title: Factors affecting metabolic cost of transport during a multi-stage running race.
abstract: The aim of this study was to investigate: (1) the role of , the fraction of (F) and the metabolic cost of transport (CoT) in determining performance during an ultra-endurance competition and (2) the effects of the race on several biomechanical and morphological parameters of the lower limbs that are likely to affect CoT. Eleven runners (aged 29-54 years) participated in an ultra-endurance competition consisting of three running stages of 25, 55 and 13 km on three consecutive days. Anthropometric characteristics, body composition, morphological properties of the gastrocnemius medialis, maximal explosive power of the lower limb and were determined before the competition. In addition, biomechanics of running and CoT were determined, before and immediately after each running stage. Performance was directly proportional to (r=0.77) and F (r=0.36), and inversely proportional to CoT (r=-0.30). Low CoT values were significantly related to high maximal power of the lower limbs (r=-0.74) and vertical stiffness (r=-0.65) and low footprint index (FPI, r=0.70), step frequency (r=0.62) and external work (r=0.60). About 50% of the increase in CoT during the stages of the competition was accounted for by changes in FPI, which represents a global evaluation of medio-lateral displacement of the foot during the whole stance phase, which in turn is associated with the myotendinous characteristics of the lower limb. Thus, lower CoT values were related to greater muscular power and lower FPI, suggesting that a better ankle stability is likely to achieve better performance in an ultra-endurance running competition.
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, 33100 Udine, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Lazzer
authors.forename: Paolo
authors.initials: P
authors.lastname: Taboga
authors.forename: Desy
authors.initials: D
authors.lastname: Salvadego
authors.forename: Enrico
authors.initials: E
authors.lastname: Rejc
authors.forename: Bostjan
authors.initials: B
authors.lastname: Simunic
authors.forename: Marco V
authors.initials: MV
authors.lastname: Narici
authors.forename: Antonio
authors.initials: A
authors.lastname: Buglione
authors.forename: Nicola
authors.initials: N
authors.lastname: Giovanelli
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Antonutto
authors.forename: Bruno
authors.initials: B
authors.lastname: Grassi
authors.forename: Rado
authors.initials: R
authors.lastname: Pisot
authors.forename: Pietro E
authors.initials: PE
authors.lastname: di Prampero
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology*; D010101:Oxygen Consumption; D010807:Physical Endurance; D012420:Running; D013710:Tendons / Q000502:physiology*
keywords: Energy cost of running; Kinematics; Maximal oxygen uptake; Stiffness; Ultra-marathon