Peak physiological responses were compared in 12 male triathletes during maximal treadmill running (TR), cycle ergometry (CE) and tethered swimming (TS) tests. Expired air was measured continuously during TR, CE and during the last minute of each workload during TS. Heart rate (HR) was measured from electrocardiogram tracings during TR and CE, and from telemetry during TS. Blood lactate concentration (HLa) was measured four minutes after each maximal test with a YSI Model 23L analyzer. Significant differences (p < 0.05) were observed in all peak physiological responses except HLa. Mean HLa was 6.9, 7.8 and 8.0 mmol*l-1 after maximal running, cycling and swimming, respectively. Peak [latin capital V with dot above]O2 relative to body weight was significantly different among TR, CE and TS (67.0, 62.9 and 59.4 ml*kg-1*min-1, respectively). Mean [latin capital V with dot above]O2 peak during CE and TS was 94 percent and 89 percent, respectively, of the TR value. Peak HR during TS was significantly lower by approximately 15 and 22 bpm compared to CE and TR, respectively. Peak ventilation and respiratory exchange ratio were also significantly lower during TS compared to CE and TR. These data suggest that athletes who are well trained in several modes of exercise (swimming, cycling and running) exhibit mode-specific differences in peak physiological responses other than HLa. These differences should be considered when determining optimal training intensities based on either peak [latin capital V with dot above]O2 or HR.
(C) 1991 National Strength and Conditioning Association