EFFECTS OF RIDER POSITION ON CONTINUOUS-WAVE DOPPLER RESPONSES TO MAXIMAL CYCLE ERGOMETRY

Using 10 well-trained (Vo(2peak) = 60.6 ml kg(-1) min(-1)) college age cyclists and continuous wave Doppler echocardiography, peak accelerat ion (PkA) and velocity (PkV) of blood flow in the ascending aorta, and the stroke velocity integral (SVI) were assessed to determine if ride r position influenced the central haemodynamic responses to graded max imal cycle ergometry. Cyclist position was determined by hand placemen t on the uprights (UPRI) or drops (DROP) of conventional handlebars or using aerodynamic handlebars (AHB). All subjects consistently achieve d a peak workload of 300 W. The Doppler variables did not differ signi ficantly between rider positions at each stage of the maximal exercise tests but did change in response to increasing workloads. PkA was sig nificantly (P < 0.05) greater at workloads greater than or equal to 24 0 W versus less than or equal to 120 W. PkV increased significantly (P < 0.05) up to 180 W and then reached a plateau. SVI increased to a wo rkload of 120 W and then progressively declined, becoming significantl y (P < 0.05) less at 300 W. For each stage, neither submaximal Vo(2), V-1 nor heart rate (HR) differed significantly between each trial. The se results suggest that rider position does not affect the physiologic al response to maximal bicycle ergometry as responses to each position are similar.