The effects of priming exercise on the V̇O2 slow component and the time-course of muscle fatigue during very-heavy-intensity exercise in humans

• Published in: Applied physiology, nutrition, and metabolism nutrition, and metabolism, 2018, Vol.43 (9), p.909-919
• Main Authors: do Nascimento Salvador, Paulo Cesar, Souza, Kristopher Mendes de, De Lucas, Ricardo Dantas, Guglielmo, Luiz Guilherme Antonacci, Denadai, Benedito Sérgio
• Format: Article
• Language: English
• Subjects: cinétique du V̇O; composante lente de la consommation d’oxygène; exercice d’amorce; exercice d’intensité élevée; Exercise; high-intensity exercise; kinetics; Muscle fatigue; muscle force production; priming exercise; production de force musculaire; slow component of oxygen uptake; V̇O
• ISSN: 1715-5312; 1715-5320
• DOI: 10.1139/apnm-2017-0769

We hypothesized that prior exercise would attenuate the muscle fatigue accompanied by oxygen uptake slow-component (V̇O 2SC ) behavior during a subsequent very-heavy (VH)-intensity cycling exercise. Thirteen healthy male subjects performed tests to determine the critical power (CP) and the fixed amount of work above CP ( ) and performed 6 square-wave bouts until 3 or 8 min, each at a work rate set to deplete 70% in 8 min, with a maximal isokinetic effort before and after the conditions without (VH CON ) and with prior exercise (VH EXP ), to measure the cycling peak torque decrement. The V̇O 2SC magnitude at 3 min (VH CON = 0.280 ± 0.234, VH EXP = 0.116 ± 0.109 L·min −1 ; p = 0.04) and the V̇O 2SC trajectory were significantly lower for VH EXP (VH CON = 0.108 ± 0.042, VH EXP = 0.063 ± 0.031 L·min −2 ; p < 0.01), leading to a V̇O 2SC magnitude at the eighth minute that was significantly lower than VH CON (VH CON = 0.626 ± 0.296 L·min −1 , VH EXP = 0.337 ± 0.179; p < 0.01). Conversely, peak torque progressively decreased from pre-exercise to 3 min (Δtorque = 21.5 ± 7.7 vs. 19.6 ± 9.2 Nm) and to 8 min (Δtorque = 29.4 ± 15.8 vs. 27.5 ± 12.0 Nm) at VH CON and VH EXP , respectively, without significant differences between conditions. Regardless of the condition, there was a significant relationship between Δtorque and the V̇O 2SC (R 2 : VH CON = 0.23, VH EXP = 0.25; p = 0.01). Considering that “priming” effects on the V̇O 2SC were not accompanied by the muscle force behavior, these findings do not support the hypothesis of a “causal” relationship between the time-course of muscle fatigue and V̇O 2SC .