The abductors are the outermost head of the quadricep muscle, responsible for the sweeping shape of the thigh. Their main function is to extend the leg outwards from the body, allowing you to perform splits.
The training of the abductor muscles is best lumped in with the training of the other heads of the quadricep. However, a deficiency in this area may be corrected by using the techniques listed below when performing these exercises. When altering how you perform a heavy exercise, make sure you start out with lighter weights to avoid injury.
The abductors are the outermost section of the thigh, seen here on Stan's right leg extremely ripped and highly stirated.