Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy

• Published in: Medicine and science in sports and exercise Vol. 38; no. 11; pp. 1918 - 1925
• Main Authors: CRIBB, Paul J, HAYES, Alan
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01-11-2006
• Subjects: Absorptiometry, Photon; Adult; Biological and medical sciences; Biopsy, Needle; Body Composition; Contractile Proteins - metabolism; Creatine - metabolism; Dietary Supplements; Fundamental and applied biological sciences. Psychology; Glycogen - metabolism; Humans; Hypertrophy; Male; Muscle Fibers, Skeletal - metabolism; Muscle Fibers, Skeletal - pathology; Muscle Strength; Muscle, Skeletal - metabolism; Muscle, Skeletal - pathology; Physical Education and Training - methods; Single-Blind Method; Space life sciences; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Physical exercise; Human; WHEY PROTEIN; Creatine; Striated muscle; Protein; HISTOCHEMISTRY; Sport; Lean body mass; Carbohydrate; Supplementation; Timing; Hypertrophy
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1249/01.mss.0000233790.08788.3e

Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program.
In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content.
PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content. PRE-POST supplementation also resulted in higher muscle Cr and glycogen values after the training program (P < 0.05).
Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.