title: Effects of creatine supplementation associated with resistance training on oxidative stress in different tissues of rats.
abstract: BACKGROUND
  Creatine supplementation is known to exert an effect by increasing strength in high intensity and short duration exercises. There is a hypothesis which suggests that creatine supplementation may provide antioxidant activity by scavenging Reactive Oxygen Species. However, the antioxidant effect of creatine supplementation associated with resistance training has not yet been described in the literature. Therefore, we investigated the effect of creatine monohydrate supplementation associated with resistance training over maximum strength gain and oxidative stress in rats.
  
  
  METHODS
  Forty male Wistar rats (250-300 g, 90 days old) were randomly allocated into 4 groups: Sedentary (SED, n = 10), Sedentary + Creatine (SED-Cr, n = 10), Resistance Training (RT, n = 10) and Resistance Training + Creatine (RT-Cr, n = 10). Trained animals were submitted to the RT protocol (4 series of 10-12 repetitions, 90 second interval, 4 times per week, 65% to 75% of 1MR, for 8 weeks).
  
  
  RESULTS
  In this study, greater strength gain was observed in the SED-Cr, RT and RT-Cr groups compared to the SED group (P < 0.001). The RT-Cr group showed a higher maximum strength gain when compared to other groups (P < 0.001). Creatine supplementation associated with resistance training was able to reduce lipoperoxidation in the plasma (P < 0.05), the heart (P < 0.05), the liver (P < 0.05) and the gastrocnemius (P < 0.05) when compared to control groups. However, the supplementation had no influence on catalase activity (CAT) in the analyzed organs. Only in the heart was the CAT activity higher in the RT-Cr group (P < 0.05). The activity of superoxide dismutase (SOD) was lower in all of the analyzed organs in the SED-Cr group (P < 0.05), while SOD activity was lower in the trained group and sedentary supplemented group (P < 0.05).
  
  
  CONCLUSIONS
  Creatine was shown to be an effective non-enzymatic antioxidant with supplementation alone and also when it was associated with resistance training in rats.
authors.forename: Giuseppe Potrick
authors.initials: GP
authors.lastname: Stefani
authors.affiliation: Laboratório de Fisiologia - UFCSPA/Porto Alegre, Rua Sarmento Leite, 245, 900050-170 Porto Alegre, RS, Brazil. ramiro.barcos@gmail.com.
authors.forename: Ramiro Barcos
authors.initials: RB
authors.lastname: Nunes
authors.forename: André Zuanazzi
authors.initials: AZ
authors.lastname: Dornelles
authors.forename: Jadson Pereira
authors.initials: JP
authors.lastname: Alves
authors.forename: Marcella Ody
authors.initials: MO
authors.lastname: Piva
authors.forename: Marlise Di
authors.initials: MD
authors.lastname: Domenico
authors.forename: Cláudia Ramos
authors.initials: CR
authors.lastname: Rhoden
authors.forename: Pedro Dal
authors.initials: PD
authors.lastname: Lago