The hamstring is any of the three tendons at the back of the knee that are contracted by three posterior thigh muscles. Inflexibility in the hamstring can therefore cause serious leg injuries, such as tears and inflammation. By keeping hamstrings flexible through a wide range of motion, many of these injuries and ailments can be prevented. Hamstring flexibility is not only important to athletes such as runners and cyclists, but it is also important for people working desk jobs, for daily activities like walking, and for battling symptoms like lower back pain. Yoga is a great way to increase flexibility in the hamstring. The following are 10 yoga poses that can help with tight hamstrings. Each pose will have a rating of ease and effectiveness. The "ease" rating rates how easy it is to do the pose correctly, and without potentially aggravating a muscle. The "effectiveness" rating rates how effective it is in stretching the hamstrings.
The Down Angle Pose

While in a tall sitting position, press the soles of your feet together and drop your knees to the side. Keep your back flat and hold your feet with your hands, activating the abdominal muscles. Slowly lower your torso towards your feet, leading with your chest and while maintaining a straight back. Continue to lean until you feel your hamstrings resisting the motion. Hold that position in resistance for a bout five breathes as you relax into the stretch, then try to press a little farther. Slowly release the stretch and repeat.
The Forward Fold/Uttanasana

While standing tall with feet shoulder-width apart, bend your knees slightly and keep your arms at your sides. Take a deep breath then, on the exhale, bend your body forward at the hips, lowering the head to the floor. Continue this fold, with your head, neck, and shoulder relaxed, until your hamstrings have resistance. Hold this position for 30 seconds. Wrap your arms around your head and grab your elbows to pull more weight and add intensity to the stretch. You may slowly rock side to side as well. When ready to release the stretch, bend your knees and roll up slowly to a standing position. Doing this slowly prevents a head rush. Repeat as desired.
The Standing Split/Urdhva Prasarita Eka Padasana

In a standing position with your arms at your side, inhale and reach your arms overhead. As you exhale, bend at the hips and move into a folding position with your chest heading downwards. Shift your weight onto one leg and put both hands on the floor. After balanced, raise the free leg as high as possible behind you. By walking your hands back toward your standing leg, tuck your chin and deepen the stress. While keeping your hips parallel to the ground, continue reaching to the ceiling with your extended leg and hold for five breaths. Slowly lower the leg to release and return to a standing position.
The Reclining Hand-To-Big-Toe Pose/Supta Padangusthasana

Lie on your back on your mat with your leg extended. Bend one knee and hug it to your torso. Hook your fingers around your big toe and straight your knee, extending your leg and straightening the knee until resistance if felt, all while keeping your head and shoulder blades relaxed on the floor. Hold this position for 30 seconds before releasing and switching legs.
The Downward Dog/Adho Mukha Svanasana

While on your hands and knees in a table position and with toes turned under, place your hands just in front of your shoulders and life your knees away from the floor until your legs are straight. Press through your hands as you shift your weight to your heels and keep your back flat and head between elbows. Lower your heels as you relax with each breath. Hold 30 seconds before releasing.
The Staff Pose/Dandasana

Sit on the floor with a straight tall back and extend your legs in front of you. Flex your feet with toes pointing to the ceiling and draw down your shoulder blades until you are in a 90-degree angle. Hold for 30 seconds and release.
The Head to Knee Forward Bend/Janusirsasana

While sitting, with your legs in front of you and back straight, bend one knee until your foot is inside the opposite thigh. Maintain a straight back while rotating your torso to the straightened leg. Bend forward at the waist so that your head comes toward your knee until you feel resistance. Hold 30 seconds, release, and switch sides.
The Wide-Legged Forward Bend/Prasarita Padottanasana

With both feet on the ends of your mat in a wide stance, turn your toes to face forward. Lift your chest and fold forward at the waist with a flat back. In a position parallel to the ground, reach to touch the ground below your shoulders. Raise your head and look toward the ceiling, holding for five breaths before walking your hands toward your feet and folding completely at the waist. Bring your head as far between your legs as possible, if not resting the top of your head on the floor. Hold 30 seconds and release slowly, maintaining a flat back as you rise.
The Seated Forward Bend/Paschimottanasana

Extend both legs in front of you as you sit up tall on your mat. With a long and straight back, slowly lean from the hips forward until you feel hamstring resistance. Grab your feet if possible and rest there for 5 breaths before leaning further into the stretch. Hold 30 seconds before releasing.
The Gate Pose/Parighasana

While kneeling on the floor with extended hips, extend one leg to the side and rotate your hip so that the toes point towards the ceiling. Use a block to prop your leg up if necessary. Keeping the opposite knee in line below you, line the extended heel with the planted knee and keep hips forward-facing. Extend arms to the sides with shoulders square. Reach with the hand on the extended side for the extended foot while brining the other arm over head. Contract your core while keeping your torso over your hips, hold for 30 seconds, release, and switch sides.
