The back squat starts with a barbell across your upper back, and from there you sit your hips down and back until your hip crease drops below your knees, then drive back up to standing. It’s one of the most effective exercises for building lower body strength, but the setup and execution details matter more than most people realize. Here’s how to do it right.
Choosing Your Bar Position
Before you even unrack the bar, you need to decide where it sits on your back. There are two options, and each one changes the entire feel of the lift.
A high bar position places the barbell directly on your traps, the meaty muscle at the top of your upper back. This lets your torso stay relatively upright throughout the squat, which most beginners find more natural and comfortable. It emphasizes the quads and is the default position for general fitness training and Olympic-style lifting.
A low bar position places the barbell further down, resting on the bony shelf created by your rear shoulder muscles. This forces more forward lean in your torso (advanced lifters typically reach about a 60-degree trunk angle at the bottom) and shifts more work onto the glutes and hamstrings. Powerlifters favor this position because it generally allows you to move heavier weight. The tradeoff is that it demands more shoulder flexibility and takes time to feel stable. If you’re just learning, start with high bar.
Setting Up Under the Bar
Walk up to the bar in the squat rack so it sits across the middle of your chest, roughly at collarbone height. Duck under it and position it in your chosen spot on your back. Grip the bar with both hands slightly wider than shoulder width, pulling your shoulder blades together to create a tight shelf of muscle for the bar to rest on. The tighter your upper back, the more stable the bar feels.
Stand up with the bar by extending your hips and knees together. Take two or three small, controlled steps backward to clear the rack. That’s it. Long walkouts waste energy and increase the chance of losing balance. Set your feet roughly shoulder-width apart, toes pointed out between 15 and 30 degrees. Find the angle that lets you sit deep without your knees collapsing inward.
How to Brace Your Core
Proper bracing is the single most important safety habit in the back squat. Before you descend, take a deep breath into your belly (not your chest) and hold it by closing your throat, as if you’re about to cough. Then push your abdominal muscles outward in all directions, like you’re inflating a cylinder around your spine. This creates intra-abdominal pressure that protects your lower back under load.
Hold that brace through the entire rep. Exhale only once you’ve passed the sticking point on the way back up, or after you’ve returned to standing. If you’re doing sets of five or more, you’ll take a fresh breath and re-brace at the top of each rep. Losing your brace mid-squat is one of the fastest ways to round your lower back under load.
The Descent
With your feet set and your core locked, initiate the squat by bending at the hips and knees simultaneously. Think about sitting down between your legs rather than pushing your hips straight back. Your knees should track directly over your toes as you descend. Keep your weight distributed across your whole foot, with your heels firmly on the ground.
Descend until the crease of your hip drops below the top of your kneecap. This is full depth. Going to this depth isn’t just an arbitrary standard: compressive forces at the knee are actually minimal between 0 and 50 degrees of flexion, and once you reach a deep squat, contact between the back of your thigh and calf reduces knee compressive forces by approximately 30%. In other words, a deep squat with good form distributes stress more favorably than stopping halfway down. There’s no evidence that deep squatting harms healthy knees.
Your spine should stay in a neutral position throughout. A slight natural arch in your lower back is fine. What you want to avoid is rounding or excessive arching.
Standing Back Up
Drive out of the bottom by pressing through your whole foot and pushing your back into the bar. Your hips and chest should rise at the same rate. If your hips shoot up first while your chest stays low, you’ve turned the squat into a good morning, and the load shifts dangerously onto your lower back. Think “chest up, hips forward” as you push through the sticking point, which usually hits just above parallel.
Lock your hips and knees fully at the top. That’s one rep. Re-brace, and go again.
Muscles the Back Squat Works
The back squat is a full lower-body exercise, but it doesn’t hit every muscle equally. EMG data measuring muscle activation during squats at various intensities shows a clear hierarchy. The inner and outer quadriceps are the hardest-working muscles, reaching 57 to 74 percent of their maximum activation at moderate to heavy loads. The spinal erectors (the muscles running along your spine that keep your torso from collapsing forward) come next, at around 41 to 54 percent. The glutes work at roughly 28 to 39 percent activation, and the hamstrings contribute at a lower level, around 22 to 30 percent.
This tells you something practical: the back squat is primarily a quad exercise with significant core and glute involvement. If your goal is specifically to build your hamstrings or isolate your glutes, you’ll want additional exercises beyond squats alone.
Fixing Knees That Cave Inward
Knee valgus, where your knees collapse toward each other during the squat, is one of the most common form breakdowns. It’s typically caused by weak hip abductors (the smaller glute muscles on the outside of your hip) being overpowered by stronger inner thigh muscles. This isn’t just an aesthetic problem. Repeated valgus under load increases stress on your knee ligaments over time.
The fix has two parts. During the squat itself, actively push your knees out over your toes throughout the movement. Between squat sessions, strengthen your hip abductors with exercises like lateral band walks, clamshells, or side-lying hip abductions. Using a light resistance band around your knees during warm-up squats can also train the “knees out” pattern by giving you something to push against. If you practice banded squats, keep tension on the band throughout the movement rather than letting your feet come together between reps.
What Causes the “Butt Wink”
The butt wink is a posterior tilt of the pelvis that happens at the bottom of the squat, causing your lower back to round into flexion. It looks like your tailbone tucking under you. A small amount is normal and harmless, but a pronounced butt wink under heavy load puts shear stress on your lumbar discs.
Despite what you may have heard, tight hamstrings are rarely the culprit. Because the hamstrings cross both the hip and knee joints, and both joints flex simultaneously during a squat, the hamstrings don’t actually change length much during the movement. This biomechanical quirk, known as Lombard’s Paradox, means stretching your hamstrings won’t fix butt wink.
The real causes fall into three categories. Limited ankle mobility prevents your shins from tilting forward enough, which forces your pelvis to compensate at the bottom. Restricted hip mobility, particularly internal rotation, limits how deep you can go before your pelvis tucks. And in some cases, the depth of your hip socket (a structural trait you’re born with) simply prevents you from reaching full depth without pelvic tilt. Mobility issues in the ankles, hips, and thoracic spine are worth working on. Structural limitations are not something you can stretch away, and squatting to a slightly higher depth is the appropriate adjustment.
How Footwear Affects Your Squat
Weightlifting shoes have a rigid, elevated heel, typically 0.5 to 1 inch higher than the forefoot. Research shows they decrease trunk lean and increase plantarflexion compared to running shoes or barefoot lifting. In practical terms, the raised heel reduces how much ankle flexibility you need to hit depth, which helps keep your torso more upright and makes the squat feel smoother if you have stiff ankles.
If you don’t want to invest in weightlifting shoes, placing small weight plates or squat wedges under your heels produces a similar effect. Running shoes, on the other hand, are the worst option for squatting. Their soft, compressible soles make you unstable under load. If you’re squatting in a commercial gym without lifting shoes, flat-soled shoes like Converse or even bare feet on a clean surface are better choices than running sneakers.
Programming Tips for Beginners
Start with the empty barbell (45 pounds or 20 kilograms) and add weight only when you can complete your sets with consistent form. A simple starting approach is three sets of five reps, two to three times per week, adding five pounds each session. This linear progression works for most beginners for several months before you need anything more complex.
Film yourself from the side and from behind. You cannot feel what your squat looks like, and common errors like forward lean, knee valgus, and butt wink are easy to spot on video but nearly impossible to detect by feel alone. Compare your footage to the cues above, pick one thing to fix per session, and build the movement pattern gradually. Rushing to add weight before your form is solid is how injuries happen.