As any trainer worth her salt will tell you, it’s crucial to watch your form when doing leg exercises. Here’s why: “Making sure your knees, hips and other body parts are in just the right place both helps you avoid injuries and ensures that you’re actually working the muscles you intended to work,” says New York City-based personal trainer Jenny Joseph Williamson (http://www.fitnessbyjj.com). Read on to discover the leg exercises most people do wrong—and how to fix them.
RELATED: Leg Exercises Everyone Should Do
Leg exercise: Squat
Biggest mistake: Letting your knees cave in or splay out, or lifting your heels. “Allowing your knees to lean in or out not only puts unnecessary stress on your knees, but you miss out on an opportunity to strengthen the muscles on the sides of your legs,”says Williamson. Lifting your heels can also do a number on your knees, plus it removes the solid foundation you need if you’re using weights.
Do it right: Stand with feet parallel and shoulder-width apart. Slowly begin to sit your weight back into your heels as you bend your knees and push your hips back; stop when your knees reach 90 degrees (as shown). Knees should remain shoulder-width apart throughout the move. Push into your heels to return to standing.
Leg exercise: Lateral (Side) Lunge
Biggest mistake: Pushing your leading knee too far to the side or bending the assisting leg. “The first puts extra stress on the knee, while the second removes some of the challenge from your inner thighs,” says Williamson. The less you challenge your muscles, the less effective the leg exercise is.
Do it right: Stand with feet together and hands on your hips. Keeping your right leg straight, step your left foot out to the left side, bending your left knee (keep it in line with and behind your second and third toes) and hinging forward from the hip (as shown). Push off with your left foot to return to starting position, then repeat on the opposite side.
RELATED: 5 Ballet-Inspired Leg Exercises
Leg exercise: Side Lying Hip Abduction
Biggest mistake: Rotating your top leg out or kicking with that leg. “When you turn the hip out that way, it changes the muscles you’re using to do the movement, so your outer thighs don’t get as much of the action as they should,” says Williamson. Kicking isn’t ideal because the momentum you build up make the move easier—so you get less out of it.
Do it right: Lie on your right side with your head resting on your right hand, legs extended with one stacked on top of the other, feet flexed. Your hips should be straight up and down (don’t lean forward or roll back). Keeping your top leg straight, lift it up, leading with the side of your foot. Pause, then lower the leg back down. Repeat on the opposite side.
Leg exercise: Straight Leg Deadlift
Biggest mistake: Rounding your back or locking out your knees. “If you round your back, you end up using your back muscles instead of your butt and hamstrings to lift the weight,” says Williamson. And yes, it’s called a “straight leg deadlift,” but bending your knees slightly will help you keep your back flat.
Do it right: Stand with feet hip-distance apart, a dumbbell in each hand in front of your thighs with arms straight and palms back. Slowly begin to hinge forward from your hips, sticking your butt out and keeping your back flat as you lower the weights toward the ground. With back still flat, squeeze your butt muscles and slowly return to previous position.
Leg exercise: Curtsy Lunge
Biggest mistake: Turning your hips when you lunge. “Doing that takes the ‘curtsy’ out of the move,” says Williamson. “That’s the part that really targets your outer thighs. Without it, you’re basically just doing a regular lunge.”
Do it perfectly: Stand with feet shoulder-width apart, hands on hips. Keeping hips squared and facing forward throughout the move, cross your right leg behind your left leg and bend both knees to come into lunge position. Push into both feet to return to standing, then repeat on the opposite side.