Article

OBJECTIVES: To create a comprehensive definition of the manual wheelchair stroke
cycle, which includes multiple periods of pushrim contact, and to show its
improved clinical benefit to wheelchair propulsion analyses. DESIGN:
Cross-sectional biomechanics study. SETTING: Three motion analysis laboratories.
PARTICIPANTS: Persons (N=54) with paraplegia who use a manual wheelchair.
MAIN OUTCOME MEASURES: Pushrim forces, axle
moments, and contact angles measured during wheelchair propulsion. RESULTS: Total
force on the pushrim was used to define pushrim contact and positive axle moment
was used to identify the included period of propulsive contact. During most
strokes, periods of nonpropulsive contact existed before and after propulsive
contact. Within these periods, braking moments were applied to the pushrim,
resulting in negative power output, or power loss. Including nonpropulsive data
decreased mean stroke moment and power. The magnitude and the angle over which
braking moments and power loss occurred increased with wheel speed. Mean braking
moment and power loss within the initial contact period were significantly
(P<.001) related to stroke pattern. CONCLUSIONS: The proposed definition of the
stroke cycle provides a thorough and practical description of wheelchair
propulsion. Researchers and clinicians should use this definition to understand
and minimize the impact of nonpropulsive contact throughout the stroke.

Langue : ANGLAIS