How Squat Depth Impacts the Muscles You Work

Image of Cathe doing a squat during Strong & Sweaty Total Body Giant Sets. Learn how squat depth impacts the muscles you work

Squats are a no-frills move that works the muscles in your lower body. Being a compound movement, you work multiple muscle groups simultaneously when you do squats and that makes it superior to isolation exercises for calorie and fat burning. The more muscles you work, particularly the large muscles in the lower body, the more calories you burn and, according to some studies, the greater the anabolic response. The anabolic response refers to how much an exercise activates key anabolic and fat-burning hormones such as testosterone and growth hormone. So, squats are a winning exercise for building strength, muscle size, and burning fat.

Of course, you get more of an anabolic and fat-burning response if you squat against a heavier resistance than if you use no resistance or light weights. That’s why it’s important to push yourself to go heavier over time, using the principles of progressive overload. Another issue is HOW you squat, particularly how low you go. If you’ve ever watched people in a gym doing squats, you might have noticed that some don’t go very low into their squats. In effect, they’re doing partial squats rather than full ones. To do a full squat, you at least need to squat to 90 -100 degrees. Anything less than this is a partial squat. A deep squat is where you descend below 100 degrees.

The vast majority of people don’t venture below 100 degrees when they squat – and you might wonder whether it matters. When you squat below 100 degrees, are you emphasizing different muscle groups or getting added benefits? Studies show that squatting deeper targets all of the muscle groups in the lower body more, particularly the muscles in the posterior chain, the hamstrings, and glutes. But, the quadriceps in the front of the thighs are also activated more by deep squats, based on EMG measurements. Particularly when you compare deep squats to partial squats, deep squats hit the quads, glutes, and hamstrings harder. So, squat depth by going deeper may help you better accomplish your goals if your goal is to build lower body strength or size.

Going deep with squats may also boost athletic performance. One study found that going deep with barbell back squats boosted vertical jump height by 13%. Partial squats only enhanced vertical jump height by 7%.

Why are some people able to squat deeper than others? One limiting factor is mobility. If you lack mobility in your hips, ankles, and spine, doing a deep squat will be difficult. The danger is that people with limited mobility shift too much of their weight to the lower back, thereby increasing the risk of disc herniation. Hip anatomy is a factor too.

Not all hips are the same. Some people may be precluded from deep squatting due to the architecture of their pelvis and femurs. If your pelvis is wider and deeper with a narrow base, your anatomy is more conducive to squatting deeper than someone with a narrow pelvis. This type of structure gives you greater hip flexibility for squatting. So, your anatomy may or may not be ideally suited for squatting low.

How Does Squat Depth Affect Your Knees?

You often hear that deep squats are hard on the knees. It’s true that compressive forces on the knees increase as you descend deeper into a squat but healthy knees are capable of handling these forces, assuming you’re using good form. Your knees also sustain shear forces during a squat that are absorbed by the ligaments in your knees. It’s the cartilage that experiences the greatest compressive forces during a squat. As you descend into a squat, compressive forces increase while shearing forces decrease. When you squat past parallel, compressive forces at the tibiofemoral joint are the only forces that increase but, as mentioned, healthy knees are capable of handling these forces if your form is on target regardless of squat depth.

That’s why if you do deep squats, it’s important to use impeccable form and perfect the technique with no resistance before adding weight. Doing deep squats consistently using good form may actually protect your knees against injury by strengthening the muscles that support and stabilize the knees. If you have problems doing them, you may have mobility issues in the ankles, hips, or spine that are limiting your ability and squat depth.

When you’re squatting deep, don’t use the same weight that you use for a partial squat, especially if you’re using a barbell. Placing a barbell on your shoulders places a significant load on your spine and increases the compressive forces on your spinal column.

It’s also not a good idea to deep squat every day. Of course, you shouldn’t be doing that anyway since you shouldn’t train the same muscle groups within a 48-hour period. Yet, there’s no need to deep squat every time you do squats. Reserve them for once or, at most, twice per week. If you have knee problems already, it’s best to talk to an orthopedist before doing deep squats. Also, be aware that some people have a harder time doing deep squats due to mobility and anatomical differences. You can increase your mobility with focused training, but you can’t change your anatomy. Don’t force yourself to do deep squats if they’re uncomfortable and stick to a squat depth that you’re capable of doing with good form.

The Bottom Line

Deep squats activate the quads and the muscles in the posterior chain more than doing partial squats. They also improve vertical jump height more, making them more effective for improving athletic skills that involve jumping. But, make sure your knees are healthy before doing them and be rigorous with your form. Lighten up on the weights. Don’t try to use the same resistance you would with a partial squat. You don’t need to. You’ll still get the benefits with a weight that’s lighter since you’re activating the muscles more.



T-Nation. “Do You Need to Squat Deeply?”

Poloquin. “Don’t Be Afraid to Squat Low: 7 Reasons to Deep Squat”

Deep Squats and Knee Health: A Scientific Review. Tony Ciccone, Kyle Davis, Dr. Jimmy Bagley, & Dr. Andy Galpin. Center for Sports Performance, California State University, Fullerton


Related Articles by Cathe:

Why Squat Depth Matters

When Squats Hurt Your Back

Squat Depth: How Low Should You Go?

5 Ways to Get More Benefits from Bodyweight Squats


Related Cathe Friedrich Workout DVDs:

STS Strength 90 Day Workout Program

All of Cathe’s Strength & Toning Workout DVDs
Total Body Workouts
Lower Body Workouts


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