Effect of a prior intermittent run at vV̇O(2max) on oxygen kinetics during an all-out severe run in humans

Background. The purpose of this study was to examine the influence of prior intermittent running at V̇O(2max) on oxygen kinetics during a continuous severe intensity run and the time spent at V̇O(2max). Methods. Eight long-distance runners performed three maximal tests on a synthetic track (400 m) whilst breathing through the COSMED K4 portable telemetric metabolic analyser: i) an incremental test which determined velocity at the lactate threshold (vLT), V̇O(2max) and velocity associated with V̇O(2max) (vV̇O(2max)), ii) a continuous severe intensity run at vLT+50% (vΔ50) of the difference between vLT and vV̇O(2max) (91.3±1.6% vV̇O(2max)) preceded by a light continuous 20 minute run at 50% of vV̇O(2max) (light warm-up), iii) the same continuous severe intensity run at vΔ50 with a prior interval training exercise (hard warm-up) of repeated hard running bouts performed at 100% of vV̇O(2max) and light running at 50% of vV̇O(2max) (of 30 seconds each) performed until exhaustion (on average 19±5 min with 19±5 interval repetitions). This hard warm-up speeded the V̇O₂ kinetics: the time constant was reduced by 45% (28±7 see vs 51±37 sec) and the slow component of V̇O₂ (ΔV̇O₂ 6-3 min) was deleted (-143±271 ml·mi.kgn^-1 vs 291±153 ml·min-¹). In conclusion, despite a significantly lower total run time at vΔ50 (6 min 19±0 min 17 vs 8 min 20±1 min 45, p=0.02) after the intermittent warm-up at V̇O(2max), the time spent specifically at V̇O(2max) in the severe continuous run at vΔ50 was not significantly different.