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Brandon Oto 02-02-2009 04:15 PM

Leg Extensions
 
If glute-ham raises are so good for improving hip extension, why aren't we all doing leg extensions to develop beastly hip flexion and powerful quads?

George Mounce 02-02-2009 04:35 PM

Who said glute-ham raises were so good?

Garrett Smith 02-02-2009 04:55 PM

Brandon,
I think you've got the wrong analogy, if that's the right term here.

My impression of an equivalent anterior chain exercise to the GHD for the posterior chain would be something along the lines of:
Imagine a flat or decline bench with roller pads in front of the shin. Subject lies on bench in the normal supine fashion. Subject then raises his entire body (straight or nearly straight from knees to head, knees begin at a 90 degree or less angle) around the pivot point of the knee to a standing position (the feet would likely be against the front roller pad and the floor the entire movement).

Sounds hard to me, and would likely be brutal on the knees (assuming one could even lift off!). It would also stress the hips and quads at the same time, unlike the knee extension machine. The shear force from the thigh pad of the knee extension machine would also be gone, as the thighs would be in the air most of the movement.

The mechanical disadvantage of the quads in the movement I described would appear to be pretty outrageous.

IMO.

Brandon Oto 02-02-2009 05:26 PM

George: lots of strong people seem to like it...

Garrett: I agree that the analogy is missing some elements. If nothing else, in one case you're moving your body (rather than an extremity) and are working the distal connection of the muscle to strengthen the proximal (rather than working the distal to strengthen the distal).

But I'm not sure why it should be that these differences make the exercise pointless. It may be less effective, but just speaking in terms of muscles, are those differences really so vast that the GHR is a great exercise and the leg extension, or something similar, is a useless one?

Because although there are other things going on, in the end the main thing happening in a GHR seems to be that a leg curl.

Garrett Smith 02-02-2009 05:48 PM

I'd say that my perception of the difference between a GHR and a seated machine leg curl are quite vast, so I would extend that analogy to the exercise I described and a seated machine leg extension.

Moving the distal ends of extremities around the body is (relatively) easy, moving the body around the extremities is (relatively) hard. Compare a decline bench press to a tuck planche. It's not too hard for most anyone to do a BW decline press (and move their arms around their body). It's pretty darn hard for any untrained person to do a tuck planche (and move their body around their arms), which also involves more "body control"--another difference between the machine exercises and the GHR.

If you've done both, you know that there's a lot more going on in a tuck planche than just an upside-down decline BP and a reverse crunch.

That may not be the best analogy, but I hope it gets my point across.

Have you ever had the pleasure of using a GHR? Or done the similar movement on a pad? I have, and I find them worlds apart from a simple leg curl.

Brian DeGennaro 02-02-2009 06:28 PM

I think we already have the equivalent of the GHR: the GHD situp.

Brandon Oto 02-02-2009 06:55 PM

Could be, Brian. Although seems like we need the range of motion witnessed in the knee flexion of the GHR; in the GHD situp there's no major movement around the hip (because it doesn't bend that way, of course). Mainly just isometric. Garrett's example might be closer.

Garrett: so in your view, the radical difference in efficacy between those two movements (assuming there is one) is the moving-body vs. moving-extremity distinction? That's the difference that makes the difference?

Garrett Smith 02-02-2009 07:08 PM

Quote:

Originally Posted by Brandon Oto (Post 49346)
If glute-ham raises are so good for improving hip extension, why aren't we all doing leg extensions to develop beastly hip flexion and powerful quads?

Back to your original question, the leg extension does nothing for hip flexion training as the hips don't really move and there is no appreciable isometric load being imposed on them. The point of the leg extension is to attempt to remove the hips from the movement.

The leg extension does build powerful quads, but only in the "leg extension" format. Not very useful IMO--same might be said of the GHR movement. Problem with the leg extension is mainly the shearing force imposed on the ACL towards the top of the movement by the thigh pad. I'm not swayed much by the Cybex pro - leg extension article, as I personally know a guy who says he re-tore his newly repaired ACL when his PT made him do leg extensions too heavy, too soon--he heard the POP during the leg extensions!

Cressey's article on Leg Extensions.

I'm not saying the GHR is a crucial part of any programming...I don't have one, and it would be about #200 on the list of things I'd like to get next for my gym (heck, it would take up half the floor space!).

I'm just saying that comparing a GHR for the posterior chain to the Leg Extension for the anterior chain is comparing apples and oranges.

EDIT: Just saw Brandon's last post.

I think the major differences are twofold:
  1. Moving the body around a fixed point is generally harder and tends to come with greater benefits IMO. Hence the difficulty with which men's gymnastics is regarded.
  2. The GHR and the movement I describe involve two major things--first is moving the body around the knee, second is maintaining the rest of the body isometrically through space. Much harder than sitting on one's arse.

Brandon Oto 02-02-2009 07:38 PM

Quote:

Originally Posted by Garrett Smith (Post 49372)
Back to your original question, the leg extension does nothing for hip flexion training as the hips don't really move and there is no appreciable isometric load being imposed on them. The point of the leg extension is to attempt to remove the hips from the movement.

Ah -- but the whole point of the GHR example is that it seems like training one attachment of a muscle also strengthens the other one. Training the hamstrings via knee flexion -- which nobody cares much about -- also strengthens the hamstrings for hip extension -- which everyone cares about. Shouldn't we be able to apply this lesson elsewhere too?

Anyway, that's not so important. I guess my main point here is that the GHR requires compound stabilization, moves the body, and is safe for the joints, blah blah blah... but in terms of the prime movers, it's still, essentially, a single-joint exercise. So why is it that we've all shunned single-joint exercises from our strength programs, on the principle that they don't contribute to larger compound strength? Within the right context (adequately strong stabilizers and auxiliary muscles, for instance), the entire lesson of the GHR seems to be that this DOES work.

Unless, of course, those other elements (the stabilization element, for instance) are fundamental to the efficacy of the exercise, and without them, there is no benefit. But I don't see why that should be the case. We could all try doing leg curls, to remove those auxiliary benefits and see if it STILL improved our deadlifts, I suppose...

But yeah, my broader point is something like, "are we avoiding curls because they don't make us stronger, or are we avoiding curls because they're not the perfect exercise?"

Steven Low 02-02-2009 07:39 PM

Hip extension is pretty much THE "athletic" movement. Most people have imbalances with too strong quads as opposed to hams & glutes. Posturally and occupationally related... sitting... + bad movement patterns. Can never have enough glute/ham strength.

Also, anecdotally I've heard leg extensions tend to be... not so great for the ACL.


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