Whether or not you squat ass-to-grass is one of the most contentious topics in strength training circles.
You have some coaches who believe that anything shy of squatting full depth is ineffective. You have others who believe that the risks far outweigh the benefits when it comes to squeezing out a few more inches of depth.
So, should you squat ass-to-grass? Squatting ass-to-grass should be used if your sport or activity demands require that you build strength in deep knee flexion. For Olympic weightlifters, squatting ass-to-grass is beneficial. For powerlifters, bodybuilders, and other strength athletes, squatting ass-to-grass should only be used for specific purposes, but not all the time.
In this article, I’ll discuss:
- Ass-To-Grass Squats vs. Powerlifting Squats vs. Parallel Squats
- What Muscles Do Ass-To-Grass Squats Use?
- 5 Reasons For Doing Ass-To-Grass Squats
- 5 Reasons Against Doing Ass-To-Grass Squats
- Tips For How To Do Ass-To-Grass Squats
Ass-To-Grass Squats vs. Powerlifting Squats vs. Parallel Squats
Let’s get into the specifics on how to define each of these squat styles in terms of their depth.
What Are Ass-To-Grass Squats?
Ass to grass squats are when you bring your hips down as far as possible, traveling well below the parallel plane of your knees.
The endpoint of the movement doesn’t stop because you make a conscious effort to decelerate the barbell and begin the upward phase. The endpoint occurs when you literally can’t go any deeper and you have no option but to go up.
The ass-to-grass squat is typically trained in the sport of Olympic weightlifting where athletes use it to better their performance in the snatch and clean and jerk (more on this later).
What Are Powerlifting Squats?
Powerlifting squats are when you bring your hips just below the parallel plane of your knees. The reason for this level of depth in the powerlifting squat is because athletes are required to do so by the rules of their sport. If they squat any higher, their lift won’t count in competition.
With that said, they don’t want to go any lower. It would be considered wasteful to go deeper than what the rules require because they would be doing more work without any extra reward. It would simply make the squat harder, and they would be lifting less weight, which is not the goal.
So the powerlifting squat is a fine balance; squatting deep enough to follow the rules, but not too deep where you’re wasting energy. Check out my article on How Low Should Powerlifters Squat if you want to learn more.
What Are Parallel Squats?
Parallel squats are when your hips stop at the parallel plane of the knees before starting the upward phase of the lift.
This happens because lifters either make a conscious effort to decelerate the barbell on the way down in order to limit the range of motion, or can’t get any deeper because of mobility restrictions.
This squat style is most commonly seen in general populations where the advice is not to break the parallel plane in order to keep the knees in a safer position (I’ll discuss later why this is untrue).
However, we also see the parallel squat among strength and conditioning coaches who program it for their athletes because they believe it to have a higher transfer effect to their sport movements (more on this later).
What Muscles Do Ass-To-Grass Squats Use?
So which muscles do ass-to-grass squats work? The quads are used to much more of an extent in ass-to-grass squats compared with any other squat variation.
I wrote a complete guide on the muscles used in the squat, including different variations of the movement, but let’s summarize the most important parts when it comes to the ass-to-grass squats.
Each segment of the squat will incorporate different muscle groups to more or less of a degree.
- In the deepest end range of the movement, when you’re at the bottom, the loading demand will be far greater on your knee extensors. This means that the muscles responsible for knee extension will be the most active, i.e. your quads.
- Near the top of the squat, as you’re pushing to finish the movement, the loading demand will be far greater on your hip extensors. This means that the muscles responsible for hip extension will be most active, i.e. your glutes, adductor magnus (inner thigh), and to a lesser extent, hamstrings.
You can think of the muscles used in the squat from the bottom of the lift to the top as a sliding scale. When you’re at the bottom, you’ll use more quads than glutes. At some point in the mid-range, you’ll use your quads and glutes equally. But then, as you stand up, you’ll use less quads, and more glutes.
5 Reasons For Doing Ass-To-Grass Squats
Here are 5 reasons why ass-to-grass squats can be beneficial:
- Your activity demands require you to build strength in deep knee flexion
- You want to build size and strength in your quads
- It will help correct the ‘good-morning’ squat
- It will teach you how to bend your knees forward when squatting
- It will force you to improve your flexibility and mobility
1. Your activity demands require you to build strength in deep knee flexion
One of the fundamental principles in strength training is the idea of ‘specificity’.
The specificity principle states that our training environment needs to be specific to the type of outcome we want to perform. For example, if we want to get a stronger squat, we must prioritize squatting over other exercises such as leg press.
Taking this idea further, if we are required to be strong in the deep end ranges of the squat, then it’s not enough to simply squat, but we must squat as low as possible to see positive adaptations.
This is where you need to take a look at your goals, and what you want to accomplish, to determine whether squatting ass-to-grass will produce the training environment that will allow you to adapt toward your goals.
Olympic weightlifters are a perfect example of athletes who need to train using ass-to-grass squats.
In their sport, they are required to catch a snatch and clean at the very bottom of their squat end range. If they didn’t train ass-to-grass squats they might be able to catch the snatch or clean, but they would fail to have the strength to stand up with the weight from that bottom position.
2. You want to build size and strength in your quads
Due to the ass-to-grass squat placing greater loading demand on the knee extensors, this means your quads will need to work a lot harder.
If you’re someone who wants to target their quads specifically, the ass to grass squat is a good candidate. You can further place loading demand on your quads by implementing a slow tempo or pause squat as you descend into the bottom position.
These variations combined with an ass-to-grass squat will become a highly quad-dominant exercise. This is one reason why you see high-level bodybuilders trying to take their squats as low as possible either by using a barbell or the smith machine. They are trying to build their quads.
3. It will help correct the ‘good-morning squat’
The ‘good-morning’ squat is when you drive out of the bottom position and your hips rise faster than the barbell. This change in position will place your torso more parallel to the floor, which turns the lift into a ‘good morning’ rather than a standard squat.
If you come into this position under heavy load it can place a lot of stress on the structures in the low and mid-back, which aren’t necessarily designed to take that kind of loading demand.
The reason why the ‘good-morning’ squat happens is that the quads are weak and unable to extend the knees properly out of the bottom of the squat. As a result, the hip extensors, like your glutes, take over to support the movement.
Therefore, one way to fix this deficiency is to build up the strength in your quads so the glutes don’t have to take-over at the bottom of the squat. If I have an athlete who is starting to show signs of a ‘good-morning’ squat, I will use ass-to-grass squats to drive strength adaptations for the quads.
4. It will teach you how to bend your knees forward when squatting
When you’re just learning how to squat, you’re trying to figure out where your body should be in space. You’re figuring out the proper position for your hips, knees, and torso, and how they relate to moving a barbell under load.
It can feel somewhat unnatural at first learning how to push your knees forward as you descend below parallel in the squat. However, this is a key position to learn as you can’t get any lower if you don’t have your knees flexing forward.
Whether or not lifters choose to implement the ass-to-grass squat on an ongoing basis, it’s still important to have the motor skills to understand how the knees should respond under deep flexion.
This is why I wrote an article on Asian Squats, which profiles people in Asian countries using the squat as part of their everyday life.
5. It will force you to improve your flexibility and mobility
Ass-to-grass squats will require you to have superior flexibility and mobility.
Therefore, if you start programming ass-to-grass squats, you’ll naturally need to implement some sort of flexibility and mobility routine to compliment your squatting efforts. For this reason, I think it can be a helpful way to force people to improve their flexibility and mobility.
You can obviously still squat ass-to-grass with limited flexibility and mobility; however, your technique won’t be optimal. If your ankles are tight, you’ll start leaning too far forward. If your hips are tight, your pelvis will start to tuck and the low back will round.
However, working on your flexibility and mobility will improve your posture while squatting.
5 Reasons Against Doing Ass-To-Grass Squats
Here are 5 reasons why you may want to consider not squatting ass-to-grass:
- Your activity demands don’t require you to build strength in deep knee flexion
- You want to purposely target your hip extensors to a greater degree
- You don’t have the natural limb proportions necessary
- You don’t have the mobility necessary
- You deem the movement ‘too high risk’
1. Your activity demands don’t require you to build strength in deep knee flexion
Using the strength training principle of ‘specificity’, if you want to get stronger in the deep end ranges of the squat, then you must squat to the deep end ranges.
However, if you don’t need to build strength in that position of the movement, then doing any extra range of motion is probably not going to work you closer toward your goal.
For example, if you’re a speed skater, you’re required to have strong legs. However, your knees are never more than 45 degrees bent while performing your sport. Therefore, there’s probably little transfer effect to your speed skating efforts for taking your squats ass-to-grass.
Fun fact: In 2014 I was the strength and conditioning coach for the Chinese National Speed Skating team for one season. We never did more than parallel squats.
2. You want to purposely target your hip extensors to a greater degree
There are times where you might want to prioritize building up the strength of your hip extensors more than your knee extensors.
In this case, you can use the parallel squat to prioritize the load on the barbell versus the range of motion. The goal is to use this partial range of motion to overload how hard the glutes and other hip extensors need to work.
This is where you’d be using a heavier load than normal (compared with an ass-to-grass squat), but maximize the contraction of the muscles that are only responsible to finish the top half of the movement.
Therefore, whether you’re a bodybuilder who wants to target their glutes or a powerlifter who seems to always fail in the top range of motion, then squatting to parallel with a heavier load can be highly effective.
3. You don’t have the natural limb proportions necessary
There are simply cases where some lifters don’t have the proportions to squat ass-to-grass. For these lifters, their efforts would be better squatting to parallel, rather than forcing their body to squat into ranges of motion that aren’t suitable to them.
When I refer to ‘body proportions’, I’m talking about the length of a lifter’s torso and leg lengths in relation to one another. For more of an explanation on this when it comes to squatting, check out this short video:
There are two scenarios where no matter how much you try to squat ass-to-grass, that it will be extremely difficult:
- If you have a really long femur (upper thigh bone) compared with a short tibia (lower leg bone)
- If you generally have long legs combined with a short torso.
Before asking “are ass-to-grass squats better?’, think about whether someone even has the proportions to squat ass-to-grass.
4. You don’t have the mobility necessary
Squatting ass-to-grass requires superior mobility through the ankles, knees, and hips. You may not have the required mobility at the current time to squat below parallel.
This is not to say that you shouldn’t continue to work on your mobility to try and achieve deeper squats. But while you’re working on your mobility, you don’t want to force your body into a position where you’re sacrificing good technique.
My general rule of thumb when teaching ass-to-grass squats is to squat as low as possible given your current mobility. Then, if there are any restrictions, I would implement a mobility routine in order to continue getting the squats lower over time.
However, for the time being, I would not push someone beyond their mechanical limitations.
5. You deem the movement ‘too high risk’
Some strength and conditioning coaches view the ass-to-grass squat as too high risk.
These coaches generally work with professional athletes who have multi-million dollar contracts. Their job as coaches is to keep these athletes healthy so that they can perform at their best on the field or court. If an athlete gets injured, it’s a huge liability for the team generally.
Therefore, these coaches want to set up the training environment in such a way that it is as low risk as possible. If they believe that the ass-to-grass is only marginally better than the parallel squat, but it increases the athletes’ risk of potential injury, then they will avoid it at all costs.
Now, whether or not the risk of injury is real or perceived is another question. But these coaches are in control of million-dollar assets, and they are much more likely to err on the side of caution in all of their decision-making.
Tips For How To Do Ass-To-Grass Squats
If you want to start implementing ass-to-grass squats, then you’ll need to learn how to squat deeper. I wrote a full guide on how to squat deeper, but here are a few of those tips:
- Start by dropping the weight by 5-10%. Do this load modification for the same set/rep ranges that you normally would do.
- Squat with raised heels. Click HERE for my favorite heeled squat shoe.
- Practice consistency. Commit to being consistent with your squat depth every time you get under the bar.
- Experiment with your squat stance width. You may find squatting narrower or wider will help you get deeper.
Frequently Asked Questions
Are Ass To Grass Bad For Your Knees?
In a 2013 study by Hartmann et al., they found that the highest compressive forces are placed on the knee when it’s at a 90-degree flexion angle. In other words, squatting to parallel.
Therefore, it was concluded that letting lifters move their knees freely in a full range of motion helped build tissue strength around the knee. They said that provided correct squat technique is learned with progressive training loads, the deep squat can help protect against knee injuries.
How Much Harder Are Ass-To-Grass Squats?
If a lifter already has strong quad muscles, the ass-to-grass squat will be less difficult compared with someone who has weak quad muscles. This is because the ass-to-grass squat places greater loading demand on the knee extensors. However, most people can expect to lift 5-10% less doing ass-to-grass squats vs parallel squats.
The ass-to-grass squat can be used to produce specific results. You need to determine whether or not those results are part of your own individual goals, and how much emphasis you want to place on them. Remember to weigh out the risks and benefits, and understand whether your body is built for squatting ass-to-grass in the first place.
What to read next? Partial Squats: Benefits, Muscles Worked, Are They Safe?
Hartmann, H., Wirth, K., Klusemann, M. (2013). Analysis of the load on the knee joint and vertebral column with change in squatting depth and weight load. Sport Medicine, 43(10): 993-1008.