Lie flat on back.

Bend one leg (e.g., right) so hip and knee are both at 90 degrees (thigh perpendicular to floor, shin parallel).

Hold behind the thigh with both hands for support.

Keep the other leg straight on floor or knee bent with foot flat.

Slowly extend the raised leg (right) towards the ceiling, straightening the knee as much as possible until a stretch is felt in hamstring.

Hold briefly, then return to 90/90 start position.

Repeat extension for desired reps. Switch legs.