title: Pacing in a self-paced world record attempt in 24-h road cycling.
abstract: BACKGROUND
  Pacing strategy plays a major role in sport performance. However, there is a dearth of knowledge concerning pacing during ultra-endurance sport events. The present case study investigated the pacing of an ultra-cyclist in a self-paced attempt to break the world record in 24-h road cycling and, with all the caveats and the limitations affecting a case report, could be useful in generating hypotheses and further studies about pacing dynamics during prolonged sport performances.
  
  
  METHODS
  A well experienced ultra-cyclist completed laps of 11.731 km during 24 h and the support crew recorded for each lap time and power output in Watt. The trend in cycling speed and power output across laps was investigated using regression analyses. A mixed-effects regression model including lap, ambient air temperature, air pressure, air humidity and wind speed as fixed variables was used to investigate a relationship of environmental factors with cycling speed.
  
  
  RESULTS
  The athlete achieved 896.173 km within the 24 h. He set a new world record by breaking the old record (Jure Robic, 2004, 834.77 km) by 61.403 km. He cycled at an average speed of 37.34 km/h with an average power output of 250.2 W. The decrease in cycling speed and power output across laps could be modelled linearly. Temperature and wind speed were related to cycling speed during the whole event. There was a significant interaction air temperature × relative humidity for the whole event.
  
  
  CONCLUSIONS
  The athlete adopted a positive pacing (i.e. speed gradually declined throughout the event) and environmental factors (i.e. temperature and wind speed) influenced cycling speed during the event.
authors.affiliation: Facharzt FMH für Allgemeinmedizin, Gesundheitszentrum St. Gallen, Vadianstrasse 26, 9001 St. Gallen, Switzerland ; Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Knechtle
authors.affiliation: Department of Health Sciences (DISSAL), School of Public Health, University of Genoa, Genoa, Italy.
authors.forename: Nicola Luigi
authors.initials: NL
authors.lastname: Bragazzi
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosemann
authors.affiliation: Institute of Primary Care, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Rüst
keywords: Cycling speed; Power output; Ultra-endurance