Abstract des Autors

Introduction Loss of motor units (MU) and alterations in MU properties are major factors in development of sarcopenia. The purpose of this study was to compare MU properties among 3 groups categorized as either pre-sarcopenic (n=7), sarcopenic (n=7), or severely sarcopenic (n=5), all of similar ages (75-82y). Methods Using decomposition-enhanced quantitative electromyography, MU number estimates and neuromuscular stability measures of near-fiber (NF) jitter and jiggle were derived in addition to contractile properties of ankle dorsiflexors. Results MU number estimates were similar across groups, however maximal voluntary strength in the severe sarcopenia group was 27% and 37% less than the sarcopenic and pre-sarcopenic groups, respectively. Moreover, NF jiggle was 31% greater in the severe group compared with pre-sarcopenia, NF jitter was 43% greater in the severe group compared with the pre-sarcopenic group. Conclusion Unlike MU number estimates, strength and MU stability differed across groups and related to degree of sarcopenia. This article is protected by copyright. All rights reserved.