Which muscles are included in the posterior chain?

• A. Hamstrings (biceps femoris, semitendinosus, semimembranosus)
• B. Quads
• C. Deltoids
• D. Pectoralis major

Answer: (A)

The posterior chain is the group of muscles on the back side of the body that power hip extension and spine stability. The hamstrings—biceps femoris, semitendinosus, and semimembranosus—are a central part of that group. They cross both the hip and knee joints, allowing hip extension when you hinge or stand tall and assisting knee flexion. In movements like deadlifts and other hip-dominant lifts, these muscles work with the glutes to extend the hips, which is exactly what the posterior chain does. The quads are the main knee extensors on the front of the thigh, so they belong to the anterior chain. Deltoids and pectoralis major sit in the shoulder and chest regions, not in the backside muscle group.