Walking economy in male adults with Down syndrome.

The purpose of this study was to investigate walking economy in response to steady-state locomotion in adult males with Down syndrome (DS) and in healthy controls. Twelve participants with DS (34.5 +/- 7.0 years) and 11 non-disabled controls (34.3 +/- 8.7 years) performed submaximal (0% grade, 2.5 km h(-1) for 8 min) and maximal treadmill tests with metabolic and heart-rate measurements. For submaximal walking, submaximal oxygen uptake (VO(2)) (9.1 vs. 9.5 mL kg(-1) min(-1)), net VO(2) (5.9 vs. 5.4 mL kg(-1) min(-1)) were not different between the groups (P > 0.05). However, oxygen-pulse (6.6 vs. 8.6 mL/beat) was lower and relative work intensity (44.6 vs. 19.9% of max) was higher in individuals with DS compared to controls (P < 0.05). Findings indicate similar walking economy between groups. Nevertheless, participants with DS exercised at lower submaximal oxygen-pulse and higher percentage of VO(2peak). Therefore, despite similar walking economy, participants with DS have lower cardiorespiratory function than controls for a given steady-state treadmill speed.