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Paul Rogers

How Low Should You Squat - Full or Half?

By May 13, 2008

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Whether squatting "ass to ground" (ATG or full squat) is more beneficial, or hazardous, than squatting with upper or lower thighs parallel to the ground (parallel or half squat) is a perennial question in weight training and weightlifting circles. Here is my view of it.

Photo by Ryan McVay / Getty Images

In ATG you go right down so that your butt is closest to the ground. This requires almost maximum flexion then extension of the knee joint under load as you lower then push "out of the the hole" to stand upright. With parallel and half squats you only go low enough so that your thighs are parallel to the ground or even higher with knee joints at about 90 degrees or a bit more. Even less flexion is sometimes called a quarter squat.

The first thing to note is that if you do Olympic lifting -- snatches, and clean and jerks -- the ATG or full squat is a part of the formal lift protocol and technique that you need to learn.

Beyond that, there is a common belief that ATG squats are superior to parallel or half squats because the full range of motion promotes balanced and superior muscle and strength development. The implication is that parallel squats don't involve the hamstrings and gluteus (butt) muscles like full squats and therefore you get a muscle strength imbalance between the quadricep muscles at the front of the thigh and the posterior chain, which includes the hamstrings and the glutes. This belief seems to be widespread because it's repeated regularly.

I could find no justification for this position. In studies of muscle activation comparisons between half and full squats, the main hamstring muscle, the biceps femoris, is involved almost equally in full or half squats. The main butt muscle, the gluteus maximus, is involved slightly more in the full squat but full squats are likely to utilize less heavy weights so that any general advantage in muscle or strength development may be minimal for full squats. And somewhat contrary to widespread opinion, the rectus femoris muscle of the front of the thigh -- in one study at least -- got hammered twice as hard in the ATG squat as the parallel squat. Muscle imbalance development with parallel squats is unlikely to be a problem. In this context one could almost argue that full squats are more likely to cause muscle imbalance by emphasizing the rectus femoris compared to the posterior chain.

Finally, some sports medicine authorities claim that full squats can damage the knees. Experienced Olympic lifters tend to dispute this claim -- they have the experience to know -- and there is little medical evidence to support the idea that full squats are inherently dangerous. Even so, there are additional compression forces involved in full squats, so for novices starting out, or for people who have less than ideal biomechanical knee joint structure or pre-existing injury, caution is warranted. But that goes for any exercise, including parallel squats. If it hurts, don't do it. Proper form and technique is paramount for injury prevention.

Summing up, there are few compelling reasons to exclude either full or half squats from your program. Naturally if you train for Olympic lifting you will need to do full squats. I mix it up by doing both.

Photo by Ryan McVay / Getty Images

Sources:

J Strength Cond Res. 2002 Aug;16(3):428-32. The effect of back squat depth on the EMG activity of 4 superficial hip and thigh muscles. Caterisano A, Moss RF, Pellinger TK, et al.

12th Annual Congress of the ECSS, 11-14 July 2007, Jyväskylä, Finland. An electromyographic analysis of four methods in squat training. Sogabe Akitoshi (Konan University, Japan)

Comments
February 25, 2009 at 2:38 pm
(1) cameron mikkelsen says:

While this article is well written, it is incorrect. To say that half squats involve the hamstring and glutes nearly as much as full squats is incorrect. Also you neglected to mention the danger it poses to your knees by placing the all the stress of stopping the weight’s momentum with the knee joint.

February 25, 2009 at 7:16 pm
(2) weighttraining says:

Cameron, you may disagree, but the evidence suggests I am correct. If you explored the references at the bottom of the article, including the linked one, you will see some experimental confirmation of what I wrote. If you have some evidence to the contrary, please post it here. On what basis do you base your beliefs?

Regarding injury to the knees with half or parallel squats, do you also believe that power cleans and power snatches are injurious to the knees? There is no medical evidence for this, of which I am aware, based on any reasonable program of squats. Again, please post your sources.

Thanks, Paul Rogers

February 25, 2009 at 7:17 pm
(3) weighttraining says:

Cameron, you may disagree, but the evidence suggests I am correct. If you explored the references at the bottom of the article, including the linked one, you will see some experimental confirmation of what I wrote. If you have some experimental evidence to the contrary, please post it here. On what basis do you base your beliefs?

Regarding injury to the knees with half or parallel squats, do you also believe that power cleans and power snatches are injurious to the knees? There is no medical evidence for this, of which I am aware, based on any reasonable program of squats. Again, please post your sources.

Thanks, Paul Rogers

March 18, 2009 at 2:00 pm
(4) Veronica says:

Regarding power cleans/snatches vs full cleans/snatches. The load on power cleans/snatches is much less that the load used in full atg cleans/snatches, so no, power versions are not injurious to the knees. Try the load used in a full clean/snatch for a power movement and you’ll definitely feel the stress on your knees.

May 23, 2009 at 4:41 pm
(5) cameron mikkelsen says:

sorry it took me so long to get back, been busy lifting and working. as for sources here you go:
The knee has four main protective ligaments that keep the femur from displacing on the tibia (ACL, PCL, MCL, LCL). These four ligaments are most effective at their protection during full extension and full flexion. Full extension would be when you are standing; full flexion would be when there is no daylight between your hamstring and your calf. When the knee is at 90 degrees of flexion (the halfway point), these four ligaments are almost completely lax and cannot exert much if any of a protective force at the knee (Zatsiorsky V. Kinematics of human motion. 1998 – published by Human Kinetics – p.301). Unfortunately, the position where the protective ligaments of the knee are not doing any protecting is the common recommended stopping point of a squat. Therefore, as it as it turns out, this is the exact worst place you could reverse the motion under load. If flexibility allows (heels staying planted, torso not flexing forward past 45 degrees), then a full squat where you lower yourself all the way to the ground is far safer on the knees than the traditional half squat. Guess what joint angle most leg extension machines start at? If you said 90 degrees, give yourself a pat on your healthy knee. This makes a full squat even safer than a leg extension machine (Wilk K et al. A comparison of tibiofemoral joint forces and electromyographic activity during open and closed kinetic chain exercises. Am J Sports Med; 24(4):518-527).
So am I telling you never to do parallel squats? No! Am I saying that you’ll injure yourself on a parallel squat? No, again! What I’m trying to do is simply make an argument for the safety of full squats.

May 23, 2009 at 4:43 pm
(6) cameron mikkelsen says:

sorry it took so long for me to get back. But here you go: The knee has four main protective ligaments that keep the femur from displacing on the tibia (ACL, PCL, MCL, LCL). These four ligaments are most effective at their protection during full extension and full flexion. Full extension would be when you are standing; full flexion would be when there is no daylight between your hamstring and your calf. When the knee is at 90 degrees of flexion (the halfway point), these four ligaments are almost completely lax and cannot exert much if any of a protective force at the knee (Zatsiorsky V. Kinematics of human motion. 1998 – published by Human Kinetics – p.301).
Unfortunately, the position where the protective ligaments of the knee are not doing any protecting is the common recommended stopping point of a squat. Therefore, as it as it turns out, this is the exact worst place you could reverse the motion under load.
If flexibility allows (heels staying planted, torso not flexing forward past 45 degrees), then a full squat where you lower yourself all the way to the ground is far safer on the knees than the traditional half squat. Guess what joint angle most leg extension machines start at? If you said 90 degrees, give yourself a pat on your healthy knee. This makes a full squat even safer than a leg extension machine (Wilk K et al. A comparison of tibiofemoral joint forces and electromyographic activity during open and closed kinetic chain exercises. Am J Sports Med; 24(4):518-527).
So am I telling you never to do parallel squats? No! Am I saying that you’ll injure yourself on a parallel squat? No, again! What I’m trying to do is simply make an argument for the safety of full squats,

May 24, 2009 at 4:54 am
(7) weighttraining says:

Cameron, thanks for spending the time to analyze this issue.

We agree then. For the most part, there’s no evidence either way that full or half or parallel squats injure healthy knees.

However, I disagree with your statement that “a full squat where you lower yourself all the way to the ground is far safer on the knees than the traditional half squat.”

There is absolutely no medical evidence for that statement either.

Thanks, Paul Rogers

June 11, 2009 at 3:29 pm
(8) Dylan says:

So, this is a bit of a vanity question:
I was under the impression that if you could squat to the depth where you could put your butt in a chair (upper thigh parallel to the floor), that you were doing a full squat–and could claim that weight.

Reading this article then, it appears I’ve been doing half-squats? I don’t think I’ve ever seen anyone do a full ATG squat, unless it was the Olympics.

March 11, 2010 at 7:25 am
(9) Darin says:

I can’t find any good studies comparing them. But I think there’s a good reason for that.

Let’s say you are right – there’s no real difference. I then ask, “but how do you define a half squat?” Are you thinking “half” means you go 70% down? 50%? What about if I only go 10% down – is that equal to a full squat?

No way.

That makes it hard, in a scientific setting, to define “half squat.”

But even if a study defined a half squat and found out that there was no difference, you’re still left as an individual person to figure out “how much is far enough to count as a half?”

From a practical sense, defining the target as “breaking parallel” ensures that people aren’t cheating so much that they get no benefit.

But it requires an ego check – the amount of weight I can lift when breaking parallel is much lower than if I cheat just a tiny bit. The strength curve’s dropoff is dramatic. Super-trained individuals (pro/Olympic guys) see less difference. It’s fun to put a bunch of plates on a bar and only go down partially – but for long term progress, progress you can track and show proof of getting stronger, you should break parallel. Here are some tips to help: http://worldfitnessnetwork.com/2008/01/half-full-squat-range-of-motion/ .

March 22, 2010 at 8:41 am
(10) Dr. Nathan says:

Id love to see the evidence that shows that a hamstring is involved in a squat?

April 13, 2010 at 11:59 pm
(11) Paul Rogers says:

Doc Nathan, you could read the references I posted . . . n’est-ce pas?

You might also post the evidence that hamstrings are not.

Thanks.

May 4, 2010 at 9:04 am
(12) Dr. Nathan says:

Ofcourse.

MRI evidence indicates that two joint muscles such as rectus femoris & hamstrings are not activated powerfully (if at all) during exercises involving simultaneous hip and knee extension. During deadlift and power cleans the hamstrings are more active because knee extension dominates the first pull’ of each movement and then almost ceases during the second pull when hip extension occurs almost in isolation. Two joint muscles such as rectus femoris,hamstrings, sartorius, and gracilis are more heavily activated during single joint exercises than multijoint exercises because in the latter they most often have undesirable actions at one joint. eg the hamstrings flex the knee and are therefore not activated heavily during squats, leg press or lunge. eg rectus femoris tends to flex the hip and is therefore not activated heavily during squats, leg press or lunge. Search studies done by Ploutz-Snyder et al 1995 & Tesch, 1999… who did MRI studies into this. Which is furthermore, what I have been taught. My two cents. Thanks

May 4, 2010 at 9:06 am
(13) Dr. Nathan says:

Ofcourse.

MRI evidence indicates that two joint muscles such as rectus femoris & hamstrings are not activated powerfully (if at all) during exercises involving simultaneous hip and knee extension. During deadlift and power cleans the hamstrings are more active because knee extension dominates the first pull’ of each movement and then almost ceases during the second pull when hip extension occurs almost in isolation. Two joint muscles such as rectus femoris,hamstrings, sartorius, and gracilis are more heavily activated during single joint exercises than multijoint exercises because in the latter they most often have undesirable actions at one joint. eg the hamstrings flex the knee and are therefore not activated heavily during squats, leg press or lunge. eg rectus femoris tends to flex the hip and is therefore not activated heavily during squats, leg press or lunge. Search studies done by Ploutz-Snyder et al 1995 & Tesch, 1999… who did MRI studies into this. Which is furthermore, what I have been taught.

My two cents. Thanks

May 5, 2010 at 8:03 pm
(14) weighttraining says:

It seems we have some disagreement, but that’s not unusual in the weight training sciences.

It’s worth reading Jason Shea’s analysis here, quoting Caterisano’s 2002 study at:

http://www.apec-s.com/Deep%20Squats.pdf

“In this study, the researchers found glute activation during full squats to be greater than twice that of partial squats (35.4% compared to 16.9%), hamstring activation to be similar, while quadriceps activation dominated during the partial squats only..”

(I’ve removed that link to Akitoshi as it seems that the document is no longer available.)

Thanks, Paul Rogers

December 27, 2010 at 6:38 pm
(15) christos says:

I squat slightly above parallel.
My lower body has become unrecognizable, my quads and hams and whole lower body structure looks like it doesn’t belong to me, probably because at the age of 36 I had become accustomed to my weak physique of so many years.
Why do I not go lower?
Because people tend to forget that ATG squats require a LOT of flexibility to perform safely with heavy weights and even that may not be enough.
They require the correct anatomy, that means a natural arch in the lower back for starters.
I have neither.
Some people lack either or a lack somewhat in either department.
I think actually a big percentage of people cannot safely perform an ATG squat due to anatomy limitations which all the flexibility exercises in the world will not completely cure.
A couple of points to note.
1)Stopping the momentum when doing parallel squats does not pose a danger if you do so slowly.
In the same respect exploding the weight up during bench presses will wreck your elbows in no time.
If you are aware of the danger you can avoid it.
You can wreck your knees if you let the weight shift on either side as you stand up.
You will not if you do not.

2)ATG squats involve much less weight.
So even if they involve a wider ROM, they do not work the muscles anywhere near as hard as you get above parallel.
A lot of work is done down low but less work is done as you reach the parallel point and beyond because there’s a lot less weight.
I would not believe that people who engage in ATG squats would end up with equally impressive development if they didn’t rack up the weights often and do half squats to complete the work.
In conclusion I believe that while a mix of the two would be best, my personal experience tells me half squats are perfect for enjoying the benefits of the squat in both the size and strength department.
Safety in the squat or deadlift has nothing to do with the exercises themselves, it has to do with how they’re performed and how much they fit your particular bodytype.
The fact that the full vs parallel squat discussion keeps going on forever is a good indicator that both can be safely performed depending on individual.

February 25, 2011 at 10:50 am
(16) klinton says:

this article doesnt apply any logic whatsoever

April 14, 2011 at 3:00 pm
(17) Jeremy says:

you should squat below 90 degrees. the problem with people hurting there knees is because of their poor stance. When squatting the knees should be behind the toes to prevent knee damage. also when many people squat their knees tend to come in which is also very bad for your knees.

May 7, 2011 at 2:17 am
(18) tony says:

knees go past the toes, playboy. i suffer from damaged cartialiage and tendonitis due to severe runners knee and when i squat slightly above parallel it doesn’t hurt. but my hip joint still travels lower than top of my knees, so it seems legitimate squat. to those who says parallel squat can put pressure on the knees, maybe because you put too much emphasis on putting weight on the heels and your knees don’t travel over the toes, or putting too much weight on the toes, other than that i don’t see any reason why parallel squat would put critical pressure on your knees.

May 27, 2011 at 11:16 am
(19) Derek says:

I have patellofemoral syndrome, and full squats produce an absolute loss of strength. I deadlift and clean alright, but that’s because I am exploding upwards, not contracting downwards. I wear a special brace to help sturdy my knee, and roll on the foam thing to help loosen my ITB to make my kneecap sit more proper.

with that said, i absolutely cannot squat ATG. my knee would give out completely because of the displacement of my kneecap (it would probably dislocate). I squat 315 as my comfy set of 10, and 365 is my last set. I can do 405 sometimes, depending on how my knee feels.

the kneecap is also a surprisingly important piece of the squat puzzle. If it isn’t in place, everything comes crashing down – literally.

Also, I seem to engage my hamstrings and glutes just fine. As I ease into my paralell position, I engage those muscles and explode upwards from them, using the ball of my heel as my anchor. More or less, I “ease” into my hamstrings and glutes as I get near the bottom and take the weight off my knees, and explode with force upwards to a standing position, then slowly retract into my squat.

it should also be noted I have troubles with full squatting in any condition, and prefer to take a knee whenever possible.

May 28, 2011 at 3:28 am
(20) weighttraining says:

The knees past the toes thing is pretty much a beginners safety thing for good form, eg weight on heels not on toes, no curved back, etc.

However, biomechanical differences need to be taken into consideration. Long femurs and inflexible ankles make a difference to knees and toes position in squatting.

June 2, 2011 at 6:37 pm
(21) john says:

i find i cannot do full squats due to ankle equinas poor rom.
But can compensate on a Bosu or with heals raised sopported on a body bar.
Hope this helpful.
John

October 15, 2011 at 7:27 pm
(22) Justin Poitras says:

I also perform slightly above parallel squats.
You guys seem to be forgetting the whole point in why 80% of the weightlifting general population perform squats is for bigger legs and functional strength. I love watching these young kids go all the way down ATG with 225 on the bar for 5 reps and then slam it on the power like they are the man. …. I then approach the power rack and warm up to a working set of 435 and perform 5 solid reps to slightly above parallel. These young kids then say something like …”dude didnt even go all the way” … then they catch a glimpse of how big my quads and hammies are just popping out of the bottom of my shorts. Sometimes everyone forgets that the main mechanism that will give you bigger legs is “neural activation”. You need to start improving your progressive overload or you ATG guys will never see what big legs really look like. One more thing…since switching from ATG to slightly above parallel I have never had any knee aches. Where as on the ATG squat my right knee would ache every couple of days when walking. I am so happy this article was posted. Completely sick of the young bucks yelling “ATG” with there little tiny legs.

October 17, 2011 at 5:58 am
(23) Paul Rogers says:

Well put, Justin. Horses for courses for sure.

The one thing I see lacking in young guys at my gym is leg development.

November 8, 2011 at 1:10 am
(24) John t says:

For all those who say there is problems with full squat there is a reason. That the professional Olympic athletes do them, the reason is because the get the best results and it protects your knees. Also for those who say they can’t reach the depth to be cousidered a full squat you probally have back problems because of tight ham strings if you get those loosened up you can squat low and your back can get stronger anyone can full squat you just have to work at it at first.

November 21, 2011 at 8:16 am
(25) chris heron says:

excellent article.for vanity i have always squatted atg with perfect form however i look like a giraffe would trying this because of my long limb.s im 6ft 2….for the last 2 years or so atg has been the norm however i have stalled at the terribly low weight of 90 kg…because atg was the way to go…or so i thought..then i tried just slightly above parallel..the results have been dramatic.i have been able to put an extra 40kg on the bar in just 3 months and feel stronger everytime i go back to the gym on my normal abbreviated routine.i tried going back to super strict atg techique after this addition to the bar and guess what..i could only just manage 5 kilo extra at a push..as above horses for courses!please feel free to comment thanks.

September 2, 2012 at 5:06 pm
(26) ross says:

i was doing half squats for a while and it delevoped roughness under my knee cap from aggitation from the stopping momentum etc, not been able to do them for months and still pain in my knee, only way i can do squats without it hurting is by going atg, buty still hurts when reaching half way but thats just my opinion

September 2, 2012 at 8:10 pm
(27) weighttraining says:

Ross, yes either way you may get some soft tissue injury or irritation with heavy use.

I mix up half and atg squats, which seems to work okay.

September 22, 2012 at 9:00 pm
(28) Pythons says:

I’m 6’2 with long limbs and I don’t feel safe doing ATG. A safe weight for me doing ATG would be like 180 or something. My working weight with half squats is 355. While I realize I would be better off doing 355 ATG than 355 half, I am better off doing 355 half than 180 ATG. The results speak for themselves, this is not mere theory.

September 26, 2012 at 6:17 pm
(29) weighttraining says:

Yes, same here – I’m about your height. Long femurs and inherently unstable at ATG.

December 5, 2012 at 9:11 pm
(30) Gooner says:

Starting strength- mark rippetoe. Everything you need to know about the squat. I have got stronger and bigger as a consequence.

June 9, 2013 at 4:15 am
(31) Pistol Pete says:

Full range of motion puts more pressure on yo knees but the depth is the key its like saying this how come you have to bench touching your chest if thats the case then we should bench 90 degrees then so what ever lift you do you need a full range of motion

July 5, 2013 at 12:22 pm
(32) David says:

I started workign out hard about 7 months ago. Incorporated squats in to my workout and have seen incredible gains. I have also been doing deadlifts. However, because I was only doing half squats (ie: not quite parallel) I have found that I am having troubles running because of muscle imbalances. My rectus femoris was weak. I can barely do 10 reps of cable knee raises at 10lbs but I can half squat 325lbs for 10 reps and I can deadlift 300. To correct this I need to stretch my quads/hams/calves/itband/hips big time and do more isolation of the weak helper muscles and slowly reintroduce running. I did a lot of stationary bike before. I’ve also started doing more full squats (not quite ATG). I had to start with light weight and do wall squats to get the posture correct. In both forms of squats I feel the burn in the same areas. My glutes however are typically more sore the lower I squat. I find with the lower squats I feel better though and it tends to help with flexibility. I did however have to drop the weight down to half of what I was half squatting before to get the mechanics down.

August 22, 2013 at 1:57 pm
(33) darren says:

Sorry too much science and not enough common sense

look at the Asian squat, funnily enough flat foot ATG position

in addition, so does a baby squat ATG

why because its inherent within us as it causes less damage

we only began sitting on a wc 100 years ago before this we squatted……….

of course there is hamstring activation during a squat

and most don’t do it cos they would have to lower the weight quite extensively and it hurts their ego

August 23, 2013 at 2:06 am
(34) weighttraining says:

Yes, good points, but it is a little different when you have not been raised in the squatting position!

Cheers.

February 25, 2014 at 3:44 pm
(35) Phil says:

I am a long-legged 6’3″ and I have found I can’t go below parallel without my knees making funny noises. I’ve tried several variations on form since so many people seem to claim ATG is so superior, but I haven’t had any luck. So I stick with parallel.

February 26, 2014 at 8:03 pm
(36) weighttraining says:

That’s okay Phil, parallel is find for general strength and conditioning.

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