Squat

Post date: Sep 17, 2012 6:28:45 PM

This post is the least related to my profession so far. But I spend a lot of time using my trained scientist brain to think about things that have nothing to do with my work. One of these things is proper squatting form.

In my opinion, the squat is the most important weight-lifting exercise. It is also the exercise in which there is the greatest variety and prevalence of ineffective and potentially injurious lifting technique.

Ida showed me a video by Mark Rippetoe about squatting. I liked a lot of what he said, but disagreed strongly with one of his points. Rippetoe seemed to be saying that one should drive up first with the hips, dropping the chest. That seemed like a bad idea to me, since it should increase strain on the lower back, which might increase the chances of injury. But Rippetoe was suggesting that driving up first with the hips would better engage the hamstrings. This reminded me of a piece of advice I had from one of my extremely knowledgeable lifting partners. So I decide to run these ideas past two of my friends. To protect their identities, I have assigned them code names. "Lucius Malfoy" is finishing up his PhD in human physiology, and "Thor" majored in human physiology as an undergraduate. Both are consummate scientists. What follows is an email conversation among the three of us.

Gabe:

Hi guys, I've been meaning to ask you this for a while.

Ida sent me a link to this video, in which the instructor is offering advice that is contrary to advice that I give about squat form. Could you please watch the video, and let me know what you think? I'm tempted to just say that he is wrong and that I'm right (that's my default approach, after all). But I've seen another video of this guy giving a whiteboard talk about squat technique, in which he says some stuff about engaging the hamstrings. I know that "Thor" has said similar things in the past, and that it has never made any sense to me. So, maybe I'm ignorant, and this guy is enlightened? Anyway, I'm curious to hear your thoughts.

Malfoy:

I've always thought of squats as primarily being a gluteus exercise, which is why you want to do exactly what the guy was saying: "drive your ass up".  The glutes have the best mechanical action at the bottom of the exercise (where your quads have a relatively weak lever of action). This is why going to the bottom (knees bent to about 70-90 degrees) is important. Before the bar can be driven upwards, the pelvis needs to be rotated and supported (glutes).   Small muscles with strong levers of action in this position initially get the bar moving, then the quad muscles take over (hamstrings are antagonist to this action).  I'm not sure what he was talking about when he was saying that the hamstrings lose their ability to contract when knee is bent, the hamstrings obviously bend the knee, perhaps I misunderstood him.  Hamstrings throughout the lift would be considered antagonist (braking mechanism) in my opinion, although they are a weak pelvic rotator (aid the glutes).  An analogy would be the biceps muscle to the bench press (negative throughout the lift, useful for braking) with the potential to internally rotate the scapula.  As far as form goes, the exercise looked good, straight back and flat cervical (not cranking neck up to look) is probably the most important part for safety, especially during heavy sets.  The width of the stance, to me suggests placing a greater focus on hip rotators such as the glutes and taking some of the work off of the quads and onto adductor muscles.   Let me know if something I said doesn't make sense, I'm basing most of this off of origin/insertion knowledge.

Gabe:

Thank you, "Malfoy", this is extremely helpful.

I get the "drive your ass up" part. The part that I don't get is the willingness to let one's chest drop during the first part of the upward motion. As you point out, the hamstrings can help rotate the pelvis, which is part of the upward motion. But it seems like letting one's chest drop puts a lot of strain not only on the glutes, but also on muscles in the lower back (erector spinae?). Having pulled that muscle doing dead lifts, it seems like less strain on the lower back should be the goal, right? I mean, that's why (as the guy in the video, and you point out) a straight back and flat cervical spine is important. Right? And dropping one's chest during the first part of the motion doesn't necessarily mean that one's pelvis would rotate forward - and it's only that forward rotation of the pelvis which the hamstring could work to prevent, right?

I think it's that part of the guy's explanation in the video that is the most confusing to me - and what has confused me about Thor's explanation of squat form in the past. Sure, we want to use our hamstrings some during the exercise, but in order to do so, aren't we also committing to using our lower back muscles, and isn't that a good way to get hurt?

See the attached figure. Basically, my concern is the solid red line, which I think should be more like the solid blue line. I drew the solid red line as having a slightly decreasing angle at the start of the motion, but even if it's just flat, I'd be concerned about the strain on the lower back. Let me know what y'all think.

Thor:

[Some comments redacted due to inappropriateness. -Ed.] You are completely correct - your low back angle shouldn't change much and your chest shouldn't be allowed to drop during the initial push (or ever). I will say, based on your drawing, you're not going low enough.

Gabe:

Yeah, figure 1 wasn't quite right, because in real life I put my ass (nearly) on my heels at the bottom of the motion. I drew it like that to make it easy to see the angles. But I think the numbers in figure 2 should be about right at the start of the motion, for rough guesses anyway. Maybe they're a little too high...

Malfoy:

I agree with your logic Gabe, its just physics - the more forward your chest (more parallel with the floor), the more torque on your lower back.

Just because free body diagrams are awesome!

Thor:

Check out this thread on reddit/r/fitness:  http://www.reddit.com/r/Fitness/comments/zc5io/tools_for_perfecting_your_squat_the_squattostand/ 

Fairly self explanatory; I wanted to mention that in the second video (the fellow in the orange), the position at the bottom is how I would describe the perfect squatting form. You drive straight up from there; you don't lift your butt up first like the video.