# Hack Squat (Machine): how to do it

- Main muscles: quads
- Also works: glutes, adductors
- Equipment: machine
- Level: intermediate
- 3D demo (side view): https://media.trainaq.com/exercises/hack_squat/e76b866743/side-m-720.mp4

## Steps

1. Lie back with your shoulders under the pads and your back flat.
2. Place your feet shoulder-width apart in the middle of the platform.
3. Release the safety handles and bend your knees slowly.
4. Stop when your thighs are about level with the floor.
5. Push through your whole foot until your legs are almost straight.

## Cues

- Keep your hips and back on the pad.
- Knees in line with your toes.
- Soft knees at the top.

## Common mistakes

- Letting the hips lift off the pad at the bottom.
- Rising onto the toes as you push.
- Locking your knees straight at the top.

## Starting position

Lie back on the sled with the shoulders under the shoulder pads and the back, hips and head flat on the pad. Feet in the middle of the platform, about shoulder-width apart, toes turned out a little, whole foot flat. Push the sled up off the stops, release the safety handles and hold the handles beside the shoulders.

## The movement

Bend the knees and let the sled ride down the rails. The hips stay on the line of the rails, so the trunk does not tip; only the hips and knees bend. The knees travel forward over the toes and stay in line with the feet. At the bottom, pause briefly, then push through the whole foot, heel and forefoot together, and press the sled back up the rails.

## End position

Bottom: knees bent to about 100°, thighs close to horizontal, hips and low back still on the pad. The thigh then turns about 40° away from the rail line, which is the hip flexion; the reclined back pad is why it stays far smaller than in a free squat.

## Tempo

1.9 s down, 0.3 s pause at the bottom, 1.4 s up, about 0.8 s at the top.

## Form in numbers

| Measure | Target | Good range | Sources |
| --- | --- | --- | --- |
| Rail angle to the floor | 45° | 45° (machine) | [2] |
| Foot platform tilt from the floor | 25° | 15–30° (machine) |  |
| Stance, heel to heel | 1.0 × shoulder width | 0.8–1.2 × | [1] |
| Toe-out, each foot | 10° | 0–20° | [4] |
| Knee flexion at the bottom | 100° | 90–110° | [1] |
| Knee flexion at the top | 10° (soft knee) | 5–15° | [1] |
| Pelvis lift off the pad | 0 cm | 0 cm | [1] [2] |
| Heel lift off the platform | 0 cm | 0 cm | [1] |

## Sources

1. [NFPT, How to Do Hack Squats](https://nfpt.com/how-to-do-hack-squats/)
2. [ExRx, Sled Hack Squat](https://exrx.net/WeightExercises/Quadriceps/SLHackSquat)
3. [Clark et al. 2019, J Strength Cond Res, "Trunk muscle activation in the back and hack squat at the same relative loads"](https://pubmed.ncbi.nlm.nih.gov/28704312/)
4. [Myer et al. 2014, Strength Cond J, "The back squat: a proposed assessment of functional deficits and technical factors that limit performance"](https://pmc.ncbi.nlm.nih.gov/articles/PMC4262933/)

Source: https://trainaq.com/exercises/hack-squat