RESUMEN

OBJECTIVES: The aim of this study was to analyze the effects of intermittent fasting (IF) on the performance of rats subjected to resistance training ladder climbs (RTLCs). METHODS: Thirty-two Wistar rats (80-d-old) were placed into one of the following four groups (n = 8/group): control (C), which were fed a standard diet with no exercise; intermittent fasting (IF) rats underwent IF for 16 h/d, fed a standard diet for a period of 8 h/d with no exercise; trained control (TC) were fed a standard diet and submitted to RTLC; and trained intermittent fasting (TIF) underwent IF for 16 h/d, fed a standard diet for a period of 8 h/d, and submitted to RTLC. Training groups completed 6-wk of RTLC (3 × /wk). The maximal load test (MLT) was applied on two occasions: before the first RTLC session and at the end of week 6 of physical training. Its purpose was to compare changes in performance over time. Both blood collection and total extraction of the organs were performed at the end of the experimental period. RESULTS: Food intake was higher in the TC group than in either the IF or TIF groups. TC supported a higher load (g) during the final MLT compared with the C, IF, and TIF groups, respectively. TC (initial MLT: 371.4 ± 31.1; final MLT: 593.9 ± 33.5) and TIF (initial MLT: 402.3 ± 31.8; final MLT: 495.4 ± 83.3) presented higher values when the pre- and post-RTLC moments were compared. The relative weight of the stomach was higher in TIF than in C and TC rats. There was no difference in aspartate transaminase and alanine transaminase enzyme activities or in creatinine and total cholesterol levels. CONCLUSIONS: IF negatively affected RTLC performance. IF plus RTLC increased the relative weight of the stomach as well as reduced food intake, without an increase in body weight, suggesting this combination may have promoted dilation of this organ, due, hypothetically, to the scarcity of food for several hours and the energy expenditure generated by physical training.

Asunto(s)

Condicionamiento Físico Animal , Entrenamiento de Fuerza , Animales , Peso Corporal , Ayuno , Humanos , Ratas , Ratas Wistar

RESUMEN

The study tested the hypothesis that a high protein diet based on isolated whey protein (IWP) associated with strength training improves performance and reduces body fat without promoting health damage. Male Wistar rats, 45 days old, were divided into four groups (n = 8/group): normoprotein sedentary (IWP 14%; NS); hyperprotein sedentary (IWP 35%; HS); normoprotein trained (IWP 14%; NT) and hyperprotein trained (IWP 35%; HT). All groups performed the maximum load test at the beginning and after the vertical ladder training protocol for 6 weeks (3x/week). The performance improved in HT when compared to other groups. There was no difference in the plasma levels of testosterone, IGF-1 and the hematological parameters remained normal. The relative weights of the kidneys were higher in the groups fed with high protein; the liver was higher in HT compared to NS and NT, and the heart was higher in HS compared to NS and NT. Concerning relative muscle weight, quadriceps, and gastrocnemius, HT showed higher value compared to NT. Diet containing 35% isolate whey protein associated with resistance training improved performance as well as increased muscles and organs weight of the animals, without damaging the tissues related to protein metabolism (confirmed by unchanged hematological parameters), which may minimize the risk of developing cardiometabolic disorders.