Forums: Climbing Information: Injury Treatment and Prevention: Re: [curt] Crimping evidence: Edit Log




onceahardman


Nov 4, 2013, 2:12 PM

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Registered: Aug 3, 2007
Posts: 2473

Re: [curt] Crimping evidence
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curt wrote:
onceahardman wrote:
In reply to:
I'm pretty sure there's nothing wrong with my view of the relevant mechanics. Soft tissue does maintain the angle between the distal phalanx and proximal phalanx, but as the angle becomes increasingly acute (and I never said it could or would become zero) less force is required to maintain that angle.

Curt

I'm not sure who is giving you one star, its not me. I know, you don't care, but I wanted you to know, out of my respect for you.

The tensile force on say, flexor digitorum profundus decreases with decreasing angle between the proximal and distal phalanx. Agreed.

The outward force on the A2 pulley increases, though, as this angle decreases, for the same load. These forces are nearly perpendicular. That is what tears pulleys.

Hey--no problem. I wear my one-star ratings proudly. If what you're saying is correct (and what I've read in the literature agree with you) I'm still puzzled how I have injured both middle finger and both ring finger A2 pulleys with open hand grips--but none with crimping grips.

Some of these articles claim that the forces are 30 times higher when using the crimp grip--but never injuring a pulley in 35 years of climbing when routinely using a technique that supposedly applies 30 times the force to the pulleys makes no sense. I'm only speaking for myself, so I realize this is an anecdotal observation--but on the other hand, the sample size of grip usage is huge, over many thousands of climbs and boulder problems over 35 years.

Any thoughts on that?

Curt

Yeah, your case is indeed puzzling. There are at least a couple possibilities:

1) Your diagnosis was wrong. Ultrasound (US) and MRI are pretty good, but still have pretty high false-positive and false-negative numbers. Perhaps 20%. Sometimes people (especially men) assume they have a certain diagnosis based on symptoms, but never get any imaging done to confirm. Really, exploratory surgery would be the "gold standard" for proper diagnosis. I don't know how you were diagnosed.

2) Faulty memory ( please don't be offended). Many times I think we grab for a handhold, and quickly pull up, flexing the PIPs quickly, while only the distal phalanx is on the hold. If the PIP angle gets to 90 deg, and the DIP is extended, you are biomechanically crimping, even if you don't fully lock down in a full-ring crimp. I think this is similar to what you described above, with you having a disagreement with the free-body diagram.

In a true open grip, the MCPs, PIPs, and DIPs all need to be obtuse angles.

(The obtuser, the better.)


(This post was edited by onceahardman on Nov 4, 2013, 2:22 PM)



Edit Log:
Post edited by onceahardman () on Nov 4, 2013, 2:22 PM


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