Is the leg curl underrated?

[Joao.Silva]

Hi.
Since there is no way to perform knee flexion against resistance using a barbell, why isn't the leg curl seen as an important exercise?
Wouldn't it help the squat?

Thanks

[Mark Rippetoe]

Because it doesn't help the squat, and it is a perfectly unnatural movement that does not occur in the absence of a machine to facilitate it.

[Joao.Silva]

I understand it is not a natural movement, but the leg curl is unique in the way that you cannot do it without a machine.
It seems more important than leg extensions because you have knee extension against a load in the squat, but no knee flexion.

[Mark Rippetoe]

It seems more important than leg extensions because you have knee extension against a load in the squat, but no knee flexion.

Please explain.

[Joao.Silva]

Although a totally different movement, when we squat we use the quadriceps somehow in the same way they are used in a leg extension machine, to extend the knee joint.
However, the hamstrings don't contribute to flex the knee, that action is produced by the gravity.

So, what I am trying to say, is that the leg curl is unique in the way that it can't be replaced by any barbell exercise because no barbell exercise can use the hamstrings to flex the knee joint.

[Mark Rippetoe]

This is precisely the reason it is a useless exercise for strength training.

[Mark E. Hurling]

Let's see now. Other than getting better at giving yourself a swift kick in the ass with your own heel, why else would you need to improve this particular movement?

[Paul1]

Just out of curiosity, could it sub as an assistance exercise for someone who can't do GHRs (I guess because of size). It's obviously a shell of a GHR but it seems like the only other way to train the distal action of the hamstrings.

On the other hand it's hard to imagine many people who are at a training stage where they need assistance exercises but they can't give it a go with GHRs.

[Andy Baker (KSC)]

If you want extra hamstring work after squatting just do 2-3 sets of deep goodmornings after squats. You don't even have to leave the rack. Just strip some weight off and knock em out. I assure you that your hamstrings will be fully worked from one end to the other.

If you do the GMs right, (meaning deep with the hips way back) it actually feels like an isometric "leg curl" as the balls of your feet dig into the ground, while you simultaneously push your hips forward.

[Mark Rippetoe]

Just out of curiosity, could it sub as an assistance exercise for someone who can't do GHRs (I guess because of size). It's obviously a shell of a GHR but it seems like the only other way to train the distal action of the hamstrings.

On the other hand it's hard to imagine many people who are at a training stage where they need assistance exercises but they can't give it a go with GHRs.

Yeah, it is. It's also hard to imagine we're actually talking about the leg curl.