Energetics of kayaking at sub-maximal and maximal speeds

The energy cost of kayaking per unit distance (C-k kJ.m(-1)) was assessed in eight middle- to high-class athletes (three males and five females: 45-76 kg body mass. 1.50-1.88 m height; 15-32 years of age) at submaximal and maximal speeds. At submaximal speeds, C-k was measured by dividing the steady-state oxygen consumption ((V) over dot O-2 1 . s(-l)) by the speed (nu, m . s(-l)), assuming an energy equivalent of 20.9 kJ . 1 O-2(-1). At maximal speeds, C-k was calculated from the ratio of the total metabolic energy expenditure (E, kJ) to the distance (d, m). E was assumed to be the sum of three terms, as originally proposed by Wilkie (1980): E = AnS + alpha(V) over dot O-2max . t - alpha(V) over dot O-2max . tau(1 - e(-t.tau-1)), were alpha is the energy equivalent of O-2 (20.9 kJ . 1 O-2(-1)), tau is the time constant with which (V) over dot O-2max is attained at the onset of exercise at the muscular level, AnS is the amount of energy derived from anaerobic energy utilization, alpha is the performance time, and (V) over dot O-2max is the net maximal (V) over dot O-2. Individual (V) over dot O-2max was obtained from the (V) over dot O-2 measured during the last minute of the 1000-m or 2000-m maximal run. The average metabolic power output ((E) over dot , kW) amounted to 141% and 102% of the individual maximal aerobic power ((V) over dot O-2max) from the shortest (250 m) to the longest (2000 m) distance, respectively. The average (SD) power provided by oxidative processes increased with the distance covered [from 0.64 (0.14) kW at 250 m to 1.02 (0.31) kW at 3000 m], whereas that provided by anaerobic sources showed the opposite trend. The net C-k was a continuous power function of the speed over the entire range of velocities from 2.88 to 4.45 m . s(-l): C-k = 0.02 . nu(2.26) (r = 0.937, n = 32).