Parallel vs. full ROM squat, shearing forces

All,

Many times on this forum I have read that the shearing forces on the knee are LESS with a full Range of Motion squat vs. stopping the squat at parallel. I have always performed squats with full ROM based on this understanding.

That said, do you have any links or references that actually demonstrate this to be the case? The only study I have seen seems to indicate the opposite, namely that parallel squats are safer than full ROM squats.

Thanks

Here you go.

Quote:
Kreighbaum (1996) illustrate the safe position of a deep squat with the knees extending beyond the toes. Kreighbaum explains how a deep squat can be performed little chance of injury to the knee. The variables of concern

* speed of descent
* size of calves and thighs
* strength of the controlling muscles

The primary danger to the knee occurs when the tissues of the calf and thigh press together altering the center of rotation back to the contact area creating a dislocation effect. The danger of knee injury in this situation may be prevented if either of the following factor are present

* center of gravity of the body system is keep forward of the altered center of rotation
* muscles of the thigh are strong enough to prevent the body from resting or bouncing on the calves.

There's a fair amount of info in there. Even the Doc--"The first man to squat over 800 pounds"--gets a reference.

http//www.exrx.net/ExInfo/Squats.html

Parallel vs. full ROM squat, shearing forces

Why doesn't the quote function seem to work here?

Parallel vs. full ROM squat, shearing forces

Thanks - however, in in reading this article it seems to indicate that the full ROM would be MORE DANGEROUS, as

Quote:
The primary danger to the knee occurs when the tissues of the calf and thigh press together altering the center of rotation back to the contact area creating a dislocation effect.

This would only occur to any great extent in a full ROM squat, and would not occur in a parallel squat.

I can safely say that my calves and thighs do press together quite a bit in a full ROM squat. They would not press together nearly as much in a parallel squat.

Thus, instead of indicating the full ROM squat to be safer than the parallel squat, this article indicates it (the full ROM squat) to be more dangerous.

Here is the main reason I ask. I hear people all the time say that full ROM squats are safer and that research indicates that is so. I have always believed this to be the case. Yet when I search, the research always seems to indicate the opposite.

Parallel vs. full ROM squat, shearing forces

I find full ROM squats hurt my knees alot thats why I dont do them.

Parallel vs. full ROM squat, shearing forces

John S has a good point if it hurts, don't do it.

On the other hand, the article comes out and says the obvious in several places, the gist of which is that if you do squats wrong or if they aggravate pre-existing injuires, then they're more dangerous.

The common knowledge in support of full squats is that going all the way down activates the hams more fully, which work with the quads to support the knee in the bottom position, whereas squatting to parallel reduces ham involvement, so you don't get the same support. Plus, scores of OL'ers with crazy-strong knees. After a period of adjustment, my knees and hips felt a whole lot better after switching to Oly squats. I used to do relatively wide squatting, but tyhe style just didn't fit my frog legs.

Articles on the main page (Kneed to Know article) and probably stuff on the research forum could help ya.

Parallel vs. full ROM squat, shearing forces

The 9th Time wrote:
John S has a good point: if it hurts, don't do it.

On the other hand, the article comes out and says the obvious in several places, the gist of which is that if you do squats wrong or if they aggravate pre-existing injuires, then they're more dangerous.

The common knowledge in support of full squats is that going all the way down activates the hams more fully, which work with the quads to support the knee in the bottom position, whereas squatting to parallel reduces ham involvement, so you don't get the same support. Plus, scores of OL'ers with crazy-strong knees. After a period of adjustment, my knees and hips felt a whole lot better after switching to Oly squats. I used to do relatively wide squatting, but tyhe style just didn't fit my frog legs.

Articles on the main page (Kneed to Know article) and probably stuff on the research forum could help ya.

Well frankly it isn't about helping ME. I do full ROM squats. It is satisfying scientific curiosity. The article posted in this thread indicates that full ROM squats are potentially more dangerous, at least indirectly, as the calves and hamstrings would come into greater contact. The 'kneed to know' article talks about parallel squats, not about full ROM squats, and frankly states that squats in general can be dangerous. At least that article is honest!

Everything I see in research talks about going to parallel, or states that full ROM squats are more dangerous. I have seen a bunch of trainers, etc. state that full ROM squats are safer. But I am looking for something backed up by science, not somebody saying "well sure they are safer...".

Here is the thing. Many people say full squats are safer than parallel squats. I have heard it enough and I have said it enough that I believe it. But I have also heard people say other things over and over again that aren't true. So if we are going to go around recommending full ROM squats, AND if people are going to state that the research shows that full ROM squats are safer, then I would like to be privvy to this research. If the research does NOT exist, then I will stop saying that full ROM squats are safer and change it to "I like doing full ROM squats as they work great, they provide me with an objective means of gauging my depth, and they have not, to this time, caused me any knee problems or discomfort in the knee".

Parallel vs. full ROM squat, shearing forces

Everything I see in research talks about going to parallel, or states that full ROM squats are more dangerous. I have seen a bunch of trainers, etc. state that full ROM squats are safer. But I am looking for something backed up by science, not somebody saying "well sure they are safer...".

>>>This link contains tons of info on full squats

www.google.com

Your experience with trainers is stark opposite to mine. There's only one guy I know outside of lifting that encourages his clients to go below parallel. And even that guy tells people back off even if they hear the ocassional joint mouse.

Parallel vs. full ROM squat, shearing forces

li0scc0 wrote:
Thanks - however, in in reading this article it seems to indicate that the full ROM would be MORE DANGEROUS, as
Quote:
The primary danger to the knee occurs when the tissues of the calf and thigh press together altering the center of rotation back to the contact area creating a dislocation effect.

This would only occur to any great extent in a full ROM squat, and would not occur in a parallel squat.

I can safely say that my calves and thighs do press together quite a bit in a full ROM squat. They would not press together nearly as much in a parallel squat.

Thus, instead of indicating the full ROM squat to be safer than the parallel squat, this article indicates it (the full ROM squat) to be more dangerous.

Here is the main reason I ask. I hear people all the time say that full ROM squats are safer and that research indicates that is so. I have always believed this to be the case. Yet when I search, the research always seems to indicate the opposite.

they are refering to RELAXING or BOUNCING at the bottom of the squat, not weather the thighs touch the calves! what they are saying is that if you squat all the way down and "sit" on your claves relaxing the knee joint then you will hurt yourself.

Parallel vs. full ROM squat, shearing forces

The relaxing was the thing I also heard was bad for you. On the other hand, I've been to OL meets and man, do they ever bounce at the bottom of the clean and jerk.

There are definitely a ton of factors involved. Whatever you do, ice your knees 'till they freeze after every workout just for preventative measures.

Parallel vs. full ROM squat, shearing forces

The 9th Time wrote:
>>>This link contains tons of info on full squats:

www.google.com

Why do I bother asking for expertise on this site when I get an answer like the above? Laughing out loud

Parallel vs. full ROM squat, shearing forces

The 9th Time wrote:
Your experience with trainers is stark opposite to mine. There's only one guy I know outside of lifting that encourages his clients to go below parallel. And even that guy tells people back off even if they hear the ocassional joint mouse.

I am not talking about gym personal trainers, but supposed online experts such as folks at this site and other sites who encourage full ROM squats and claim them to be safer. Myself included (I'm not claiming to be an expert but rather one who encourages performance of full ROM squats).

Last call

Last call for scientific studies that demonstrate a full Range of Motion Squat to be safer than a parallel squat. As mentioned, I do full ROM squats and recommend them. Others here and elsewhere recommend them as well and tout them as SAFER than the parallel squat. However, I tried to find journal studies, both in academic journals and online via searches and have come up with NOTHING scientific that indicates the full ROM squat is safer. What I have seen runs to the contrary, namely that the parallel squat is safer.

So if anybody has access or knows of these elusive studies that we all (myself included) seem to think exist that demonstrate the full ROM squat is safer, please let me know.

steve

Parallel vs. full ROM squat, shearing forces

I have not seen any studies published even looking at full ROM squats vs. parallel. Some measure forces/moments during different parts of the squat UNTIL parallel is reached, but not past that. These studies say that anterior tibiofemoral shearing forces increases as depth increases. It is important to note, though, that forces aren't high enough during squatting (even a maximal squat) to cause injury to the structures of the knee if the squat is performed correctly. And, during an OL style squat you can't lift as much which means that the external load will be less anyway, which influences the internal forces (the ones that would cause injury).

Anyway, after a certain point your patella is also "locked in" to a very stable position. This is past parallel. Also, many EMG studies have shown increased hamstring coactivation with increased squat depth. This has implications in terms of injury prevention.

I have seen letting the knees go forward past the toes vs. not letting them go past the toes, but the depth was parallel in both cases. But they concluded in their static analysis (ie: not dynamic so not totally accurate, and the load was only fifty five pounds or something) that, as would be expected, saggital plane back moments were higher with the not letting knees go past the toes squat than in the letting knees go past the toes squat. However, knee moments were lower. But here is the thing - the knee forces are only a little lower during the knees not going past the toes condition, while the for the back they are much higher. So it is not a 1:1 trade off.

My take - OL are more athletic and safer overall. They contribute to injury prevention and neuromuscular control of the lower extremity better.

Parallel vs. full ROM squat, shearing forces

Brian W, Thanks for the well-thought-out answer. Much appreciated!

Todd Wilson's picture

Parallel vs. full ROM squat, shearing forces

* Escamilla RF.

Michael W. Krzyzewski Human Performance Laboratory, Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, USA. rescamil@duke.edu

PURPOSE: Because a strong and stable knee is paramount to an athlete's or patient's success, an understanding of knee biomechanics while performing the squat is helpful to therapists, trainers, sports medicine physicians, researchers, coaches, and athletes who are interested in closed kinetic chain exercises, knee rehabilitation, and training for sport. The purpose of this review was to examine knee biomechanics during the dynamic squat exercise. METHODS: Tibiofemoral shear and compressive forces, patellofemoral compressive force, knee muscle activity, and knee stability were reviewed and discussed relative to athletic performance, injury potential, and rehabilitation. RESULTS: Low to moderate posterior shear forces, restrained primarily by the posterior cruciate ligament (PCL), were generated throughout the squat for all knee flexion angles. Low anterior shear forces, restrained primarily by the anterior cruciate ligament (ACL), were generated between 0 and 60 degrees knee flexion. Patellofemoral compressive forces and tibiofemoral compressive and shear forces progressively increased as the knees flexed and decreased as the knees extended, reaching peak values near maximum knee flexion. Hence, training the squat in the functional range between 0 and 50 degrees knee flexion may be appropriate for many knee rehabilitation patients, because knee forces were minimum in the functional range. Quadriceps, hamstrings, and gastrocnemius activity generally increased as knee flexion increased, which supports athletes with healthy knees performing the parallel squat (thighs parallel to ground at maximum knee flexion) between 0 and 100 degrees knee flexion. Furthermore, it was demonstrated that the parallel squat was not injurious to the healthy knee. CONCLUSIONS: The squat was shown to be an effective exercise to employ during cruciate ligament or patellofemoral rehabilitation. For athletes with healthy knees, performing the parallel squat is recommended over the deep squat, because injury potential to the menisci and cruciate and collateral ligaments may increase with the deep squat. The squat does not compromise knee stability, and can enhance stability if performed correctly. Finally, the squat can be effective in developing hip, knee, and ankle musculature, because moderate to high quadriceps, hamstrings, and gastrocnemius activity were produced during the squat.

There are a few dozen studies with similar results with regards to shearing forces.

As I've stated many times, shearing forces are of little concern in any type of squat. Critics of the squat, and more importantly the full squat are simply ignorant and have not done their homework. Therre are a handful of studies that detract from the efficacy of the full squat, but they are invariably poorly designed, hence the results they achive that conflict with both literature and empirical evidence.

Parallel vs. full ROM squat, shearing forces

Todd Wilson wrote:
*For athletes with healthy knees, performing the parallel squat is recommended over the deep squat, because injury potential to the menisci and cruciate and collateral ligaments may increase with the deep squat.

Thanks Todd, appreciate that!

I have seen that study and here was why I asked the initial question about the parallel vs. the full ROM (here referred to as 'the deep' squat).

The study is a good one yet they recommend the parallel over the full ROM squat.

Parallel vs. full ROM squat, shearing forces

This is the main study I was referring to that was behind my post. There are a few others, though. But 100 degrees of knee flexion is not a "full squat". As far as I know there aren't any studies that have looked at the full squat. But, the point remains, those who think squats (any type of squat) are bad are just wrong. The science and evidence doesn't back it up.

Escamilla has a good review paper of the squat he wrote. Probably was the lit review for his dissertation. It was published in 2001, I think in Medicine and Science in Sports and Exercise. Haven't looked at it in a while.

Todd Wilson's picture

Parallel vs. full ROM squat, shearing forces

li0scc0 wrote:
I have seen that study and here was why I asked the initial question about the parallel vs. the full ROM (here referred to as 'the deep' squat).

The study is a good one yet they recommend the parallel over the full ROM squat.

Yeah, and frankly, that's a common thread among a lot of peer reviewed research looking directly at the squat, despite what the data says. The main reason is because in studies looking at potential benefits over the parallel or half squat and full squat, the subjects were untrained college students. In 6 weeks strength gains on virtually any given muscle test will be the same. However, long term, it's a completely different story. In addition, the researcher here, Escamilla, has done some interesting work, but a lot of times, his conclusions don't equal his findings. However, I merely presented this as it was one I had easy access to that referenced the shearing forces of squat depth.

In addition he mentions "injury potential to the menisci and cruciate and collateral ligaments may increase with the deep squat." I can't find a way to get to that conclusion, and I've read the entire study before, so take it for what it's worth. But with regards to shearing forces he is absolutely correct in that shearing forces are virtually nil in all forms of the squat. One of the most common criticisms of the full squat is that introduces too much shearing force. 1) It's just not true; 2) a basic knowledge of anatomy and kinesiology demonstrates that in the low position of the full squat that not only does it not happen, it's not physically possible.

Todd Wilson's picture

Parallel vs. full ROM squat, shearing forces

Brian W. wrote:
But 100 degrees of knee flexion is not a "full squat". As far as I know there aren't any studies that have looked at the full squat.

There's several, not necessarily looking at shearing forces mind you......there was a series of posts on the Supertraining group in which at the time I believe all available one's were posted as I contributed to the list (some available from online resources, some not).

The most interesting one to me was done in Norway or finland one, and evaluated weightlifters and powerlifters. Weightlifters had lower incident of inury to the knees and low back both during and in the years following competition.

As for 100 degrees, it's not a full squat in all, but for those with a ton of leg mass, or exceptional flexibility it certainly can be. But the take home message is greater depth is not more "dangerous" as the myth resulting from the Kline "study" has always held.

Parallel vs. full ROM squat, shearing forces

Damn right! Todd is layin the smackdown with perfect form!

Also i have noticed in America most of the coaches here always talk about is this bad for your knees is that bad for your anal and so on...But overseas i never seen a top coach getting in this crap. Overseas coaches are SOLD ON RESULTS in America coaches ARE sold on GIMMICKS.

peace out

Parallel vs. full ROM squat, shearing forces

It depends on the individual. Some have knee pains at parallel and some have it at full, learn your body beats all the studys.

Todd Wilson's picture

Parallel vs. full ROM squat, shearing forces

Weightlifter wrote:
Damn right! Todd is layin the smackdown with perfect form!

Also i have noticed in America most of the coaches here always talk about is this bad for your knees is that bad for your anal and so on...But overseas i never seen a top coach getting in this crap. Overseas coaches are SOLD ON RESULTS in America coaches ARE sold on GIMMICKS.

peace out

Also understand that, at least until recent years, in foreign countries weightlifting was the predominant resistance training base/background that most gym-goers had.

Here in the U.S. it's bodybuilding and the Weider Principles. Little bit of difference.

Bottom line though is that the you can't use as much weight in the full squat as you can in other versions of the squat, it's harder, it takes a little more discipline, etc. and Americans typically don't want anything to do with those things, therefore we've made up excuses not to perform the full squat. Boot's Garland, noted speed coach, is correct that Baseball is not and has not been the national past time since the 50's because the national pasttime today is transfer of blame; I.e., making excuses for inadequacies and failures.