title: Creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players.
abstract: BACKGROUND
  Studies involving chronic creatine supplementation in elite soccer players are scarce. Therefore, the aim of this study was to examine the effects of creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players (n = 14 males) during pre-season training.
  
  
  RESULTS
  This was a randomized, double-blind, placebo-controlled parallel-group study. Brazilian professional elite soccer players participated in this study. During the pre-season (7 weeks), all the subjects underwent a standardized physical and specific soccer training. Prior to and after either creatine monohydrate or placebo supplementation, the lower-limb muscle power was measured by countermovement jump performance. The Jumping performance was compared between groups at baseline (p = 0.99). After the intervention, jumping performance was lower in the placebo group (percent change = - 0.7%; ES = - 0.3) than in the creatine group (percent change = + 2.4%; ES = + 0.1), but it did not reach statistical significance (p = 0.23 for time x group interaction). Fisher's exact test revealed that the proportion of subjects that experienced a reduction in jumping performance was significantly greater in the placebo group than in the creatine group (5 and 1, respectively; p = 0.05) after the training. The magnitude-based inferences demonstrated that placebo resulted in a possible negative effect (50%) in jumping performance, whereas creatine supplementation led to a very likely trivial effect (96%) in jumping performance in the creatine group.
  
  
  CONCLUSIONS
  Creatine monohydrate supplementation prevented the decrement in lower-limb muscle power in elite soccer players during a pre-season progressive training.
authors.affiliation: School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: João G
authors.initials: JG
authors.lastname: Claudino
authors.affiliation: School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: Bruno
authors.initials: B
authors.lastname: Mezêncio
authors.affiliation: Department of Health and Performance, Red Bull Brazil Football, João Lúcio do Prado street, Km 10, Jarinu, SP 13240-000, Brazil.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Amaral
authors.affiliation: Department of Health and Performance, Red Bull Brazil Football, João Lúcio do Prado street, Km 10, Jarinu, SP 13240-000, Brazil.
authors.forename: Vinícius
authors.initials: V
authors.lastname: Zanetti
authors.affiliation: School of Physical Education and Sport - Laboratory of Applied Nutrition and Metabolism, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Benatti
authors.affiliation: School of Physical Education and Sport - Laboratory of Applied Nutrition and Metabolism, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil ; School of Physical Education and Sport - Laboratory of Neuromuscular Adaptations to Strength Training, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil ; School of Medicine - Division of Rheumatology, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: Hamilton
authors.initials: H
authors.lastname: Roschel
authors.affiliation: School of Physical Education and Sport - Laboratory of Applied Nutrition and Metabolism, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil ; School of Medicine - Division of Rheumatology, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: Bruno
authors.initials: B
authors.lastname: Gualano
authors.affiliation: School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: Alberto C
authors.initials: AC
authors.lastname: Amadio
authors.affiliation: School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil.
authors.forename: Julio C
authors.initials: JC
authors.lastname: Serrão
keywords: Athletes; Dietary supplement; Football; Jumping; Team sports