title: Effects of altitude on the energetics of human best performances in 100 m running: a theoretical analysis.
abstract: The present study was designed to investigate the role of reduced air density on the energetics of 100 m running at altitude. A mathematical supply-demand model was used where supply had two components, aerobic and anaerobic and demand had three components: the cost of overcoming non-aerodynamic forces (C(na)), the cost of overcoming air resistance (C(aero)), and the cost due to changes in the runner's kinetic energy (C(kin)). Actual instantaneous-speed curves recorded in 100 m world champions were modelled at sea level. Then I calculated improvements in 100 m running times and changes in the components of the energy cost with changes in altitude from 0 m to 4,000 m. For the 100 m world championship for men, the model predicted times of 9.88 s at sea level, 9.80 s at 1,000 m, 9.73 s at 2,000 m, 9.64 s at 4,000 m and 9.15 s in the hypothetical situation where the air resistance was nil. In the counterpart for women the corresponding times were 10.85 s, 10.76 s, 10.70 s, 10.60 s and 10.04 s. The C(aero) was 12%-13% of demand at sea level, 10%-11% at 2,000 m and 8%-9% at 4,000 m. When C(aero) decreased this led to better performance by making more energy available for acceleration. Accordingly, C(kin) increased from 20%-24% at sea level to 23%-27% at 4,000 m. There was no effect of altitude specific to body size.
authors.affiliation: Faculté des Sciences du Sport, Domaine Universitaire, 12 avenue Camille Jullian, 33607 Pessac cedex, France. laurent.arsac@u-bordeaux2.fr
authors.forename: Laurent M
authors.initials: LM
authors.lastname: Arsac
mesh_terms: D000054:Acceleration; D000388:Air; D000531:Altitude; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D012420:Running / Q000502:physiology*
chemical_list: D010100:Oxygen