Effect of endurance training on oxygen uptake kinetics during treadmill running

The purpose of this study was to examine the effect of endurance training o n oxygen uptake ((V) over dot (2)) kinetics during moderate [below the lact ate threshold (LT)] and heavy (above LT) treadmill running. Twenty-three he althy physical education students undertook 6 wk of endurance training that involved continuous and interval running training 3-5 days per week for 20 -30 min per session. Before and after the training program, the subjects pe rformed an incremental treadmill test to exhaustion for determination of th e LT and the (V) over dot (O2max) and a series of 6-min square-wave transit ions from rest to running speeds calculated to require 80% of the LT and 50 % of the difference between LT and maximal (V) over dot (2). The training p rogram caused small (3-4%) but significant increases in LT and maximal (V) over dot (2) (P < 0.05). The (V) over dot (2) kinetics for moderate exercis e were not significantly affected by training. For heavy exercise, the time constant and amplitude of the fast component were not significantly affect ed by training, but the amplitude of the (V) over dot (2) slow component wa s significantly reduced from 321 +/- 32 to 217 +/- 23 ml/min (P < 0.05). Th e reduction in the slow component was not significantly correlated to the r eduction in blood lactate concentration (r = 0.39). Although the reduction in the slow component was significantly related to the reduction in minute ventilation (r = 0.46; P < 0.05), it was calculated that only 9-14% of the slow component could be attributed to the change in minute ventilation. We conclude that the (V) over dot (2) slow component during treadmill running can be attenuated with a short-term program of endurance running training.