E. M. P. Backx
Astrid M. H. Horstman
Gabriel N. Marzuca-Nassr
Janneau Van Kranenburg
Joey S. J. Smeets
Cas J. Fuchs
Anniek A. W. Janssen
Lisette C. P. G. M. de Groot
Lex B. Verdijk
Luc van Loon, Australian Catholic University
Backx, E. M, Horstman, A. M, Marzuca-Nassr, G. N, Van Kranenburg, J., Smeets, J. S, Fuchs, C. J, Janssen, A. A, de Groot, L. C, Snijders, T., Verdijk, L. B & van Loon, L. (2018). Leucine supplementation does not attenuate skeletal muscle loss during leg immobilization in healthy, young men. Nutrients,10(635), 1-12. Switzerland: M D P I AG. Retrieved from https://doi.org/10.3390/nu10050635
Short successive periods of physical inactivity occur throughout life and contribute considerably to the age-related loss of skeletal muscle mass. The maintenance of muscle mass during brief periods of disuse is required to prevent functional decline and maintain metabolic health.
Objective:,br> To assess whether daily leucine supplementation during a short period of disuse can attenuate subsequent muscle loss in vivo in humans. Methods: Thirty healthy (22 ± 1 y) young males were exposed to a 7-day unilateral knee immobilization intervention by means of a full leg cast with (LEU, n = 15) or without (CON, n = 15) daily leucine supplementation (2.5 g leucine, three times daily). Prior to and directly after immobilization, quadriceps muscle cross-sectional area (computed tomography (CT) scan) and leg strength (one-repetition maximum (1-RM)) were assessed. Furthermore, muscle biopsies were taken in both groups before and after immobilization to assess changes in type I and type II muscle fiber CSA.
Quadriceps muscle cross-sectional area (CSA) declined in the CON and LEU groups (p < 0.01), with no differences between the two groups (from 7712 ± 324 to 7287 ± 305 mm2 and from 7643 ± 317 to 7164 ± 328 mm2; p = 0.61, respectively). Leg muscle strength decreased from 56 ± 4 to 53 ± 4 kg in the CON group and from 63 ± 3 to 55 ± 2 kg in the LEU group (main effect of time p < 0.01), with no differences between the groups (p = 0.052). Type I and II muscle fiber size did not change significantly over time, in both groups (p > 0.05).
Free leucine supplementation with each of the three main meals (7.5 g/d) does not attenuate the decline of muscle mass and strength during a 7-day limb immobilization intervention
Mary MacKillop Institute for Health Research
Open Access Journal Article
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