Impossible Sit-up

[Dorian Brown]

So I subscribe to a lot of fitness based youtube channels just to see whats going on in the fitness world even though I only do GB. Sometimes you find interesting challenges like this one from ATHLEANX. It looks really simple but I couldn't not do it at all. However I think that will all the core work here at GB someone will easily be able to do it.

 

[Kasper Stangerup]

This seems to be just a standard Janda sit-up, as advocated by Pavel Tsatsouline in his Bullet Proof Abs book. However, there also seems to be some pseudo-scientific confusion about the explanations in the above video; he seems to be saying that the excercise is difficult because you can't use your legs as leverage. But if you completely disconnect your legs from your torso, then it obviously is physically impossible (this situation would be equivalent to doing sit-ups with amputated legs; your center of gravity would lie outside your base of support).

[Connor Davies]

Yah this situp is an impossible situp because it is actually impossible. Just like manna on the rings, some things just can't be done.

[Cole Dano]

Buy that man an Ab Pavelizer! 

[Elliot Clayton]

As above, the impossibility of this move isn't because of strength, but because of where your centre of gravity is when your legs are tucked so far up

[Jesse Frigo]

I don't think it is impossible.  My feet try to float a tiny bit, but I can keep them touching the floor as I do it.

 

I've done a lot of situps in my time in the Army, and keeping your feet in contact with the ground is required.  While people are allowed to hold your feet when you test, I normally train without any kind of bracing for my feet.  We are also not allowed to exceed a 90 degree angle with our knees, so I normally train much tighter.  This "impossible" situp is tricky, but not impossible by any means.  My problem is that when I actually test, I don't have the endurance in my hip flexors that I could have if I trained more with braced feet.

[Cole Dano]

The whole point of the Janda sit up is to not use your hip flexors. IN that regard it's closer to a crunch than a sit up.

[Kasper Stangerup]

I think the guy in the video just misunderstands the mechanics of the move, or maybe that's just the way it comes across. I think that he's showing a Janda sit-up which are, IMO, dramatically harder/more awkward than regular sit-ups or crunches, but by no means impossible. You can debate whether it is a good idea to remove the hip flexors from the movement, since they obviously also have a role to play in moving your body.

[Dorian Brown]

Honestly I don't think he is saying it is really impossible. It is just a fun challenge. A few people in the comments said they could do it and given some of the strength feats I've seen on YouTube I wouldn't be surprised if someone can do it.

[Timo Jankowski]

The whole point of the Janda sit up is to not use your hip flexors. IN that regard it's closer to a crunch than a sit up.

Stuart McGill says in Ultimate Back Fitness and Performance that, ironically, the Janda sit-up shows an even greater psoas activation than a regular bent knee sit-up. 

[Christoph Pahl]

From a physics point of view it seems possible: The cms-leverage is largest at the beginning, and the beginning he was able to do.

[Cole Dano]

Stuart McGill says in Ultimate Back Fitness and Performance that, ironically, the Janda sit-up shows an even greater psoas activation than a regular bent knee sit-up. 

 

Interesting, so I guess his subject didn't have the hip flexors off after all and was using the glute tension to create isometric resistance.

[Timo Jankowski]

Interesting, so I guess his subject didn't have the hip flexors off after all and was using the glute tension to create isometric resistance.

Found the passage! It was actually in his other book Low Back Disorders. I'll just copy+paste:

 

The press-heels sit-up was proposed by several clinical groups, on theoretical grounds, to inhibit psoas by activating the hamstrings. In fact, electromyographic assessment (Juker et aI., 1998) proved this to be mythical. (...) Activating the ham­strings creates a hip extensor moment, and sit-ups require hip flexion. During this type of sit-up, the psoas is activated to even higher levels to overcome the extensor moment from the hamstrings and produce a net flexor moment. This type of sit-up produced the highest level of psoas activation of any style of sit-up we quantified!

 

 

Interesting tidbit, but otherwise McGill's books are a horrible read for people like us here who are into gymnastics/GST. He pretty much advises against every core exercise we are doing here! Not just regular sit-ups and similar type motions like v-ups etc, but also hanging leg lifts, arch ups, even arch body holds. Basically anything that puts high compression forces on the spine, especially in flexion. I don't even wanna know what he'd be saying about Jefferson Curls...

[David McManamon]

Why you can complete the sit-up with straighter legs has a lot more to do with mobility than anything that guy mentions in the video.  Your upper back easily curves in the needed direction, you probably sit hunched over all day so you can start the sit-up.  Now how about forward articulation of your lumbar spine? Probably lousy - so you need to straighten your legs to compensate.  With excellent forward articulation you could curl-up vertebrae by vertebrae and you would succeed barely engaging your core.

I like if McGill's book laughs at the regular sit-up.  HLL is much better, nobody can disparage them, I hope the book does not consider the weight of your legs hanging from your body to be a high compression force on the spine.

[Timo Jankowski]

I like if McGill's book laughs at the regular sit-up.  HLL is much better, nobody can disparage them, I hope the book does not consider the weight of your legs hanging from your body to be a high compression force on the spine.

 

No no, his explanation is a bit different. Not the weight of the legs causes the high compression force, rather high ab activation itself is the cause. I'll just quote that part for you:

 

 

hanging with the arms from an overhead bar and flexing the hips to raise the legs is often thought to impose low spine loads because the body is hanging in tension-not compression. This is faulty logic. This hanging exercise generates well over 100 Nm of abdominal torque (Axler and McGill, 1997). This produces almost maximal abdominal activation, which in turn im­poses compressive forces on the spine (...). Similar activation levels can be achieved with the side bridge (shown later and discussed in detail) with lower spine loads. Having stated this, those not interested in sparing their back and who are training with performance objectives may benefit from the high psoas challenge, together with rectus abdominis and oblique activity. (McGill, Low Back Disorders, 2007: 89-90) 

 

[Andrew Long]

google the 7-stage sit up test this would be the equivalent of about stage 5-6 of the test.  This is certainly not impossible and nor is it particularly hard but different body types can play a big role in the ability to do this sit up.  when i did the 7-stage sit up test during class a long time ago i managed 1 rep at level 7 and although my core has never been particularly weak i wouldnt consider it super strong either.  id imagine having finished f1 for most people  this situp would be a walk in the park. 

[John Kiggundu]

So I subscribe to a lot of fitness based youtube channels just to see whats going on in the fitness world even though I only do GB. Sometimes you find interesting challenges like this one from ATHLEANX. It looks really simple but I couldn't not do it at all. However I think that will all the core work here at GB someone will easily be able to do it.

 

 

I did a few reps yesterday and could have done more. Let's just say that I didn't think it warranted the title of "impossible."

 

And I'm not anything close to the super humans here at Gymnastic Bodies, that are currently doing F3 and F4. (I spent more time than I can care to remember on Straddle Ups.)

 

If the super humans here attempted it, I'm sure they could knock out 50 reps without blinking an eye.