Define "flexibility" within the context of Pilates.

Flexibility in the context of Pilates is defined as the ability of joints to move through their full range of motion safely and effectively. This definition emphasizes not just the extent of movement possible at a joint, but also the aspects of safety and effectiveness. In Pilates, flexibility is crucial because many of the exercises are designed to enhance the body's flexibility, allowing for better posture, increased mobility, and injury prevention.

Pilates incorporates stretching and the use of controlled movements that focus on lengthening the muscles while also promoting strength, thereby improving the overall flexibility of the body. This concept is integral to achieving the balanced body that Pilates aims for, where flexibility and strength work synergistically. Other choices do not align with the core principles of Pilates regarding flexibility, as they relate more to strength, endurance, or movement dynamics than to the capacity for joint movement.