Paschimottanasana (Seated Forward Bend)

Paschimottanasana is usually translated as the seated forward bend, but the Sanskrit is more interesting than that. Paschima means west, and in the old convention a person facing the rising sun has the whole back of the body facing west. Uttana means an intense stretch. So the name means the intense stretch of the west, meaning the entire back surface of the body from the heels to the crown of the head.

That is a better description of what the pose is doing than any anatomical list. It is not a hamstring stretch, although the hamstrings certainly notice. It is one continuous lengthening of everything down the back: calves, hamstrings, the muscles alongside the spine, the upper back, and the base of the skull.

It is also, of all the poses on this site, the one with the clearest pose specific research behind it. A randomised controlled trial of four weeks of practice found lumbar flexion angle improving from 80.24 to 68.86 degrees in the group who practised it, with no significant change in the control group who simply lay in Savasana. Four weeks is not long, and the change was real.

These two instructions solve about ninety percent of everything that goes wrong in this pose, and neither is what people expect.

Sit higher. When you sit flat on the floor with straight legs, tight hamstrings pull the sitting bones downward and tip the pelvis backwards. A backward tipped pelvis means the lower back is already rounded before you have folded at all, so every centimetre of the fold comes out of the spine rather than the hip. Sit on the front edge of one, two or three folded blankets until the pelvis tips slightly forward and the lower back has its natural inward curve. Then start.

Bend the knees. This feels like cheating in a pose whose photograph shows legs flat as a plank. It is not. Bending the knees slackens the hamstrings, which lets the pelvis tip, which lets the spine stay long, which puts the stretch where it belongs. Over months the knees straighten themselves. Over the same months, a forced straight leg practice produces a rounded lumbar spine and often a sore back.

Once both are in place, the pose changes character entirely. Students who have avoided it for years suddenly find it comfortable, and comfortable is what allows the three minute hold that actually changes tissue.

There are two ways to get your head towards your knees, and they are entirely different poses.

The rounding way. Reach for the toes, pull with the arms, and let the spine curl. The head gets low quickly. The hamstrings are barely lengthened, the lumbar discs are loaded in flexion, and the shoulders end up around the ears.

The hinging way. Keep the front of the body long from the pubic bone to the breastbone, and tip the whole trunk forward from the hip creases as one piece. The head stays high for a long time. It looks far less impressive. It is the pose.

The way to tell which one you are doing is to watch where you feel it. A hinged fold is felt as a broad pull along the backs of the thighs. A rounded fold is felt in the lower back, or in a sharp line right up at the sitting bone, which is where hamstring tendons get irritated and where they take months to settle.

Lead with the breastbone, use a belt so you are not tempted to pull, and accept a much shallower looking pose. The same lesson, standing up, is on the Uttanasana page.

This is the pose that taught me most about patience, and I still watch students try to argue with it.

A muscle under a mild sustained stretch releases gradually, over a minute or two, as the nervous system decides the position is safe. A muscle that is yanked contracts protectively, which is the opposite of what you want. So the technique is: set up carefully for the first thirty seconds, and then stop working.

• First thirty seconds: arrange the height, the knees, the hinge. Active.
• Thirty seconds to a minute: stop adjusting. Let each exhale soften you a little.
• One to three minutes: do nothing at all. Let the pose deepen without your permission.

What most people do instead is spend three minutes pulling, and come up having achieved nothing but a sore hamstring tendon. If you find you cannot stop working, use the supported version with a bolster across the thighs, which physically removes the option.

Practise it in the evening rather than the morning if you can. The body is warmer, the hamstrings are far more willing, and the quietening effect is more useful at the end of the day.

Two contradictory things are true, so I will state both.

It helps a great many stiff, tired backs. A long passive lengthening of the lower back, held for two or three minutes with the chest supported on a bolster, is genuinely relieving for the ache that comes from sitting or driving all day. It is one of the poses I recommend most often for that.

It can aggravate a disc problem. Sitting and folding forward loads the lumbar spine in flexion, and for an irritated disc that is the position that hurts. If your pain is sharp, if it shoots down a leg, if it is worse first thing in the morning or worse for sitting, this is not your pose in its full form.

What to do if you are unsure: practise the lying down version. On your back, one leg at a time, a belt around the foot, the other knee bent with the foot on the floor. The hamstring gets its lengthening and the spine stays neutral and supported on the ground throughout. If that feels good and the seated version does not, you have your answer. There is more about which movements suit which backs on the yoga for back pain page.

One to three minutes, once or twice. In the supported version with a bolster, up to five minutes.

It belongs late in a practice, after the standing poses and after any backbends, because the body is warm by then and because a long forward fold begins the settling that leads into rest. In a traditional sequence it follows the inversions and precedes Savasana.

A month:

• Week one: sitting high on two blankets, knees well bent, belt around the feet, one minute.
• Week two: the same, ninety seconds, checking that you stop working after thirty seconds.
• Week three: two minutes, letting the knees straighten only as far as the spine allows.
• Week four: three minutes, or five in the bolster supported version at the end of the day.

Its counter pose is a gentle backbend. Thirty seconds in a low Bhujangasana or a sphinx after a long forward fold returns the spine to neutral. Do not skip it, particularly if you have been folding for several minutes.

Time rather than force is the whole method in this pose. Every row assumes bent knees and a strap, because that is what makes the time bearable.

If a back currently hurts, leave this pose out for now. It is in the avoid list on two of the condition pages here for exactly that reason.

This is a pose with a split reputation on this site: it is used deliberately in one place and advised against in two others, and the difference is entirely about whether a back currently hurts.

• Yoga for back pain puts it in the avoid list, because a deep seated forward bend loads a lumbar spine that is already complaining, and because most people do it from the waist rather than the hips.
• Yoga for neck and shoulder pain leaves it out as well, since the usual way it is practised drags the head towards the knees and the neck goes with it.

For a back that is merely stiff rather than sore, the pose is useful with the knees bent and a strap around the feet. It is the counter to Padmasana and to the backbends, and it is where the bedtime sequence slows down before the practice ends.

Practically: bend the knees, put a strap or a towel around the feet, and stop when the back stops being long. The hamstrings will let go over months, and never on the day you decide they should. Warm the spine with Marjariasana first, take Balasana afterwards if the lower back has anything to say, and finish in Savasana. In a hatha class it is usually held for five breaths; in a yin class it is held for minutes with the back deliberately round, which is a different practice with the same name. If you are over forty and coming back to movement, yoga for beginners over 40 is the sensible frame, and a class is where somebody tells you which of the two you are doing.