Mechanical perturbation of the wrist during one-handed catching.
In the present study, the co-ordination of grasp and transport components of one-handed catching was examined following mechanical perturbations applied to the wrist. Six skilled catchers (mean age = 27.5 years) performed 64 trials in which tennis balls were projected at approximately 8 ms-1. The trial blocks consisted of 10 non-perturbed trials (NPTs) (baseline), and a block of 54 trials of which 20 trials were perturbed. The perturbation was in the form of a resistive force (12 N) applied via a piece of cord attached to a mechanical brake. In baseline trials participants reached maximal wrist velocity closer to the time of hand-ball contact (237 ms +/- 68) than in the perturbed (309 ms +/- 61) condition. Furthermore the wrist velocity profile of five out of six participants exhibited a double peak immediately after a perturbation. However, aperture variables such as the relative moment of final hand closure (approximately 70% of overall movement time) were not typically affected. The stability of grasp and transport coupling for one-handed catching was shown to vary from trial to trial. Skilled performers exploited redundant degrees of freedom in the motor system when faced with a sudden, unexpected change in task constraints.
Button
C
C
Department of Exercise and Sport Science, Manchester Metropolitan University, Alsager, Stoke-on-Trent, Cheshire, UK. c.button@education.ed.ac.uk
Davids
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K
Bennett
S J
SJ
Taylor
M A
MA
D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D018737:Hand Strength; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D013177:Sports; D014955:Wrist Joint / Q000502:physiology*