Abstract
Purpose: The Doha 2019 women’s World Championship marathon took place in extreme hot (32 °C), humid conditions (74% relative humidity) culminating in unprecedented (41%) failure rates. We explored whether extreme heat or suboptimal pacing was responsible for diminished performance against a temperate “control” (London 2017: 19 °C, 59% relative humidity) and whether physical characteristics (eg, body surface area, estimated maximal oxygen uptake, habitual heat exposure) explained performance.
Method: Five-kilometer-pace (km·h−1) data underwent repeated-measures analyses of hot (Doha, n = 40) versus temperate pacing and performance (London, n = 78) within and between marathon pacing (finisher quartiles normalized against personal best; n = 10 per group) and within hot marathon finishers versus nonfinishers (up to 10 km; normalized data). Possible predictors (multiple regression) of hot marathon pacing were explored. Tests to .05 alpha level, partial eta squared (η2p) indicates effect size.
Results: Mean (SD) of Doha (14.82 [0.96] km·h−1) pace was slower (London: 15.74 [0.96] km·h−1; P = .00; η2p=.500). In hot conditions, athletes finishing in positions 1 to 10 (group 1) started more conservatively (93.7% [2.1%] of personal best) than slower runners (groups 3 and 4; 96.6% [2.8%] of personal best; P < .05, η2p=.303). Groups were not different at 15 km and then slowed immediately (groups 3 and 4) or after 20 km (group 2). Finishers and nonfinishers adopted similar pace up to 10 km (P > .05, η2p = .003). World ranking predicted (P = .00; r2 = .248) average pace in Doha.
Conclusion: Extreme hot conditions reduced performance. Top 10 athletes adopted a conservative initial pace, whereas lower-placing athletes adopted a faster, aggressive start. Pacing alone does not explain high failure rates in nonfinishers. Athletes competing in the heat should initially pace conservatively to optimize performance.
Method: Five-kilometer-pace (km·h−1) data underwent repeated-measures analyses of hot (Doha, n = 40) versus temperate pacing and performance (London, n = 78) within and between marathon pacing (finisher quartiles normalized against personal best; n = 10 per group) and within hot marathon finishers versus nonfinishers (up to 10 km; normalized data). Possible predictors (multiple regression) of hot marathon pacing were explored. Tests to .05 alpha level, partial eta squared (η2p) indicates effect size.
Results: Mean (SD) of Doha (14.82 [0.96] km·h−1) pace was slower (London: 15.74 [0.96] km·h−1; P = .00; η2p=.500). In hot conditions, athletes finishing in positions 1 to 10 (group 1) started more conservatively (93.7% [2.1%] of personal best) than slower runners (groups 3 and 4; 96.6% [2.8%] of personal best; P < .05, η2p=.303). Groups were not different at 15 km and then slowed immediately (groups 3 and 4) or after 20 km (group 2). Finishers and nonfinishers adopted similar pace up to 10 km (P > .05, η2p = .003). World ranking predicted (P = .00; r2 = .248) average pace in Doha.
Conclusion: Extreme hot conditions reduced performance. Top 10 athletes adopted a conservative initial pace, whereas lower-placing athletes adopted a faster, aggressive start. Pacing alone does not explain high failure rates in nonfinishers. Athletes competing in the heat should initially pace conservatively to optimize performance.
| Original language | English |
|---|---|
| Pages (from-to) | 1119-1125 |
| Number of pages | 7 |
| Journal | International Journal of Sports Physiology and Performance |
| Volume | 17 |
| Issue number | 7 |
| Early online date | 17 May 2022 |
| DOIs | |
| Publication status | Published - 1 Jul 2022 |
Keywords
- marathon running
- pacing strategies
- IAAF world championship
- temperature change