It can be a challenge to lift the arms in this relationship to gravity, with the spine in extension. If the latissimus dorsi are used to extend the spine (rather than the deeper, intrinsic spinal muscles), they will inhibit the movement in the arms. This position of the legs uses a complex interaction among adductors, medial rotators, and hip extensors. This is because many of the muscle actions that lift and support the body in this position create other actions that must be neutralized by opposing or synergistic muscles. For example, because the gluteus maximus, a powerful hip extensor, also externally rotates the legs, it’s preferable to use the hamstrings for hip extension. People will have different priorities, or challenges, depending on where they start and their preexisting patterns of strength and weakness as well as flexibility and tightness.