Influence of temperature and performance level on pacing a 161 km trail ultramarathon.

Sutter Institute for Medical Research, Sacramento, CA, USA.
International journal of sports physiology and performance (Impact Factor: 2.68). 06/2011; 6(2):243-51.
Source: PubMed

ABSTRACT Even pacing has been recommended for optimal performances in running distances up to 100 km. Trail ultramarathons traverse varied terrain, which does not allow for even pacing.
This study examined differences in how runners of various abilities paced their efforts in the Western States Endurance Run (WSER), a 161 km trail ultramarathon in North America, under hot vs cooler temperatures.
Temperatures in 2006 (hot) and 2007 (cooler) ranged from 7-38°C and 2-30°C, respectively. Arrival times at 13 checkpoints were recorded for 50 runners who finished the race in both years. After stratification into three groups based on finish time in 2007 (<22, 22-24, 24-30 h), paired t tests were used to compare the difference in pace across checkpoints between the years within each group. The χ2 test was used to compare differences between the groups on the number of segments run slower in the hot vs cooler years.
For all groups, mean pace across the entire 161 km race was slower in 2006 than in 2007 (9:23 ± 1:13 min/km vs 8:42 ± 1:15 min/km, P < .001) and the pace was slower from the start of the race when temperatures were still relatively cool. Overall, the <22 h cohort ran slower in 2006 than 2007 over 12 of the 14 segments examined, the 22-24 h cohort was slower across 10 of the segments, and the >24 h cohort was slower across only 6 of the segments χ(2)2 = 6.00, P = .050). Comparable pacing between the 2 y corresponded with onset of nighttime and cooling temperatures.
Extreme heat impairs all runners' ability to perform in 161 km ultramarathons, but faster runners are at a greater disadvantage compared with slower competitors because they complete a greater proportion of the race in the hotter conditions.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective To examine the medical care at a highly competitive 161-km mountain ultramarathon. Methods Encounter forms from the 2010 through 2013 Western States Endurance Run were analyzed for trends in consultation and use of intravenous fluids. Results A total of 63 consultations (8.2% of starters) were documented in 2012 and 2013, of which 10% involved noncompetitors. Most (77%) of the consultations with competitors occurred on the course rather than at the finish line, and were generally during the middle third of the race. Of the on-course consultations, the runner was able to continue the race 55% of the time, and 75% of those who continued after consultation ultimately finished the race. Relative number of consultations did not differ among competitors within 10-year age groups (P = .7) or between men and women (P = .2). Overall, consultations for medical issues were predominant, and nausea and vomiting accounted for the single highest reason for consultation (24%). Although there was an overall decrease in finish line consultations and intravenous fluid use from 2010 through 2013 (P < .0001 for both) that was independent of maximum ambient temperature (P = .3 and P = .4), the proportion of those being treated with intravenous fluids relative to those receiving consultation at the finish line was directly related to maximum ambient temperature (r = .93, P = .037). Both 2012 and 2013 had a single medical emergency that required emergency evacuation. Conclusions This work demonstrates that the medical needs in a 161-km ultramarathon are mostly for minor issues. However, occasional serious issues arise that warrant a well-organized medical system.
    Wilderness and Environmental Medicine 09/2014; 26(1). DOI:10.1016/j.wem.2014.06.015 · 0.79 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aims of the present study were to examine (a) participation and performance trends and (b) the age of peak running performance in master athletes competing in 24-h ultra-marathons held worldwide between 1998 and 2011. Changes in both running speed and the age of peak running speed in 24-h master ultra-marathoners (39,664 finishers, including 8,013 women and 31,651 men) were analyzed. The number of 24-h ultra-marathoners increased for both women and men across years (P < 0.01). The age of the annual fastest woman decreased from 48 years in 1998 to 35 years in 2011. The age of peaking running speed remained unchanged across time at 42.5 ± 5.2 years for the annual fastest men (P > 0.05). The age of the annual top ten women decreased from 42.6 ± 5.9 years (1998) to 40.1 ± 7.0 years (2011) (P < 0.01). For the annual top ten men, the age of peak running speed remained unchanged at 42 ± 2 years (P > 0.05). Running speed remained unchanged over time at 11.4 ± 0.4 km h-1 for the annual fastest men and 10.0 ± 0.2 km/h for the annual fastest women, respectively (P > 0.05). For the annual ten fastest women, running speed increased over time by 3.2% from 9.3 ± 0.3 to 9.6 ± 0.3 km/h (P < 0.01). Running speed of the annual top ten men remained unchanged at 10.8 ± 0.3 km/h (P > 0.05). Women in age groups 25-29 (r2 = 0.61, P < 0.01), 30-34 (r2 = 0.48, P < 0.01), 35-39 (r2 = 0.42, P = 0.01), 40-44 (r2 = 0.46, P < 0.01), 55-59 (r2 = 0.41, P = 0.03), and 60-64 (r2 = 0.57, P < 0.01) improved running speed; while women in age groups 45-49 and 50-54 maintained running speed (P > 0.05). Men improved running speed in age groups 25-29 (r2 = 0.48, P = 0.02), 45-49 (r2 = 0.34, P = 0.03), 50-54 (r2 = 0.50, P < 0.01), 55-59 (r2 = 0.70, P < 0.01), and 60-64 (r2 = 0.44, P = 0.03); while runners in age groups 30-34, 35-39, and 40-44 maintained running speed (P > 0.05). Female and male age group runners improved running speed. Runners aged >40 years achieved the fastest running speeds. By definition, runners aged >35 are master runners. The definition of master runners aged >35 years needs to be questioned for ultra-marathoners competing in 24-h ultra-marathons.
    07/2013; 2(1):21. DOI:10.1186/2046-7648-2-21
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study was to examine the sex and age-related differences in performance in a draft-legal ultra-cycling event.
    05/2014; 6:19. DOI:10.1186/2052-1847-6-19