What is an assist for the footwork exercise on the reformer?

In the context of the footwork exercise on the reformer, using a ball between the knees serves as an effective assist by promoting awareness and engagement of the inner thigh muscles. This can enhance the stability and alignment of the pelvis while performing the footwork. By placing the ball between the knees, the practitioner is encouraged to actively squeeze the ball, which not only activates the adductors but also encourages proper pelvic positioning. This assist helps maintain the focus on controlling the movements of the legs and ensuring that the back remains stable, providing a more integrated and safe practice.

The other choices, while they may serve specific purposes in different contexts, do not directly assist with the footwork exercise in the same beneficial manner. A resistance band might offer additional resistance but could detract from the focus on leg movements. Elevating the feet on a platform changes the mechanics of the exercise and may not support the intended alignment or engagement as effectively as the ball. Extending the arms overhead tends to shift the focus and load to the upper body rather than helping with the lower body work that footwork exercises emphasize. Thus, the use of a ball between the knees is particularly well-suited to enhancing the footwork exercise on the reformer.