Lisa Walford’s reply:
The way you place your foot on the floor affects the knees, the groins, and the distribution of weight throughout the spine. In addition, the integrity and strength of the shin muscles contribute to the structure of the three arches in the foot. This is especially evident in balancing postures, but is true for every pose.
The foot really has three arches, the lateral, medial, and transverse arch. The lateral or outer arch consists of the outer edge of the foot, including the baby toe and the fourth toe. The lateral arch supports the medial arch, which, in a healthy foot, would not touch the floor. In your case, the ligaments of the medial arch and ankle may be overstretched and are therefore unable to support their normal lift. Meanwhile the peroneal muscles, which are the muscles of the outer shin, lack the ability to support the lateral arch. To remedy this, the shin muscles need to hug in toward the midline as the toes fan out and extend, just as the outer thighs do when you balance on one leg.
Start to focus on your alignment by using the wall as a prop. Begin with both feet together in Tadasana (Mountain Pose) and stabilize your pelvis by drawing the outer thighs in toward the midline of your body. Resist the temptation to squeeze the buttocks or rotate the thighs; keep the legs in Tadasana. It is important to establish this compactness in the outer thighs and support of the pelvis before balancing on one leg because shifting your weight onto one leg can distort the position of the hips, the knee, and the ankle.
Use the support of the wall for balance and shift your weight onto one leg. Lift the opposite foot slightly off the floor. Notice if your standing leg hip shifts away from the midline of the body. Draw the outer thigh in toward the midline to best maintain the alignment of the pelvis above the standing foot.
Now bring the weight into your toes to lift your standing heel slightly off the floor. Lengthen the big toe forward and fan the other toes wide until you feel the inner ankle being drawn in toward the shin and the inner arch being sucked upward. Slowly lower the heel, but resist by sucking the ankle up off the heel. Place the inner and outer sides of the heel on the floor at the same time.
If you continue to work diligently and focus on your feet in all of the standing poses, with time, the muscles in the outer shin, the sole of the foot, and the inner ankle will strengthen and realign to track and hold the ankle firmly so that you can balance with confidence.
Lisa Walford is a senior intermediate Iyengar Yoga instructor and has been teaching for more than twenty years. She is one of the directors of the Teacher Training Program at Yoga Works, in Los Angeles. She has served on the faculty of the 1990 and 1993 National Iyengar Yoga Conventions and studies regularly with the Iyengars.