Quads
 

Quads

Barbell Front Squat with Heels Elevated

"Elevating your heels helps keep your torso upright, reducing the chance of a lower-back injury," says Dowdell. It also increases the load on your quads.

Do this: With your heels on weight plates, hold a barbell across the front of your shoulders with your palms facing up. Squat until your thighs are parallel to the floor. Do 10 reps.