What is the purpose of placing a tennis ball between the knees during the side to side exercise?

Placing a tennis ball between the knees during the side-to-side exercise serves to challenge stability and control throughout the movement. This setup creates a need for the practitioner to actively engage the inner thigh muscles, as they work to hold the ball in place while executing the exercise. The requirement to maintain pressure against the ball enhances proprioceptive awareness and helps build strength in the surrounding stabilizing muscles.

Additionally, this setup promotes proper alignment and encourages a focus on the core and pelvic stability, contributing to a more controlled execution of the exercise. The dynamic interaction with the ball reinforces coordination between the upper and lower body, ultimately leading to improved overall body awareness and performance in Pilates. This approach not only amplifies the effectiveness of the exercise but also integrates a playful aspect, making the workout more engaging.