How to Do a Hack Squat
A hack squat is a squat on an angled sled machine. With your back on the pad and feet shoulder-width in the middle of the platform, bend your knees as deep as your heels stay down. It mainly trains the quads, with the glutes and adductors helping. Most lifters do 3 to 4 sets of 8 to 12 reps.
- 1Start. Back flat on the pad, shoulders under the pads, feet shoulder-width in the middle of the platform.
- 2Bottom. Lower until your knees bend to at least 90 degrees, then drive through your whole foot to stand.
Watch 3 video demonstrations
Find more video demonstrations in the Gravitus app
How to do a hack squat
- Set the shoulder pads so they sit on top of your shoulders while your whole back rests on the pad.
- Place your feet shoulder-width apart in the middle of the platform, toes turned out slightly.
- Stand up to take the weight off the stops, then swing the safety handles out.
- Bend your knees and lower the sled under control. Let your knees travel forward over your toes, and go as deep as you can with your heels down and your hips on the pad.
- Drive through your whole foot to stand, stopping just short of locking your knees. Swing the safety handles back in before you step off.
Hack squat foot placement
No study has tested foot placement on the hack squat itself, so these come from leg press and squat studies. On the leg press, low feet drew more quad activity and high feet more glute activity (Da Silva 2008), and foot height did not change the forces on the knee (Escamilla 2001). Stance width changed glute and adductor activity but not quad activity (McCaw 1999, Paoli 2009, Martín-Fuentes 2022). Start shoulder-width in the middle, then move your feet lower for quads as far as your heels allow.
How deep to go on a hack squat
Go as deep as you can while your heels stay down and your hips stay on the pad. For most lifters that is well past 90 degrees of knee bend.
Depth grows more muscle. Over 12 weeks, deep squats to 120 degrees of knee bend grew the front of the thigh 4 to 7% more than shallow squats to 60 degrees (Bloomquist 2013). Full squats and half squats grew the quads by the same amount, but full squats grew the glutes and adductors 2 to 3 times as much (Kubo 2019). A review of 16 studies found full range of motion built more leg muscle than partial reps (Pallarés 2021).
Knees travel past the toes on a deep hack squat, and that is fine. In a squat study, stopping the knees at the toes cut knee torque by 22% but raised hip torque more than tenfold (Fry 2003).
How much weight should you hack squat?
On Gravitus, the median man lifts 180 lb (82.5 kg) for 10 reps on the hack squat, and the median woman 95 lb (42.5 kg).
- Most lift
- 125 to 255 lb
- Top 10% lift
- 330 lb or more
- Starting out
- under 125 lb
- Most lift
- 55 to 145 lb
- Top 10% lift
- 215 lb or more
- Starting out
- under 55 lb
- Most lift
- 55 to 115 kg
- Top 10% lift
- 150 kg or more
- Starting out
- under 55 kg
- Most lift
- 25 to 65 kg
- Top 10% lift
- 97.5 kg or more
- Starting out
- under 25 kg
Muscles worked
Hack squat vs leg press vs back squat
| Attribute | Hack squat | Leg press | Back squat |
|---|---|---|---|
| Load on the spine | Through the shoulder pads | Little, you sit | Full bar on your back |
| Balance needed | Little | Least | Most |
| Trunk work | Low | Lowest | High |
| Best for | Deep quad work, heavy | Most leg volume | Strength and carryover |
Close to a tie for leg growth. Over 8 weeks, full squats on a machine and with free weights grew the quads within 2% of each other (Hernández-Belmonte 2023). Lifters hack squat more weight than they back squat, but the back squat works the trunk harder (Clark 2019).
Sets, reps and progression
Stop each set 1 to 2 reps short of failure. Sets taken close to failure build muscle across a wide range of reps (Schoenfeld 2021), so pick a range where you can keep full depth.
Add reps first. When every set reaches 12 clean reps, add 10 to 20 lb (5 to 10 kg) and go back to 8.
Common mistakes
-
Heels liftingYour feet are too low for your ankles. Move them up the platform a few inches until your heels stay down at the bottom.
-
Hips rolling off the padYour lower back rounds at the bottom. Stop just above that point and move your feet a little higher.
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Quarter repsHeavy half reps build less muscle than full ones. Take the weight down until you can go past 90 degrees.
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Knees caving inPush your knees out over your toes on the way up. Go lighter if they still drift in.
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Bouncing off the bottomLower under control and drive up without a rebound, so your legs do the work and not the stretch.
Hack squat variations
Questions people ask
How deep should I go on hack squat?
As deep as your heels stay down and your hips stay on the pad, which is past 90 degrees of knee bend for most lifters. Deep squats grew the thighs more than shallow ones (Bloomquist 2013).
Does hack squat work lower back?
Very little. The pad supports your torso, and the trunk muscles, lower back included, were less active than in a back squat at the same relative load (Clark 2019). Your lower back should stay on the pad for the whole rep.
Is hack squat better than leg press?
Not for growth; both build the quads. Adding hack squats and Smith squats to leg press training gave the same thigh growth over 10 weeks as leg press alone (Kassiano 2025). Pick the one you can load and go deep on without pain.
How much does the hack squat machine weigh without weights?
It depends on the brand, so check the machine or the maker's spec sheet. On a 45 degree sled you push about 71% of the sled and plates together, because only the part of the weight along the track resists you.
How much weight should I hack squat?
For 10 reps, the median on Gravitus is 180 lb (82.5 kg) for men and 95 lb (42.5 kg) for women. The strongest quarter lifts 255 lb (115 kg) and 145 lb (65 kg) or more.
Log every set and see your percentile on every lift, hack squat included.
Get GravitusRelated exercises
- Da Silva et al. 2008. J Strength Cond Res 22(4):1059-1065.
- Escamilla et al. 2001. Med Sci Sports Exerc 33(9):1552-1566.
- McCaw and Melrose 1999. Med Sci Sports Exerc 31(3):428-436.
- Paoli et al. 2009. J Strength Cond Res 23(1):246-250.
- Martín-Fuentes et al. 2022. Sports Health 14(3):317-327.
- Bloomquist et al. 2013. Eur J Appl Physiol 113(8):2133-2142.
- Kubo et al. 2019. Eur J Appl Physiol 119(9):1933-1942.
- Pallarés et al. 2021. Scand J Med Sci Sports 31(10):1866-1881.
- Fry et al. 2003. J Strength Cond Res 17(4):629-633.
- Clark et al. 2019. J Strength Cond Res 33(7S):S60-S69.
- Hernández-Belmonte et al. 2023. Med Sci Sports Exerc 55(12):2316-2327.
- Kassiano et al. 2025. Res Q Exerc Sport 96(2):371-381.
- Schoenfeld et al. 2021. Sports 9(2):32.