Muscle performance, size, and safety responses after eight weeks of resistance training and protein supplementation: a randomized, double-blinded, placebo-controlled clinical trial

J Strength Cond Res. 2013 Nov;27(11):3091-100. doi: 10.1519/JSC.0b013e31828c289f.

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.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Dietary Proteins / administration & dosage*
  • Dietary Proteins / adverse effects
  • Dietary Supplements* / adverse effects
  • Double-Blind Method
  • Humans
  • Male
  • Muscle Strength
  • Physical Endurance
  • Quadriceps Muscle / anatomy & histology*
  • Quadriceps Muscle / physiology*
  • Resistance Training* / adverse effects
  • Resistance Training* / methods
  • Serum Albumin / metabolism
  • Serum Globulins / metabolism
  • Young Adult

Substances

  • Dietary Proteins
  • Serum Albumin
  • Serum Globulins