title: Creatine supplementation spares muscle glycogen during high intensity intermittent exercise in rats.
abstract: BACKGROUND
  The effects of creatine (CR) supplementation on glycogen content are still debatable. Thus, due to the current lack of clarity, we investigated the effects of CR supplementation on muscle glycogen content after high intensity intermittent exercise in rats.
  
  
  METHODS
  First, the animals were submitted to a high intensity intermittent maximal swimming exercise protocol to ensure that CR-supplementation was able to delay fatigue (experiment 1). Then, the CR-mediated glycogen sparing effect was examined using a high intensity intermittent sub-maximal exercise test (fixed number of bouts; six bouts of 30-second duration interspersed by two-minute rest interval) (experiment 2). For both experiments, male Wistar rats were given either CR supplementation or placebo (Pl) for 5 days.
  
  
  RESULTS
  As expected, CR-supplemented animals were able to exercise for a significant higher number of bouts than Pl. Experiment 2 revealed a higher gastrocnemius glycogen content for the CR vs. the Pl group (33.59%). Additionally, CR animals presented lower blood lactate concentrations throughout the intermittent exercise bouts compared to Pl. No difference was found between groups in soleus glycogen content.
  
  
  CONCLUSIONS
  The major finding of this study is that CR supplementation was able to spare muscle glycogen during a high intensity intermittent exercise in rats.
authors.affiliation: School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil. lanchajr@usp.br.
authors.forename: Hamilton
authors.initials: H
authors.lastname: Roschel
authors.forename: Bruno
authors.initials: B
authors.lastname: Gualano
authors.forename: Marcelo
authors.initials: M
authors.lastname: Marquezi
authors.forename: André
authors.initials: A
authors.lastname: Costa
authors.forename: Antonio H
authors.initials: AH
authors.lastname: Lancha