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CrossFit Journal Article Reprint. First Published in CrossFit Journal Issue 38 - October 2005

The Glute-HamDeveloper Sit-Up

Greg Glassman

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We have four glute-ham developers (GHDs) ( http://store.sorinex.com/product_p/ghb-1.htm ) atCrossFit Santa Cruz. We use them for back extensionsand sit-ups. This month we explore the glute-hamdeveloper sit-up, once more commonly referred to as aroman chair sit-up.

The GHD sit-up was once a gym staple. In the gymtoday only rarely will someone be found doing otherthan back extensions on the GHD. In no small measurethe decline of the GHD or roman chair sit-up coincidedwith the advent of the crunch. The crunch came tofashion on warnings and claims in popular media of thetraditional sit-ups destructive impact on the back.

It was argued that the GHD style sit-ups primarymovers were the hip flexors and not the abs andconsequently this sit-up, and sit-ups like it, were actuallynot good abdominal exercises. It was further arguedthat recruiting the hip flexors to lift the torso wasdestructive to the lumbar spine.

Once every couple of years we get lucky and find anexercise physiologist to repeat this message of poorab recruitment and lower back destruction standing infront of the GHD apparatus. What we do is ask them tomount the GHD and perform a set of thirty sit-ups forus while rehashing the poor recruitment claim.

The fun comes the following day when the report comesback from the exercise scientist that they are almost

too sore to sit upright. Laughing, walking, standing, andmoving are all excruciating. Where are they hit? Theabs.

Our favorite story along these same lines comes fromMatt Weaver ( www.speed101.com ), arguably theworlds fastest human being. On top of being knownfor hitting 85 mph on a bike, Matt was crowned KingSit-Up in high school for completing 100 perfect-formbodyslapping sit-ups in one minute. In one of his earliervisits to CrossFit Santa Cruz he found himself in a multi-station circuit with a group of CrossFit veterans thatincluded twenty-one reps of GHD sit-ups with a fullrange of motion, hands reaching back to the floor.

The workout left Matt sick in the immediate af termath.This was a surprise for sure but nothing prepared Mattfor what came the following morning: I awoke laterwithout the slightest ability to sit up. It was as if thesix pack was totally gone, though all ribs remained. Thecurse had left me merely able to roll over and slither likea snake off the edge of the bed. From there I had to usemy arms in humiliating ways to move about. I avoidedbeing seen. A week passed, and I began to revitalize.

The worst was yet to come! In the wake of Mattsbeing dethroned as King Sit-Up, his abs had swollen anddistended markedly. This k id looked fat and sunburnedwhere the week before hed been ripped and lily white.As the swelling subsided, his scrotum grew and grew
http://www.crossfit.com/http://store.crossfit.com/mailto:[email protected]://store.crossfit.com/cgi-bin/cp-app.cgi?usr=51F7597282&rnd=3672082&rrc=N&affl=&cip=&act=&aff=&pg=prod&ref=cfj038&cat=cfjbak&catstr=HOME:cfjbakhttp://store.sorinex.com/product_p/ghb-1.htmhttp://store.sorinex.com/product_p/ghb-1.htmhttp://www.speed101.com/http://www.speed101.com/http://store.sorinex.com/product_p/ghb-1.htmhttp://store.sorinex.com/product_p/ghb-1.htmhttps://store.crossfit.com/cgi-bin/cp-app.cgi?usr=51F7597282&rnd=3672082&rrc=N&affl=&cip=&act=&aff=&pg=prod&ref=cfj038&cat=cfjbak&catstr=HOME:cfjbakmailto:[email protected]://store.crossfit.com/http://www.crossfit.com/

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Glute-Ham Developer Sit-Up (continued...)

and grew. Matts father, John, is an ER doc, so he wasconsulted. He laughed himself to near seizure. (Ourkind of doc.)

Before the swelling stopped Matts scrotum had becomethe size of a small and very ugly cantaloupe. Why wehave no pictures well never understand.

Apparently the fluids that had swollen Matts abs haddrained into the inguinal canal and filled the scrotum.Oh, and apparently GHD sit-ups recruit the abs. Mattis convinced.

The lesson weve drawn from the GHD sit-up is that inspite of the primacy of hip flexors over trunk flexors,or the abs, in this sit-up it recruits the abs powerfullyin two ways. First, the movement takes the trunk fromhyperextension to full flexion, albeit with negligible load.(No crunch can match this range of motion.) Second,the role of the abs in this sit-up is powerful and largelyisometrici.e., they stabilize the torso from undueextension.

This second point is consistent with our belief thatthe most powerful, functional, and developmentalcontractions of the trunk are isometric, not isokinetic.Our favorite ab exercises are predominantly stabilizationor isometric exercises. The GHD sit-up, the L sit, andthe overhead squat share this stabilization role. Thelack of trunk flexion in these moves hides their potencyfrom the uninitiated.

Our experience with athletes and static hip flexionwork like the L sit and more dynamic exercises like theGHD sit-up have led us to several conclusions:

The hip flexors purchase and strength suggest theirimportance to functional movement. One expertcalculated that they are capable of generatingmany times the force that the abs can. To thinkthat muscles with that much mechanical advantageshould not be used to that advantage is ridiculous.

Most modern athletes are hip flexion weak and itaffects most performance.

Weak hip flexors assure weak absespeciallyweak lower absand no amount of crunches cancompensate. (It seems that every gym has an abs class

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instructor who has a prominent lower abdominalpooch. Ask her to hold one knee up while standingon the other leg and to resist your pushing the kneedownward with a couple of fingers. Its easy to pushthe knee down, and it shouldnt be).

Without static contraction/stabilization exercises,

the abs never learn to perform their most critical,functional, rolemidline stabilization.

What about the danger to the lower back purported tobe induced by strong hip flexor work? We have neitherinduced nor seen this damage. We do however havesome hunches as to how this might have occurred incommunities where roman chair sit-ups and traditionalmilitary PT sit-ups were in wide acceptance.

First, in military and law enforcement PT where thesit-up was king, it was and is essentially a biphasicmovement. With feet anchored and knees bent, thissitup comes up with a slight pause in the middle of theaction. Look at video of someone doing these sit-upsand youll see the pause.

What is happening is that the upper back makes solidcontact with the ground under the upper abs and sothey can flex the trunk and fulcrum off the contactpoint. As the sit-up continues, the middle abs flex thetorso but the lumbar curve surrenders without findingresistance and at full middle rectus contraction the spineis neutral and not flexed. The contraction occurredwith no real load; the belly and back just sank closer

to the ground. This stalls the sit-up but the pelvis andlow back have solid contact with the ground so the hipflexors complete the movement. The natural, biphasic,one-two count of the military sit-up is a repeat of upperabs throwing the movement to the hip flexors wherethey complete the movement. Upper abs, hip flexors.Upper abs, hip flexors. No effective middle ab work.

This deficiency of middle ab work, and consequentlystrength in the middle rectus, and the violence of thetoss from upper to lower abs may have presentedunhealthy wear and tear on the lumbar spine. This

understanding came, in part, from some brilliant workby Koch, Blom, and Jacob in producing the Ab Mat(http://www.backbuilder.com/abmat_situps.htm ).

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Glute-Ham Developer Sit-Up (continued...)

We start newcomers out on the GHD sit-up byspotting to make sure that they can come down toparallel without collapsing. (Last year, and very briefly,we trained a Stanford University coach who made a

huge point of sharing his focus on core training on theSwiss ball. When we got him on the GHD, he fell backoff of the horizon and couldnt get up. He had to bedeadlifted back to horizontal.) If our athlete is afflictedwith a core as weak as the Stanford coachs, we starthim on the AbMat and reintroduce the GHD sit-up at alater datewhen more rudimentary strength has beendeveloped.

We also caution against unbridled bouts on the GHDfor newcomers to avoid the Matt Weaver cantaloupesyndrome described above. This is a potent exerciseand it has sidelined dozens of strong, strong, athletesfor a few days to a week. Greg Glassman is the founder (with LaurenGlassman) of CrossFit, Inc. and CrossFit Santa

Cruz and is the publisher of the CrossFit Journal .
http://www.crossfit.com/http://store.crossfit.com/mailto:[email protected]://www.crossfit.com/http://www.crossfitsantacruz.com/http://www.crossfitsantacruz.com/http://www.crossfitsantacruz.com/http://www.crossfitsantacruz.com/http://www.crossfit.com/mailto:[email protected]://store.crossfit.com/http://www.crossfit.com/

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