RESUMO
The purpose of this study was to investigate the effects of ß-alanine supplementation on a 10 km running time trial and lactate concentration in physically active adults. Sixteen healthy subjects were divided randomly into two groups: ß-alanine (n = 8) and placebo group (n = 8). The experimental group ingested 5 g/day of ß-alanine plus 1 g of resistant starch, and control group ingested 6 g of resistant starch, both for 23 days. Time to complete a 10-km running time trial and lactate concentration following the test were assessed at baseline and post 23 days. The running training program was performed three times per week on non-consecutive days (day 1: running 7 km; day 2: six sprints of 500 m at maximum speed with 2 min of recovery; day 3: running 12 km). The time to complete a 10-km running time trial decreased significantly only for the ß-alanine group (Pre = 3441 ± 326.7, Post = 3209 ± 270.5 s, p < 0.05). When analyzing the delta (Time post minus Time at baseline value) there was a statistically significant difference between the ß-alanine vs placebo group (-168.8 ± 156.6 vs. -53.60 ± 78.81 s, p = 0.007), respectively. In addition, the ß-alanine group presented lower blood lactate concentration after the 10-km test (ß-alanine: Pre = 8.45 ± 1.94 vs. Post = 6.95 ± 2.44 mmol/L; Placebo: Pre = 8.7 ± 3.0 vs. Post = 10.8 ± 2.5 mmol/L, p = 0.03). In conclusion, ß-alanine supplementation improved the 10-km running time trial and reduced lactate concentration in physically active adults.
RESUMO
BACKGROUND: Little information is available on the effects of resistance training on the aortic wall. OBJECTIVE: This study aimed to quantify the effects of a resistance-training program on blood pressure and aortic wall structural components. METHODS: Rats (aged three months) were randomized into sedentary group (control group, CG; n=10) or trained group (TG; n=10). The TG rats performed resistance training by climbing a 1.1-m vertical ladder (80° incline) five times a week for 12 weeks, and the CG remained sedentary. The rats were sacrificed and 5mm of the ascending aorta was submitted to histological sections, which were stained with hematoxylin-eosin, Picrosirius red, and Verhoeff's elastin, and used for morphometric studies. Left ventricle (LV) hypertrophy was determined by measuring LV wall thickness and LV internal diameter. RESULTS: The rats had similar repetition maximum before the resistance training. At the end of the resistance training period, the repetition maximum of the TG was 3.04-fold greater than the body weight. In the twelfth month, the left ventricular weight was 15.3% larger in the TG than in the CG, and the left ventricular internal diameter was reduced by 10% in the TG. Rats exposed to resistance training had a significant increase in aortic wall thickness, in both elastic lamina and collagen fibers, and in the thickness of collagen fibrils. CONCLUSION: Resistance training induces the development of concentric cardiac hypertrophy and improves the aortic wall components by producing a morphological expression pattern distinct from aortic pathological adaptation.