Abstract

Objective
This study examined how residual fatigue affects the relationship between ratings of perceived exertion (RPE), physiological responses, and pacing during triathlon performance.

Methods
Eight male triathletes completed a sprint-distance triathlon (750 m swim, 20 km cycle and 5 km run) and isolated 5 km run on separate days. RPE, core temperature (Tcore), heart rate and blood lactate concentration [BLa-] were recorded during both, in addition to performance time and speed.

Results
Triathlon run time (1248 ± 121 s) was significantly slower than the isolated run (1167 ± 90 s) (p<0.01). Significant differences were observed at the start of the two conditions for all physiological measures (Heart rate 162±4 vs 154±5 beats∙min- 1; Tcore 38.3±0.8 vs 36.7±0.6°C; [BLa-] 9.1±2.8 vs 2.1±0.4 mmol·L- 1, for triathlon and isolated run, respectively, p<0.05). No significant differences were observed for initial RPE (p=0.083), rate of RPE increase (p = 0.412), or final RPE (p = 0.329) between run trials.

Conclusions
The maintenance of a scalar-linear increase in RPE by the brain remains the primary mechanism for pace regulation during both single and multi-modal endurance performance, with physiological responses being only indirectly related to this process. The apparent absence of any RPE ‘resetting’ between disciplines suggests that during shorter distance multi-sport performances (60-90 mins) a cognitive pacing strategy for the entire event is employed. However, as subtle alterations in RPE development between disciplines were observed the existence of discipline-specific RPE ‘templates’ should not be discounted.