Improvement of oxygen-uptake kinetics and cycling performance with combined prior exercise and fast start

Purpose: To investigate whether oxygen uptake ( O2) kinetics and simulated 4-km cycling performance are synergistically improved by prior ‘priming’ exercise and an all-out starting strategy. Methods: Nine males completed four target work trials (114 ± 17 kJ) to assess O2 kinetics and cycling performance in a repeated-measures, cross-over experimental design. Trials were initiated with either a 12-s all-out start or a self-selected start and preceded by prior severe-intensity (70%Δ) priming exercise or no priming exercise. Results: The O2 MRT was lower (indicative of faster O2 kinetics) in the all-out primed condition (20 ± 6 s) compared to the all-out unprimed (23 ± 6 s), self-paced-unprimed (42 ± 13 s) and self-paced-primed (42 ± 11 s) trials (P<0.05), with the O2 MRT also lower in the all-out unprimed compared to self-paced-unprimed and self-paced-primed trials (P<0.05). Trial completion time was shorter (performance was enhanced) in the all-out primed trial (402 ± 14 s) compared to the all-out unprimed (408 ± 14 s), self-paced-unprimed (411 ± 16 s) and self-paced-primed (411 ± 19 s) trials (P<0.05) with no differences between the latter three trials. Conclusions: The findings from this study suggest that combining severe-intensity priming exercise with a short-duration all-out starting strategy can expedite the adjustment of O2 and lower completion time during a cycling performance trial to a greater extent than either intervention administered independently. These results might have implications for optimising performance in short-duration high-intensity competitive events such as a 4-km cycling time trial.