The squat is one of the most famous exercise movements of all time—and a movement that comes to our aid every time we need to use the toilet, get up off the couch, and more. Still, despite how often we squat both in sport and in life, many of us execute it with sub-optimal form. 

“The squat is one of seven basic human movement patterns, so not squatting at all would interfere with your ability to do things like sit or go to the bathroom independently,” shares Kenny Santucci, founder of Strong New York and The Strength Club.

Given the importance of squatting, it’s important to get the move right so you can stay safe and reap maximum benefits from every rep. Here, trainers break down the most common squat form mistakes and how to fix them. 

The Benefits Of Squats

“Whether unweighted or weighted, squats are an excellent strength exercise that can strengthen all the muscles in the lower body,” says John Gardner, C.P.T., CEO of fitness platform Kickoff. This means that your quads, glutes, calves, hamstrings, and hip flexors all get lots of love. 

Read More: 5 Strength Moves Everyone Should Do

Not only does a stronger lower body offer benefits in itself, but having strong muscles also reduces the risk of injury to the joints, ligaments, and tendons around them, Gardner says. “Because squats involve bending and stretching the leg muscles, they help make the surrounding tendons and ligaments more elastic,” he explains. The result? Greater range of motion, mobility, and flexibility, a trio with injury-prevention perks. 

Exactly How To Squat Properly

In order to reap these squat benefits, you need to squat correctly. Gardner recommends starting with your feet shoulder-width apart and your toes pointing outward slightly (though the ideal foot angle varies from person to person). When you’re ready to begin, engage your core and bend at your knees and hips to send your butt backward and down as if sitting onto a chair. Continue lowering as far as you can while maintaining an upright torso and knees pressed outward. From there, press into your heels to return to the starting position, keeping your back neutral.

5 Common Squat Form Mistakes—And How To Remedy Them

Squatting correctly sounds easy enough, but a number of form flubs can affect the safety and impact of the exercise if you’re not careful. 

1. You have noodle knees 

Specifically: cooked noodle knees. When you lower into a squat, your knees shouldn’t rotate inward excessively, Santucci says. This puts undue stress on your knee joints and their surrounding tissues, increasing your risk of injury over time. (You’ll be able to tell if you do this by taking a head-on video of yourself squatting, but a personal trainer can point it out after peeking at a squat rep or two.)

If your knees do tilt inwards, Santucci suggests de-loading the movement (read: drop the weights) and working with a resistance band looped around your legs just above the knees. The pressure of the band provides a reminder to actively press your knees out as you sit back into, and stand up out of, your squat. “You should feel like you’re fighting the band the entire time,” he says. 

2. You’re hinging Instead

As far as lower-body movements go, two movement patterns reign supreme: The squat and the hinge. 

The squat pattern, which you use anytime you squat clean, front squat, box jump, or air squat, involves bending at the knees and sitting your hips back. The hinge pattern, which you use anytime you deadlift, kettlebell, hip thrust, or sumo deadlift high pull, meanwhile, involves bending at the hips and pushing your butt back. 

Indeed, both movements are vital to keeping your lower half strong and mobile—but they are two distinct movements that have different muscle groups and joints as their primary movers, explains Gardner. While your quads do the bulk of the work during the squat, your hamstrings take over during the hinge. “The main joint leading the squat is the knees, while in the hinge it’s the hips,” he says. 

You might be hinging rather than squatting if your thighs don’t become parallel to the floor as you complete a squat rep but your chest does. 

If that’s you, Gardner recommends thinking about initiating the movement from both your knobs and hips. “Bend your knees while simultaneously pushing your butt back behind you,” he says. “Then, as you lower, think about keeping an open chest and upright position.” 

3. You’re step-dancing 

Squatting isn’t like ballet; you don’t want to shift all your weight into your toes! Why? You’re much less stable on your tip-toes than flat-footed. And whether you’re squatting fat stacks or just bodyweight, you want to move with control, explains Gardner. Pushing through your entire foot also allows you to stand out of the bottom of a squat with much more power than pushing from your toes alone, he says. 

If your squat session ever turns into a step-dancing class, spend some time tweaking your form or the conditions you’re squatting under. 

“The main reason someone goes up onto their toes is limited ankle mobility,” says Gardner. “To improve your mobility, spend extra time warming up so that you can tap into your full range of motion and stretch your calf muscles on a regular basis.” 

Read More: What’s The Difference Between Mobility And Flexibility?

Since improving mobility takes time, Santucci recommends putting two small weight plates under each heel during squats in the meantime. “This reduces the amount of ankle flexion required to hit depth, and thus will help you keep your heel in contact with the ground the entire time,” he explains. 

4. You’re squatting too low (or not low enough) 

Generally speaking, you want to lower into a squat until your thighs pass being parallel to the floor, meaning that the angle between your hamstring and calf is less than 90 degrees. 

However, this rule does not apply to everyone. “Not everyone has the flexibility or mobility in their hips, knees, ankles, and thoracic spine required to drop to the bottom of a squat,” Santucci says. And if someone with inadequate mobility in one (or more) of these joints tries to go super-low, other joints are forced to compensate. For example, if someone does not have sound ankle mobility, their knees do double-duty, which is capital-b Bad for them.

To see if you have the mobility required to squat deeply, Gardner suggests trying a test popularized by the CrossFit community known as squat therapy. Start by setting up a medicine ball about 18 inches from a wall. Then, position yourself between the ball and the wall, facing the wall. Next, raise your arms overhead and slowly sit your butt back towards the ball. The goal is to be able to sit back and down onto the ball without your arms, knees, or face hitting the wall.

If you can comfortably do this test, squat to depth to really work the squat muscles through their full range of motion and increase the movement’s muscle-building potential, Gardner says. If not, squat only as low as you can before you come into contact with the wall.

5. Your midline is asleep 

If you care about the health of your lower back (and you should!), you need to keep your core contracted from start to finish on every single squat rep you do.

“Keeping your core engaged helps keep your spine in a neutral position,” explains Gardner. “If your core is not engaged, it puts pressure on your lower back and can cause your spine to arch.” 

Luckily, a loosey-goosey core is one of the most common—and easiest to fix—squat form mistakes out there. To keep your midline turned ‘on’ throughout the movement, think about filling up your abdominals with air by breathing deeply into your belly, he says. Another way to think about it is to pretend you’re bracing for a sucker punch to the gut.