The effect of pedal rate on pulmonary O2 uptake kinetics during very heavy intensity exercise in trained and untrained teenage boys

Abstract

This study tested the hypothesis that the V̇O2 kinetic response would be slowed in untrained (UT) but not trained (T) teenage participants whilst cycling at 115revmin-1 compared to 50revmin-1. Eight UT and seven T boys completed two square-wave transitions to very heavy-intensity exercise pedalling at 50revmin-1 and 115revmin-1. In UT at the higher pedal rate, the phase II V̇O2 τ was significantly (P<0.01) slower (50revmin-1: 32±5 vs. 115revmin-1: 42±11s) and the relative V̇O2 slow component was significantly (P<0.01) elevated (50revmin-1: 10±3 vs. 115revmin-1: 16±5%). The phase II V̇O2 τ (50revmin-1: 26±4 vs. 115revmin-1: 22±6s) and relative V̇O2 slow component (50revmin-1: 14±5 vs. 115revmin-1: 17±3%) were unaltered by pedal rate in T (P>0.05). These data are consistent with the notion that V̇O2 kinetics are influenced by muscle fibre recruitment in youth but this effect is attenuated in endurance trained teenage boys. © 2011 Elsevier B.V.