This is a very important post about what I believe far too many coaches and climbers neglect; grip positions. To simply state my thesis up front; I firmly believe that one should grip edges in only one of two ways; Grip position A or Grip position B.
Here we have grip position A.
This is the most powerful way to hold an edge.
One should keep in mind that whenever you are setting up for a powerful move or a hard lockoff, or really some sort of movement that is near your limit, the hand that you are moving off of should generally be in Grip position A.
Here we have Grip position B.
This is a very versatile grip which serves a number of functions, one of which is to prevent people who think Grip A is too stressful on the fingers from bitching at me.
Essentially the main purpose of this grip is increased tension and to a smaller extent some energy savings. This grip should be much more commonly used on steep walls and on very poor edges, or those where the danger of dry firing may be high.
The basic logic behind Grip B is to address the weaknesses of Grip A. Grip A requires more energy, pulls in one direction, and one cannot really do a move pre-Gripped A. Grip B is really the more dynamic grip. On dynamic moves and deadpoints one should hit edges in Grip B.
First off it is easy to hit a hold immediately into Grip B. On this note it is easy to explain some of the tension element. So on a dynamic move on the steep, you move up at the hold, your fingers connect on the hold and your body then starts to move away from the wall, right as you hit the hold your thumb should engage into Grip B, which then resists the outwards sag of your body. I think it is pretty easy to see and most people would agree it is pretty absurd to hit a hold in Grip A, if you have a video of someone going for a hold with their thumb over their fingers before on the hold please share. It is possible I suppose but completely loony.
Most people then of course hit holds open handed or half crimped without the thumb; like when climbing on campus rungs. Hitting holds without the thumb is of course very easy to do but is neglecting a very strong digit and a very high force generating grip. When actively using the thumb you have a greater chance of staying on the wall. This also will help keep your feet on as it prevents your body from moving away from the wall.
The other important and even more neglected use for Grip B is as the lower hand when the upper hand starts to connect with the next hold. In this case it is used for the same general reason; increased tension in the outwards dimension. So this is the very crucial to the steep A to B Flip. You power off a hold in Grip A and as your upper hand starts to connect on the next hold your lower hand should flip to B to help it, and your body stay on the wall. This is even more relevant if your feet cut as in this situation the lower hand will be doing next to nothing if it is not in Grip B.
And as a detail alluded to earlier, Grip B is superior on holds that you may be afraid of dry firing off of, or very poor side pulling edges. When you are in Grip A on a very poor edge you may be applying too much force in general and certainly too much force straight down. Grip B will force you to spread your weight over a slightly larger surface area on your fingers and will be applying pressure to the bottom of the hold with your thumb. This is even more relevant to very poor side pulls where if one attempts to straight A them there is too much downwards force for your hand to stay securely.
In this video you can see the B-A-B flip. Although in this particular shoot my hand cuts, but you get the idea.
And here you see a better example of hitting something with more speed in B and then flipping to A. The third to last move to the pale blue, but there are some good flips on the bottom as well but they are harder to see.
I believe that this is a very large part of training that is very neglected. I am not perfect and I am sure if you go through my videos you can find some poor grip positions. But I try to climb on edges using only these two grips. Essentially the two biggest problem most people have climbing this way is that they either overuse Grip A, or they climb half-crimped but neglect the thumb. There is no advantage to climbing without the thumb pinching the bottom of the hold (Grip B). I am aware there is some argument that training with the thumb over the finger(Grip A) is bad because it is simply a crutch for your fingers. I would say that you should train in a way that you climb and that if you never train Grip A then you will be unprepared for it outdoors. But climbing without using the thumb at all is a waste and not superior in any way that I can think of.
Grip A delivers maximum strength on a hold. Grip B is for energy savings and increased tension.
If your look at a lot of the really strong climbers like Daniel, and I think the biggest exponent of Grip A and B; Jon Cardwell (Lots of fantastic A B action between 1:10 - 1:40). You see that they do not frequently half-crimp without the thumb. That is a lazy grip.
I think keeping in mind these two grips and using them as exclusively as possible will certainly make you a stronger better climber. It is one of my most important pieces of advice for those who are looking for some.
None of this applies to route climbers.