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Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.
J Physiol. 2005 Oct 01; 568(Pt 1):283-90.JP

Abstract

The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.

Authors+Show Affiliations

Department of Kinesiology, IWC AB116, McMaster University, 1280 Main Street W., Hamilton, ON, Canada L8S 4K1.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16051622

Citation

Kim, Paul L., et al. "Fasted-state Skeletal Muscle Protein Synthesis After Resistance Exercise Is Altered With Training." The Journal of Physiology, vol. 568, no. Pt 1, 2005, pp. 283-90.
Kim PL, Staron RS, Phillips SM. Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training. J Physiol (Lond). 2005;568(Pt 1):283-90.
Kim, P. L., Staron, R. S., & Phillips, S. M. (2005). Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training. The Journal of Physiology, 568(Pt 1), 283-90.
Kim PL, Staron RS, Phillips SM. Fasted-state Skeletal Muscle Protein Synthesis After Resistance Exercise Is Altered With Training. J Physiol (Lond). 2005 Oct 1;568(Pt 1):283-90. PubMed PMID: 16051622.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training. AU - Kim,Paul L, AU - Staron,Robert S, AU - Phillips,Stuart M, Y1 - 2005/07/28/ PY - 2005/7/30/pubmed PY - 2005/12/13/medline PY - 2005/7/30/entrez SP - 283 EP - 90 JF - The Journal of physiology JO - J. Physiol. (Lond.) VL - 568 IS - Pt 1 N2 - The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins. SN - 0022-3751 UR - https://www.unboundmedicine.com/medline/citation/16051622/Fasted_state_skeletal_muscle_protein_synthesis_after_resistance_exercise_is_altered_with_training_ L2 - https://doi.org/10.1113/jphysiol.2005.093708 DB - PRIME DP - Unbound Medicine ER -