The Thumb During the Crimp Grip

Abstract

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.

finger injury - rock-climbing - hand control - thumb

References

• 1 Danion F, Latash ML, Li ZM, Ziatsiorsky VM. The effect of fatigue on multifinger coordination in force production tasks in human.  J Physiol. 2000;  523 523-532
• 2 Gazeau JP, Zeghloul S, Ramirez G. Manipulation with a poly articulated mechanical hand: a new effiency real-time method for computing fingertip forces for a global manipulation strategy.  Robotica. 2005;  23 479-490
• 3 Gazeau JP, Zeghloul S, Fernandez A, Arsicault M. Object manipulation task with a dextrous mechanical hand including regrasp.  WESAS Transaction on Systems. 2007;  6 815-822
• 4 Harriss DJ, Atkinson G. International Journal of Sports Medicine – Ethical Standards in Sport and Exercise Science Research.  Int J Sports Med. 2009;  30 701-702
• 5 Klauser A, Frauscher F, Bodner G, Halpern EJ, Schocke F, Springer P, Gabl M, Judmaier W, Nedden D. Finger pulley injuries in extreme rock climbers: depiction with dynamic US.  Radiology. 2002;  222 755-761
• 6 Li ZM, Latash M, Zatsiorsky VM. Force sharing among fingers as a model of the redundancy problem.  Exp Brain Res. 1998;  119 276-286
• 7 Marco RA, Sharkey NA, Smith TS, Zissimos AG. Pathomechanics of closed rupture of the flexor tendon pulleys in rock climbers.  J Bone Joint Surg Am. 1998;  80 1012-1019
• 8 Marske MW, Marszke RF. Evolution of the human hand: approach to acquiring, analysing, and interpreting the anatomical evidence.  J Anat. 2000;  197 121-140
• 9 Moutet F. Flexor tendon pulley system: anatomy, pathology, treatement.  Chir Main. 2003;  22 1-12
• 10 Napier J. The prehensile movements of the human hand.  J Bone Joint Surg Br. 1956;  38 902-913
• 11 Quaine F, Vigouroux L, Martin L. Effect of simulated rock climbing finger postures on force sharing among the fingers.  Clin Biomech (Bristol, Avon).. 2003;  18 78-84
• 12 Schöffl V, Schöffl I. Finger pain in rock climbers: reaching the right differential diagnosis and therapy.  J Sports Med Phys Fitness.. 2007;  47 70-78
• 13 Schweizer A. Biomechanical properties of the crimp grip position in rock climbers.  J Biomech. 2001;  34 217-223
• 14 Vigouroux L, Ferry M, Colloud F, Paclet F, Cahouet V, Quaine F. Is the principle of minimization of secondary moment validated during various fingertip force production conditions?.  Hum Mov Sci. 2008;  27 396-407
• 15 Watts PB, Jensen RL. Reliability of peak forces during a finger curl motion common in rock climbing.  Meas Phys Ed Exerc Sci. 2003;  7 263-267
• 16 Young RW. Evolution of the human hand: the role of throwing and clubbing.  J Anat. 2003;  202 165-174
• 17 Zatsiorsky VM, Gao F, Latash ML. Finger force vectors in multi-finger prehension.  J Biomech. 2003;  36 1745-1749
• 18 Zatsiorsky VM, Li ZM, Latash ML. Coordination force production multi-finger tasks: finger interaction and neural network modeling.  Biol Cybern. 1998;  79 139-150
• 19 Zuo BR, Qian WH. A general dynamic force distribution algorithm for multifingered grasping.  IEEE Trans Syst Man Cybern. 2000;  30 185-192

Correspondence