title: Voluntary pacing and energy cost of off-road cycling and running.
abstract: OBJECTIVE
  The purposes of this study were (1) to compare self-chosen speed of off-road cyclists and runners on a hilly course, (2) to compare the energy expenditure of off-road cyclists and runners on the same terrain, and (3) to describe changes in energy expenditure over the course of the exercise period.
  
  
  METHODS
  Runners and cyclists performed three laps on a 2.75 km gravel course in a single exercise bout. The course was divided into 13 segments differing in grade and length. Position on the course and heart rate were recorded every few seconds. Speed was computed for each course segment on each lap; energy expenditure was estimated using recorded heart rates and exercise-specific maximal oxygen uptake measurements made prior to participation in the study.
  
  
  RESULTS
  There were significant relationships between grade and speed for both runners (r = 0.64) and cyclists (r = 0.44). The differences between cyclists and runners were greatest on downhill segments. Energy expenditure rates were not significantly different for runners (71.6% VO2 peak) and cyclists (68.5% VO2 peak).
  
  
  CONCLUSIONS
  Off-road cycling and running are comparable in energy demands. Variation in skill levels may account for the increased variability in speed among cyclists on downhill terrain.
authors.affiliation: Department of Behavioral Sciences and Leadership, United States Air Force Academy, Colorado Springs, CO 80840, USA.
authors.forename: G R
authors.initials: GR
authors.lastname: Mastroianni
authors.forename: M F
authors.initials: MF
authors.lastname: Zupan
authors.forename: D M
authors.initials: DM
authors.lastname: Chuba
authors.forename: R C
authors.initials: RC
authors.lastname: Berger
authors.forename: A L
authors.initials: AL
authors.lastname: Wile
mesh_terms: D000531:Altitude; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology* / Q000706:statistics & numerical data; D001823:Body Composition / Q000502:physiology; D003120:Colorado; D004734:Energy Metabolism / Q000502:physiology*; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008297:Male; D015541:Off-Road Motor Vehicles / Q000706:statistics & numerical data; D012420:Running / Q000502:physiology* / Q000706:statistics & numerical data