Are Squats on the Smith Machine bad for your knees?

[needsize]

leg extensions do put far more shearing force on the knees than squats. I got to experience this first hand prepping for my show. I squat up to around 455 for reps, ass to the floor and never have any knee pain. My trainer told me to start doing extensions before the show, within a few weeks my knees were screwed, still hurt 6 months later

 

[Fina Junkie]

Re: "ox yolk"

How in the hell did you manage that? I've used it up to 405 lbs, the bar resting particularly comfortable accross my shoulders. We have powerlifters in my gym who have piled 700+ on the thing and used nothing more than their fingertips on the rack to stablize themselves.

I had either 465 or 455 on there. The U shaped pad rested directly over the joints i guess. I finished my set of 3, racked the weight and couldn't move my arms. I got to ride in an ambulance that day

 

[mt]

leg extensions do put far more shearing force on the knees than squats. I got to experience this first hand prepping for my show. I squat up to around 455 for reps, ass to the floor and never have any knee pain. My trainer told me to start doing extensions before the show, within a few weeks my knees were screwed, still hurt 6 months later

What kind of weight were you using on the leg extensions and was it done with strict form? It is rare to see a person doing leg extensions without them kicking that weight up. I think that as long as a movement doesn't twist your joint out of it's socket and is done in a controlled and deliberate fashion it would seem to me to be relatively safe. And what's up with all this "shearing force" talk? Is there a lot of shearing force on the elbow joint with a tricep extension? Why or why not? It would seem to me that when doing a squat or a bench press the joint is more compressed because it is directly in line in the lock out position with the much greater resistance than with an extension movement. Bending the joint in this compressed position (in addition to either your feet or hands being held in a fixed position) under the greater weight than can be used in an extension type movement might contribute to this "joint shearing" but I've never felt any pain when doing any extension type movement in a strict fashion. The same cannot be said for exercises like squats and bench presses (which can take its toll on the shoulders and elbows)

 

[Lumberg]

Why is straightening your leg while sitting by far the most unnatural movement for the knee structure? Even old people that can barely walk can do this movement effortlessly. Not everyone can do a full squat with ease even without any outside resistance. I've had surgeries on both my knees (due to contact sports not exercise) and the first rehabilitaing exercise the PT had me do was leg extentions. In fact, this was really the only exercise I could do for the quads since even partial bodyweight squats caused pain. I think poor feet positioning (say, toes pointed in excessively) will cause more harm to your knee joint since your feet are in a fixed position throughout the movement whereas with the leg extension your toes tend to point in the position that is most comfortable and causes the least strain on the joint.

leg extensions with low weight are an excellend rehab exercise. I think what he is saying is that working at very high loads for weeks with leg extensions will hurt your knee more than help it. The reverse is true for squats.

 

[Silent Method]

Olympic lifters' knees go fairly far beyond their toes.

Not all of them.

If what you're saying were true, every olympic squatter would have wrecked knees.

Not all of them, but some. (Squattng isn't an O lift, but I know what you mean.)

 

[Silent Method]

Re: "ox yolk"

I had either 465 or 455 on there. The U shaped pad rested directly over the joints i guess. I finished my set of 3, racked the weight and couldn't move my arms. I got to ride in an ambulance that day

Yuck. How did you position your arms? The pad on the ones I have used fit well between my shoulder joints.

 

[Fina Junkie]

Re: "ox yolk"

Yuck. How did you position your arms? The pad on the ones I have used fit well between my shoulder joints.

I was holding on to the pegs on the rack to balance myself. I think I may have extended my arms too far out in front of me.

Eitherway I'll just be using the straight bar from now on.

 

[needsize]

I was doing sets of 10-15 reps, slow and in control, at the very end of the qud routine. The weight was 2/3 of the stack which isnt a whole lot. The bit about shearing force I got from an orthopedic surgeon that I went to see, he also specialilzed in treating athletes

 

[Nelson Montana]

To an extent, all exercises are shearing to the joints. The diffrence with leg extentions is that the joint was never intendd to move against resitance in that manner. No where in life do you need to "kick out" against continual resistance. Movements like squats and tricep extentions simply mirror daily movement , just with an increased load. Leg extentions are abnormal.

I do believe extentions work nicely as a pre-exaust movement or as a "finisher." But trying to build quad mass with extentions will be inneffectual and damaging to the knees.

 

[mt]

To an extent, all exercises are shearing to the joints. The diffrence with leg extentions is that the joint was never intendd to move against resitance in that manner. No where in life do you need to "kick out" against continual resistance. Movements like squats and tricep extentions simply mirror daily movement , just with an increased load. Leg extentions are abnormal.

I do believe extentions work nicely as a pre-exaust movement or as a "finisher." But trying to build quad mass with extentions will be inneffectual and damaging to the knees.

I find this notion that because a movement under continuous resistance occurs "no where in life" therefore it is possibly dangerous to be rather suspect. The body moves as the body moves. If you want to strengthen that movement you do it under a load, in a non-explosive manner -- preferably over the full range of motion. Are the neck muscles, anywhere in life, subjected to continuous resistance? If you are a wrestler strong neck muscles are a must and nothing beats the Nautilus neck machine. How about wrist extensions or wrist curls? Stiff leg dead lifts? How about that machine where you sit and twist your body from side to side under continual resistance? For those familiar with submission wrestling/Jiu-Jitsu you know about the foot lock. I have found myself almost impervious to foot locks by doing a simply exercise on the leg curl machine. I sit on the machine, legs straight (face up) and hook my toes under the pads and curl my instep toward my shins. This has strenghten the tendons and whatever muscle is on the front of the shins to such an extent that straight foot locks are ineffective against me. Does this motion occur anywhere in nature? Am I shearing my ankle joints? Do you ever in life need to curl your leg to your butt against continual resistance?