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: 2.66). 06/2011; 6(2):243-51.
Source: PubMed


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.

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    • "In this study, we included the daily highest and the daily lowest air temperatures as co-variables to investigate a potential influence of environmental temperatures on performance since it has been reported for both runners [37,38] and cyclists [30,36] that air temperature has an influence on performance. However, performance and sex difference in performance was not influenced. "
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    ABSTRACT: Background The purpose of this study was to examine the sex and age-related differences in performance in a draft-legal ultra-cycling event. Methods Age-related changes in performance across years were investigated in the 24-hour draft-legal cycling event held in Schotz, Switzerland, between 2000 and 2011 using multi-level regression analyses including age, repeated participation and environmental temperatures as co-variables. Results For all finishers, the age of peak cycling performance decreased significantly (Ss = -0.273, p = 0.036) from 38 +/- 10 to 35 +/- 6 years in females but remained unchanged (Ss = -0.035, p = 0.906) at 41.0 +/- 10.3 years in males. For the annual fastest females and males, the age of peak cycling performance remained unchanged at 37.3 +/- 8.5 and 38.3 +/- 5.4 years, respectively. For all female and male finishers, males improved significantly (Ss = 7.010, p = 0.006) the cycling distance from 497.8 +/- 219.6 km to 546.7 +/- 205.0 km whereas females (Ss = -0.085, p = 0.987) showed an unchanged performance of 593.7 +/- 132.3 km. The mean cycling distance achieved by the male winners of 960.5 +/- 51.9 km was significantly (p < 0.001) greater than the distance covered by the female winners with 769.7 +/- 65.7 km but was not different between the sexes (p > 0.05). The sex difference in performance for the annual winners of 19.7 +/- 7.8% remained unchanged across years (p > 0.05). The achieved cycling distance decreased in a curvilinear manner with advancing age. There was a significant age effect (F = 28.4, p < 0.0001) for cycling performance where the fastest cyclists were in age group 35-39 years. Conclusion In this 24-h cycling draft-legal event, performance in females remained unchanged while their age of peak cycling performance decreased and performance in males improved while their age of peak cycling performance remained unchanged. The annual fastest females and males were 37.3 +/- 8.5 and 38.3 +/- 5.4 years old, respectively. The sex difference for the fastest finishers was ~20%. It seems that women were not able to profit from drafting to improve their ultra-cycling performance.
    Full-text · Article · May 2014
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    • "A significant correlation was found dependent on body mass index and percent body fat with running speed in ultra-marathoners (Hoffman, 2008a; Hoffman et al., 2010a; Hoffman & Fogard, 2011). Environmental factors such as hot temperatures also proved to have a negative effect on running performance, although to a higher extent on faster athletes (Parise & Hoffman, 2011; Wegelin & Hoffman, 2011). Hoffman & Fogard (2011) revealed a high overall use of non-steroidal anti-inflammatory drugs (NSAIDs). "
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    ABSTRACT: This study investigated the nationalities of finishers, the annual number of finishers participating in a specific region and the performance of athletes regarding their nationality of all 161km ultra-marathons held worldwide from 1998 to 2011. The associations between nationality and performance and changes in performance across years in 36,425 finishers were analysed using correlation and linear regression analyses. Participation increased significantly for athletes originating from North America, Europe and Australia (P<0.01). Most runners originated from the USA (84%). The share of US-American athletes decreased significantly from 89.6% (1998) to 75.9% (2011) (P<0.01), while the share of European finishers increased significantly from 1.6% (1998) to 14.5% (2011) (P<0.01). The share of finishers competing in races held in the USA decreased significantly from 92.1% (1998) to 80.7% (2011) (P<0.01), while the share of finishers competing in European races increased significantly from 0% (1998) to 12.8% (2011) (P<0.01). The share of US-American athletes in the annual top ten decreased significantly from 76% (1998) to 52% (2011) (P<0.01), while the share of European athletes in the annual top ten increased significantly from 1% (1998) to 18% (2011) (P<0.01). Top ten US-American athletes achieved the fastest race times ever in women and men. Top ten European runners improved their performance to a higher extent than US-American athletes. These findings indicate that (i) ultra-marathoners originating from the USA dominated 161km ultra-marathons in participation and performance, (ii) 161km ultra-marathons were becoming more popular in Europe, and (iii) European athletes increasingly tended to compete in European races rather than to compete in the USA and improved their performance across years.
    Preview · Article · Jan 2014 · Journal of Human Sport and Exercise
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    • "Master runners participate in endurance events all around the world [2-5] and accomplish top results up to approximately 50 years of age [2,4,5]. Especially in ultra-endurance events, where a variety of anthropometric [1,6,7], psychological [8], and environmental factors such as heat [9,10] may affect running performance, master runners have the chance to reach top rankings [11,12] and compensate age-related deficits such as the decrease in cardiovascular capacity [13]. "
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    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.
    Full-text · Article · Jul 2013
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