Circulatory and metabolic responses of women to arm crank and wheelchair ergometry.

Abstract

This study compared the circulatory and metabolic responses of arm crank ergometer (ACE) exercise to those of wheelchair ergometer (WCE) exercise during maximal and submaximal intensities. Maximal intensity exercise was defined as the highest power output (PO) achieved on each ergometer. The submaximal responses were compared at an equivalent absolute (PO = 25W) and relative (66% peak oxygen uptake [VO2]) intensity. On separate days and in random sequence, nine untrained able-bodied women performed a discontinuous incremental test for peak VO2 using either ACE or WCE. Each exercise bout was approximately six minutes, interspersed with four-minute rest periods. VO2 and heart rate (HR) were measured during each stage of the test and blood lactate concentrations were measured five minutes postexercise. Peak PO, ventilation (VE), and HR were significantly higher (p less than 0.05) on the ACE, with no significant difference in peak VO2 or postexercise blood lactate concentration. When compared at equivalent submaximal PO levels (25W), VO2, VE, and HR were significantly higher (p less than 0.05) on the WCE than on the ACE. In contrast, ACE exercise elicited a higher PO (p less than 0.05) at an equivalent relative metabolic load (66% peak VO2). These results suggest that in women wheelchair ergometry is less metabolically efficient than arm crank ergometry at submaximal exercise intensities. However, at maximal intensity exercise, ACE exercise imposes greater central circulatory stress. The finding that a higher peak HR was elicited by the ACE than the WCE suggests that exercise testing needs to be ergometer-specific when the results are to be used for exercise prescription.