Nitrate supplementation does not alter the V̇O2p SC-muscle fatigue relationship in recreationally active men

James Joseph George Vanhie, The University of Western Ontario

Abstract

The current study assessed alterations to the linear V̇O_2p slow component (V̇O_{2p SC})-muscle fatigue development relationship using dietary nitrate (NO_3^- ) supplementation during very heavy (VH)-intensity constant-work rate cycling exercise. Using a double- blind, block-randomised, crossover design, 8 healthy men (age, 24±2 yr [mean±SD]; V̇O_2p-max, 43.8±6.0 mL/kg/min) consumed NO_3^- -rich (BRJ) or -depleted (PLAC) beetroot juice daily for 20 d. Participants completed pre/post-condition incremental leg cycling V̇O_2p-max and 3-min “sprint” verification exercises. An initial 5 d loading phase was followed, on alternate days, by single trials of VH- or moderate-intensity exercise at select time points with a 14 d washout period separating conditions. Muscle fatigue was assessed pre/post- exercise by electrically stimulated quadriceps muscle torque production. NO₃- supplementation had no effect on the development of the V̇O_{2p SC} amplitude or muscle fatigue or the linear relationship between the two variables (slope = 6.85 (BRJ) vs. 8.34 (PLAC) (mL/min)/(10/50 Hz ratio; P = 0.628).