title: Muscle performance, size, and safety responses after eight weeks of resistance training and protein supplementation: a randomized, double-blinded, placebo-controlled clinical trial.
abstract: The purpose of this study was to examine the effects of 2 different types of protein supplementation on thigh muscle cross-sectional area (CSA), blood markers, muscular strength, endurance, and body composition after 8 weeks of low- or moderate-volume resistance training in healthy, recreationally trained, college-aged men. One hundred and six men were randomized into 5 groups: low-volume resistance training with bioenhanced whey protein (BWPLV; n = 22), moderate-volume resistance training with BWP (BWPMV; n = 20), moderate-volume resistance training with standard whey protein (SWPMV; n = 22), moderate-volume resistance training with a placebo (PLA; n = 21), or moderate-volume resistance training with no supplementation (CON; n = 21). Except for CON, all groups consumed 1 shake before and after each exercise session and one each on the nontraining day. The BWPLV, BWPMV, and SWPMV groups received approximately 20 g of whey protein per shake, whereas the BWP groups received 5 g of additional polyethylene glycosylated (PEG) leucine. Resistance training sessions were performed 3 times per week for 8 weeks. There were no interactions (p > 0.05) for muscle strength and endurance variables, body composition, muscle CSA, and safety blood markers, but the main effects for training were observed (p ≤ 0.05). However, the Albumin:Globulin ratio for SWPMV was lower (p = 0.037) than BWPLV and BWPMV. Relative protein intake (PROREL) indicated a significant interaction (p < 0.001) with no differences across groups at pre; however, BWPLV, BWPMV, and SWPMV had a greater intake than did PLA or CON at post (p < 0.001). This study indicated that 8 weeks of resistance training improved muscle performance and size similarly among groups regardless of supplementation.
authors: 1Department of Ophthalmology, KU Eye, University of Kansas Medical Center, Prairie Village, Kansas; 2Department of Health, Sport, and Exercise Sciences, Biomechanics Laboratory, University of Kansas, Lawrence, Kansas; 3Department of Kinesiology, Human Performance Laboratory, California State University-San Bernardino, San Bernardino, California; 4Department of Exercise and Sport Science, Neuromuscular Research Laboratory, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina; 5Department of Sport and Exercise Science, University of Central Florida, Orlando, Florida; and 6Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska.
authors: Ashley A
authors: AA
authors: Herda
authors: Trent J
authors: TJ
authors: Herda
authors: Pablo B
authors: PB
authors: Costa
authors: Eric D
authors: ED
authors: Ryan
authors: Jeffrey R
authors: JR
authors: Stout
authors: Joel T
authors: JT
authors: Cramer
mesh_terms: D000293:Adolescent; D000328:Adult; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000009:adverse effects; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D053580:Muscle Strength; D010807:Physical Endurance; D052097:Quadriceps Muscle / Q000033:anatomy & histology* / Q000502:physiology*; D055070:Resistance Training / Q000009:adverse effects / Q000379:methods; D012709:Serum Albumin / Q000378:metabolism; D012712:Serum Globulins / Q000378:metabolism; D055815:Young Adult
chemical_list: D004044:Dietary Proteins; D012709:Serum Albumin; D012712:Serum Globulins