Prolonged stage duration during incremental cycle exercise: effects on thelactate threshold and onset of blood lactate accumulation

The aim of this study was to investigate whether increasing the duration of workloads from 3 min to 8 min during incremental exercise would influence workload (W), oxygen consumption ((V) over dot O-2) and heart rate (HR) at the lactate threshold (LT) and the onset of blood lactate accumulation (OBL A). Two groups of six male cyclists were assigned to a well-trained (WT) an d recreational (REC) group on the basis of their performance in a maximal i ncremental ramp test. Each subject then performed two incremental lactate t ests (EXT) consisting of six workloads of either 3 min (EXT3-min) or 8 min (EXT8-min) duration. At the completion of each workload whole capillary blo od samples were obtained for the determination of blood lactate (BLa) conce ntration (mM). Power output (Watts, W), HR and (V) over dot O-2 were averag ed in the final minute of each workload as well as in the third minute of t he EXT8-min. The workload, HR and (V) over dot O-2 at the LT and OBLA were subsequently determined from the data of EXT3-min and EXT8-min. The results demonstrate that workload and (V) over dot O-2, but not HR, at the LT and OBLA were higher in the WT cyclists. At the same time, the workload at the LT obtained from the results of the EXT3-min was significantly (P<0.05) hig her then the value obtained in the EXT8-min in the WT subjects but not the REC subjects. However, the workload, (V) over dot O-2 and HR at the OBLA, t ogether with the (V) over dot O-2 and HR at the LT were not significantly d ifferent when calculated from data obtained from EXT3-min or EXT8-min. The data obtained in this study suggest that incremental exercise protocols usi ng workloads of duration longer than 3 min have the effect of increasing th e workload at the LT in well-trained cyclists. However, the OBLA determined in exercise tests using stage increments of either 3 min or 8 min is simil ar in cyclists of different training status.