BENOIT SMEUNINX, LEIGH BREEN*
*Corresponding Author
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom

Abstract

Age-related muscle wasting (sarcopenia) has dire consequences on the quality of life in older individuals and represents a major socio-economic burden. Sarcopenia is ‘driven’ by a blunted muscle response to anabolic stimuli. Development of non-pharmacological strategies to restore anabolic responsiveness in older muscles is of primordial importance. The most effective intervention to mitigate sarcopenia is resistance-type exercise. Consumption of adequate protein-based nutrition following resistance exercise enhances the muscle building response. Recent evidence suggests that the dose, source and frequency of ingested post-exercise protein are important determinants for the muscle building response to resistance exercise in older individuals. Evidence to support the role of protein nutrition in resistance exercise-induced muscle hypertrophy for older adults is discussed herein.

INTRODUCTION

The world’s population is getting older (1). Currently, 10 million people in the U.K. are aged 65 and over. By the year 2030 this number is estimated to reach 15.5 million, and will have nearly doubled to 19 million by 2050 (2). The age-related decline in skeletal muscle mass, termed sarcopenia, starts around the 4^th to 5^th decade of life and is thought to continue at an average annual rate of ~0.6% thereafter (3). Sarcopenia is prevalent in 13-24% of those aged 50-70 y and up to 50% for those in their eighties (4). The accompanying age-related loss of neuromuscular function, termed dynapenia, occurs at a much greater rate than that of muscle at around 2-4% per annum. Importantly, acute disuse events, ranging from relatively trivial (i.e. reduced ambulation) through severe (i.e. bed-rest immobilization) will exacerbate the normal progression of sarcopenia and dynapenia (5-7). Sarcopenia is associated with a diminished capacity to perform the physical activities associated with daily living and an increased risk of falls and fractures, all of which can reduce quality of life, and ultimately increase mortality risk (8). ...