Age-Related Modifications of Muscle Synergies during Daily-Living Tasks: A Scoping Review

Abstract

AbstractPurposeAging is associated with changes in neuromuscular control that can lead to difficulties in performing daily-living tasks. Based on electromyography, muscle synergy analysis provides a valuable tool for assessing neuromuscular control strategies. However, the age-related changes of muscle synergies during daily living tasks are scattered throughout the literature. This review aimed to synthesize the existing literature on muscle synergies in elderly people during daily-living tasks and examine how they differ from those exhibited by young adults.MethodsA search was conducted across the Medline, CINHAL, and Web of Science databases. Studies were included if they focused on muscle synergies in elderly people during walking, sit-to-stand or stair ascent, and if muscle synergies were obtained by a matrix factorization algorithm.ResultsThe research strategy identified 4849 studies, of which 17 studies were included after the screening process. The muscle synergies of 295 elderly people and 182 young adults were reported. Results suggest that: 1) elderly people and young adults retain similar muscle synergies’ number, 2) elderly people have higher muscles contribution during walking, and 3) an increased inter and intra-subject variability during specific tasks (i.e., walking and stair ascent, respectively) was reported in elderly people compared to young adults.ConclusionThis review provides a comprehensive understanding of age-related changes in neuromuscular control during daily-living tasks. Our findings suggested that although the number of synergies remains similar, metrics such as spatial and temporal structures of synergies are more suitable to identify neuromuscular control deficits between young adults and elderly people.