ACSM Personal Trainer Certification Practice Exam

Which muscle group is primarily worked during back extension exercises?

1. Quadriceps

2. Erector spinae

3. Hamstrings

4. Deltoids

The correct answer is: Erector spinae

The muscle group primarily worked during back extension exercises is the erector spinae. This group of muscles runs along the spine and is responsible for extending the back, helping to maintain an upright posture and assist in bending the trunk backward. Engaging the erector spinae allows individuals to perform movements that require extension of the spine, which is essential for various activities, including lifting and standing. The quadriceps, which are located at the front of the thigh, are involved primarily in knee extension, while the hamstrings, located at the back of the thigh, play a significant role in knee flexion and hip extension. Deltoids are shoulder muscles responsible for arm movement and stabilization and are not involved in back extension. Therefore, the action of back extension specifically targets the erector spinae, making it the correct answer.