Considered the king of exercises for lower body, squats are key to developing the quads, the largest muscles in the body. Advanced lifters often use extremely heavy weights, but it's important to master correct form before you go heavy. Feet shoulder width apart, take the weight on your shoulders. Keep your back straight, chest out, head up. Bend at the hips and knees, taking the knees in a straight line in front of you. Aim to take the thighs parallel to the floor, especially at first. The lower you go, the more you work the glutes. Make sure you have a weight you can control on the way up.