Effects of -alanine and sodium bicarbonate supplementation on the estimated energy system contribution during high-intensity intermittent exercise

摘要

The effects of -alanine (BA) and sodium bicarbonate (SB) on energy metabolism during work-matched high-intensity exercise and cycling time-trial performance were examined in 71 male cyclists. They were randomised to receive BA+placebo (BA, n=18), placebo+SB (SB, n=17), BA+SB (BASB, n=19), or placebo+placebo (PLA, n=18). BA was supplemented for 28days (6.4gday(-1)) and SB (0.3gkg(-1)) ingested 60min before exercise on the post-supplementation trial. Dextrose and calcium carbonate were placebos for BA and SB, respectively. Before (PRE) and after (POST) supplementation, participants performed a high-intensity intermittent cycling test (HICT-110%) consisting of four 60-s bouts at 110% of their maximal power output (60-s rest between bouts). The estimated contribution of the energy systems was calculated for each bout in 39 of the participants (BA: n=9; SB: n=10; BASB: n=10, PLA: n=10). Ten minutes after HICT-110%, cycling performance was determined in a 30-kJ time-trial test in all participants. Both groups receiving SB increased estimated glycolytic contribution in the overall HICT-110%, which approached significance (SB: +23%, p=0.068 vs. PRE; BASB: +18%, p=0.059 vs. PRE). No effects of supplementation were observed for the estimated oxidative and ATP-PCr systems. Time to complete 30 kJ was not significantly changed by any of the treatments, although a trend toward significance was shown in the BASB group (p=0.06). We conclude that SB, but not BA, increases the estimated glycolytic contribution to high-intensity intermittent exercise when total work done is controlled and that BA and SB, either alone or in combination, do not improve short-duration cycling time-trial performance.