Need help in defence of deep squats.

[JPOD]

Hi Mark,

I am a huge fan of your work and a great admirer. I am also a member of another general fitness site and am currently in a debate with a fellow who is intent on claiming that deep squats are bad for the knees and that they are not an efficient way to build strength. This is the thread below (the last couple of posts is all you really have to read):

http://forums.johnstonefitness.com/s...t=40604&page=2

I am trying to argue against his points, however, I lack the ability to pull fancy online quotes and studies, as I am just a simple, non-scientific kind of guy. Was wondering if you could give some insight as to where he is going right/wrong.

Much appreciated and I understand if you don't have time for this kind of debate.

[Mark Rippetoe]

I think I remember writing a book about this, and it's pretty well explained in there. I appreciate what you're trying to do, but you can't make people smarter. You can expose them to information, but your responsibility stops there.

[Polynomial]

I've got a question about this study that someone posted on the above linked board.

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, adn 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.

I'm not familiar with most of the terminology, but it seems to me that they've determined that the ACL picks up the slack when stopping a half-squat, and that a full squat is the safest of them all. After all, I don't know what "thighs parallel to ground at maximum knee flexion" means since my thighs don't form a plane (I'm a mathematician, I know), and 0-100 degree knee flexion sounds like where most correct, full squats would fall (well, 50-100?). I didn't access the full article so I'm not sure what their idea of a squat is anyway, but it sounds like when accounted for their possibly poor form, these results support what's in SS? (and I don't mean that as an insult

[Mark Rippetoe]

I don't think they said that the full squat was the safest of them all; they said they were okay for athletes with healthy knees. But this statement: "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." and this statement: "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." are rather equivocal. The problem is that no one conducting these studies really actually honestly knows how to do a correct squat, and they are therefore evaluating an exercise that I do not consider to be a correct squat. If you do a high-bar squat on a Smith machine down to a 90-degree knee angle and testing determines that it produces ACL/PCL and meniscial shear, you don't really get to say that squats are bad for your knees.

This is from http://www.nizkor.org/features/fallacies/straw-man.html

The Straw Man fallacy is committed when a person simply ignores a person's actual position and substitutes a distorted, exaggerated or misrepresented version of that position. This sort of "reasoning" has the following pattern:

1. Person A has position X.
2. Person B presents position Y (which is a distorted version of X).
3. Person B attacks position Y.
4. Therefore X is false/incorrect/flawed.

This sort of "reasoning" is fallacious because attacking a distorted version of a position simply does not constitute an attack on the position itself. One might as well expect an attack on a poor drawing of a person to hurt the person.

[galapogos]

I go to for physical therapy at a local hospital for my injury, and just the other day the therapist wanted to see what I was doing at the gym, so I just loaded 1 plate on the bar and proceeded to front and back squat for him to see. As soon as I was in the hole, he and a "trainer" standing by was exclaiming that I was going to kill my knees. The next session, he sat me down and tried to explain to me why deep squatting was bad for the knees. Geez, what a load of crock...

[Mark Rippetoe]

This makes it very difficult to respect their profession, doesn't it?

[Tuesday]

I've got a question about this study that someone posted on the above linked board.



I'm not familiar with most of the terminology, but it seems to me that they've determined that the ACL picks up the slack when stopping a half-squat, and that a full squat is the safest of them all. After all, I don't know what "thighs parallel to ground at maximum knee flexion" means since my thighs don't form a plane (I'm a mathematician, I know), and 0-100 degree knee flexion sounds like where most correct, full squats would fall (well, 50-100?). I didn't access the full article so I'm not sure what their idea of a squat is anyway, but it sounds like when accounted for their possibly poor form, these results support what's in SS? (and I don't mean that as an insult

Your thighs do form a plane. The knee only pivots in one direction (along an axis, if you will) and the ball and socket of the hip pivots around a point inside the femoral head, so you get a line and a point, which define a plane (I'm also a mathematician).

The study you quoted is in effect saying that because deep squatting causes greater shearing forces on the knee, it should be avoided. Completely ignoring the authors' notions of correct form (Rip's gonna yell at me), their basic assumption is that the shearing forces are inherently bad, yet they fail to provide sufficient evidence to support such a conclusion.

In fact, I suspect the increased shearing forces are likely a good thing. Consider the purpose of weight training: gradual overload to stimulate increases in strength. And strength means the strength of all involved structures, not just the muscles' contractile force. The increased shearing forces, when applied in a careful and controlled manner as in weight training (as opposed to, say, getting tackled in football), are just a stimulus for the body to adapt to and so will likely result in stronger, less injury-prone knees in the long run. And I've got a bright, shiny nickle that says it's so. Any takers?

There's all kinds of other potential problems with the study. For example: A deeper squat means a greater range of motion, which means more work for a given amount of weight, which means the deeper an athlete squats, the less weight she'll be able to use relative to her strength levels. And so the shearing forces of a 300lb deep squat cannot be compared to the shearing forces of a 300lb parallel squat.

[tyciol]

You don't need to defend squats, your accuser must defend his accusations. Ask him the specific reason they are bad for the knees.

No doubt you are more vulnerable and weak in that position. But training there with control will strengthen your weaknesses, so it strengthens you.

[galapogos]

Well here are some food for thought, if you need ammo to defend the full squat

A comparison of tibiofemoral joint forces and electromyographic activity during open and closed kinetic chain exercises - basically they found that max tibiofemoral compression forces on the knee occur at ~90deg knee flexion for the squat, which is right about a half squat. They also found that max posterior shear force(stress on the PCL) occurs between 95-105deg, which is again near a parallel/half squat.

Patellofemoral joint kinetics during squatting in collegiate women athletes - basically they found no differences in stress on the patellofemoral joint between squatting to 70deg, 90deg or 110deg.

Also, it has been shown that the lower you squat, the more hamstring and glute involvement there is, hence bringing it from a knee dominant to a more hip dominant movement. And we all know that the hip is much more able to handle these loads than the knee.

So in conclusion, I really don't know where people get the idea that squatting to parallel is somehow BETTER than squatting all the way down, UNLESS you have some mobility/flexibility problems that prevent you from full squatting with good form.

[Polynomial]

Your thighs do form a plane. The knee only pivots in one direction (along an axis, if you will) and the ball and socket of the hip pivots around a point inside the femoral head, so you get a line and a point, which define a plane (I'm also a mathematician).

You can talk about whether or not your femur is parallel to the floor, which is why it makes sense to think about the hip joint and the top of the knee forming a line. The thighs are a big chunk of meet on top of the femur, so talking about them being parallel to the floor seems strange to me. When is a irregularly-shaped hunk of meat parallel to the floor? When some made-up tangent line to the top of the thigh is parallel? If so, why not just say that?

For example: A deeper squat means a greater range of motion, which means more work for a given amount of weight, which means the deeper an athlete squats, the less weight she'll be able to use relative to her strength levels.

I don't understand what you mean since to me squat strength levels are evaluated using a correct, deep squat, and an advanced athlete squatting his 1RM of 600lbs is not using less weight "relative to his strength levels."