Date of Award

2014

Degree Type

Thesis

Degree Name

Doctor of Philosophy

School

School of Exercise and Health Sciences

Faculty

Health, Engineering and Science

First Advisor

Dr Chris R. Abbiss

Second Advisor

Dr Jeremiah J. Peiffer

Third Advisor

Prof Ken Nosaka

Abstract

Pacing is an integral aspect of performance during all exercise, including multi-sport events such as triathlon. However, to date, the optimal pacing strategies to adopt over an entire triathlon, as well as during each specific discipline (i.e. swim, cycle and run), is not well understood. Therefore, the primary purpose of this thesis was to identify and understand current pacing strategies adopted by highly performing triathletes across different triathlon distances. This research aids in identifying pacing strategies that may improve overall performance during triathlon.

In the first study, the influence of sex and race distance on the age-related declines in the sprint, Olympic, half-Ironman (HIM) and Ironman distance triathlons were examined. An earlier, larger and faster rate of decline (p=0.01) in performance with ageing was observed in females (≥30 years, 9.3%, 3.0% per decade respectively) and males (≥40 years, 5.9%, 2.2% per decade, respectively) for the longer events (half-Ironman and Ironman) compared with the shorter distances (sprint and Olympic, ≥50 years for both sexes). A larger magnitude of decline was observed in the swim discipline, as compared with the cycle and run disciplines (12.8%, 5.6%, 9.3% for females, 9.4%, 3.7%, 7.3% for males, in the swim, cycle and run disciplines, respectively). These results indicate that sex and race distance influence the agerelated decline in triathlon performance and should be considered when manipulating training programs to attenuate the age-related declines in performance across different disciplines and distances. Furthermore, a greater emphasis should be placed on maintaining swim performance due to the rapid age-related decline observed in this discipline.

The second study within this thesis examined the influence of age and sex on cycle and run pacing during the sprint, Olympic, half-Ironman and Ironman distance triathlons in top performing triathletes. Interestingly, females employed a more aggressive pacing strategy during the initial stages of the cycle discipline across all distances (sprint - 2.1%; Olympic - 1.6%; half-Ironman- 1.5%; Ironman - 1.7% higher relative to mean, as compared with males). Likewise, younger athletes (20-29 y) tend to start the run more aggressively during

the sprint, Olympic and half-Ironman events (2.0 to 3.0% faster on average than other agegroups, p

Eight well-trained male triathletes performed a sprint, Olympic and half-Ironman triathlon race, each separated by three weeks. Prior to the races, participants performed a cycle to exhaustion test to determine maximal aerobic power, V ˙ O2peak and the power outputs corresponding to the first and second ventilatory thresholds,. A power meter (SRM) was fitted onto their bikes to determine power output and speed during the cycle discipline, while a global positioning system (GPS) was worn throughout the race to determine speed and heart rate throughout. The variability in power output during the cycle discipline was analysed using exposure variation analysis. Results showed that swim pacing was comparable across distances. Cycle pacing was similar during the sprint and Olympic cycle discipline (more even when compared with the half-Ironman). During the run, comparable pacing was observed during the Olympic and half Ironman (more positive when compared with the sprint). Power output during the cycle discipline of the half-Ironman was more variable (standard deviation of exposure variation analysis: EVASD=3.21 ± 0.61) than the sprint cycle discipline (EVASD=3.84 ± 0.44). The results of this study indicate that well-trained triathletes pace differently during triathlons of various distances. Athletes may need to trial different pacing strategies based on race distance, fitness, discipline-specific strengths and race conditions in order to determine their individual optimal pacing strategies.

The aim of the final study within this thesis was to determine the influence of pacing during the swim on subsequent sprint triathlon performance. Nine well-trained triathletes performed three sprint triathlons with different swim pacing strategies. The swim of the sprint triathlons were work matched but pacing was manipulated to be either positive (i.e. speed gradually decreasing from 92 to 73% of an initial swim time-trial), negative (i.e. speed gradually increasing from 73 to 92% of the swim time-trial) or even (constant speed of 82.5% of the swim time-trial). Subsequent cycling and running were completed at a self-selected pace. When compared with the even (31.4 ± 1.0 and 67.7 ± 3.9 min respectively) and negatively paced swim (31.8 ± 1.6 and 67.3 ± 3.7 min respectively), faster cycle and overall triathlon times were achieved with a positively paced swim (30.5 ± 1.8 and 65.9 ± 4.0 min respectively). A lower RPE was observed following the positively paced swim time-trial (9 ± 2) when compared with the negatively pacing swim (11 ± 2). No performance differences occurred during the run discipline between trials. This indicates that a more conservative swim start strategy may improve sprint triathlon performance in age-group athletes.

The aim of this series of studies was to examine the pacing of top non-drafting age-group triathletes across various standard triathlon distances, in order to understand and improve pacing strategies. The series of four studies in this thesis research project has demonstrated the influence of biological sex, age and distance on performance and pacing during various standard triathlons. The results of this study are of significance to athletes, coaches and sport scientists, as the different pacing strategies adopted in males and females across various age-groups and triathlon distances can have implications for training and racing. Further, a more conservative positive swim pacing strategy could benefit sprint triathlon performance.

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