International Journal of Industrial Ergonomics vol:17 pages:163-173
To study the muscular activity pattern adaptations to changes in handrim velocity, independent of external power output, 40 wheelchair basketball players with extensive expertiuse in wheelchair propulsion performed wheelchair exercise tests on a motor-driven treadmill in six situations: two exercise levels (60% and 80% of individual VO2 peak) and three velocities (1.11, 1.67 and 2.22 m/sec) with constant power output at each level. During each test, cardiorespiratory, kinematic and EMG data were recorded synchroniously. A two factor analysis of variance, with "exercise level" and "wheelchair velocity" as the amin factors (p<0.5), revealed a significant effect on gross mechanical efficiency when velocity was increased. Mechanical work increased significantly during the recovery phase, amounting to 1/3 of the entiore mechanical during the propulse cycle. Calculation of the concnetric muscular work (CMW i.e. muscular activity integrated for each muscle separately as a function of the corresponding angular displacement), gave insight into the energy contribution of each skeletal muscle, used to propel the wheelchair. A close relationship (mean correlation coefficient = + 0.84) was demonstrated between metabloic energy expenditure (oxygen consumption) and CMW, indicating that CMW could be a valid standard to analyse individual energy patterns in wheelchair propulsion.