In the present study, we determined both anaerobic capacity (the maximal accumulated oxygen deficit) and maximal oxygen uptake (VO2max) during arm stroke (A), leg kicking (K), and whole body swimming (S), and compared them. The subjects were six trained college swimmers (two male and four female), aged 20 +/- 1 years. To determine VO2max for A, K and S, VO2max was measured during a 6-min swim at constant water flow rates. VO2 was measured by the Douglas bag method. Anaerobic capacity was determined by accumulated oxygen deficit during exercise lasting 2-3 min according to the methods of Medbø et al. Mean values of VO2max during A, K and S were 2.53 +/- 0.37 L min-1, 2.93 +/- 0.37 L min-1, and 3.23 +/- 0.43 L min-1, respectively. Those in A and K corresponded to 78.2% and 91.0% of that in S. Mean values of anaerobic capacity during A, K and S were 2.15 +/- 0.31 L, 2.52 +/- 1.08 L and 2.99 +/- 0.52 L, respectively. Those in A and K corresponded to 73.3% and 81.7% of that in S. Both VO2max and anaerobic capacity in S were much lower than the sum of A and K, corresponding to only 59.3% and 65.9%, respectively. These results suggest that the total energy production during S is lower than simply the sum of A and K because the potentials of both the anaerobic and aerobic energy releasing processes in the muscle groups involved in A and K cannot be fully reached during S.