pulled long. Uttanasana, Paschimottanasana, Pyramid Pose and Downward-Facing Dog all ask for this.
• Extend the hip. Together with the gluteus maximus they lift the hips in Bridge and Upward Plank and lift the back leg in Warrior III and Locust.
• Bend and protect the knee. They pull the heel toward the buttock and, as the leg straightens, they brake the movement so the knee does not snap back. That is why teachers ask for a micro-bend in the knees when someone tends to lock them.
• Tilt the pelvis. Pulling down on the sitting bones, they tip the top of the pelvis back. Tight hamstrings in a seated fold round the lower back for this reason: the pelvis cannot tip forward, so the spine bends instead.

Yoga poses to stretch the hamstrings

Hold each stretch for 30 seconds to a minute and breathe slowly. Fold from the hip joints, and let the knees bend as much as you need to keep the lower back long.

Uttanasana (Standing Forward Bend)

1. Stand with your feet hip-width apart, toes forward.
2. Bend your knees a little and fold forward from the hips, as if your pelvis were a bowl tipping forward.
3. Rest your belly on your thighs. Put your hands on the floor or on blocks.
4. Keep the belly on the thighs and straighten the legs slowly, only as far as the belly stays there.
5. Stay for five to eight breaths.

To add strength work in the same pose: shift your weight into the right foot and drag the left heel back against the floor, as if you wanted to bend the left knee. The heel does not move, but the left hamstrings switch on. Hold for two breaths and change sides.

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

The easiest way to stretch the hamstrings without the lower back taking over. Lie on your back with the left leg long, the left foot against a wall. Loop a strap around the ball of the right foot and lift the leg. Keep both legs straight and the pelvis level on the floor. Stop as soon as you feel the stretch, and stay there. When the stretch fades, draw the leg a little closer. The standing version of this pose is Utthita Hasta Padangusthasana.

More folds

• Adho Mukha Svanasana (Downward-Facing Dog): bend the knees first to lift the sitting bones, then press the heels down.
• Paschimottanasana (Seated Forward Bend): sit on a folded blanket so the pelvis can tip forward.
• Janu Sirsasana (Head-to-Knee Pose): one leg at a time, which makes it easier to feel each side.
• Prasarita Padottanasana (Wide-Legged Forward Bend) and Upavistha Konasana (Wide-Angle Seated Forward Bend): the inner hamstrings and the adductor magnus stretch together.
• Urdhva Prasarita Eka Padasana (Standing Split) and, at the far end, Hanumanasana (Monkey Pose).

Yoga poses to strengthen the hamstrings

Most yoga classes stretch the hamstrings far more than they load them. These poses work them. Hold each for five to eight breaths, or move in and out slowly six to eight times.

Setu Bandha Sarvangasana (Bridge Pose)

Lie on your back with the knees bent. Walk your feet a little further from the hips than usual and lift the hips. The further away the feet, the more the hamstrings work and the less the glutes do. For more load, lift one foot and hold for five breaths. See Setu Bandha Sarvangasana (Bridge Pose).

Hamstring slides

A bridge with sliding feet. Put your heels on a towel or on socks on a smooth floor. Lift into Bridge. Slowly slide the heels away until the legs are almost straight, keeping the hips lifted, then pull the heels back under the knees. Start with five slow slides. The slow slide out is the hard part: the hamstrings work as they lengthen, which is the kind of load that research links to fewer hamstring strains.

Purvottanasana (Upward Plank Pose)

1. Sit in Dandasana (Staff Pose) with the legs long in front of you.
2. Place your hands about a hand's length behind the hips, fingers pointing toward your feet.
3. Press into the hands and heels and lift the hips until the body makes a line from shoulders to feet.
4. Press the heels down and draw the inner thighs toward each other. You will feel the back of the legs and the buttocks hold you up.
5. Stay for three to five breaths. A gentler start: bend the knees and lift into a tabletop.

Legs lifting behind you

In Salabhasana (Locust Pose) and in Virabhadrasana III (Warrior III), the hamstrings and glutes lift and hold the leg behind you. In Warrior III the standing leg works too, holding the hip steady as you tip forward.

Who should go gently

• Pain at the sitting bone. A deep ache where the hamstrings attach, worse when you sit or fold, can be a tendon problem (proximal hamstring tendinopathy). Deep folds usually make it worse. Bend the knees in folds and see a physiotherapist.
• A recent hamstring strain. Skip deep stretching for the first days. Gentle movement and, later, strength work help more than pushing into a fold.
• Pain that runs down the leg. Tingling or pain along the back of the leg in a fold can come from the sciatic nerve, not the muscle. Back off and bend the knees. If it keeps happening, get it checked.
• Hypermobile knees. If your knees bow backward when you straighten them, keep a small bend in forward folds.

Common mistakes

• Folding from the waist. Rounding the spine to reach the floor moves the stretch into the lower back. Hinge at the hips, bend the knees.
• Pulling hard with the arms. In seated folds, grabbing the feet and tugging forces the stretch. Let gravity and your breath do it.
• Bouncing. A quick, repeated push to the end of your range gives the muscle no time to settle. Arrive and stay.
• Stretching cold. A few Sun Salutations or a brisk walk before a long hold make the folds more comfortable.
• Only stretching. A hamstring that is long but weak has little control at the end of its range. Add one or two strength poses to every practice.

Where sources disagree

Does stretching make the muscle longer? Classes often say regular stretching lengthens the hamstrings. Most research on short stretching programmes finds that the range you gain in the first weeks comes mainly from a higher tolerance to the stretch, not from a longer muscle. The gain is real: you can fold further. What changes in the tissue over months of practice is less clear.

Are tight hamstrings a cause of injury or back pain? The old version of this post listed tight hamstrings and strong quadriceps as risk factors for a strain. Studies in sports such as football point more consistently to a previous hamstring injury, age and weak hamstrings in eccentric work. Tightness and the quadriceps-to-hamstring strength ratio show mixed results. The link between tight hamstrings and low back pain is also weaker than it is often presented.

Can you target the inner or outer hamstrings? Some teachers say narrow folds stretch the biceps femoris and wide folds stretch the inner hamstrings. Turning the leg in or out and moving it to the side does shift the stretch a little, and wide folds do add the adductor magnus. The claim that one fold isolates one muscle goes further than the anatomy supports.

Too flexible? The old text warned against highly flexible hamstrings. There is no agreed point where flexibility becomes a problem, but teachers who work with hypermobile students report more hamstring tendon pain from deep folds, and strength at the end of the range is the usual advice. That fits the sports research on strength and injury.

Emotions in the hamstrings. Some yoga and bodywork teachers say the hamstrings hold fear or old emotions. There is no research behind that. What is true: a long, slow stretch with steady breathing can feel calming, and a tense, hurried fold feels tighter.

The old version of this post cited an undated patient guide on hamstring injury and a 2017 article by Miller. Related guides: glutes and yoga, quads and yoga, and why yogis need strength training. For a guided class, Strengthen Your Hamstrings is 45 minutes of Vinyasa that builds hamstring strength, level 1-2, and Everyday Hamstring Stretch is 15 minutes with Pyramid Pose and Half Splits, no props.

Frequently asked questions

What is the fastest way to fix tight hamstrings?

Stretch a little every day rather than hard once a week. Hold a fold such as Supta Padangusthasana with a strap for 30 seconds to a minute, two or three times per leg. Most people notice more range within a few weeks. Add strength work so the new range comes with control.

What is the number one exercise for hamstrings?

In sports research the Nordic hamstring curl stands out: a kneeling exercise where you lower your body forward slowly while a partner holds your heels. Programmes that include it have lowered hamstring strains in football. On a yoga mat, hamstring slides and single-leg Bridge give a similar lengthening load.

Can you do yoga with a hamstring injury?

Often yes, with changes. Skip deep forward folds while the injury is fresh, bend the knees in any fold and stop at the first sign of pain. Gentle strength work such as Bridge usually comes before stretching in recovery. Tell your teacher, and follow your physiotherapist's plan for a moderate or severe tear.

What emotion is held in the hamstrings?

None that research can show. The idea that the hamstrings store fear comes from some bodywork and yoga teaching, not from anatomy. Long holds with slow breathing can feel calming, and some people feel emotional in them, but that is the breathing and the stillness rather than something stored in the muscle.

Why are my hamstrings so tight in yoga?

Partly build: some people have less range at the hip, whatever they do. Partly habit: long sitting and little stretching lower your tolerance to the stretch. And partly technique: rounding the back in a fold makes the hamstrings feel tighter than they are. Bend the knees and hinge at the hips.

Should I bend my knees in forward folds?

Yes, as much as you need to keep the lower back long and the fold coming from the hips. Bent knees move the stretch away from the sitting bone and the back of the knee. Straighten the legs gradually as the hamstrings allow.

Which yoga poses strengthen the hamstrings?

Bridge Pose with the feet a little further away, single-leg Bridge, hamstring slides, Purvottanasana (Upward Plank), Locust and Warrior III. In a standing fold, dragging one heel back against the floor also switches the hamstrings on.