Combined cycle and run performance is maximised when the cycle is completed at the highest sustainable intensity.

The aim of this study was to determine the effect of cycle intensity on subsequent running performance and combined cycle-run (CR) performance. Seven triathletes undertook a cycling graded exercise test to exhaustion, an isolated 500-kJ cycle time trial (CTT) and an isolated 5-km running time trial. Then they performed a series of CR tests, at various cycle intensities, followed by an all-out, 5-km run. The CR tests were separated into four categories based on the percentage of the CTT at which the cycle was performed (CR 81-85%, CR 86-90%, CR 91-95%, and CR 96-100%). Running performance was slower during CR 96-100% compared to CR 81-85% and CR 86-90% (20:45 ± 1:19 vs. 19:56 ± 0:40 and 19:46 ± 0:49 min; P < 0.05), but not CR 91-95% (20:19 ± 1:08 min; P > 0.05). CR performance was maximised during CR 96-100% when compared to CR 81-85, CR 86-90 and CR 91-95% (56:37 ± 4:04 vs. 62:40 ± 5:30, 59:53 ± 4:41 and 58:29 ± 4:40 min; P < 0.05). The results suggest that combined cycle and run performance is maximised when the cycle is completed at the highest sustainable intensity.