Perceived exertion as a tool to self-regulate exercise in individuals with tetraplegia

The purpose of this investigation was to examine the use of subjective rating of perceived exertion (RPE) as a tool to self-regulate the intensity of wheelchair propulsive exercise in individuals with tetraplegia. Eight motor complete tetraplegic (C5/6 and below; ASIA Impairment Scale = A) participants completed a submaximal incremental exercise test followed by a graded exercise test to exhaustion to determine peak oxygen uptake (\( \dot{V}O_{{ 2 {\text{peak}}}} \)) on a wheelchair ergometer. On a separate day, a 20-min exercise bout was completed at an individualised imposed power output (PO) equating to 70 % of \( \dot{V}O_{{ 2 {\text{peak}}}} \). On a third occasion, participants were instructed to maintain a workload equivalent to the average RPE for the 20-min imposed condition. \( \dot{V}O_{2} \), heart rate (HR) and PO were measured at 1-min intervals and blood lactate concentration [BLa⁻] was measured at 0, 10 and 20 min. No differences (P > 0.17) were found between mean \( \dot{V}O_{2} \), % \( \dot{V}O_{{ 2 {\text{peak}}}} \), HR, % HR_peak, [BLa⁻], velocity or PO between the imposed and RPE-regulated trials. No significant (P > 0.05) time-by-trial interaction was present for \( \dot{V}O_{2} \) data. A significant interaction (P < 0.001) for the PO data represented a trend for an increase in PO from 10 min to the end of exercise during the RPE-regulated condition. However, post hoc analysis revealed none of the differences in PO across time were significant (P > 0.05). In conclusion, these findings suggest that RPE can be an effective tool for self-regulating 20 min of wheelchair propulsion in a group of trained participants with tetraplegia who are experienced in wheelchair propulsion.