Effects of deceptive running speed on physiology, perceptual responses, and performance during sprint-distance triathlon.

OBJECTIVE This study examined the effects of speed deception on performance, physiological and perceptual responses, and pacing during sprint-distance triathlon running. METHODS Eight competitive triathletes completed three simulated sprint-distance triathlons (0.75 km swim, 20 km bike, 5 km run) in a randomised order, with swimming and cycling sections replicating baseline triathlon performance. During the first 1.66 km of the run participants maintained an imposed speed, completing the remaining 3.33 km as quickly as possible. Although the participants were informed that initially prescribed running speed would reflect baseline performance, this was true during only one trial (Tri-Run100%). As such, other trials were either 3% faster (Tri-Run103%), or 3% slower (Tri-Run97%) than baseline during this initial period. RESULTS Performance during Tri-Run103% (1346±108 s) was likely faster than Tri-Run97% (1371±108 s), and possibly faster than Tri-Run100% (1360±125 s), with these differences likely to be competitively meaningful. The first 1.66 km of Tri-Run103% induced greater physiological strain compared to other conditions, whilst perceptual responses were not significantly different between trials. CONCLUSIONS It appears that even during 'all-out' triathlon running, athletes maintain some form of 'reserve' capacity which can be accessed by deception. This suggests that expectations and beliefs have a practically meaningful effect on pacing and performance during triathlon, although it is apparent that an individual's conscious intentions are secondary to the brains sensitivity to potentially harmful levels of physiological and perceptual strain.