Exercise and dietary-protein as a countermeasure to skeletal muscle weakness: Liverpool Hope University - Sarcopenia Aging Trial (LHU-SAT)

�� 2019 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher���s website: https://doi.org/10.3389/fphys.2019.00445Objective: To investigate the effects of a 16-week concurrent exercise regimen [resistance exercise (RE) + functional exercise (FE)] in combination with, or without, a leucine-enriched whey protein isolate supplement on muscle strength, physical functioning, aerobic capacity, and cardiometabolic health in older adults (���60 years). Physical activity levels were also evaluated 6 months post-cessation of the intervention. Methods: Forty-six, community-dwelling, previously untrained males, and females [age: 68 �� 5 years (mean �� SD); BMI: 27.8 �� 6.2 kg/m2] who completed the trial were initially randomized to one of two independent arms [Exercise n = 24 (E); Exercise+Protein n = 22 (EP)]. Both arms completed 16 weeks of RE (performed to fatigue) (2 times/week) with FE (1 time/week) on non-consecutive days. Additionally, EP were administered a leucine-enriched whey protein supplement (3 times/day) for 16 weeks based on individual body-weight (1.5 g/kg/day). Results: As a result of dietary supplementation, protein intake increased in EP (���1.2 �� 0.4 to 1.5 �� 0.7 g/kg/day) during the intervention. Maximal strength (1RM) values for leg press (E: +39 �� 7 kg, p = 0.006; EP: +63 �� 7 kg, p 0.05). Physical functioning in the obstacle course (E: -5.1 �� 6.8 s, p 0.05). No significant change was observed for markers of cardiometabolic health (glycaemic control or blood pressure) (p > 0.05). At follow-up, 86% of older adults reported to performing physical activity ���1 per week. Of those, 61% were still participating in strength- and cardiovascular- based exercise. Conclusion: Concurrent exercise (RE + FE) offers a potent method to combat age-related muscle weakness, and our results suggest a high proportion of older adults may continue to exercise unsupervised. However, leucine-enriched whey protein isolate supplementation did not confer any additional benefit in those already consuming ample amounts of dietary protein at trial enrolment. Future trials should utilize a whole-foods approach and investigate the effects in frail and non-frail older adults habitually consuming the RDA of protein, to assess if a higher intake of protein is needed to delay the onset of muscle weakness.Published versio