title: Sprint performance-duration relationships are set by the fractional duration of external force application.
abstract: We hypothesized that the maximum mechanical power outputs that can be maintained during all-out sprint cycling efforts lasting from a few seconds to several minutes can be accurately estimated from a single exponential time constant (k(cycle)) and two measurements on individual cyclists: the peak 3-s power output (P(mech max)) and the maximum mechanical power output that can be supported aerobically (P(aer)). Tests were conducted on seven subjects, four males and three females, on a stationary cycle ergometer at a pedal frequency of 100 rpm. Peak mechanical power output (P(mech max)) was the highest mean power output attained during a 3-s burst; the maximum power output supported aerobically (P(aer)) was determined from rates of oxygen uptake measured during a progressive, discontinuous cycling test to failure. Individual power output-duration relationships were determined from 13 to 16 all-out constant load sprints lasting from 5 to 350 s. In accordance with the above hypothesis, the power outputs measured during all-out sprinting efforts were estimated to within an average of 34 W or 6.6% from P(mech max), P(aer), and a single exponential constant (k(cycle) = 0.026 s(-1)) across a sixfold range of power outputs and a 70-fold range of sprint trial durations (R2 = 0.96 vs. identity, n = 105; range: 180 to 1,136 W). Duration-dependent decrements in sprint cycling power outputs were two times greater than those previously identified for sprint running speed (k(run) = 0.013 s(-1)). When related to the respective times of pedal and ground force application rather than total sprint time, decrements in sprint cycling and running performance followed the same time course (k = 0.054 s(-1)). We conclude that the duration-dependent decrements in sprinting performance are set by the fractional duration of the relevant muscular contractions.
authors.affiliation: Locomotion Laboratory, Kinesiology Department, Rice University, Houston, Texas 77005, USA.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Weyand
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Lin
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Bundle
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008954:Models, Biological; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013223:Statistics as Topic; D013314:Stress, Mechanical