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The leg extension

Leg Extensions - Why you shouldn't go nuts over them

Its interesting to observe that post knee surgery, extensions are completely avoided in physical therapy because of the stress they place on the knee. They place a lot of stress on the ACL for healthy knees. Seated leg extensions is classed as an open chain movement. No open chain lower body movement will ever be better or more functional than a closed chain one.

When I had a niggle in the knee from playing squash a coupla months ago, the phyio prescribed single leg squats on a box. No leg extensions, he said. So what closed chain movement is best for quads do you say? Say hello to the banded terminal knee extension:


So in summary leg extensions are functionally useless and are dangerous because the knee isn't meant to function in that locked position. These days IF i do them it's never below 12reps and mostly single leg.
 
Depends who you talk to, some physios have people start doing light leg extensions as rehab.

In general there aren't many exercises that are dangerous. It's just the people doing them that fuck it up.
 
I had a serious stress fracture in lateral condyle of femur. I started doing stepups gradually increasing height.
 
There was a whole topic on leg extensions not long ago, where were you?

From my experience of 30 years, the leg extension is the key to knee joint health, most doctors, physios and chiros do not know how to exercise properly.

That band exercise looks fucking ridiculous and outright dangerous.
 
The problem here juganaut is that you assume the doctor knows what is good exercise and weight training.
done correctly, leg extensions are a great exercise injury or not, as long as you're not stupid about it.
 
I think a lot of the issues come from people trying to do the whole stack and smashing the reps out with no regards to form.
Like any exercise, focus on the contraction and slow the negative down. You'll lift less weight but your body will thank you for it in years to come
 
I think getting your seating position set up correctly will help avoid potential injuries. Having it too far forward means your knee is always under constant pressure, even at the bottom of the movement.

Of all the quad exercises I do, nothing pumps blood into the quads like leg extensions. Yes, not a functional movement, but great for isolation.
 
[MENTION=10084]Jungnaut[/MENTION];
Next time you visit the physio, ask him; what is the primary function of the biceps.
He will not know, that it is to firstly suppinate the hand and secondly lift the arm over the head.
 
All good points! and I couldn't find the old thread so cheers for linking that @Silverback;

The role of physios is in rehab, not muscle hypertrophy. So yes I agree leg extensions do have their place for people who understand fully what they are doing. Most don't so to err on the side of caution, be conservative and all that shizz I'd recommend to the average beginner gym rat not to do them (yet). Hence the title don't go nutso over them.

I think we all agree that setup is crucial for this machine, that it's best to go light and to perform unilateral sets. The problem I've seen is that a lot of machines are just plain fucked up. Like in my old gym you can't even adjust the seat so you're in an awkward position no matter how hard you try. Well that to me is a recipe for disaster.

Not to mention the number of times I walked past it to find that the pin is on the full stack.. lmao.
 
Ugh.. don't get me started on phucked up machines.

Anyone else seen the seated leg curl?

Y'know. The one where you have to have a set of pads to hold your quads in place as opposed to lying leg curls (which can be problem enough when fully loaded with max weight on your lower back).

Machine doesn't do chit other than give you lower back problems... By the time you get weight enough on the stack to feel your hamstrings, your struggling to stay seated in the correct position.

Anyways. I digress...
 
While we’re on the topic of knee flexion, properly designed seated leg curl machines (with a coupled movement arm) are better than prone leg curl machines for several reasons. Earlier leg curl machine designs used a prone body position because they were based on the designs of leg extension and leg curl attachments developed for flat benches. The seated position for later knee extension machines was obvious since this was the position they were performed in on the bench, but rather than design knee flexion machines based on joint function, earlier machines just copied the exercise as performed with the equipment already available.A prone leg curl is superior to an improperly designed seated leg curl machine, however (just about every leg curl machine other than Nautilus, MedX, and SuperSlow Systems). The worst seated leg curl designs incorporate a pad which presses down on the top of the thighs, often with handles for the user to hold to brace against being pulled forwards. This is a very poor method of countering the changing reactionary force over the range of the exercise, and these designs typically have a seat bottom which extends all the way to the back of the knees rather than ending just a little past the ischial tuberosities of the pelvis (the “sit” bones), which means not only are you sitting on the muscles you are attempting to contract, but you also have a restraining pad pushing the thighs down into the seat.

A prone leg curl is superior to an improperly designed seated leg curl machine, however (just about every leg curl machine other than Nautilus, MedX, and SuperSlow Systems). The worst seated leg curl designs incorporate a pad which presses down on the top of the thighs, often with handles for the user to hold to brace against being pulled forwards. This is a very poor method of countering the changing reactionary force over the range of the exercise, and these designs typically have a seat bottom which extends all the way to the back of the knees rather than ending just a little past the ischial tuberosities of the pelvis (the “sit” bones), which means not only are you sitting on the muscles you are attempting to contract, but you also have a restraining pad pushing the thighs down into the seat.On a prone leg curl machine the weight of the thighs is on the quadriceps, not the hamstrings which you are trying to contract, which is a big improvement.A properly designed seated leg curl also has the advantage of easier entry and exit and with the coupled movement arm reactionary force is countered without the need for the user to pull (prone designs) or push (seated designs with thigh pads and handles) with the arms to maintain proper positioning and alignment. It is also easier for people to learn the exercise when the movement is occurring in front of them (Ken Hutchins’ heirarchy of motor learning difficulty).The optimal seat design for the leg curl is very different than what is optimal for a leg extension, which is also a big problem for companies which make “combo” machines providing both functions. The Exerbotics leg curl is a great example of how not to design a leg curl machine:1. A thigh restraint with handles is a very poor solution for countering reactionary force and maintaining proper positioning and alignment during seated leg curls. The Exerbotics machine uses a thigh restraint with handles instead of a coupled movement arm (which can be designed to work in both flexion and extension with a simple position change).2. The seat bottom should only extend far enough to provide support for the pelvis so the user is not sitting on the hamstrings while trying to contract them. The thigh restraint pressing down on the thighs makes this even worse. The Exerbotics seat bottom extends too far.3. A seat belt is required for optimal countering of reactionary force during leg extensions while minimizing tension in the neck and shoulders from pulling up on the handles, and also a better solution for countering forwards reactionary force along with a coupled movement arm during seated leg curls. The Exerbotics machine has no seat belt.

 
Last edited by a moderator:
El Testicle said:
Ugh.. don't get me started on phucked up machines.

Anyone else seen the seated leg curl?

Y'know. The one where you have to have a set of pads to hold your quads in place as opposed to lying leg curls (which can be problem enough when fully loaded with max weight on your lower back).

Machine doesn't do chit other than give you lower back problems... By the time you get weight enough on the stack to feel your hamstrings, your struggling to stay seated in the correct position.

Anyways. I digress...
Click to expand...
That's all I've seen for a long time!
I tell you what works, pick a weight you can do 10 reps, drop 2 plates and do another 10. Then go back up and do 10 1/4 ROM partial reps. Hits the hammies very well!
 
Silverback said:
While we’re on the topic of knee flexion, properly designed seated leg curl machines (with a coupled movement arm) are better than prone leg curl machines for several reasons. Earlier leg curl machine designs used a prone body position because they were based on the designs of leg extension and leg curl attachments developed for flat benches. The seated position for later knee extension machines was obvious since this was the position they were performed in on the bench, but rather than design knee flexion machines based on joint function, earlier machines just copied the exercise as performed with the equipment already available.A prone leg curl is superior to an improperly designed seated leg curl machine, however (just about every leg curl machine other than Nautilus, MedX, and SuperSlow Systems). The worst seated leg curl designs incorporate a pad which presses down on the top of the thighs, often with handles for the user to hold to brace against being pulled forwards. This is a very poor method of countering the changing reactionary force over the range of the exercise, and these designs typically have a seat bottom which extends all the way to the back of the knees rather than ending just a little past the ischial tuberosities of the pelvis (the “sit” bones), which means not only are you sitting on the muscles you are attempting to contract, but you also have a restraining pad pushing the thighs down into the seat.

A prone leg curl is superior to an improperly designed seated leg curl machine, however (just about every leg curl machine other than Nautilus, MedX, and SuperSlow Systems). The worst seated leg curl designs incorporate a pad which presses down on the top of the thighs, often with handles for the user to hold to brace against being pulled forwards. This is a very poor method of countering the changing reactionary force over the range of the exercise, and these designs typically have a seat bottom which extends all the way to the back of the knees rather than ending just a little past the ischial tuberosities of the pelvis (the “sit” bones), which means not only are you sitting on the muscles you are attempting to contract, but you also have a restraining pad pushing the thighs down into the seat.On a prone leg curl machine the weight of the thighs is on the quadriceps, not the hamstrings which you are trying to contract, which is a big improvement.A properly designed seated leg curl also has the advantage of easier entry and exit and with the coupled movement arm reactionary force is countered without the need for the user to pull (prone designs) or push (seated designs with thigh pads and handles) with the arms to maintain proper positioning and alignment. It is also easier for people to learn the exercise when the movement is occurring in front of them (Ken Hutchins’ heirarchy of motor learning difficulty).The optimal seat design for the leg curl is very different than what is optimal for a leg extension, which is also a big problem for companies which make “combo” machines providing both functions. The Exerbotics leg curl is a great example of how not to design a leg curl machine:1. A thigh restraint with handles is a very poor solution for countering reactionary force and maintaining proper positioning and alignment during seated leg curls. The Exerbotics machine uses a thigh restraint with handles instead of a coupled movement arm (which can be designed to work in both flexion and extension with a simple position change).2. The seat bottom should only extend far enough to provide support for the pelvis so the user is not sitting on the hamstrings while trying to contract them. The thigh restraint pressing down on the thighs makes this even worse. The Exerbotics seat bottom extends too far.3. A seat belt is required for optimal countering of reactionary force during leg extensions while minimizing tension in the neck and shoulders from pulling up on the handles, and also a better solution for countering forwards reactionary force along with a coupled movement arm during seated leg curls. The Exerbotics machine has no seat belt.
Click to expand...

Let me get my monocle...
 
Silverback said:
The worst seated leg curl designs incorporate a pad which presses down on the top of the thighs, often with handles for the user to hold to brace against being pulled forwards. This is a very poor method of countering the changing reactionary force over the range of the exercise, and these designs typically have a seat bottom which extends all the way to the back of the knees rather than ending just a little past the ischial tuberosities of the pelvis (the “sit” bones), which means not only are you sitting on the muscles you are attempting to contract, but you also have a restraining pad pushing the thighs down into the seat.
Click to expand...

Pretty much exactly what I was trying to say, but with better England.
 
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