What I mean is that no pressure is added in the body axis direction - which is the direction that loads the discs in the spine - by pressing when the legs are perpendicular to that axis, which is the case in that leg press machine. Of course, if the back rest is not horizontal there is some pressure due to gravity, but it is not affected by the extra weight or machine resistance (and it is actually less than the pressure while sitting, due to the incline of the back rest).KPj wrote:I don't understand how this can be the case. There is rarely no pressure on your spine.
Mr. DeSimone claims that by applying a lot of pressure for many years you (probably?) harm your discs. Maybe by using a perfect technique the damage can be minimized or even eliminated (I have no idea. Personally I never consider what will happen to me if I apply a perfect technique for the same reason I don't give much thought to how I will spend the money I'm gonna win in the lottery) but his point is that with heavy squats your spine is bent a little inevitably, so more pressure is applied to one side of the discs than the other, and doing it over and over again for years will eventually harm them. As I said I'm just a layman, so I can only say that the argument sounds reasonable to me. While muscles, bones and tendons will get stronger with use, it's not the case with the discs which are made of cartilage. I would suggest they are more like your teeth; lifting heavy weights is the equivalent of crushing nuts by chewing them.Again, though, what's the problem with pressure on the spine? Why is it a bad thing, unless it's applied wrongly, of course.
OTOH I guess it may be argued that by strengthening the back muscles you get better stabilization of the spine so maybe there is less wear and tear on the discs throughout the day and maybe it compensates for the extra pressure while squatting.
That's a valid objection, if true. However, I guess some will argue that those who continue to lift for a long time are those who happen to have a fortunate genetics that protects their backs while the rest of the population avoids it altogether or stops doing it after a short time since they feel it's not right for their backs. So if weight lifters are really suffering less than the general population it's not because lifting protects them but the other way around: only those who are naturally protected are heavy lifters. I guess some research is needed, but it wouldn't be easy to carry out.This makes the implication that those who use free weights will be prone to serious back problems when, actually, just the general population, in fact the majority, are almost certain to develop back problems.
Tell me about it :-( But the claim is that by squatting heavily you will also be more prone to "back injury" next time you lift your sock. BTW, it happened to me once and put me in bed for a week.Also, the majority of "back injuries" occur when bending over, picking up low load items such as a pen or newspaper.
That's where Mr. Desimone begs to differ.The notion that lifting heavy weights = serious back problems just has no basis, in itself.
At the risk of turning this into physics 101, yes, force is mass x acceleration, and yes, you'd better apply the maximum force you can in order to generate the maximum acceleration when you jump. The claim is, however, that in this case you just cannot generate the same amount of force that you can when you press or lift at a slower rate. This claim assumes your muscles are limited by the power they can generate. Compare it to driving a car: low gear means less speed and more force, so the idea is if you want to train with maximum force do it in low gear, which implies low velocity. However, IIRC Mr. DeSimone did not mention the fact we actually have more than one engine in our muscles (kind of hybrid car, I guess). i.e. the red and white fibers, so I'm not sure about the bio-mechanics of the situation: In theory your "fast speed" motor (white fibers) might be able to generate more power than the slow ones, and if that's the case, and if you really use one type or the other by changing the speed of your motion, the whole analysis is invalid. I have no idea. Again. Doc? Anybody?I'm definitely not a physics pro so, I'm open to being criticized here but, I just don't get what you're saying. Doesn't force = mass times acceleration?
Well, Mr. Desimone makes the case that mother nature did not intend us to carry heavy weights on our shoulders - that's the point of the pyramid analogy he made.Movement as in, our primitive, instinctive, intuitive capacity to move efficiently that mother nature provided us with and modern lifestyle sucks out of us.
While this is encouraging, the issue is more about accumulated damage for the long run rather than injuries while training. Still, a good point.No one has ever been injured during any session with me
I wish I could have this kind of discussion with the trainers in my gym... On second thought, in that case I would probably spend the whole training time discussing the issues which I much prefer over sweating, any day of the week :-) Oh, well.
edited: changed "disk" to "disc". grrrr.