Metabolic and circulatory responses to wheelchair and arm crank exercise

To compare metabolic and circulatory responses for wheelchair ergometer (WERG) and arm crank ergometer (ACE) exercise at equal power-output (PO) levels, wheelchair-dependent (n = 7) and able-bodied (n = 10) subjects exercised at PO levels at 30, 90, 150, and 210 kpm times min-1 for each mode of ergometry. Steady-state values of oxygen uptake (VO2), pulmonary ventilation (VE), ventilatory equivalent of oxygen (VE times VO2-1), cardiac output (Q), stroke volume (SV), arteriovenous oxygen difference (a-VO2), heart rate (HR), systolic blood pressure (SBP), and rate pressure product (RPP) were determined at each PO. With the exception of VE times VO2-1 and a-VO2, each variable tended to increase with PO. Generally, VO2, VE, Q, SV, HR, SBP, and RPP responses were higher for WERG than ACE exercise at each PO level. When Q and RPP were expressed in relation to VO2, both variables were higher for WERG exercise. These data suggest that the wheelchair hand-rim system is inherently more strenuous than arm cranking, and that the latter should be studied further as an alternative method for wheelchair propulsion.