RESUMEN
BACKGROUND: To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d-1 during 14 d) on muscle power output in elite youth soccer players. METHODS: Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr (N = 9) or placebo (N = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work. RESULTS: There were significant increases in both PPO and MPO after the Cr supplementation period (P ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods (P ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after (P ≤ 0.05) but not before the 14 d supplementation period. CONCLUSION: There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.
Asunto(s)
Creatina/administración & dosificación , Suplementos Dietéticos , Músculo Esquelético/fisiología , Fútbol , Adolescente , Creatina/farmacología , Método Doble Ciego , Humanos , Masculino , Músculo Esquelético/efectos de los fármacos , Resistencia Física/efectos de los fármacos , Fenómenos Fisiológicos en la Nutrición Deportiva , Análisis y Desempeño de TareasRESUMEN
Aging is a degenerative process marked by recognized functional, physiological, and metabolic impairments, such as dynapenia and diminished cognitive capacity. Therefore, the search for innovative strategies to prevent/delay these physiological and cognitive disorders is essential to guarantee the independence and life quality of an elderly population. The aim of this work is to verify the effect of a 12-week resistance exercise program on the general physical aptitude and cognitive capacities of elderly and sedentary women. Twenty-nine women (65.87±5.69 years) were divided into two groups. The control group was composed of eight elderly women who met the same inclusion criteria of the study and the strength training group was composed of 29 elderly women who were subjected to a resistance exercise program defined by 12 upper and lower limb exercises combined in 3×10 repetitions with 1-minute interval between repetitions and two resting minutes between exercises (three times/week). Weight loads were fixed between 60% and 75% of the apparent 1 repetition maximum, which was estimated by the test of 10 maximum repetitions. The direct curl was performed for upper body strength evaluation with 2.3 kg dumbbells for 30 seconds, whereas the chair test was used for lower body evaluation (total sit-stand movements in 30 seconds). The cognitive capacities of subjects were evaluated by "The Montreal Cognitive Assessment" questionnaire. After 12 weeks, the elderly group showed significant increases in the average upper body strength (58%), lower body strength (68%), and cognitive capacity (19%). The present study demonstrated that regular resistance exercises could provide significant gains on the upper and lower body strength concomitant to positive improvements on cognitive capacities of elderly women, bringing enhanced life quality.