Abstract:
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PURPOSE: The dynamics of speed selection as a function of
distance, or pacing, are used in recreational, competitive, and
scientific research situations as an indirect measure of the
psycho-physiological status of an individual. The purpose of
this study was to determine pacing on level, uphill and downhill
sections of participants in a long (>80 km) ultramarathon
performed on trails in hilly terrain. METHODS: Fifteen
ultramarathon runners competed in a 173 km event (five finished
at 103 km) carrying a Global-Positioning System (GPS) device.
Using the GPS data, we determined the speed, relative to average
total speed, in level (LEV), uphill (UH) and downhill (DH)
gradient categories as a function of total distance, as well as
the correlation between overall performance and speed
variability, speed loss, and total time stopped. RESULTS: There
were no significant differences in normality, variances or means
in the relative speed in 173-km and 103-km participants.
Relative speed decreased in LEV, UH and DH. The main component
of speed loss occurred between 5% and 50% of the event distance
in LEV, and between 5% and 95% in UH and DH. There were no
significant correlations between overall performance and speed
loss, the variability of speed, or total time stopped.
CONCLUSIONS: Positive pacing was observed at all gradients, with
the main component of speed loss occurring earlier (mixed
pacing) in LEV compared to UH and DH. A speed reserve (increased
speed in the last section) was observed in LEV and UH. The
decrease in speed and variability of speed were more important
in LEV and DH than in UH. The absence of a significant
correlation between overall performance and descriptors of
pacing is novel and indicates that pacing in ultramarathons in
trails and hilly terrain differs to other types of running
events. |