What muscles does the barbell squat work and how can they be effectively targeted during the exercise?

The barbell squat primarily works the quadriceps, hamstrings, glutes, and lower back muscles. To effectively target these muscles during the exercise, focus on maintaining proper form, such as keeping your back straight, lowering your body until your thighs are parallel to the ground, and pushing through your heels as you stand back up. Additionally, using a full range of motion and gradually increasing the weight can help target these muscles more effectively.