ACSM Personal Trainer Certification Practice Exam

The main function of the bar squat exercise primarily involves knee extension and hip extension. When performing a squat, the primary movement pattern requires the knees to flex and extend as the body lowers and raises. Specifically, the quadriceps are heavily engaged during knee extension to help straighten the leg from the squat position. Concurrently, the gluteal muscles and the hamstrings are activated for hip extension as the hips move downward in the squat and then return to a standing position.

While other options involve movements of different body parts, they do not relate directly to the fundamental mechanics of the squat. Knee extension and hip extension are pivotal for effectively executing the squat, making option A the correct answer. This exercise is essential for lower body strength development, contributing to overall muscle balance and functional movement, relevant for athletic performance and everyday activities.