Energetics of best performances in track cycling

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˙VO2max and best performance times (BPTs) obtained during maximal voluntary trials over 1, 2, 5, and 10 km from a stationary start were assessed in 10 elite cyclists. Steady-state ˙VO2 and peak blood lactate concentration ([La]b) were also determined in the same subjects pedaling on a track at constant submaximal speeds. The energy cost of cycling(Cc, J·m-1) was calculated as the ratio of˙VO2, corrected for glycolytic energy production and expressed in W, to v (m·s-1). Individual relationships between Cc and v were described by: Cc = Ccrr + k′ v2 where Ccrr is the energy spent against friction and k′ v2 is that spent against drag. Overall energy cost of cycling (Cctot) was obtained, adding to Cc the energy spent to accelerate the total moving mass from a stationary start. Individual theoretical BPTs were then calculated and compared with the actual ones as follows. The maximal metabolic power sustained at a constant level by a given subject (Ėmax, W) is a known function of the exhaustion time (te). It depends on his˙VO2max and maximal anaerobic capacity; it was obtained from individual ˙VO2max and [La]b values. The metabolic power(Ėc, W) necessary to cover any given distance (d) is a known function of the performance time over d (td); it is given byĖc = Cctot v = Cctot d td-1. For all subjects and distances, the t values solving the equalities Ėmax F(te) = Ėc F(td) were calculated and assumed to yield theoretical BPTs. Calculations showed a fairly good agreement between actual and calculated BPTs with an average ratio of 1.035 ± 0.058.

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