I have tight hamstrings and the first two standing postures after the sun salutations, padangusthasana and padahastasana, not only help to lengthen my hamstrings and calves, they reduce stress and help with my frequent headaches. Inhale hop your feet six inches apart and place your hands on your waist. Exhale hinge forward from your hips and grab your big toes with yoga toe grip. Inhale look up and lengthen, exhale fold. Reach your elbows out to the sides of the room, keep as much bend in your knees as you need to lengthen your spine. Breathe for five breaths. Inhale lift and lengthen and exhale slide your hands under your feet so your toes touch your wrists. Inhale look up and lengthen and exhale fold again. Transfer some weight to the balls of your feet to increase the stretch in your hamstrings and take five breaths. Inhale look up, exhale hands to your waist, inhale rise with a flat back. Exhale samasthiti.