Yoga Glossary · Muscles
Hamstrings
The back-thigh muscles that bend the knee and extend the hip — the limit in most forward folds.
The hamstrings are three muscles at the back of the thigh — biceps femoris on the outer side, semitendinosus and semimembranosus on the inner side. They run from the sitting bones to below the knee, so they cross two joints: they flex the knee and extend the hip, and in forward folds they are stretched across both joints at once.
That two-joint anatomy explains fold mechanics: bend the knees and the hamstrings slacken, letting the pelvis tip; straighten them and the pull at the sitting bones caps how far the fold goes. The hamstrings also power hip extension in Bridge and Locust together with the glutes. Because they attach at the sitting bones, yanking into folds stresses that attachment — the reason teachers prize long spines and bent knees over depth.
In practice
- The pull behind the thigh in a fold is hamstrings; the pull at the sitting bone is their attachment — back off if it feels sharp or sit-bone deep.
- Bending the knees in a fold is not cheating; it moves the stretch from the low back into the hamstrings.
- Bridge and Locust strengthen them; folds lengthen them. A full practice does both.
Poses that engage it
Poses that lengthen it
- Triangle Pose
- Standing Forward Fold
- Ragdoll
- Halfway Lift
- Gorilla Pose
- Wide-Leg Forward Fold
- Seated Forward Fold
- Happy Baby
- Boat Pose
- Downward Facing Dog
- Shoulder Stand
Related terms
Test yourself
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The Yoga Glossary is an educational study reference. Definitions are standard yoga and anatomy knowledge in plain language; nothing here is medical advice.