Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy.
OBJECTIVE
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.
Cribb
Paul J
PJ
Exercise Metabolism Unit, Center for Ageing, Rehabilitation, Exercise and Sport; and the School of Biomedical Sciences, Victoria University, Melbourne, Victoria, Australia.
Hayes
Alan
A
D015502:Absorptiometry, Photon; D000328:Adult; D001707:Biopsy, Needle; D001823:Body Composition; D003285:Contractile Proteins / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D019587:Dietary Supplements; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D006984:Hypertrophy; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D010806:Physical Education and Training / Q000379:methods*; D016037:Single-Blind Method
D003285:Contractile Proteins; D006003:Glycogen; D003401:Creatine