Filters
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.
Effects of chronic betaine supplementation on exercise performance: Systematic review and meta-analysis
The Effect of Caffeine Supplementation on Resistance and Jumping Exercise: The Interaction with CYP1A2 and ADORA2A Genotypes
Purpose: To evaluate the association of CYP1A2 and ADORA2A gene polymorphisms, paraxanthine concentrations, and habitual caffeine (CAF) intake with respect to muscular performance after acute CAF supplementation. Methods: A total of 27 resistance-trained males participating in the study ingested either 5 mg/kg of CAF or PL 45 min before a battery of exercise tests in a cross-over design. DNA was tested for the rs5751876 and rs762551 polymorphisms. Results: CAF improved performance in jumping average power, average velocity, max velocity, bench press in the first set, and peak power in the second set. For the CYP1A2 genotype, C allele carriers improved in jumping average velocity (CAF: 1.77 ± 0.14 m/s, PL: 1.71 ± 0.16 m/s, p < 0.001), and AA homozygotes improved set 1 bench press (CAF: 9.7 ± 1.7 reps, PL: 8.9 ± 1.8 reps, p = 0.046). For the ADORA2A genotype, CC (CAF: 1.70 ± 0.20 m/s, PL: 1.67 ± 0.19 m/s, p = 0.005) and CT (CAF: 1.79 ± 0.09 m/s, PL: 1.74 ± 0.11 m/s, p < 0.001) improved in jumping average velocity and CT also improved in bench press set 2 peak power (CAF: 363 ± 76 W, PL: 323 ± 59 W, p = 0.021). For CAF habituation, CAF improved jumping average power (p = 0.007) and jumping average velocity (p < 0.001) in high users but not in low users (p > 0.05). Conclusions: CAF may improve jumping and bench press performance, irrespective of genotypes, but the associations with the genotypes in CYP1A2 and ADORA2A genes, as well as habitual CAF intake, are not clear and require further investigation.
Betaine and aging: A narrative review of findings, possible mechanisms, research perspectives, and practical recommendations
Wpływ suplementacji betainą na skład ciała i wydolność fizyczną mężczyzn trenujących sporty szybkościowo-siłowe
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
The impact of N‐acetylcysteine on lactate, biomarkers of oxidative stress, immune response, and muscle damage: A systematic review and meta‐analysis
AbstractN‐acetylcysteine (NAC) is a compound whose mechanism of action is intricately linked to the provision of cysteine for glutathione synthesis. It has been used in medicine and has also made significant inroads into sports, as it can modify the levels of several biomarkers, including those of oxidative processes, inflammation and muscle damage after exercise. Because the effectiveness of NAC supplementation is unclear, the primary objective of the present study was to perform a meta‐analysis elucidating how NAC supplementation alters the concentrations of GSH (glutathione), GSSG (glutathione disulfide), TBARS (thiobarbituric acid reactive substances), IL‐6 (interleukin 6), TNF‐α (tumour necrosis factor alpha), CK (creatine kinase), lactate, and muscle soreness after physical exertion. Suitable studies were searched for from February to September 2023, and the results of those included (n = 20) indicate that NAC supplementation significantly diminishes both muscle soreness (p = 0.03; the mean difference (MD) of NAC's effect was −0.43 with a 95% confidence interval (CI), −0.81, −0.04) and lactate concentrations after exercise (p = 0.03; the MD −0.56 mmol/L; 95% CI, −1.07, −0.06). A substantial decrease was observed in concentrations of IL‐6 (p = 0.03; the standardized MD (SMD) was −1.71; 95% CI, −3.26, −0.16) and TBARS (p = 0.02; SMD was −1.03, 95% CI, −1.90, −0.15). Furthermore, an elevation in GSH concentration was observed following supplementation. However, we saw no significant effect of NAC on TNF‐α, CK or GSSG concentrations. NAC supplementation holds promise for attenuating muscle soreness, lactate, TBARS and IL‐6 concentrations and increasing GSH level following physical exertion.