What muscle group is primarily engaged during the exercise called "Breast Stroke"?

The primary muscle group engaged during the "Breast Stroke" exercise is the erector spinae. This group of muscles runs along the spine and is crucial for spinal extension, stability, and posture. In the context of the Breast Stroke exercise, the erector spinae facilitates the extension of the back as the upper body lifts and lowers. It supports the spinal alignment while performing the movements, enhancing strength and control in the back. This engagement aids in developing flexibility and endurance of the back muscles, which is essential for effective performance in Pilates and other physical activities.

While other muscle groups contribute to the movement in varying degrees, they do not play the central role that the erector spinae does. Glutes primarily assist in hip extension and support pelvic stability but are not the focus of this specific exercise. The hip flexors work to assist in lifting the legs and pelvis but are less involved compared to the targeted engagement of the back muscles. The transversus abdominus functions to stabilize the core, but it does not play as direct a role in the main movement pattern of the Breast Stroke as the erector spinae does.