Hack squat: foot placement, depth, and how it compares

The hack squat is a squat on a machine. You stand on an angled platform with your back against a padded sled and your shoulders under two pads, and the sled slides up and down on rails as you squat. You stand like a squat, but the machine holds your torso in place like a leg press, so there's no bar to balance and you can load the legs heavily.

This page covers the setup, where to put your feet and what it changes, how deep to go, how the hack squat compares with the leg press and the barbell squat, and the faults. The barbell squat itself is on squat form, and the leg press has its own page.

How to set up the hack squat

1. Step onto the platform with your back to the sled, and set your back flat against the pad with your shoulders under the shoulder pads.
2. Place your feet about shoulder-width apart, centred on the platform, with the toes straight or slightly out and both heels down.
3. Stand up to lift the sled and release the lock handles at your sides.
4. Check the stops, if the machine has adjustable ones, so they'd catch the sled just below your lowest position.

The rep

1. Bend your knees and sink slowly, letting them track over your toes while your back and hips stay against the pad.
2. Reach your depth: thighs at least parallel to the platform, deeper if your heels stay down and your hips stay on the pad.
3. Stand back up, pushing through your heels and the balls of your feet, and stop just short of locking your knees.
4. Lock the sled with the handles before you step out.

Hack squat foot placement: what it changes

No study of foot placement on the hack squat itself was found. The closest evidence is from the leg press, a similar machine with the torso supported:

• Higher or lower feet. On the leg press, 14 women showed more glute activity with their feet high on the platform than low, and more front-of-thigh activity with their feet low, at the heavier of the two loads tested.¹
• Wide feet, set high. Among 10 experienced male lifters on the leg press, a wide, high stance drew more hamstring activity than a narrow one, and turning the toes out changed nothing.²

On a hack squat, feet lower on the platform let your knees travel further forward and tend to bring your heels up sooner; feet higher keep the heels down and bend the hips more. Pick the placement where your heels stay flat and you reach your depth, then keep it so the weights you write down compare. The leg press page has the full table.

How deep to go

For the barbell squat, a 10-week trial of 17 men found the front of the thigh grew about the same with full and half squats, while the glutes and inner thighs grew more with full squats.³ On a machine, the leg press trial is the closest match: in 23 resistance-trained people, one leg trained to about 100 degrees of knee bend and the other as deep as it could go, and front-of-thigh thickness grew similarly in both.⁴ Neither is a hack squat study.

A practical rule: thighs at least parallel to the platform, deeper if your hips stay on the pad and your heels stay down, and the same depth every rep. If the glutes are part of the goal, deeper is the side to err on.

Hack squat vs squat

• Heavier, with less trunk work. In 10 men tested on both, the hack squat allowed a heavier one-rep max than the back squat, but at the same relative loads the back squat produced more activity in the trunk muscles.⁵ The machine holds the torso, so the trunk does less.
• Similar results in a short trial. In 23 athletes, 15 men and 8 women, who added five weeks of squats, forward hack squats or neither to their sprint and jump training, front-of-thigh muscle thickness near the hip rose in all three groups, with no differences between the groups in squat or hack squat strength, sprinting or jumping.⁶
• You get strongest at what you practise. A 2023 meta-analysis pooled 13 studies and 1,016 participants. Its lower-body comparisons mostly set the squat against a machine (the leg press, the hack squat or the Smith machine squat). Free-weight training raised free-weight test scores more, and in the five studies that measured muscle growth, the two kinds of training didn't differ.⁷

So if the goal is bigger, stronger legs, use whichever of the two you can push hard and add weight to. If the goal is a better barbell squat, the barbell squat has to stay in your week. The hack squat is also a way to train the legs hard on a day the back or the balance isn't up to a heavy bar.

Hack squat vs leg press

Both are machines that hold your torso and load your legs. The difference is the position: on a hack squat you stand under the load and squat down, with your torso fairly upright; on a leg press you sit or lie back and push the load away. No study comparing the two directly was found. One trial rotated them: 70 young women trained legs three times a week for ten weeks, either with the 45-degree leg press every session or with the leg press, the hack squat and the Smith machine squat on different days. Thigh muscle thickness and strength rose similarly in both groups.⁸ Use whichever your gym has, or both on different days.

Common mistakes

• Heels coming up. Your weight has drifted to your toes. Shift your feet a few inches up the platform and try again.
• The hips or lower back leaving the pad. You've gone deeper than your setup allows. Find the point just before it happens and make that your bottom.
• Shallow reps under a loaded sled. If your thighs never reach parallel, the weight is too heavy for the full rep. Strip a plate.
• Knees drifting inward. Push them out over your toes on the way up.
• Dropping into the bottom. Control the sled down, settle, then drive.
• Squatting through pain. Sharp pain is not soreness. Stop, and see a doctor or a physical therapist.

Sets and reps

• When it opens the session: 3 sets of 6 to 10, stopping two or three reps short of failure.
• When it follows a barbell squat: 2 or 3 sets of 10 to 15, taken closer to failure. (How to judge reps left.)
• Add it to your weekly count. The American College of Sports Medicine's 2026 position stand found muscle growth was enhanced by ten or more sets per muscle group a week,⁹ and every hard hack squat set is a set for the front of the thigh.
• End the day with the leg extension and the leg curl, the front and back of the thigh on their own. (The leg day workout has the full session.)

If you'd rather not plan it alone

The hack squat is quick to learn; working out where it sits next to your squats and presses, and how much leg work your week can carry, is the part a page can't do. Coaching is the version where your workouts are built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one. Coaching to build muscle explains how that works, and here's how to apply. Otherwise: feet shoulder-width in the middle of the platform, and three sets of 8 to parallel or deeper.