Light-load resistance exercise increases muscle protein synthesis and hypertrophy signaling in elderly men.
Jakob Agergaard, Jacob Bülow, Jacob K Jensen, Søren Reitelseder, Micah J Drummond, Peter Schjerling, Thomas Scheike, Anja Serena, Lars Holm
Author Information
Jakob Agergaard: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; jakobagergaard@hotmail.com.
Jacob Bülow: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Jacob K Jensen: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Søren Reitelseder: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Micah J Drummond: Department of Physical Therapy, University of Utah, Salt Lake City, Utah.
Peter Schjerling: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. ORCID
Thomas Scheike: Department of Biostatistics, Institute of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; and.
Anja Serena: Arla Foods Ingredients Group P/S, Viby, Denmark.
Lars Holm: Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Ageing, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
The present study investigated whether well-tolerated light-load resistance exercise (LL-RE) affects skeletal muscle fractional synthetic rate (FSR) and anabolic intracellular signaling as a way to counteract age-related loss of muscle mass. Untrained healthy elderly (>65-yr-old) men were subjected to 13 h of supine rest. After 2.5 h of rest, unilateral LL-RE, consisting of leg extensions (10 sets, 36 repetitions) at 16% of 1 repetition maximum (RM), was conducted. Subsequently, the subjects were randomized to oral intake of 4 g of whey protein per hour (PULSE, = 10), 28 g of whey protein at 0 h and 12 g of whey protein at 7 h postexercise (BOLUS, = 10), or 4 g of maltodextrin per hour (placebo, = 10). Quadriceps muscle biopsies were taken at 0, 3, 7, and 10 h postexercise from the resting and the exercised leg of each subject. Myofibrillar FSR and activity of select targets from the mechanistic target of rapamycin complex 1-signaling cascade were analyzed from the biopsies. LL-RE increased myofibrillar FSR compared with the resting leg throughout the 10-h postexercise period. Phosphorylated (T308) AKT expression increased in the exercised leg immediately after exercise. This increase persisted in the placebo group only. Levels of phosphorylated (T37/46) eukaryotic translation initiation factor 4E-binding protein 1 increased throughout the postexercise period in the exercised leg in the placebo and BOLUS groups and peaked at 7 h. In all three groups, phosphorylated (T56) eukaryotic elongation factor 2 decreased in response to LL-RE. We conclude that resistance exercise at only 16% of 1 RM increased myofibrillar FSR, irrespective of nutrient type and feeding pattern, which indicates an anabolic effect of LL-RE in elderly individuals. This finding was supported by increased signaling for translation initiation and translation elongation in response to LL-RE.
