Journal of Science and Medicine in Sport (2007) 10, 244—251 ORIGINAL PAPER Variable power output during cycling improves subsequent treadmill run time to exhaustion R. Suriano a , F. Vercruyssen c , D. Bishop b,* , J. Brisswalter c a School of Human Movement and Exercise Science, The University of Western Australia, Australia b Universit` a di Verona, Italy c Unit´ e Ergonomie Sportive et Performance, Universit´ e de Toulon-Var, France Accepted 29 June 2006 KEYWORDS Physical education and training; Bicycling; Exercise test; Physical endurance; Running; Triathlon Summary The aim of this study was to investigate the effect of constant versus variable power output cycling exercise on subsequent high-intensity, running perfor- mance. Eight triathletes completed two testing sessions (in a random order), which required the subjects to perform 30 min of cycling at either, a constant power output (90% of the lactate threshold), or a variable power output with power output alter- nating every 5 min (±20% of the constant workload). Each cycling bout was imme- diately followed by a high-intensity treadmill run (16.7 ± 0.7 km h -1 ) to exhaustion. No significant differences were found for mean metabolic values or power output between cycling conditions. However, a significant (P < 0.05) improvement in run time to exhaustion was reported after 30 min of variable cycling (15:09 ± 4:43 min) compared to constant cycling (10:51 ± 3:32 min). The results of this study demon- strate that, despite similar average physiological responses during 30 min of cycling, variable-intensity cycling results in an improved running performance compared to constant-intensity cycling. It is hypothesised that the reduced power output in the final 5 min of variable cycling protocol may allow recovery before transition, how- ever the mechanisms involved cannot be determined from the current study. © 2006 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Introduction Multi-sport events involve completing different exercise modalities in a sequential order, and per- formance may be determined by the ability to tran- sition from one modality to the next. In order to optimise performance in such events, researchers ∗ Corresponding author. E-mail address: bishop@motorie.univr.it (D. Bishop). have attempted to better understand the effect that one exercise modality may have on subsequent modalities. 1—3 Studies have shown that the com- pletion of a prior swim and/or cycle reduces sub- sequent running economy and performance com- pared to an isolated run. 1,2,4 However, one limi- tation of these studies was that the cycling session required the subjects to maintain a constant power output throughout the experimental trials. In con- trast, large variations in intensity and power out- puts have typically been observed during mass-start 1440-2440/$ — see front matter © 2006 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2006.06.019