Physiological comparisons among three maximal treadmill exercise protocolsin trained and untrained individuals

The present investigation was undertaken to examine whether maximal oxygen uptake ((V)over dot O-2max) and anaerobic threshold (AT) measured during in cremental treadmill exercise would be affected by the exercise protocol in trained and untrained individuals. Fifteen untrained men, 10 untrained wome n, and 12 trained individuals participated in this study. The Astrand, Bruc e, and Costill/Fox protocols were selected for comparison. Each subject was tested using all three protocols and the three tests were conducted in a r andomized counterbalanced order. During each test, oxygen uptake was measur ed every 30 s and the test was terminated according to the standard criteri a. The (V)over dot O-2max was determined by averaging the two consecutive h ighest measurements, whereas AT was determined using ventilatory parameters following the V-slope technique. The Astrand, Bruce, and Costill/Fox proto cols produced test durations of 9.8 (SEM 0.5), 12.4 (SEM 0.4), and 4.9 (SEM 0.3) min, respectively, in the untrained men, 9.0 (SEM 0.8), 11.0 (SEM 0.6 ), and 5.3 (SEM 0.6) min, respectively, in the untrained women, and 14.5 (S EM 0.5), 17.0 (SEM 0.5) and 10.4 (SEM 0.4) min, respectively, in the traine d men. In the untrained men and women, no differences in (V)over dot O-2max were observed among the three different protocols, but AT was lower when u sing the Bruce compared to the Astrand protocol. In the trained men, (V)ove r dot O-2max and AT were lower when using the Bruce protocol than either th e Astrand or Costill/Fox protocols. In conclusion, (V)over dot O-2max measu red during treadmill exercise is not affected by the protocol of the test a nd using a running protocol of short duration (i.e, about 5 min) could be a time-efficient way of assessing (V)over dot O-2max in healthy untrained su bjects. In trained subjects, however, a protocol consisting of running with small increments in gradient is effective in eliciting a higher (V)over do t O-2max. The lower AT associated with the Bruce protocol seen in both untr ained and trained groups suggests this aerobic parameter is protocol depend ent and this dependency is not affected by training status.