Hard-Core Arm Balance: Lolasana
Lolasana is called Pendant Pose for a reason: The body really dangles and even swings a little bit. The foundation of the pose is the hands; the rib cage hangs from the upper arms and shoulders; the spine and pelvis hang from the rib cage; and the legs hang from the spine and pelvis. The pose is highly effective for strengthening all of the abdominal muscles, most of the hip flexors, and several shoulder muscles, but it puts extraordinary demands on the external oblique abdominals, making it especially powerful for strengthening the sides of the waist.
To get an intuitive sense of the muscles involved, sit in a sturdy chair, put your hands on the seat on either side of your hips, lean forward about 45 degrees, and push down firmly to take most of the weight off your pelvis. At first, relax your abdomen and hips, allowing your pelvis and legs to hang down so all the work is in your arms, chest, and shoulders. Notice that the triceps muscles on the backs of your upper arms tighten to straighten your elbows, and two other muscle groups—the pectorals, on the front of your chest, and the serratus anterior muscles, which run from your inner shoulder blades to your side ribs in front of your armpits—work together to lift your rib cage upward. This upward pull tends to make your ribs swing up and away from your dangling pelvis, similar to the movement they make when you inhale deeply.