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Timing of post‐exercise protein intake is important for muscle hypertrophy with resistance training in elderly humans
Author(s) -
Esmarck B.,
Andersen J. L.,
Olsen S.,
Richter E. A.,
Mizuno M.,
Kjaer M.
Publication year - 2002
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1034/j.1600-0838.2002.120111_2.x
Subject(s) - muscle hypertrophy , resistance training , medicine , skeletal muscle , sarcopenia , strength training , endocrinology , muscle strength , insulin resistance , muscle protein , muscle mass , physical therapy , obesity
(1) Age‐associated loss of skeletal muscle mass and strength can partly be counteracted by resistance training, causing a net synthesis of muscular proteins. Protein synthesis is influenced synergistically by post‐exercise amino acid supplementation, but the importance of the timing of protein intake remains unresolved. (2) The study investigated the importance of immediate (P0) or delayed (P2) intake of an oral protein supplement upon muscle hypertrophy and strength over a period of resistance training in elderly males. (3) Thirteen men (age 74 ± 1 years; body mass index (BMI), 25 ± 1 kg m − 2 (means ± SEM)) completed a 12‐week resistance training program (three times per week) receiving oral protein in liquid form (10 g protein, 7 g carbohydrate, 3 g fat) immediately after (P0) or 2 h after (P2) each training session. Muscle hypertrophy was evaluated by magnetic resonance imaging (MRI) and from muscle biopsies and muscle strength was determined using dynamic and isokinetic strength measurements. Body composition was determined from dual‐energy X‐ray absorptiometry (DEXA) and food records were obtained over 4 days. The plasma insulin response to protein supplementation was also determined. (4) In response to training, the cross‐sectional area of m. quadriceps femoris (54.6 ± 0.5–58.3 ± 0.5 cm 2 ) and mean fiber area (4047 ± 320–5019 ± 615 μ m 2 ) increased in the P0 group, whereas no significant increase was observed in P2. For P0 both dynamic and isokinetic strength increased, by 46 and 15%, respectively ( P < 0.05), whereas P2 only improved in dynamic strength, by 36% ( P < 0.05). No differences in glucose or insulin response were observed between protein intake at 0 and 2 h post‐exercise. (5) We conclude that early intake of an oral protein supplement after resistance training is important for the development of hypertrophy in skeletal muscle of elderly men in response to resistance training.