The hack squat can add that extra bit of intensity (and gains) to your leg workout. Bodybuilders and home gym enthusiasts, alike, can benefit from the hack squat. Why? Because it literally works the entire posterior chain: glutes, hamstrings, quads, and calves. It also works the core, but you’ll probably feel it most in your quads (front side of your upper legs) if you don’t do a lot of leg workouts.
Every version of the traditional squat exercise (front, back, hack, and many others) changes the mechanical demands on your legs — or the muscles you’re stressing most. The hack squat changes the angle of the movement by leaning back and stabilizing your back, therefore placing the primary emphasis on the quads.
The hack squat, named after George Hackenschmidt, was conceived with one goal in mind: build strength my moving significant weight. The only way to allow this much weight was to take the back muscles out of it. The exercise places the weight directly on the shoulders, unlike traditional squats which place the weight behind or in front of the shoulders. With the weight directly on top of the shoulder, your upper body has less responsibility to keep the bar directly over your center of gravity. If all you care about is leg development (and not power or compound movements), then the hack squat is your new best friend.
The hack squat is great for building power and mass, but not great for explosiveness or athleticism. Make sure your fitness goals align with the proper exercise.
When using a hack squat machine, it’s important to be aware of form since the angle of the squat isn’t natural to everyday movement. There’s just no real need to ever squat down at a declined angle, so it’s not a move the body performs naturally. Go slow, make sure your legs are shoulder-width apart, and don’t overload the weight until you feel how the movement affects your knees.
When you lose focus on the form, your lower back becomes over-activated and is asked to perform a function it is not meant to perform: pushing weight vertically. You don’t want that, especially as you hack squat heavier loads. The legs were always meant to move weight vertically (just ask a furniture mover with a bad back).
Smaller, boutique gyms don’t always have hack squat machines, unfortunately. If you don’t have access to a machine, you can still replicate the hack squat in a standard gym using a barbell and something to elevate your heels, like large weight plates. The key to the barbell hack squat is to move the bar from your shoulders to behind your legs, starting with the weight on the floor and legs bent. Elevate your heels on a pair of plates on the ground, and your knees will shift over your toes, emphasizing your quad engagement.
The only issue with a non-machine hack squat is that you will be limited by what your grip strength can handle. But otherwise, the exercise feels extremely challenging in a good way, and doesn’t put much stress on the lower back.