Respiratory metabolic parameters*.

*Routine oxygen consumption rate (MO2, routine, mean ± S.E.) is the oxygen consumption rate (MO2) at 0.3∼0.5 BL/s; maximum oxygen consumption rate (MO2, max, mean ± S.E.) is the maximum value of MO2 during the stepped velocity test; the aerobic scope (AS) is the difference between MO2, max and MO2, routine; active oxygen consumption (AOC) is the difference between aerobic oxygen consumption and routine oxygen consumption during swimming period; excess post-exercise oxygen consumption (EPOC) is the difference between aerobic oxygen consumption and routine oxygen consumption during recovery from exhaustion. Differences in MO2, routine and MO2, max not significant among successive tests: MO2, routine, F = 0.392, P = 0.759; MO2, max, F = 1.050, P = 0.390.