Hack Squat: Muscles Worked and How to Do It
TL;DR
The hack squat works your quads as the prime mover, extending your knees against the machine's fixed path. Your glutes and hamstrings extend your hips alongside them, and your calves stabilize your ankles, though the machine's support lets you push your legs harder with less balance demand than a free squat.
- Primary muscle:
- Quadriceps
- Secondary muscles:
- Calves, Glutes, Hamstrings
Muscles worked
Your quads take on most of the load in a hack squat because the machine's angled, fixed path keeps your torso supported and your hips more locked in place than in a free-standing squat, shifting emphasis toward the front of your thigh.
Your glutes and hamstrings still assist by extending your hips as you press back up, and your calves work to stabilize your ankles against the footplate. Because the machine handles your balance, you can often push closer to failure safely than with a barbell squat.
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How to do it
- Place the back of your torso against the back pad of the machine and hook your shoulders under the shoulder pads provided.
- Position your legs in the platform using a shoulder width medium stance with the toes slightly pointed out. Tip: Keep your head up at all times and also maintain the back on the pad at all times.
- Place your arms on the side handles of the machine and disengage the safety bars (which on most designs is done by moving the side handles from a facing front position to a diagonal position).
- Now straighten your legs without locking the knees. This will be your starting position. (Note: For the purposes of this discussion we will use the medium stance described above which targets overall development; however you can choose any of the three stances described in the foot positioning section).
- Begin to slowly lower the unit by bending the knees as you maintain a straight posture with the head up (back on the pad at all times). Continue down until the angle between the upper leg and the calves becomes slightly less than 90-degrees (which is the point in which the upper legs are below parallel to the floor). Inhale as you perform this portion of the movement. Tip: If you performed the exercise correctly, the front of the knees should make an imaginary straight line with the toes that is perpendicular to the front. If your knees are past that imaginary line (if they are past your toes) then you are placing undue stress on the knee and the exercise has been performed incorrectly.
- Begin to raise the unit as you exhale by pushing the floor with mainly with the heel of your foot as you straighten the legs again and go back to the starting position.
- Repeat for the recommended amount of repetitions.
Form tips
- Set your feet shoulder-width on the platform, slightly lower for more quad emphasis.
- Keep your lower back and head against the pad throughout the set.
- Lower until your thighs are at least parallel to the platform, if your hips stay in contact with the pad.
- Don't let your knees cave inward as you press back up.
- Unlock the safety only once you're braced and ready to control the descent.
Exercise details
| Equipment | Machine |
|---|---|
| Level | Beginner |
| Mechanic | Compound |
Used by lifters following PPL, 5x5, upper/lower, and more.
Frequently Asked Questions
Is the hack squat as good as a barbell squat for quads?
The hack squat isolates your quads more directly because the machine supports your torso and stabilizers, letting you focus on knee extension. A barbell squat builds more total-body strength and balance, so many lifters pair the two, finishing with an isolation move like leg extensions.
Where should I place my feet on a hack squat?
A lower foot position, closer to the bottom of the platform, shifts more work to your quads. Moving your feet higher brings your glutes and hamstrings in more. Keep your feet shoulder-width apart either way, and adjust based on where you want the emphasis.
More quadriceps exercises
Exercise instructions and photos come from the free-exercise-db library, public domain, the same library used inside the PR Streak app.
