Impact of Cycling Intensity on Cycle-run Transition in Female Triathletes

Abstract

PURPOSE:  The purpose of the study was to determine the impact of intensity during the final km of a cycling bout on subsequent run and overall cycle-run (CR) performance.  A secondary aim of the study was to examine how manipulations in cycling power affect cycle-run performance in female triathletes exclusively.

METHODS:  Nine well-trained female triathletes participated in the study.  The triathletes completed two CR sessions (20 km cycle, 5 km run).  The intensity of the first 19 km of cycling was equivalent to peak power at 70% of peak oxygen consumption (O₂peak) and the final 1 km varied between power achieved at 95% of O₂peak (high intensity, HI) and power achieved at 50% of O₂peak (low intensity, LI).  The 5 km run was completed as fast as possible.

RESULTS:  Mean blood lactate concentration [La^-] was significantly higher during the run following the cycling bout ending with a HI rather than a LI (11.5 ± 0.64 mmol/L vs. 9.3 ± 0.72 mmol/L).  Run performance was not significantly different between HI and LI (24:54 ± 02:53 min vs. 00:24:36 ± 00:03:17 min).  As well, no significant differences were found between overall CR sessions (01:23:23 h ± 00:05:47 min vs. 01:23:50 h ± 00:07:01 min).

CONCLUSION:  Despite increases in [La^-], cycling intensity during the final stages of a 20 km cycling bout does not impact run or CR performance in well-trained female triathletes.