Squat form mistakes: what goes wrong, why, and how to fix it

Knees caving, heels lifting, a rounded lower back: most squat problems are small leaks with clear causes. Here is how to build a solid squat, spot your own mistakes on video and fix them one at a time.

Most squat form mistakes aren't dramatic. They're small leaks: knees drifting in, heels peeling off the floor, a few centimetres missing at the bottom. They get worse as the weight climbs and the set drags on. The good news is that each one has a likely cause and a fairly simple fix. Below you'll find the basics of a solid squat, the five mistakes lifters make most often, how to catch them on video, and the drills that help.

How a good squat is built

These cues are written for a barbell back squat, but they carry over to goblet and bodyweight squats. Hip structure and limb lengths vary, so treat this as a starting point rather than a rulebook.

Stance

Set your feet around shoulder width or slightly wider, toes turned out somewhere around 15 to 30 degrees. Try a few options with an empty 20 kg (45 lb) bar and keep the one that lets you sit deepest while staying balanced. Spread your weight across the whole foot, heel, big toe and little toe, like a tripod.

Breathing and bracing

Before each rep, take a big breath into your belly rather than your chest, then brace as if someone were about to poke you in the stomach. That pressure stiffens your torso and helps your back hold its position.

Hold the breath on the way down and through the hardest part of the way up, then exhale near the top. If you have high blood pressure or another health condition, ask your doctor about holding your breath during heavy lifts.

The descent

Bend at the hips and knees together and sit down between your feet, not back onto an imaginary chair. Let your knees track in line with your toes. It's normal for them to travel past your toes, especially with long thighs. Control the way down so you could stop at any point.

Depth

A common benchmark is the crease of your hip level with or just below the top of your knee, so your thighs are at least parallel to the floor. If you can go deeper while keeping your back position, there's rarely a reason not to. Your right depth is the deepest you can reach with a neutral spine and heels down, and it usually improves over time.

The ascent

Push through your whole foot so your hips and chest rise at the same rate. "Chest up, knees out" tends to work better than "drive your hips up". Stay braced until you're fully upright. The bar should move in a fairly straight line over mid-foot; if it drifts forward, one of the mistakes below is usually why.

5 common squat form mistakes and how to fix them

Almost everyone makes some of these, especially on heavy sets or the last reps of a long set. The goal isn't perfection. It's making the mistakes smaller and less frequent.

1. Knees caving in

What it looks like: your knees collapse toward each other, usually as you start to stand up out of the hole.

Common causes: under-used muscles on the outside of the hip, a stance that's too narrow, a load that's too heavy, or simply not thinking about your knees.

The fix: drop the weight, push your knees out over your toes and "screw" your feet into the floor without moving them. Try a slightly wider stance. A mini band around your knees in warm-ups gives instant feedback when they start to drift.

2. Heels coming up

What it looks like: your weight shifts onto the balls of your feet and your heels lift at the bottom.

Common causes: limited ankle mobility, starting the movement with your knees, or soft, thick-soled running shoes.

The fix: work on ankle mobility and squat in flat, hard-soled shoes or weightlifting shoes with a raised heel. As a stopgap, put a 2.5 kg (5 lb) plate under each heel, but keep working on the mobility itself.

3. Lower back rounding at the bottom

What it looks like: your pelvis tucks under and your lower back rounds in the deepest position. Most people call it "butt wink".

Common causes: going deeper than your current mobility allows, losing your brace at the bottom, or a stance that doesn't suit your hips.

The fix: film yourself and find where the rounding starts. For a while, stop just above that point and focus on bracing. Try a wider stance with your toes turned out a bit more. A small amount of pelvic movement on light sets is common, and coaches don't agree on how much it matters. With heavy weights, though, it makes sense to keep your back as neutral as you can.

4. Cutting depth

What it looks like: you turn around well above parallel, often without realising it.

Common causes: too much weight, fear of getting stuck, or not knowing where parallel actually is.

The fix: lower the load until you hit full depth and use a box or bench as a depth target for a few weeks. A side-on video is the quickest way to check whether you're really getting there.

5. Too much forward lean

What it looks like: your hips shoot up faster than your chest out of the bottom, and the squat turns into something closer to a good morning.

Common causes: quads that are weak relative to your posterior chain, a lost brace, or your weight sliding toward your toes. Some lean is normal, especially with a low-bar position and long thighs.

The fix: think "chest first" as you come out of the hole, keep the pressure in your belly and lower the weight until your hips and chest rise together.

Film yourself to catch the mistakes

What you feel and what you actually do rarely match, especially under a heavy bar. A few seconds of video tells you more than ten glances in the mirror.

• From the side: phone at hip height, square to your side, roughly 3 to 4 metres (10 to 13 ft) away. This shows depth, forward lean, back rounding and bar path.
• From the front: same height and distance. This shows knees caving and any shift to one side.
• Whole body in frame: from your feet to the bar, including at lockout.
• Same setup every time: so you can compare week to week.

Film your last set, because mistakes often show up only when you're tired, and pause the clip at the bottom. If you'd like help reading the footage, you can film your squat from the side in TANK and get a score from 0 to 100 with tips for every rep, so you can see which reps went off track.

Simple drills that help

You don't need a complicated corrective program. These fit into your warm-up or as accessory work:

• Goblet squat: holding a 12 to 16 kg (25 to 35 lb) dumbbell or kettlebell at your chest makes it easier to stay upright and find depth.
• Pause squat: hold the bottom for two to three seconds while staying tight. You learn to own the position and see whether your back gives way.
• Box squat: sit lightly onto a box at the right height and stand without relaxing. Great if you tend to cut depth.
• Tempo squat: a three-second descent gives you time to feel where your knees and heels are.
• Knee-to-wall drill: drive your knee toward a wall while keeping your heel down, 10 reps per side, for better ankle mobility.
• Banded side steps: strengthen the outside of your hips and make it easier to keep your knees out.

Building from here

Once your technique is consistent, add weight gradually, but only as long as the movement looks the same. If the next jump makes your knees cave or your depth shrink, stay at that weight for a while. We cover how to plan increases over time in our guide to progressive overload.

Log the weight, the reps and a quick note on how your form felt. After a few weeks you'll spot patterns, like your knees only caving on the last rep. Fix one thing at a time and let the weight follow.