Factors limiting maximal performance in humans.

摘要: Theoretical best performance times (t theor) in track running are calculated as follows. Maximal metabolic power (Ė max) is a known function of maximal oxygen uptake (VO2max), anaerobic capacity (AnS) and effort duration to exhaustion e): Ė max=f e). Metabolic requirement r) cover the distance (d) time t p product energy cost locomotion per unit (C) speed: r=C×d/t p. The values for which max e)=Ė r p), assumed yield theor, can be obtained any given subject provided that VO2max, AnS C known, compared with actual performances act). For 15 min≥t e≥100 s, overall ratio act/t theor was rather close 1.0. To estimate relative role different factors limiting several resistances O2 transport identified, inversely proportional to: alveolar ventilation (R V*), by circulation Q), diffusion from capillary blood mitochondria t), mitochondrial m). Observed changes VO2max accompanied measured resistances. each resistance therefore means conductance equation. In exercise large muscle groups (two legs), R Q major (75%) factor downstream lung, its being reduced 50% during small (one leg). t m account remaining fractions. normoxia V* negligible; at high altitude it increases progressively, together m, expense Q.