The adductors are a group of 5 muscles that make up the musculature of the inner thigh. They are called the Pectineus, the Adductor Magnus, the Gracilis, the Adductor Brevis, and the Adductor Longus. Their job is to connect the inner thigh bone to the pelvis via the pubis (part of the pubic bone) and/or the ishium (part of the sitting bone). From the pubis and/or sitting bone they fan out toward the thigh bone attaching at various locations along that bone. (see picture below, care of Spence, Alexander: Basic Human Anatomy, 3rd Ed., 1990).
The Adductors "other" Role
I call this the "other role" because it is one which we don't consider often. It is the role of core stability - where the adductors act to bring the legs together to create a foundation for safe, fluid and deep movement, enabling you to move more smoothly and with greater ease into backbends, twists and forward bends.
How do the Adductors do this?
In drawing the legs together, the adductors bring the action of the asanas inward to the core of the body. When we do this effectively - with a balanced pelvis - we automatically cause the pelvic floor muscles and Mula Bandha to activate. When the pelvic floor muscles and Mula Bandha have activated, we have created a very subtle yet solid foundation and our movement becomes easy.
Something to try
Next time you are moving into Supta Virasana (backbending toward the floor while kneeling with your bum on your heels or on the floor), take 2 blocks or 2 phone books between your inner thighs and gently squeeze them. Be sure that you place the blocks or books in such a way that your knees are in line with your hip joints. Continue to gently squeeze your props as you move backwards. You may have the pleasure of enjoying a much more fluid and deeper sense of movement.