There’s a fun phenomenon that occurs sometimes in yoga classes. You’ll be so precisely and earnestly focused on maintaining a straight back that you extend right past the point of normal curvature and assume a pose that a personal-training colleague of mine once called “stripper.” Your shoulders will be drawn back, which is generally supportive, but you’ll have pressed your chest too far forward and your tailbone backward and upward. It’s essentially voluntary (and hugely exaggerated) lordosis. In most standing and seated poses, this intense curvature is unhelpful. The spinal length that we seek in these poses cannot be achieved if we’re so acutely arched that we could launch ourselves forward for sheer potential energy.
Kaminoff and Matthews, in the second edition of Yoga Anatomy, provide an excellent overview of normal spinal curvature, including its development in the human body. They discuss the formation of the spine in utero, and compare this process in humans to the evolution of various skeletal structures in animals. Commonly, a neutral spinal alignment, in which the lordotic (or forward-pointing) curves of the cervical spine (roughly neck) and lumbar spine (roughly lower-back), and the kyphotic (or backward-pointing) curves of the thoracic spine (roughly shoulders) and sacral region (near the tail-bone) are maintained without exertion, is the most useful. There are poses that require exaggeration in these curves, an obvious example being matsyasana (Fish Pose).
Knowing the purpose of the poses that you’re doing and the muscles involved in supporting them is important. These factors will help to guide you in determining whether or not a neutral spine or emphasis in a particular region is necessary.
A helpful exercise involves tadasana (Mountain Pose). It’s very easy to assume “stripper” here, so it’s a great asana in which to practice a more mindful, modulated stance. Some branches of yoga differ as to the placement of the feet in Mountain Pose, but a valuable guideline to remember is that the larger the base of support, the less unsteady everything above it. This means that if you find balance difficult to maintain, if you have severe back/hip issues, or if you are working on rehabilitating your ankles, it will be safer for you to part your feet to hips’ distance as opposed to keeping them together. If, on the other hand, you would like to challenge yourself and you have no injuries to consider, keeping your big toes and ankles touching will allow you to work on balance as well as alignment.
Starting off, place your feet either hip-distance apart or touching. Press the ball underneath your big toe down firmly into the mat. Do the same with the ball beneath the pinky toe. Press your heel down as well. Imagine this creating a triangle of support, and envision “sucking” your arches upward. What you may notice is that your quadriceps (front of the thighs) and adductors (the inside part of the thighs that face each other) activate when you do this. Now, imagine someone standing above you, drawing you upward by a string at the top of your head. Feel your spine lengthening upward; drop your shoulders down and away from your ears.
Take note of where your pelvis, tailbone, and the front of your ribs are. You may find, if you’re having a particularly enthusiastic day and no access to a mirror, that the front of your ribcage and chest have been thrust forward, and your hips and tailbone backward and up. Here we have stripper! The combination of an exaggerated lordotic curve through the lumbar spine and a flattening out of the kyphotic curve in the thoracic spine, though, is not what we’re looking for in tadasana. To correct this, it’s easiest to work our way from bottom to top. Draw your tailbone down, until you’re performing a very mild posterior pelvic tilt. Moving upward, “knit” the lower ribs together and draw them in. This will have the effect of positioning your sternum in a forward-facing direction. If you were to look in a mirror now, a more natural set of curves would be present in the spine.
From here, continue to lengthen upward while relaxing the shoulders. Play with this pose by purposefully emphasizing the curves in the spine and then coming back into neutral alignment. Remember to check in with your pelvis and the front of your ribs. As always, it is helpful to have a mirror available – think of it as instant biofeedback – or a friend/instructor who can give you an idea of whether or not what you’re sensing in your musculature is what’s visible externally.