squats v leg extensions

KarlW · 12-14-2004, 11:05 PM

Here's an article I stumbled upon while Googling around for info:

First a question: Is it possible that leg extensions could cause more knee problems than squats? Has anyone experienced knee injury from either exercise?

Now here's the article:

Quote:

According to some fitness experts, squats are bad for the knees and should never be performed under any circumstances. In reality, however, these sentiments are decidedly misguided. Studies have repeatedly shown the squat to be a safe, effective exercise; when performed properly, it poses little risk to those who have healthy patellar function. Even elite athletes who squat several times their bodyweight have few reported injuries directly attributable to the activity.

In fact, contrary to popular belief, squatting actually places less stress on the knee joint than leg extensions. This has to do with the way that force is applied during exercise performance. Stay with me here as I need to cover a little exercise physiology.

In the leg extension, loading is applied perpendicular to the long axis of the tibia (one of the bones in the lower leg) - a fact that creates tremendous shear force in the patellar region. Alternatively, loading during the squat is mainly compressive, with forces applied parallel to the long axis of the tibia. Since a joint is better able to withstand forces from compression as opposed to shear, it therefore follows that squats are more joint-friendly than leg extensions.

What's more, leg extensions tend to overstress the anterior cruciate ligament (ACL). During performance, the quadriceps reacts by pulling the tibia forward (a phenomenon called tibial translation). The ACL in turn opposes the quadriceps by trying to prevent translation of the tibia. These two antithetic actions place a considerable amount of stress on the ACL, and can potentially injure the ligament (and other soft tissue structures, as well).

Squats, on the other hand, have somewhat of a protective effect on the knee ligaments. Due to the multi-joint nature of the squatting movement (both the hip and knee are involved in performance), the hamstrings are activated as co-contractors and exert a counter-regulatory effect on the pull of the quadriceps. The co-contraction of the hamstrings and quads help to neutralize tibial translation, alleviating stress on the ACL.

All things considered, squats are a terrific exercise that works not only the lower body, but a significant portion of the torso, as well. Squat performance requires the assistance of many stabilizer muscles. Without the active participation of these stabilizers, the act of squatting simply cannot take place. Hence, while the glutes and thighs are the prime muscle movers, synergistic muscle action is derived from the abdominals, spinal erectors, rhomboids, trapezius and other muscles. Squats therefore have a systemic effect on anabolism, helping to promote overall muscular development.

Further, the squat is an extremely functional exercise. It is used in many activities of daily living. Any time you lift an object from the floor, squatting is involved in the movement. Consequently, squats can help build the kind of practical strength and kinesthetic awareness that facilitates better performance of everyday tasks. In many cases it can even help to prevent lifting-related injuries at home and in the workplace. Now this is not to say that squats are appropriate for all populations. Conditions such as degenerative arthritis and various connective tissue disorders can be contraindications for squatting movements. But it's not the squat, per se, that is harmful; in these afflictions, any form of loaded (or even unloaded) knee flexion and extension can exacerbate a patellar-related injury. Hence, for those with pre-existing knee pathology, caution must be utilized in both the choice and execution of thigh exercises. But as long as you have healthy knees, you should have no problem squatting on a regular basis.

**CowPimp** · 12-14-2004, 11:48 PM

I have always heard that leg extensions cause a lot of stress on one's kness, although I have never taken the time to substantiate that claim.

LAM · 12-15-2004, 12:01 AM

properly performed squats do not cause knee problems...

Pumpster · 12-15-2004, 07:41 AM

More knee stress from extensions. Main benefit from extensions is cuts, which can be achieve from other exercises. IMO extensions aren't really necessary.

BigDyl · 12-15-2004, 04:01 PM

Main benefit from extensions is cuts?

Wouldnt cuts come from diet?

Machher · 12-15-2004, 04:05 PM

Quote:

Originally Posted by Pumpster

More knee stress from extensions. Main benefit from extensions is cuts, which can be achieve from other exercises. IMO extensions aren't really necessary.

what do you mean "cuts"

LAM · 12-15-2004, 04:18 PM

Quote:

Originally Posted by BigDyl

Wouldnt cuts come from diet?

exactly...

Pumpster · 12-15-2004, 04:21 PM

Both, guys. There are mass and refining exercises; different animals.

LAM · 12-15-2004, 04:22 PM

Quote:

Originally Posted by Pumpster

refining exercise

there is no such thing...

**Mudge** · 12-15-2004, 04:54 PM

Leg extentions place a shearing stress on the knee, we have known this.

The use of the word REFINING when talking about a movement is completely ridiculous and unfounded.

There are heavy compound movements, and there are lighter more isolated movements.

fUnc17 · 12-15-2004, 05:00 PM

My right knee begin to bother me the day after doing leg extensions. I never did them again and the pain never came back.

KarlW · 12-15-2004, 05:10 PM

Quote:

Originally Posted by fUnc17

My right knee begin to bother me the day after doing leg extensions. I never did them again and the pain never came back.

yeah same here hence the question.
I've done squats for years with the occasional set of LE's but recently I incorporated heavy LE's into my routine and ever since my right knee has been "weird". After a weekend of lots of running it swelled up slightly and became difficult to bend to full flexion, like it was going to pop or something if I pushed it. I figured it was some soft tissue damage, gave it the ice/heat treatment and strapped it for 2 days, then started to use it again. Today I did some light squats and it seemed OK.

Pumpster · 12-15-2004, 06:33 PM

Forget extensions, too tough on the legs even though they're good for refining and cutting there are other things. If it's possible to be ignorant of this into adulthod, i'm only too happy to school you.

"Leg extensionsreally define and accentuate the front of the thigh. Leg Extensions are great for getting really deep definition in the legs without losing size, and particularly for improving the area around the knees".

LAM · 12-15-2004, 06:41 PM

Quote:

Originally Posted by Pumpster

"Leg extensionsreally define and accentuate the front of the thigh. Leg Extensions are great for getting really deep definition in the legs without losing size, and particularly for improving the area around the knees".

hmmm...so leg extensions effect lipolysis locally. who would have thought..

Machher · 12-15-2004, 06:53 PM

lol english please LAM, not all of us have brains as big as our biceps rofl...

Quote:

Originally Posted by LAM

hmmm...so leg extensions effect lipolysis locally. who would have thought..

doesnt that mean the decomposition of fats?

Jeeper · 12-15-2004, 08:10 PM

Quote:

Originally Posted by LAM

hmmm...so leg extensions effect lipolysis locally. who would have thought..

I thought that the ab-roller, crunch-chair, or whatever the hell suzanne summers is selling now were the only devices that made you burn fat in only one specific area.

BigDyl · 12-15-2004, 08:21 PM

Quote:

Originally Posted by Machher

lol english please LAM, not all of us have brains as big as our biceps rofl...

Wouldn't that technically be an insult?

Machher · 12-15-2004, 08:31 PM

Quote:

Originally Posted by BigDyl

Wouldn't that technically be an insult?

not really, im complimenting his buff, and hes smart...

LAM · 12-15-2004, 10:38 PM

Quote:

Originally Posted by Machher

lol english please LAM, not all of us have brains as big as our biceps rofl...

doesnt that mean the decomposition of fats?

yup...Lipolysis is the breakdown of fat stored in adipocytes (fat cells). During this process, free fatty acids (FFA's) are released into the bloodstream and circulate throughout the body...

ph8bringer · 12-15-2004, 10:44 PM

What about leg press? Is that the same as squats?

sabre81 · 12-16-2004, 01:33 PM

hmm, so everyones believe leg extensions should not be done??? ive always done legs extensions. Very heavy leg extensions. Never had any knee pain or anything.

LAM · 12-16-2004, 01:37 PM

I do them and always have, but I don't go even near as heavy as I could. they are always my last exercise for quads...

sabre81 · 12-16-2004, 01:45 PM

hmm i may have to cool it with the leg extensions. I usually go to failure on my leg extensions.

Cold Iron · 12-16-2004, 02:01 PM

My patellar tendons in both knees act up really badly when i'm doing extensions, lunges and squats. It's genetics, im just not built to workout I guess, legs specifically

ChrisROCK · 12-16-2004, 02:20 PM

Quote:

Originally Posted by sabre81

hmm, so everyones believe leg extensions should not be done??? ive always done legs extensions. Very heavy leg extensions. Never had any knee pain or anything.

Me either...

Weird! I'm when an exercise is bad for a particular body part...i usually feel it!!!

ph8bringer · 12-17-2004, 07:55 AM

Somebody please answer my question... ^

Cold Iron · 12-17-2004, 10:23 AM

Quote:

Originally Posted by ph8bringer

Somebody please answer my question... ^

It's not the same as squats. Nothing compares to squats in regards to working your legs. However, if squats are not an option, for whtever reason, leg press is the next best thing and is an adequate replacement.

ph8bringer · 12-19-2004, 07:49 AM

Ok cool, thanks dude. I've started doing squats AND leg presses on my leg day. That's turned out to be quite awesome.

12-14-2004, 11:48 PM	#2
CowPimp Fueled by Testosterone Moderator Join Date: Jan 2004 Location: Silver Spring, MD Posts: 15,428	I have always heard that leg extensions cause a lot of stress on one's kness, although I have never taken the time to substantiate that claim.
	The only time it's bad to feel the burn is when you're peeing... CowPimp Picks Up Heavy Shit MySpace YouTube Videos

12-15-2004, 12:01 AM	#3
LAM Gym ratt/Part-time pimp Join Date: May 2002 Location: Las Vegas, NV Posts: 7,384 Photos: 2	properly performed squats do not cause knee problems...
	Dumbest statement made in the Anabolic Zone for Nov TBD ----------------------------------------------------- What you talking about Willis ?

12-15-2004, 04:54 PM	#10
Mudge Pizza the Hut Super Moderator Join Date: Jun 2002 Posts: 23,056 Photos: 1	Leg extentions place a shearing stress on the knee, we have known this. The use of the word REFINING when talking about a movement is completely ridiculous and unfounded. There are heavy compound movements, and there are lighter more isolated movements.
	Kinesiology Vote @ Top 25 Deads Comp Bench Motivation Bench form MaxCalc Charles Poliquin When I let go of what I am, I become what I might be. Lao-Tzu I don't know any sources so don't ask - thanks

12-15-2004, 05:00 PM	#11
fUnc17 Drop and give me 100 Join Date: Nov 2004 Location: Jersey Shore BJJ Posts: 1,868 Photos: 10	My right knee begin to bother me the day after doing leg extensions. I never did them again and the pain never came back.
	Heres how I train. Strength Edge

12-15-2004, 06:33 PM	#13
Pumpster Registered User Join Date: Oct 2004 Posts: 106 Photos: 3	Forget extensions, too tough on the legs even though they're good for refining and cutting there are other things. If it's possible to be ignorant of this into adulthod, i'm only too happy to school you. "Leg extensionsreally define and accentuate the front of the thigh. Leg Extensions are great for getting really deep definition in the legs without losing size, and particularly for improving the area around the knees". Last edited by Pumpster : 12-15-2004 at 06:47 PM.

12-15-2004, 07:41 AM	#4
Pumpster Registered User Join Date: Oct 2004 Posts: 106 Photos: 3	More knee stress from extensions. Main benefit from extensions is cuts, which can be achieve from other exercises. IMO extensions aren't really necessary.

12-15-2004, 04:21 PM	#8
Pumpster Registered User Join Date: Oct 2004 Posts: 106 Photos: 3	Both, guys. There are mass and refining exercises; different animals.

12-15-2004, 10:44 PM	#20
ph8bringer Registered User Join Date: Dec 2004 Location: Sydney, Australia Posts: 91	What about leg press? Is that the same as squats?

12-16-2004, 01:33 PM	#21
sabre81 mmmm weights.. Join Date: Nov 2002 Location: Western New York Posts: 386	hmm, so everyones believe leg extensions should not be done??? ive always done legs extensions. Very heavy leg extensions. Never had any knee pain or anything.

12-16-2004, 01:37 PM	#22
LAM Gym ratt/Part-time pimp Join Date: May 2002 Location: Las Vegas, NV Posts: 7,384 Photos: 2	I do them and always have, but I don't go even near as heavy as I could. they are always my last exercise for quads...
	Dumbest statement made in the Anabolic Zone for Nov TBD ----------------------------------------------------- What you talking about Willis ?

12-16-2004, 01:45 PM	#23
sabre81 mmmm weights.. Join Date: Nov 2002 Location: Western New York Posts: 386	hmm i may have to cool it with the leg extensions. I usually go to failure on my leg extensions.

12-16-2004, 02:01 PM	#24
Cold Iron High $ociety Join Date: Jul 2003 Location: ONtario Posts: 1,615	My patellar tendons in both knees act up really badly when i'm doing extensions, lunges and squats. It's genetics, im just not built to workout I guess, legs specifically

12-17-2004, 07:55 AM	#26
ph8bringer Registered User Join Date: Dec 2004 Location: Sydney, Australia Posts: 91	Somebody please answer my question... ^

12-19-2004, 07:49 AM	#28
ph8bringer Registered User Join Date: Dec 2004 Location: Sydney, Australia Posts: 91	Ok cool, thanks dude. I've started doing squats AND leg presses on my leg day. That's turned out to be quite awesome.