Logo for the Journal of Rehab R&D

Volume 45 Number 1, 2008
   Pages 109 — 116

Abstract - Effects of backrest positioning and gear ratio on nondisabled subjects' handcycling sprinting performance and kinematics

Arnaud Faupin, PhD;1-2* Philippe Gorce, PhD;3 Christophe Meyer, MS;4 André Thevenon, MD, PhD1,5

1Laboratoire d'Etudes de la Motricité Humaine, Faculté des Sciences du Sport et de l'Education Physique,
Université de Lille 2, Ronchin, France; 2Laboratoire d'Automatique de Mécanique et d'informatique Industrielles et Humaines, Université de Valenciennes, Valenciennes, France; 3Laboratoire Ergonomie Sportive et Performance,
Université du Sud Toulon-Var, La Garde, France; 4Department of Rehabilitation Sciences, Katholieke Universiteit
Leuven, Leuven, Belgium; 5Centre Hospitalier Régional Universitaire de Lille, Service Médecine Physique et
Réadaptation, Lille, France

Abstract — Backrest position is a significant parameter in handcycling that one must consider when seeking to optimize the user-to-chair interface. We studied the effects of backrest position on handcycle propulsion kinematics. Ten nondisabled participants with no handcycle propulsion experience repeated an 8 s sprint with three backrest positions (backrest angle between 45° and 50° to the horizontal, backrest angle between 65° and 70° to the horizontal, and without backrest) and three gear ratios (GRs) (GR22/21 = low, GR32/21 = medium, and GR44/21 = high). We used three-dimensional movement analysis to calculate the average maximal velocity, cycle frequency, and angle parameters for the arms and trunk. Our results showed statistically higher trunk flexion/extension (p < 0.001) and maximal velocity (p < 0.001) when a backrest was not used. Moreover, these differences were accentuated as the GR increased (GR44/21). Our results suggest that handcycle users with unimpaired upper-body and trunk function can improve handcycling performance by removing the backrest. Nevertheless, future studies on specific groups of subjects with spinal cord injury should be conducted.

Key words: backrest, gear ratio, handcycle, kinematics, performance, rehabilitation, spinal cord injury, sports, trunk, wheelchair.

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