Hack Squat vs Barbell Back Squat: Differences and Which to Do

The hack squat and the barbell back squat both load your legs hard, and picking between them mostly comes down to one question: do you want the machine to hold your torso for you, or do you want to hold it yourself?

That single difference drives everything else. The hack squat pins your back against a pad and fixes the bar path, so your quads take almost all of the work and your core and stabilizers take very little. The barbell squat makes you brace and balance the load yourself, which recruits far more muscle but caps how much weight you can safely handle when you’re training alone.

Below I go through the real differences, the pros and cons of each, how to perform them, and the question most people are actually asking: whether a hack squat can stand in for barbell squats entirely.

Is a Hack Squat the Same as a Squat?

No. A hack squat is a machine exercise where your back rests on an angled pad and the sled travels on a fixed rail.

A barbell back squat is a free-weight lift where you carry the load across your upper back and control the bar path yourself. Both bend the knees and hips under load, and that’s where the similarity stops.

The practical consequence is which muscles get worked. The hack squat sends most of the tension to the quads. The barbell squat spreads it across quads, glutes, hamstrings, spinal erectors and your whole trunk, because you have to stay rigid to keep the bar over midfoot.

Is the Hack Squat Easier Than a Barbell Squat?

Easier to learn and easier to balance, yes. Easier on your legs, no.

The machine removes the skill and stability demands, which means you can push closer to failure without a spotter and without technique breaking down first. Plenty of lifters find a hard set of hack squats more uncomfortable than a hard set of barbell squats, because nothing else gives out before the quads do.

Can Hack Squats Replace Barbell Squats?

It depends on what you’re training for, and this is the one place where the answer is genuinely clear-cut.

• If you compete in powerlifting or weightlifting, no. The back squat is a contest lift or a direct carryover to one. A machine that braces your torso can’t train the bracing you get judged on.
• If you’re training for leg size, yes, it can carry most of the load. Quad growth responds to tension and proximity to failure, and the hack squat delivers both with less systemic fatigue. Plenty of bodybuilders build their quad work around machines for exactly this reason.
• If you have a back injury or a mobility limitation that makes barbell squatting painful, yes. This is the strongest case for the swap. The hack squat lets you keep training legs hard while the spine stays supported.
• If you want general strength and athleticism, keep the barbell squat. The stabilizer and core work is the part you lose, and it’s the part that transfers to everything else you do.

My own take is that this rarely has to be either/or. Barbell squat first while you’re fresh, then use the hack squat as your second movement to add quad volume once fatigue would make the barbell risky.

If your gym has both, running them together beats arguing about which one wins. For more options, see our hack squat alternatives.

What’s the Main Difference Between a Hack Squat and a Barbell Squat?

The main difference between back squats and hack squats is that the hack squat primarily targets the quads. The back squat engages the quads, glutes, hamstrings, core, and other muscle groups. The back squat is considered to be more of a full-body exercise since it develops the entire lower body.

On the other hand, if your primary goal is to grow your quads, then the hack squat is a great alternative to the back squat.

Another key difference between back squats and hack squats is that a back squat is a free-weight exercise and a hack squat is performed on a machine. Some people prefer the stability that a machine offers, however it doesn’t strengthen the stabilizer muscles as well as a free weight movement.

What’s more, a back squat can easily be adjusted to fit anyone’s body, regardless of your height. Most machines are built for lifters of average height, so the fixed path of motion is a problem if you’re much taller or shorter.

If you have the ability to squat, then it’s hard to make an argument that any other exercise is better. But there are a few pros and cons we’ll cover next that will help you determine which exercise is better for your goals, body type, and experience level.

Pros and Cons

Back Squat Pros

Here are some benefits of back squats:

• It’s a functional movement that’s often used in sports and daily life. For example, every time you sit down and stand up, you perform a squat.
• Back squats engage the core and the stabilizer muscles around your hips and spine, whereas hack squats do not.
• They are one of the most effective exercises for adding size and strength to the lower body, not just the quads.
• Back squats are better for athletic performance compared to hack squats.
• Minimal equipment is required to do a back squat, all you need is a rack, barbell, and some plates.
• Back squats are a free weight exercise and your stance can easily be adjusted to target different areas of the legs.
• They are used in powerlifting, Crossfit and Strongman to assess strength.

Back Squat Cons

Here are some disadvantages of back squats:

• Although you can train to failure with squats, unless you have safety bars set up or a spotter, they are not as safe as hack squats. There’s more room for error and another body part may fatigue before your quads do.
• Back squats are very demanding on the entire body, so recovery time is greater.
• They are more complex to learn than hack squats.
• Back squats place more stress on the spine, which can be problematic if you suffer from back pain or have a previous injury.
• Ego-lifting is more common with the back squat than the hack squat. If too much weight is added, the range of motion will be shortened.
• They don’t isolate the quads as well as hack squats.
• Your range of motion may be limited due to poor ankle and/or knee mobility.

Hack Squat Pros

Here are some pros of hack squats:

• Hack squats are easier to learn than back squats and are great for beginners.
• They place less pressure on the spine, and even those with back pain or a previous back injury can still effectively train their legs.
• There are safety bars built in so you can safely train to failure without a spotter.
• Hack squats isolate the quads more than back squats. If quads are a weak point for you, hack squats may be better.
• You are on a fixed path of motion, so there’s a lesser chance of form deviation and injury.
• Hack squats aren’t as fatiguing as back squats, reducing your recovery time.
• Most gyms have a hack squat machine, but they are not as common as a squat rack. You can perform hack squats using a smith machine and even a barbell with some plates, but it’s trickier to set up.

Hack Squat Cons

Here are some cons of hack squats:

• Hack squat machines differ from gym to gym, which cuts both ways. Some machines will suit your body better, while others may cause issues. Different hack squat machines will make it difficult to track progress.
• You’re limited to a specific path and range of motion on a hack squat. With barbell squats, you can freely adjust your form, range of motion, and stance.
• Hack squats don’t strengthen or develop the stabilizer muscles, such as the core, as well as squats.
• They aren’t as functional and don’t have as much carry-over to other lifts, sports, and activities of daily living.
• Hack squats primarily target the quads and most people are already quad dominant. Squats are a better option if you want to develop and strengthen your glutes and hamstrings. 

• In regards to athletic performance, hack squats are inferior to squats.
• The sled’s weight on a hack squat may be a limiting factor for some beginners because it might be too heavy. Whereas with back squats, you can scale down to just the bar or your bodyweight.

Exercise Form

How to Do a Back Squat Correctly

1. To do a back squat, you will need an Olympic barbell, squat rack, weight clips, and Olympic plates. Also, flat-soled shoes, lifters, or even going barefoot is ideal for this exercise.
2. Before starting, adjust the height of the squat rack so the barbell is roughly at shoulder height. You should be able to easily un-rack and re-rack the barbell.
3. Move the safety bars to where you can safely drop the barbell in case you fail. Make sure they are not too high because that will restrict your range of motion. You should be able to squat just below parallel before the safety bars contact the barbell.
4. Step underneath the barbell and set the barbell on your upper back/shoulders. Grab the barbell on both sides with a slightly wider than shoulder-width grip.
5. Un-rack the barbell by standing straight up. Take two to three steps away from the rack.
6. Move your feet so that they are roughly shoulder-width apart with your toes slightly pointed out.
7. Take a deep breath and begin to descend by bending the knees and hips similar to how you would sit down in a chair.
8. Keep your head/neck/spine neutral by looking straight ahead, not up or down.
9. Once your hips are at or below 90-degrees, pause for a brief moment.
10. Exhale while standing back up by pushing through the floor. The weight should be evenly distributed through the foot. 
11. Once you approach full extension, squeeze your glutes and hamstrings to drive your hips forward. 
12. Repeat for the desired number of reps.

Watch this video from Squat University to see how to squat with correct form:

The Official Squat Form Checklist [Are You Squatting Wrong?]

Watch this video on YouTube.

How to Do a Hack Squat Correctly

1. To do this exercise you will need a hack squat machine, Olympic plates, and flat-soled shoes.
2. Adjust the starting height of the sled so you can safely un-rack and re-rack it.
3. Climb into the machine and rest your back and head on the back pad.
4. Position your feet on the platform so that they are in the middle of the platform with your toes slightly pointed out. You should have a shoulder-width stance with a slight bend in the knees.
5. Unrack the sled by standing straight up and moving the safety bar out of the way. They are normally found on both sides of you.
6. Take a deep breath to brace and begin the descent by bending the knees and hips.
7. Look straight ahead to keep a neutral spine.
8. Keep descending until your hips reach 90-degrees or below.
9. Pause for a brief moment, then exhale while pushing the sled upward by extending your legs at the hips and knees. Keep your heels down at all times.
10. Repeat for the desired number of reps.

Check out this video from Bodybuilding.com to see how to perform a hack squat properly:

Hack Squat | Exercise Guide

Watch this video on YouTube.

Muscles Used

Back Squat Muscles Used

The back squat primarily works the quadriceps, glutes, and hamstrings. It also recruits muscles of the core, adductors, calves, upper back, and erectors.

Primary

• Quads
  • Rectus Femoris
  • Vastus Lateralis
  • Vastus Medialis
  • Vastus Intermedius
• Glutes
  • Gluteus Maximus
  • Gluteus Minimus
  • Gluteus Medius
• Hamstrings
  • Biceps Femoris
  • Semimembranosus
  • Semitendinosus

Secondary

• Upper Back
  • Traps
  • Rhomboids
  • Lats
• Erector Spinae
• Adductors
• Calves
• Core
  • Obliques
  • Transverse Abdominus
  • Rectus Abdominus

Here’s a full breakdown of the muscles worked by squats.

Hack Squat Muscles Used

The hack squat primarily targets the quads, but it also works the glutes, hamstrings, calves, and to a lesser extent, the core.

Primary

• Quads
  • Vastus Intermedius
  • Vastus Lateralis
  • Vastus Medialis
  • Rectus Femoris

Secondary

• Glutes
  • Gluteus Maximus
  • Gluteus Minimus
• Hamstrings
  • Biceps Femoris
  • Semimembranosus
  • Semitendinosus
• Calves
• Core
  • Transverse Abdominus
  • Rectus Abdominus
  • Obliques

When to Do Each Squat

When to Do a Back Squat

If you are someone that wants to grow and strengthen your lower body, improve as an athlete, doesn’t have back pain or a previous back injury, and has the mobility to perform a squat properly, you should consider doing back squats.

Back squats are a very taxing exercise. To get the most out of the movement and reduce injury risk, you should perform them at the beginning of a workout. Although back squats engage multiple muscle groups, they are mainly considered to be a lower-body exercise.

More often than not, back squats are programmed on leg or lower body days. However, some people will do them along with the bench press and deadlifts. If your primary goal is to build strength, then stick to the 1-5 rep range. If you want to increase the size of your legs, then the 6-12 rep range will suit you best.

Squats are usually done 1-3 times per week. If you want to perform hack squats and back squats, either split them up across two sessions or do back squats before hacks squats if they are in the same session.

When to Do a Hack Squat

Anyone that wants to grow their legs, specifically their quads, and limit spinal loading should consider performing hack squats. Hack squats are most commonly programmed on lower body workouts because they primarily target the quads.

Hack squats aren’t as taxing as back squats, but they are still a compound movement so doing them early on in a workout is ideal. Most people work within the 6-15 rep range with hack squats because you can safely train to failure and they are more suited toward hypertrophy rather than strength.

Hack squats are a great accessory exercise to the barbell back squat. Depending on your training split, you can train them in the same session or split them up across the week.  If your main goal is to grow your quads, consider dedicating one day to hack squats and another to back squats. This will help add training volume to your quads while minimizing fatigue.

Hack Squat vs Barbell Squat: Which Is Better for You?

If you could only pick one leg exercise to do for the rest of your life, a back squat would be it. The back squat is better for strength, whole-leg hypertrophy, functionality and performance. In other words, the back squat is truly the king of all exercises.

But that doesn’t mean that hack squats are a worthless exercise.

Arguably, hack squats are one of the best machine exercises for quad hypertrophy. They also closely replicate the squat, so they will have carry-over to other exercises and activities of daily living. Not every gym has a hack squat machine, but if they do, incorporate it into your routine!

Doing more than one exercise for any body part will help minimize overuse injury, optimize hypertrophy, and keep training fun!

FAQs

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About Heather Jacques

Heather Jacques is a former collegiate athlete that graduated from Grand Valley State University with a Bachelor of Science in Athletic Training. Along with writing content for Lift Vault, Heather works for one of the fastest growing sports nutrition companies, Axe & Sledge Supplements, as their product specialist. Heather is an avid lifter, snowboarder, and outdoor enthusiast. She was born in Colorado, raised in northern Michigan, and currently resides in Pennsylvania. Heather's primary goal is to help others achieve their health and fitness goals through education, motivation, and inspiration.