Suplementação de creatina e treinamento de força: alterações na resultante de força máxima dinâmica e variáveis antropométricas em universitários submetidos a oito semanas de treinamento de força (hipertrofia)

Abstract

Objective: To verify the alterations promoted by creatine supplementation in the anthropometric variables and the resultant of dynamic maximum strength (RDMS) in college students submitted to 8 wk of strength training. Methodology: The sample consisted of 18 male college students, aged between 19 to 25 years. Height (cm), body mass (kg) and tests of maximum voluntary muscular action (1MVMA) weight in the squat were determined prior to the training. The subjects were divided in two groups: A (creatine) or B (placebo). The double-blind protocol was adopted. After 8 weeks of strength training, the tests battery from the pre-training was repeated. Results: After 8 wk of training, it was verified that both groups had statistically significant (SS) alterations in the RDMS in all the exercises (p = 0.007 / 0.008). The analysis of the percentile improvement (PI) and the RDMS delta in the squat exercises, military press and close-grip-extensions, showed that group A had positive SS alterations higher than group B (p = 0.008 / 0.038). Lean body mass only SS increased in group A (p = 0.038). However, the percentage of body fat did not show alterations in none of the groups. The relationship between the PI of the arm and forearm circumferences (C) and the PI in the RDMS of the development exercise was SS (r = 0.481 and 0.546, respectively), as well as between the PI in the thigh C and the PI of the RDMS of the squat exercise (r = 0.619). Conclusion: Regardless the substance ingested, strength training was able to increase in RDMS; however, creatine supplementation was shown to be more efficient that the placebo, showing higher percentual and delta improvement in strength.

Capacidade de impulsão e agilidade em praticantes de basquetebol regulares e não regulares suplementados com creatina

“…Segundo Gualano et al 12 , a influência do ganho da massa corporal pode explicar a divergência de resultados obtidos em situações laboratoriais, o que não foi observado neste estudo. Foram avaliados jovens adultos pré e pós-treinamento resistido com pesos, com suplementação de creatina, sen- do observado aumento da massa corporal total e isenta de gordura, e pouca alteração no percentual de gordura 13 . Nesta pesquisa, nas mesmas variáveis, foi possível verificar uma tendência a igual comportamento; no entanto, essas alterações não foram suficientes para demonstrar significância.…”

“…A agilidade pouco modificou nos grupos, não sendo identificada uma possível explicação para tal fato, uma vez que os elementos antropométricos pouco alteraram o que poderia influenciar na mecânica de deslocamento. Em um estudo realizado sobre suplementação de creatina em sprints de jogadores de basquetebol 13 , reportou-se o aumento do desempenho em sprints consecutivos de alta intensidade, com a suplementação de creatina. Em outro trabalho, investigou-se o efeito da ingestão de creatina monohidratada (20 g/dia/5dias) 19 , sobre o desempenho em 45 s de salto contínuo e um tiro máximo de corrida em esteira a 20 km/h -1 , (inclinação de 5 graus e duração de 60 segundos).…”

Designs of studies published in two Brazilian journals of orthopedics and sports medicine, recently indexed in the ISI Web of Science

“…Approximately 10% of the original articles published in both journals were clinical trials, whereas no systematic reviews were published. [3][4][5][6][7][8][9][10] It should be noted that only two articles in each journal presented sample calculations. In other words, among the studies published in 2007 (and after application of the exclusion criteria), sample size calculations were only found in 6.6% of the articles in AOB and 3.8% of the articles in RBME.…”

“…[3][4][5][6][7][8]10 In one of them, the randomization process was performed by taking the last general hospital registration number on each patient's medical files: those for whom the last digit was an even number were included in group A and those with an odd number were put in group B (quasi-randomization). 9 According to Jadad, the presence of adequate randomization is among the main requirements for a clinical trial of good methodological quality.…”

Creatine supplementation in exercised rats: Effects on the aerobic capacity

“…In recent years, creatine supplementation presented itself as important in physical performance within the global sporting outlook, and also practitioners of endurance exercise as well as aerobic nature [4][5][6].…”