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Kinetyka zmian potencjału buforującego i stężenia diagnostycznie istotnych wskaźników biochemicznych we krwi w aspekcie poziomu adaptacji wysiłkowej sportowców suplementowanych wodorowęglanem sod
The effect of caffeine dose on caffeine and paraxanthine changes in serum and saliva and CYP1A2 enzyme activity in athletes: a randomized placebo-controlled crossover trial
The dose-dependent effect of caffeine supplementation on performance, reaction time and postural stability in CrossFit – a randomized placebo-controlled crossover trial
The effect of preexercise meal composition on substrate oxidation during incremental cycling to exhaustion in recreationally active adults: randomized parallel pilot trial
Purpose The purpose of this study is to evaluate the effect of three different preexercise meals: high-carbohydrate, low-glycemic index (LGI), high-carbohydrate, high-GI (HGI) and low-carbohydrate high fat (LCHO) on substrate oxidation during an incremental cycling test (ICT) in recreationally active adults. Design/methodology/approach This was a parallel, randomized study in which participants ingested one of three meals (LGI, HGI or LCHO) 3 h prior to exercise testing. Testing included ICT to exhaustion with continuous ergospirometry measurement. Findings Fat oxidation rate was significantly higher in LCHO compared to HGI (p = 0.039). Carbohydrate contribution to energy production was significantly lower and fat contribution higher in LCHO compared to HGI (p = 0.034). Fat-to-carbohydrates crossover point was achieved at significantly higher heart rate in LCHO group compared to LGI and HGI (p = 0.046 and p = 0.049, respectively). Peak fat oxidation occurred significantly later during exercises in LCHO group compared to HGI (p = 0.025). In conclusion, LCHO meal results in a higher fat oxidation, reduced carbohydrates contribution-to-energy production, delayed peak fat oxidation point and altered fat-to-carbohydrates crossover dynamics. There are no differences in substrate oxidation between high-carbohydrate preexercise meals that differ only in GI. Originality/value To the best of the authors’ knowledge, this is the first study to compare the acute effect of both the amount of carbohydrates and the GI in a preexercise meal on substrate utilization during ICT.
Ocena wpływu bodźców wysiłkowych/stresowych na mechanizmy i skuteczność działania kwasu beta-hydroksy-beta-metylomasłowego (HMB) u osób wytrenowanych i niedożywionych
Betaine supplementation modulates betaine concentration by methylenetetrahydrofolate reductase genotype, but has no effect on amino acid profile in healthy active males: A randomized placebo-controlled cross-over study
Does Colostrum Bovinum Supplementation Affect Swimming Performance in Endurance-Trained Males? A Randomized Placebo-Controlled Crossover Study
Background/Objectives: Colostrum Bovinum (COL) is recognized for its unique composition and potential ergogenic and immunological benefits. Unlike mature milk, COL is rich in immunoglobulins, lactoferrin, and various growth factors, making it one of the most potent natural immune stimulants. The purpose of this study was to evaluate the effects of 12-weeks of COL supplementation on swimming-specific performance (SSP) and exercise adaptations in endurance-trained male athletes. Methods: Twenty-eight male triathletes and swimmers (age: 31.1 ± 10.2 years; body mass: 81.9 ± 9.0 kg; height: 1.82 ± 0.06 m) participated in a randomized, double-blind, placebo (PLA)-controlled crossover study and received 25 g∙day−1 of COL or PLA for 12 weeks. The study assessed the effects of COL on SSP (8 × 100 m performed at various intensities) and exercise adaptations [heart rate (HR) and blood lactate concentrations ([La−])]. Four main study visits were conducted—before and after COL (COLPRE and COLPOST) and PLA (PLAPRE and PLAPOST) supplementation. Results: COL had no significant effect on SSP. Still, the total time of the SSP test was about ~3.04 s shorter after COL supplementation, and ~7.13 s longer after PLA supplementation. Neither COL nor PLA supplementation affected HR during the SSP test. Post-exercise blood [La−] was significantly reduced after both COL and PLA supplementation. The analysis of SSP results in the consecutive study visits revealed possible existence of the practice effect. Conclusions: Colostrum Bovinum and high-quality milk protein (PLA) seem to be comparably effective in evoking exercise adaptation in endurance-trained male athletes. Long-term crossover supplementation protocols in athletes must consider the impact of possible practice effect when interpreting the outcomes related to exercise performance, but not biochemical or physiological markers of exercise adaptation.