title: Time-divided ingestion pattern of casein-based protein supplement stimulates an increase in fat-free body mass during resistance training in young untrained men.
abstract: We hypothesized that during prolonged resistance training, time-divided ingestion pattern of casein-based protein supplement is of superior efficiency in comparison with the ingestion of the same supplement immediately before each training session. In a crossover study, 13 men aged 18 to 19 years were evaluated during 2 well-controlled, 8-week training and supplementation periods. In the time-focused supplementation regimen (TFR), the subjects consumed the supplement in the morning and in the afternoon, immediately before the training session. Time-divided supplementation regimen (TDR) included 1 morning dose, whereas the second dose was ingested in the evening, 5 hours after training. The daily dose of the supplement contained approximately 70 g of protein (82% casein) and less than 1 g of carbohydrate and fat. Body mass, body composition (dual-energy x-ray absorptiometry scanned), and one-repetition maximum (1RM) for bench press and squat were determined at the beginning and at the end of both 8-week training and supplementation periods. Training produced a significant increase in 1RM strength both in the bench press (9.4% and 7.2%) and the squat exercise (10.7% and 17.8%) in the TFR and TDR, respectively, with no differences between the supplementation regimens. Fat-free mass increased from 62.4 +/- 1.2 to 63.5 +/- 1.3 kg (P = .046) with TDR, whereas no change was evident with TFR. The increase in 1RM strength in the squat exercise was related to the increase in fat-free mass in TDR (r = 0.569; P = .041). These findings may have practical implications for the timing of ingestion of protein supplements to enhance the efficacy of resistance training.
authors.affiliation: Institute of Exercise Biology and Physiotherapy, Center of Behavioral and Health Sciences, University of Tartu, 50090 Tartu, Estonia.
authors.forename: Andres
authors.initials: A
authors.lastname: Burk
authors.forename: Saima
authors.initials: S
authors.lastname: Timpmann
authors.forename: Luule
authors.initials: L
authors.lastname: Medijainen
authors.forename: Mare
authors.initials: M
authors.lastname: Vähi
authors.forename: Vahur
authors.initials: V
authors.lastname: Oöpik
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000704:Analysis of Variance; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D002364:Caseins / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004044:Dietary Proteins / Q000378:metabolism; D019587:Dietary Supplements; D004435:Eating / Q000502:physiology*; D005247:Feeding Behavior; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness; D055070:Resistance Training; D018709:Statistics, Nonparametric; D013334:Students; D013851:Thinness; D013997:Time Factors; D055815:Young Adult
chemical_list: D002364:Caseins; D004044:Dietary Proteins