title: Physiological and biological factors associated with a 24 h treadmill ultra-marathon performance.
abstract: The purpose of this study was to examine the physiological and biological factors associated with ultra-endurance performance. Fourteen male runners volunteered to run on a treadmill as many kilometers as possible over a 24-h period (24TR). Maximal oxygen uptake (VO(2max)), velocity associated with VO(2max)(VO(2max)) and running economy (RE) at 8 km/h were measured. A muscle biopsy was also performed in the vastus lateralis muscle. The subjects ran 149.2 ± 15.7 km in 18 h 39 ± 41 min of effective attendance on the treadmill, corresponding to 39.4 ± 4.2% of . Standard multiple-regression analysis showed that performance was significantly (R(2) = 0.82; P = 0.005) related to VO(2max) and specific endurance, i.e. the average speed sustained over the 24TR expressed in . VO(2max) was associated with a high capillary tortuosity (R(2) = 0.66; P = 0.01). Specific endurance was significantly related to RE and citrate synthase activity. It is concluded that a high VO(2max) and an associated developed capillary network are essential for ultra-endurance running performance. The ability to maintain a high %VO(2max) over a 24TR is another factor associated with performance and is mainly related to RE and high mitochondrial oxidative capacity in the vastus lateralis.
authors.affiliation: Exercise Physiology Laboratory, Jean Monnet University, Saint-Etienne, France. guillaume.millet@univ-st-etienne.fr
authors.forename: G Y
authors.initials: GY
authors.lastname: Millet
authors.forename: J C
authors.initials: JC
authors.lastname: Banfi
authors.forename: H
authors.initials: H
authors.lastname: Kerherve
authors.forename: J B
authors.initials: JB
authors.lastname: Morin
authors.forename: L
authors.initials: L
authors.lastname: Vincent
authors.forename: C
authors.initials: C
authors.lastname: Estrade
authors.forename: A
authors.initials: A
authors.lastname: Geyssant
authors.forename: L
authors.initials: L
authors.lastname: Feasson
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001706:Biopsy; D001823:Body Composition; D005080:Exercise Test; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D012044:Regression Analysis; D012420:Running / Q000502:physiology*; D013997:Time Factors
chemical_list: D007773:Lactates