Hack Squat
The hack squat is a machine squat on an angled sled: your back rests against a pad, the load sits on your shoulders, and you squat down and drive the platform away. It trains the quads and glutes hard with the trunk supported, so you can push your legs close to their limit without balancing a bar. In Muscla's upper/lower plans it replaces the barbell squat on the second leg day of the week.
How to do the hack squat
Step onto the platform with your back flat against the pad and your shoulders under the shoulder pads.
Place your feet about shoulder-width apart in the middle of the platform, toes turned out slightly.
Brace your trunk, push the sled up a little and release the safety handles.
Bend your knees and hips together and lower yourself under control, knees tracking over your toes.
Go as deep as you can while your lower back and hips stay against the pad, at least until your thighs are level with the platform.
Drive through your whole foot to straighten your legs, stopping just short of locking the knees, then lock the handles after the last rep.
Setting up the sled
Adjust the shoulder pads so they sit firmly on your shoulders when your back is flat against the pad and your legs are nearly straight. Too low and you start each set in a crouch; too high and the pads press into your neck. Check that the safety handles move freely before you load the sled, and set the safety stops if your machine has them.
Foot placement and stance
Stand in the middle of the platform with your feet about shoulder-width apart and your toes turned out a little. Your heels stay down the whole set, so move your feet higher on the platform if they lift at the bottom. A slightly wider stance can make deep reps easier if your hips feel cramped. Once you find your spot, use it every session: a different foot position changes how heavy the same load feels.
Bracing and breathing
Take a big breath before you release the handles and brace your trunk, even with the pad behind you. Hold it on the way down and through the bottom, and breathe out as you pass the hardest part on the way up. The brace keeps your lower back pressed into the pad when the load is heaviest.
Depth and tempo
Lower yourself under control and keep your knees moving in the direction of your toes. Your knees will travel forward past your toes in a deep hack squat; that is normal and lets you sit between your heels. Turn around at the deepest point where your hips still touch the pad, without bouncing, and drive up with intent. Use the same depth on every rep, because only comparable reps tell you when to add weight.
Muscles worked by the hack squat
- Primary
- Quads
- Glutes
- Secondary
- Adductors
The quads straighten the knees and do most of the work, especially out of the bottom. The glutes extend the hips alongside them and work hardest when you sit deep. The adductors on the inner thigh help extend the hip as well. Because the pad holds your torso, your trunk muscles do far less than in a free squat: in a study comparing both lifts at the same relative loads, the back squat produced more trunk muscle activity across almost every muscle measured. That is the trade-off: less balance and bracing, more focus on the legs.
Common hack squat mistakes
Cutting the depth short
Heavy half reps look impressive but skip the part where the glutes and adductors work hardest. Choose a load you can take to full depth with your back on the pad.
Letting the hips leave the pad
When the hips roll off the pad at the bottom, the lower back rounds under load. Stop the descent just before that point and work on depth with lighter weight.
Knees caving inward
Knees that drift toward each other on the way up take the hips out of the push. Keep your knees tracking over your toes the whole way.
Pushing through the toes
Rising onto the toes shifts the load forward and makes the bottom unstable. Keep your whole foot flat and push through the middle of it.
Slamming into locked knees
Snapping the knees straight at the top takes tension off the legs between reps. Stop just short of lockout and start the next rep.
How Muscla coaches the hack squat
- Warm up with two ramp sets: about 50% of your working weight for 8 reps, then about 75% for 3. Muscla adds them to every heavy compound lift.
- End working sets with about two reps in the tank, two to three when you train for strength; add one if you are new. After the last set Muscla asks “How heavy was that?” and plans your next session from the answer.
- Rest about 3 minutes between sets for strength, 2 minutes for muscle and 90 seconds for other goals.
- Once every set reaches the top of your rep range, add about 5% for lower-body lifts, at least the 5 kg or 10 lb step of a machine: 100 kg becomes 105 kg.
- After three sessions without progress, Muscla drops the weight by 10% and builds back up. After every third 4-week block comes a deload week at 90% of the weight with one set fewer.
Hack squat sets, reps and rest
| Goal | Reps | Rest |
|---|---|---|
| Strength | 3–6 → 2–5 → 4–8 | 3 min |
| Muscle | 6–10 → 8–12 | 2 min |
| Lose fat | 6–12 | 90 s |
| Fit | 8–12 | 90 s |
| Comeback | 8–12 | 90 s |
An arrow marks the range for the next 4-week block.
Muscla counts the hack squat as a heavy compound lift, like the barbell squat. Pick the row for your goal; the arrows show how the range moves from one 4-week block to the next. It never shares a day with another squat variation.
Estimate your hack squat one-rep max
Filled in with example values. Replace them with yours.
Estimated 1RM
Brzycki 149 · Lombardi 147.7
Epley: 120 × (1 + 8 ÷ 30) = 152 kg
| Reps | Weight | % of 1RM |
|---|---|---|
| 1 | 152.5 kg | 100 % |
| 2 | 142.5 kg | 94 % |
| 3 | 137.5 kg | 91 % |
| 4 | 135 kg | 88 % |
| 5 | 130 kg | 86 % |
| 6 | 127.5 kg | 83 % |
| 7 | 122.5 kg | 81 % |
| 8 | 120 kg | 79 % |
| 9 | 117.5 kg | 77 % |
| 10 | 115 kg | 75 % |
| 11 | 110 kg | 73 % |
| 12 | 107.5 kg | 71 % |
Hack squat alternatives
- Barbell Squat
- Leg Press
- Dumbbell Goblet Squat
- Kettlebell goblet squat
- Smith squat
- Dumbbell squat
- Dumbbell bench squat
- Barbell Front Squat
- Band squat
- Squat to overhead reach
Hack squat questions
Is the hack squat as good as the barbell squat?
For leg muscle, it can be. A meta-analysis found no difference in muscle growth between machine and free-weight training, while strength gains tended to follow the type of equipment people trained with. The free squat trains your trunk more; the hack squat lets your legs do more of the work.
Why can I lift more on the hack squat than on the squat?
The pad supports your torso and the sled guides the path, so balance and bracing limit you less. In a direct comparison, lifters had a higher one-rep max on the hack squat than on the back squat.
How deep should you go on the hack squat?
At least until your thighs are level with the platform, and deeper if your hips stay on the pad. In a barbell squat study, full-depth squats built as much front-thigh muscle as half squats and more glute and adductor muscle.
Where should I place my feet on the hack squat?
In the middle of the platform, about shoulder-width apart, suits most people. Higher feet let your hips bend more and your knees travel less; lower feet let your knees travel further forward. Pick the spot where you reach full depth with your heels down.
How much weight should I start with on the hack squat?
Muscla suggests about half your body weight for a man new to training, rounded down to the machine's 5 kg steps: 40 kg at 80 kg. The machine's own sled weight varies, so log the same way every time.
Hack squat or leg press?
Both train the quads and glutes with a supported back. In the hack squat you stand under the load as in a squat; the leg press is the easier start, which is why Muscla gives new lifters the leg press first.
Train it with Muscla
Muscla plans your sets, reps and rest, and sets the next weight after every session.
Coming to the App Store. Free to start.
Sources
- Clark DR, Lambert MI, Hunter AM. Trunk muscle activation in the back and hack squat at the same relative loads. J Strength Cond Res. 2019;33 Suppl 1:S60-S69. PubMed
- Kubo K, Ikebukuro T, Yata H. Effects of squat training with different depths on lower limb muscle volumes. Eur J Appl Physiol. 2019;119(9):1933-1942. PubMed
- Haugen ME, Vårvik FT, Larsen S, et al. Effect of free-weight vs. machine-based strength training on maximal strength, hypertrophy and jump performance - a systematic review and meta-analysis. BMC Sports Sci Med Rehabil. 2023;15(1):103. PubMed
- Schoenfeld BJ, Pope ZK, Benik FM, et al. Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. J Strength Cond Res. 2016;30(7):1805-1812. PubMed