Bodyweight Pullup biomechanics (grip question)

[offwidth]

Thanks Offwidth, I see what you mean. Doesn't look like you'd be doing a pullup (chinup) per se using that grip in that situation, but I see now how rock climbers can run into the occasional need for an underhand grip, if only to brace oneself, as it appears you are doing in that picture. When I went to the indoor rock climbing facility with my daughter, they had numerous features that looked exactly like what you are doing. Not sure what you call it but you're essentially hanging back on a greater than 90 degree angle wall. I didn't go near any routes that looked like that, lol.

This is true... it would be a rare climb indeed where a true chin up would be needed. However there are instances, especially outdoors where I recall having to do some long undercling traverses. Very taxing if not prepared.

Usually anything greater than 90 degrees is called 'steep' (go figure) or more commonly 'overhanging'.

 

[305pelusa]

I like mixed grip because you add an anti-rotation element. I cannot do one pull-up, but I can do 5-8 of other variations. Why?

Uhh I have no idea. That seems pretty crazy though. I knew overhand is a bit harder but didn't realize it could have such a disparity

 

[Karen Smith]

SFB teaches many grip variation during the course and certification but overhand is our preferred grip for a "tactical" pull up. However this overhand grip is about shoulder width apart for the best range of motion. If you select a grip that is too wide you will not be able to drive the elbows back as you near the top to get higher over the bar. With a wide grip if you try to dive the elbows down and back you will find in most cases that your traps begin to shrug and lats become disengaged.

 

[Alexey]

@305pelusa

Indeed, imo, the practical side of the Tactical Pull-up is it opens the way for the overhand Muscle-up, which mimicks the main way we cross vertical obstacles.

Concerning the SFB, we prefer to teach fewer basic skills that are at the foundation of the more advanced movements. This is why the Muscle-up is not part of the SFB curriculum (although, there's a short insert in the cert manual). But one can definitely build up to MU by working on the Tactical Pull-up.

 

[pet']

Hello,

If you select a grip that is too wide you will not be able to drive the elbows back as you near the top to get higher over the bar. With a wide grip if you try to dive the elbows down and back you will find in most cases that your traps begin to shrug and lats become disengaged.

I would add that a wide grip does not allow to put as much strength and tension as a shoulder width grip. It is more natural to put tension (at least for me) with shoulder width than wide grip.

Then, I can do a PU with shoulder width grip with 48kg, but I find it more difficult with a wide grip.

Kind regards,

Pet'

 

[305pelusa]

Hello,


I would add that a wide grip does not allow to put as much strength and tension as a shoulder width grip. It is more natural to put tension (at least for me) with shoulder width than wide grip.

Then, I can do a PU with shoulder width grip with 48kg, but I find it more difficult with a wide grip.

Kind regards,

Pet'

To be fair, there's a subtle physics phenomenon happening here.
When you hang shoulder width apart (arms perpendicular to the ground) each arm will have a tension of half of your Bodyweight. By tension, I don't mean "muscular tension". I mean the physics meaning of "tension" when applied to a rope.

If you have with a wider grip (say wide enough that your hands are at 45 degrees from vertical), then the arms not only have to provide a vertical component of half of your bodyweight, but they have to create a horizontal component that opposes each other to maintain equilibrium. To be exact, since the vertical component is of half of your Bodyweight, then the tension of each arm (the hypotenuse) will be of half of your Bodyweight divided by cosine(45). That's roughly half Bodyweight * 1.4.

Maybe that's a bit confusing, but it's a simple physics problem you should see in from Classical Mechanics. If you google "box suspended by two ropes" you'll find it.

Essentially, IF the arms are at an angle (not vertical) they will feel more virtual weight.

This explains why you can pull more with shoulder width. The wide grip Pullup is literally harder. In fact, its a popular option for gymnasts who don't use weighted Pullups. If you pick a wide enough grip, they can become very difficult.

It ALSO explains why they bother so many shoulders. There's a notable increase in tension that should feel like it's ripping your arms out of their sockets. And it does it at an angle most aren't familiar with.

Just my 2 engineering cents.

 

[offwidth]

Yes. That's the statics behind it in a nutshell. Well described @305pelusa