Influence of prior exercise on VO2 kinetics subsequent exhaustive rowing performance

Abstract

Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercise time during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderate exercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longer exercise time at VO2max. Six subjects (mean ± SD; age: 22.9±4.5 yr; height: 181.2±7.1 cm and body mass: 75.5±3.4 kg) completed square-wave transitions to 100% of VO2max from three different conditions: without prior exercise, with prior moderate and heavy exercise. VO2 was measured using a telemetric portable gas analyser (K4b(2), Cosmed, Rome, Italy) and the data were modelled using either mono or double exponential fittings. The use of prior moderate exercise resulted in a faster VO2 pulmonary kinetics response (τ1 = 13.41±3.96 s), an improved performance in the time to exhaustion (238.8±50.2 s) and similar blood lactate concentrations ([La(-)]) values (11.8±1.7 mmol.L(-1)) compared to the condition without prior exercise (16.0±5.56 s, 215.3±60.1 s and 10.7±1.2 mmol.L(-1), for τ1, time sustained at VO2max and [La(-)], respectively). Performance of prior heavy exercise, although useful in accelerating the VO2 pulmonary kinetics response during a subsequent time to exhaustion exercise (τ1 = 9.18±1.60 s), resulted in a shorter time sustained at VO2max (155.5±46.0 s), while [La(-)] was similar (13.5±1.7 mmol.L(-1)) compared to the other two conditions. Although both prior moderate and heavy exercise resulted in a faster pulmonary VO2 kinetics response, only prior moderate exercise lead to improved rowing performance.

Figure 1. Schematic illustration of the experimental protocol.

Without prior (2-min of rowing at 20% of maximal power, 7-min of passive recovery and a transition to 100% of maximal power), prior moderate (2-min of rowing at 20% of maximal power, 6-min of rowing at the moderate intensity, 7-min of passive recovery and a transition to 100% of maximal power), prior heavy (2-min of rowing at 20% of maximal power, 6-min of rowing at the heavy intensity, 7-min of passive recovery and a transition to 100% of maximal power).

Figure 2. VO₂ dynamic response of one subject performing time to exhaustion exercise bouts.

After no prior exercise (closed circles) and after prior moderate exercise (open circles) (upper panel); after no prior exercise (closed circles) and after prior heavy exercise (open circles) (middle panel); after prior moderate exercise (closed circles) and after prior heavy exercise (open circles) (lower panel). The insets in the respective VO₂ graphs represent the individual (full black and full white) and mean (full grey) values in the time sustained at the correspondent exercise bout released. ^*significant differences between the two studied conditions (p<0.05).

Figure 3. HR dynamic response of one subject performing time to exhaustion exercise bouts.

After no prior exercise (closed circles), after prior moderate exercise (open circles) and after prior heavy exercise (open squares) (upper left panel); relationships between peak heart rate and time sustained (filled circles) and between peak heart rate and amplitude of the fast component (unfilled circles) when no prior exercise was performed (upper right panel), between peak heart rate and time sustained when prior moderate exercise was performed (lower left panel) and between peak heart rate and mean response time (filled circles) and between peak heart rate and time sustained (unfilled circles) when prior heavy exercise was performed (lower right panel). The regression equations, determination coefficients and significance level values are identified.