[shark]

I was chatting with Steve Mac and he reckoned that the main mechanical advantage was the bend in your fingers from the knuckle and furthermore that the young with more finger flexibility had an advantage here but I'm not convinced that the bend has any advantage.

Also comparing the advantage of crimping to open handing (all things being equal) my view is that open handing is good for latching a hold as it is more friction dependent but pulling on a hold is better crimped as it is less friction dependent and more stable for bearing down on.

Thoughts? Science?   

[slackline]

Science?

1-5-9 (intermediates are also allowed and may be useful and you may want to go as far as 11)

[shark]

Science?

1-5-9 (intermediates are also allowed and may be useful and you may want to go as far as 11)

I saw this as more of a mechanical physics levers type question rather than something that could be answered a study on climbers and their grip

[JamieG]

Increased mechanical advantage usually is related to increasing the lever arm around which the muscle force is acting. I don't see how crimping increases the length of the lever arm, but it may allow you to apply more force without your fingers buckling (i.e. more stable hand position like Shark was suggesting). I guess you are kind of arching your fingers in a crimp which means they can possibly take the compressive loads better.

2p! And would be happy to be told I was taking nonsense.

[tommy_k]

I talked about this very topic recently with a friend of mine who is a really good coach.
He explained that there are two main differences between the (full) crimp vs the open hand grip:
1) the actual force vector
Due to the shape of your bone and the distance between bone and actual contact area between finger and rock, the full crimp can provide a different force vector thus increasing the possible force exerted on the contact area.

2) difference in reach
If you look at your wrist as a point of reference, the full crimp grip can give you an additional few centimeters of reach (if you are able to transfer the additional reach from your wrist to your center of gravity / your other hand)

I thought both points to be very interesting as I had never thought about the crimp this way...
Maybe it's worth a thought for you too

[lagerstarfish]

open hand is good for catching a hold at the end of your reach

crimp is good for getting another couple of inches height off the hold

I see the strength difference to be more to do with the flesh and bone shape in contact with the rock - the end of the finger on a crimp can gain better purchase on a small edge - and towards the back of the edge where it might be more positive and some extra friction is eaked out from the flesh being crammed into the corner

levers and shit are OK on paper

edit - posted while Tommy K was posting

[shark]

Increased mechanical advantage usually is related to increasing the lever arm around which the muscle force is acting. I don't see how crimping increases the length of the lever arm, but it may allow you to apply more force without your fingers buckling (i.e. more stable hand position like Shark was suggesting). I guess you are kind of arching your fingers in a crimp which means they can possibly take the compressive loads better.

2p! And would be happy to be told I was taking nonsense.

Good point about the finger flexing / compressive load - I hadn't thought about that. Maybe the flexing provides a micro-second advantage in the rate of force development as you move off a hold.

Serpico www.ukclimbing.com/forums/t.php?t=278152&v=1#x4120720= One of the most important differences between the various methods of training finger strength (fingerboard, system board, HIT) is rate of force development (RFD). Years ago I was a volunteer in a study on the biomechanics of campusing. I had to campus onto a hold with force sensors in. This showed a massive peak in force as you hit the hold and then moved off it. The speed at which you can recruit muscle fibres, and the synchronisity with which they fire is the mark of contact strength - the ability to latch holds at speed.
The lowest stimulus for improving RFD is probably deadhangs on a fingerboard. However it's a very controllable exercise and good at thoroughly fatiguing a grip so it's good for basic strength and Hypertrophy.
Campusing is probably the highest stimulus for RFD. It's a very exclusive exercise though as you can either do it on small enough holds to be training fingers not arms or you can't. In contrast to deadhanging it's not as good as exhausting a grip for hypertrophy.
HIT lies somewhere between these two, but loses much of it's potential benefit by it's lack of specificity; the angle at which you train at, the size of the holds, the amount of weight you need to add, the volume of work he prescribes.
If you want to effectively develop RFD through laddering then you should be hitting the hold at speed, fresh, and on the same size of hold as you want to improve on. If you want to develop basic strength and hypertrophy then HIT will probably do that, but with no real superiority to deadhanging, but more expense.
Laddering on a system board is IMO superior method as the holds are smaller and the angle is less. As well as training RFD or hypertrophy depending on angle/intensity, you're training movement more; in particular locking down to the shoulder.

[shark]

1) the actual force vector
Due to the shape of your bone and the distance between bone and actual contact area between finger and rock, the full crimp can provide a different force vector thus increasing the possible force exerted on the contact area.

What is a force vector?

[andy_e]

The direction in which the force is applied (I think), which may be different to the direction your fingers are pointing.

[tommy_k]

What is a force vector?

The direction and magnitude of a force.
In physical diagrams it is usually represented by an arrow with the length of the line representing the magnitude and it's orientation the direction of the force.

[andy_e]

Ah 

[shark]

open hand is good for catching a hold at the end of your reach

crimp is good for getting another couple of inches height off the hold

I see the strength difference to be more to do with the flesh and bone shape in contact with the rock - the end of the finger on a crimp can gain better purchase on a small edge - and towards the back of the edge where it might be more positive and some extra friction is eaked out from the flesh being crammed into the corner

levers and shit are OK on paper

[lagerstarfish]

What is a force vector?

those delta winged attack drones that The Empire use

[shark]

What is a force vector?

The direction and magnitude of a force.
In physical diagrams it is usually represented by an arrow with the length of the line representing the magnitude and it's orientation the direction of the force.

The hold remains constant so the direction of the force is the same isn't it? and similarly the body mass is constant so the magnitude of the force required is the same ?

[lagerstarfish]

only if the body remains in the same position

even route climbers move around sometimes

[shark]

I'm only answering you with videos today

[slackline]

I saw this as more of a mechanical physics levers type question rather than something that could be answered a study on climbers and their grip

You can abstract it to that, but when it comes to application it is done with flesh and bones (and tendons) which behave slightly differently than theoretical rods and pivots and can't be abstracted in that manner.

[shark]

I saw this as more of a mechanical physics levers type question rather than something that could be answered a study on climbers and their grip

You can abstract it to that, but when it comes to application it is done with flesh and bones (and tendons) which behave slightly differently than theoretical rods and pivots and can't be abstracted in that manner.

In what way do they behave differently ?

[i.munro]

Surely the other  important difference (apart from the extra couple of inches of reach) is 5 > 3?

[Paul B]

2) difference in reach
If you look at your wrist as a point of reference, the full crimp grip can give you an additional few centimeters of reach (if you are able to transfer the additional reach from your wrist to your center of gravity / your other hand)

I think this is wrong; if I crimp I lose reach (although you could say you gain 'height' on a hold you have already latched).

I also think using mechanical advantage is the wrong way of describing how the crimp grip works, its more of a mechanical action with your thumb helping stabilise things that makes it feel more secure IMO.

[abarro81]

Indeed. 'Crimping' with no thumb on anything is nails, so I think the thumb is a lot more key than any angles.

[slackline]

A rod is uniform in its length and thickness, bones are not uniform, in the fingers they bulge at the joints (I'm assuming in asking your question you are talking about using more than one finger).

You take a hypothetical rod and pivot model with a fixed force applied to one end and then try applying it to the human body it will be of limited use since people have bodies attached to their fingers which vary in shape, size form and strength which influence the application of force to the rods through the pivots.  The actual contact point will not be a flat (or machine rounded) surface of consistent shape or size, your finger tips are a bit soft and squidgy/pulpy which could have a drastic effect on the ability to apply the mechanical force.

Perhaps ask Steve about what was presented at the BMC injury symposium...

At the BMC injury symposium, at last, the answer to the mystery. How come some people can hang on tiny crimps but don't have amazing finger strength? I fit into this category, hang me off a campus rung and I'm nothing special, but on a 5mm razor at Ravenstor and I do OK. Its all to do with the finger pulp, the stuff between skin and bone, with studies showing strength on small holds is not dependent on strength measured in standard ways. This pulpy stuff is developed over years, basically by pulling on bits of rubbish. So there you go, forget the campusing!

They are as always with this sort of study small sample sizes so caveat emptor, but If you read the abstracts you might find them to have some potential use...

Amca AM, Vigouroux L, Aritan S, Berton E. (2012) Effect of hold depth and grip technique on maximal finger forces in rock climbing. J Sports Sci. 30(7):669-77. doi: 10.1080/02640414.2012.658845. Epub 2012 Feb 17.

The aim of this study was to understand how the commonly used climbing-specific grip techniques and hold depths influence the finger force capacities. Ten advanced climbers performed maximal voluntary force on four different hold depths (from 1 to 4 cm) and in two force directions (antero-posterior and vertical) using three grip techniques (slope, half crimp and full crimp). A specially designed platform instrumented with a 6-degrees-of-freedom (DoF) force/torque sensor was used to record force values. Results showed that the maximal vertical forces differed significantly according to the hold depth and the grip technique (ranged from 350.8 N to 575.7 N). The maximal vertical forces increased according to the hold depth but the form of this increase differed depending on grip technique. These results seemed to be more associated with finger-hold contact/interaction than with internal biomechanical factors. Similar results were revealed for antero-posterior forces (ranged from 69.9 N to 138.0 N) but, it was additionally noted that climbers have different hand-forearm posture strategies with slope and crimp grip techniques when applying antero-posterior forces. This point is important as it could influence the body position adopted during climbing according to the chosen grip technique. For trainers and designers, a polynomial regression model was proposed in order to predict the mean maximal force based on hold depth and adopted grip technique.

Quaine F, Vigouroux L, Paclet F, Colloud F. (2011) The thumb during the crimp grip. Int J Sports Med. 32(1):49-53. doi: 10.1055/s-0030-1267230. Epub 2010 Nov 17.

During rock-climbing, fingers grasp holds of various shapes with high force intensities. To ideally place the fingertips on the holds, the thumb is sometimes positioned on the nail of the index finger. This allows using the thumb as an additional actuator by exerting a supplementary force in the same direction as the index, middle, ring and little fingers. This study analysed how the forces exerted by the fingers are modified by the additional action of the thumb. The results showed that the thumb increases the resultant forces exerted on the hold. It was shown that the pathology risks of the middle, ring and little fingers were not modified in this condition. The finger force sharing was totally re-organized due to the support of the thumb. This led to the conclusion that the central nervous system organised the association of the 5 fingers. The results were discussed in regard to the established theories of the virtual fingers and the neutral line of the hand.




This one may be what Steve is talking about...

Bourne R1, Halaki M, Vanwanseele B, Clarke J. (2011) Measuring lifting forces in rock climbing: effect of hold size and fingertip structure. J Appl Biomech. 27(1):40-6.




This study investigates the hypothesis that shallow edge lifting force in high-level rock climbers is more strongly related to fingertip soft tissue anatomy than to absolute strength or strength to body mass ratio. Fifteen experienced climbers performed repeated maximal single hand lifting exercises on rectangular sandstone edges of depth 2.8, 4.3, 5.8, 7.3, and 12.5 mm while standing on a force measurement platform. Fingertip soft tissue dimensions were assessed by ultrasound imaging. Shallow edge (2.8 and 4.3 mm) lifting force, in newtons or body mass normalized, was uncorrelated with deep edge (12.5 mm) lifting force (r < .1). There was a positive correlation (r = .65) between lifting force in newtons at 2.8 mm edge depth and tip of bone to tip of finger pulp measurement (r < .37 at other edge depths). The results confirm the common perception that maximum lifting force on a deep edge ("strength") does not predict maximum force production on very shallow edges. It is suggested that increased fingertip pulp dimension or plasticity may enable increased deformation of the fingertip, increasing the skin to rock contact area on very shallow edges, and thus increase the limit of force production. The study also confirmed previous assumptions of left/right force symmetry in climbers.

I can't be bothered copying and pasting any more.

[shark]

I can't be bothered copying and pasting any more.

Thanks for the info Slackers 

[lagerstarfish]

yet again Slackers has taken all the fun out of a science question by using actual science to answer it

(nice one    )

[Oldmanmatt]

It's all magic.

Your star sign is the main determining factor on the choice between crimp or drag.

Remember to check wether Uranus is rising before sticking your fingers in.