Journal of Applied Physiology, Vol 49, Issue 1 16-21, Copyright © 1980 by American Physiological Society
Energy expenditure during oxygen deficit of submaximal concentric and eccentric exercise
P. Pahud, E. Ravussin, K. J. Acheson and E. Jequier
Aerobic (MR) and anaerobic (Man) energy production was determined in five
subjects during the 1st min of concentric and eccentric exercise
(steady-state energy expenditure approximately 415 W in both situations).
Man was obtained by solving the heat balance equation, MR + Man - S = (R +
C + E) +/- parallel to W parallel to, all other variables of which could be
measured [S is heat storage; (R + C + E) are the radiative, convective, and
evaporative heat losses; and W is work output]. The size of the O2 deficit
was similar whatever the type of exercise (99 +/- 19 W concentric and 102
+/- 19 W eccentric). MR + Man was lower than the steady-state MR in both
types of exercise (concentric; 364 +/- 19 and 407 +/- 24 W, respectively,
and eccentric; 346 +/- 25 and 430 +/- 21 W, respectively). The size of the
O2 deficit during the 1st min of muscular exercise is imposed by the
steady-state energy requirement whatever the type of exercise. The smaller
energy expenditure during this phase is probably due to less energy being
released when creatinge phosphate is split without resynthesis (O2 deficit)
than during splitting and resynthesis of high-energy phosphate bonds
(steady state).
