Short-term training decreased the time constant of oxygen uptake by ~14% (32.3 to 27.9 s, P < 0.05) after one session, with a further ~11% decrease after two sessions.
RCT (n=12)
Does short-term training improve oxygen uptake kinetics in young men?
Speeding of V˙O2 kinetics occurs remarkably quickly, after just one or two training sessions, with no further changes during continuous training or detraining.
Effect estimate: 14% decrease
Absolute Event Rate: 27.9% vs 32.3%
p-value: p=< 0.05
This study examined the time course of short-term training and detraining-induced changes in oxygen uptake ( V ˙ O 2 ) kinetics. Twelve men (24 ± 3 years) were assigned to either a 50% or a 70% of V ˙ O 2 m a x training intensity (n = 6 per group). V ˙ O 2 was measured breath-by-breath. Changes in deoxygenated-hemoglobin concentration (ΔHHb) were measured by near-infrared spectroscopy. Moderate-intensity exercise on-transient V ˙ O 2 and ΔHHb were modeled with a mono-exponential and normalized (0-100% of response) and the H H b / V ˙ O 2 ratio was calculated. Similar changes in time constant of V ˙ O 2 ( t V ˙ O 2 ) were observed in both groups. The combined group mean for t V ˙ O 2 decreased ∼14% (32.3 to 27.9 s, P < 0.05) after one training session with a further ∼11% decrease (27.9 to 24.8 s, P < 0.05) following two training sessions. The t V ˙ O 2 p remained unchanged throughout the remaining of training and detraining. A significant "overshoot" in the H H b / V ˙ O 2 ratio was decreased (albeit not significant) after one training session, and abolished (P < 0.05) after the second one, with no overshoot observed thereafter. Speeding of V ˙ O 2 kinetics was remarkably quick with no further changes being observed with continuous training or during detraining. Improve matching of local O2 delivery to O2 utilization is a mechanism proposed to influence this response.
Murias et al. (Wed,) reported a rct. Short-term training vs. Baseline was evaluated on Time constant of oxygen uptake (tVO2) (14% decrease, p=< 0.05). Short-term training decreased the time constant of oxygen uptake by ~14% (32.3 to 27.9 s, P < 0.05) after one session, with a further ~11% decrease after two sessions.