In short: sphinx is the gentlest yin backbend. You lie on the belly, prop yourself up on the forearms and let the lower back settle into a soft arch while the belly, buttocks and legs relax, then stay for several minutes. Seal is the stronger version on straight arms. Bernie Clark teaches the two together.
This page compares yin sphinx with the active sphinx pose and with cobra, explains elbow and hand placement, and covers the cautions.
The name and the related asanas
Sphinx and Seal are English names, used in yin and in other styles; neither has an established Sanskrit name. The shape of yin sphinx is the same as the active sphinx pose. The difference is in the effort: in yin you let the lower back hang into the arch with the muscles relaxed, if your back tolerates that, and stay for minutes. Paul Grilley describes Seal as the yin variation of cobra (Bhujaṅgāsana): unlike cobra, you support your weight on the arms and release the spine.
Setting up with props
Clark has you clasp the elbows and place them just ahead of the shoulders; Sarah Powers puts them shoulder-distance apart and about an inch in front of the shoulders. Moving the elbows forward lessens the arch. A cushion under the elbows lifts the chest, and a bolster under the armpits lets you relax completely. A blanket or bolster under the pubic bone softens the pressure on the front of the pelvis.
You have choices for the arms and legs too. Clark offers palms flat on the floor in front of you, like the statue, instead of clasped elbows. For a very gentle version he lets you rest lower on the ribs with the elbows slid well forward, and notes that simply lying on the belly may be enough of a backbend for some people. Legs apart tends to deepen the feeling in the lower back; legs together spreads it more evenly along the spine. Powers adds one cue for the shoulders: rest on the arms without slumping down into the shoulders or hunching them up.
The long hold
Let the belly drape toward the floor and the legs go soft. Yoga Journal’s 12-pose sequence holds sphinx for four to five minutes. If the lower back complains, Powers suggests engaging the outer buttocks and inner legs for part of the hold, or skipping the pose; Clark suggests moving the elbows forward.
If the head starts to feel heavy, Clark suggests resting the chin on your fists or the head in your hands, so the neck can let go. Keep the breath slow and easy. Sphinx can be held longer than Seal, which makes it a good place to settle and simply watch the breath. In a class, Clark places Sphinx before saddle, because it is the milder backbend, and Seal after it, because straight arms make it deeper than saddle.
Seal
Seal is Sphinx on straight arms, and it arches the lower back much more. Powers slides the hands about four inches in front of the shoulders and a little wider, turned out slightly like flippers; Grilley places them in front of and to the sides of the shoulders with the fingers angled out, and lets the shoulders rise unless the neck feels pinched. Clark suggests starting with one-minute holds, resting and repeating, and building up slowly; Grilley holds at least a minute, working up to five. Powers notes it may take months before the buttocks and legs can stay relaxed; until then, contract them from time to time. Leave Seal at any sharp sensation.
Coming out and the rebound
Lower the chest slowly, turn the head and rest the cheek on the hands, and lie still for a few breaths. Powers lowers down on an exhalation and then stays still, breathing into the back while it rests. Clark suggests sliding one knee up to the side to ease the lower back (the knee on the side you are facing, with the knee and foot staying on the floor), then child’s pose or a few slow rounds of cat-cow. Keep that cat-cow soft and in time with the breath; Clark’s advice is not to make these your deepest cats ever. Move into child’s pose slowly, since the back has been still in one shape for minutes.
Precautions in plain words
Clark lists a poor back condition, a tight sacrum, sharp pain, pregnancy without modification and headaches as reasons to skip or adapt these poses. Keep Sphinx low and short if your lower back is sensitive, and stay out of Seal until Sphinx is easy. In pregnancy use generous bolsters under the hips and chest or choose another pose. This page is general information, not individual advice.
Before, after and where it is taught
Crocodile is a good way to arrive on the belly. Cobra is the active cousin, and melting heart and saddle are the other yin backbends. You will meet it in yin yoga classes, which hold mostly floor poses for several minutes with the muscles relaxed, and in some gentle and restorative classes.
