Movement - core: Gluteus Maximus.

• A. Rectus Abdominis
• B. Gluteus Maximus
• C. Latissimus Dorsi
• D. Hamstring Complex

Answer: (B)

Hip extension is the movement involved, and the gluteus maximus is the primary muscle driving that action. It extends the thigh at the hip, which powers movements where the leg moves backward or you stand up from a bent-knee position, such as squats, bridges, running, or stairs. The rectus abdominis mainly flexes and stabilizes the spine, not extend the hip. The latissimus dorsi works on the back and arms, not the hip joint. The hamstring complex helps with hip extension as well, especially when the knee is straight, but it plays a supporting role to the gluteus maximus, which provides the strongest hip-extension force.