How is the Pilates stance defined?

The Pilates stance is defined as standing tall with the feet positioned in a "V" shape and the heels together. This posture is fundamental in Pilates as it promotes proper alignment of the body, engages the core, and encourages balance and stability. The "V" position emphasizes the external rotation of the hips, which helps activate the gluteal muscles and maintain a strong posture. This stance is often used as a starting point for various exercises in Pilates, as it sets the foundation for movement while ensuring that the practitioner maintains awareness of body alignment and core engagement.

In contrast, the other options represent different positions that do not capture the essence of the Pilates stance. Lying down with legs extended, sitting with legs crossed, or being in a prone position facing down do not facilitate the same alignment and engagement that is critical for the foundational "V" stance in Pilates practice.