What muscle is responsible for rotating the trunk during a Pilates twist?

• A. Rectus abdominis
• B. External oblique
• C. Transverse abdominis
• D. Sartorius

Answer: (B)

The external oblique muscle plays a crucial role in rotating the trunk during movements such as a Pilates twist. This muscle is located on the sides of the abdomen and is responsible for the lateral flexion and rotation of the torso. When performing a twist, the external oblique on the side towards which you are twisting engages to pull the ribcage down towards the pelvis, facilitating the rotational movement.

In contrast, the rectus abdominis primarily aids in flexing the vertebral column and does not significantly contribute to trunk rotation. The transverse abdominis serves mainly to stabilize the core and support the spine rather than facilitate rotation. The sartorius muscle is located in the thigh and is involved in hip flexion and rotation of the hip joint, making it unrelated to the action of twisting the trunk. Therefore, the external oblique is the muscle specifically designed for the rotational movement required during a Pilates twist.