Energetics of best performances in track cycling

Abstract

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 + k1 v2 where Ccrr is the energy spent against friction and k1 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 (Emax, 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 (Ec, W) necessary to cover any given distance (d) is a known function of the performance time over d (td); it is given by Ec = Cctot v = Cctot d td. For all subjects and distances, the t values solving the equalities Emax F(te) = Ec 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.

Influence of pedalling rate on the energy cost of cycling in humans

“…Assuming that muscle efficiency is constant, the Cr of cycling in the field is therefore a function of the square of the ground speed (Capelli et al 1998). Using this model, di Prampero (1986) found a Cr of 1.01 JAEkg -1 AEm -1 during track cycling at a power output of 150 W. It is important here to note Fig.…”

“…It is noteworthy here that in human locomotion, the concept of the energy cost of locomotion (Cr) defined as the quotient of energy expenditure divided by locomotion speed during a submaximal exercise (i.e. the amount of metabolic energy required to transport the subject over one unit distance, and expressed in joules per kilogram per metre) has been developed (Margaria et al 1963;di Prampero 1986; to understand further the energetics of locomotion, especially during track cycling (di Prampero 1986;Capelli et al 1993Capelli et al , 1998. This concept appears essential to the analysis of the performance of humans over long distances since it takes into account both the metabolic and the mechanical constraints of field conditions (di Prampero 1986).…”

Factors limiting maximal performance in humans

“…This approach was originally proposed by di Prampero (1984Prampero ( , 1989 and further developed by several other authors for running (Pe´ronnet and Thibault 1989;di Prampero et al 1993;Alvarez-Ramirez 2002;Arsac 2002;Arsac and Locatelli 2002) and cycling (Olds et al 1993(Olds et al , 1995Capelli et al 1998). For a comprehensive analysis of this approach, the reader is referred to these studies as well as to van Ingen Schenau (1991) and Capelli (1999).…”

Human locomotion on ice: the evolution of ice-skating energetics through history

“…Iso-metabolic power curves (cost X speed=constant) are represented by the two hyperbolae. Data referring to walking, running and riding a racing bicycle on firm terrain are shown for the sake of comparison and were taken from previous publications (Cavagna and Kaneko, 1977;Capelli et al, 1998). The cost of walking on snow at 0.67·m·s -1 is also shown in respect to the footprint depth, reported in cm, as measured by Pandolf et al (Pandolf et al, 1976).…”