%0 Journal Article
%T Age-Related Increase in Electromyography Burst Activity in Males and Females
%A Olga Theou
%A Darl Edwards
%A Gareth R. Jones
%A Jennifer M. Jakobi
%J Journal of Aging Research
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/720246
%X The rapid advancement of electromyography (EMG) technology facilitates measurement of muscle activity outside the laboratory during daily life. The purpose of this study was to determine whether bursts in EMG recorded over a typical 8-hour day differed between young and old males and females. Muscle activity was recorded from biceps brachii, triceps brachii, vastus lateralis, and biceps femoris of 16 young and 15 old adults using portable surface EMG. Old muscles were active 16¨C27% of the time compared to 5¨C9% in young muscles. The number of bursts was greater in old than young adults and in females compared to males. Burst percentage and mean amplitude were greater in the flexor muscles compared with the extensor muscles. The greater burst activity in old adults coupled with the unique activity patterns across muscles in males and females provides further understanding of how changes in neuromuscular activity effects age-related functional decline between the sexes. 1. Introduction Accelerometers, pedometers, and global position system (GPS) have become familiar tools for assessing age-related changes in mobility and physical activity during daily life [1, 2], but these devices provide no indication of muscle activity governing movement. Laboratory studies using electromyography (EMG) have provided considerable understanding of age-related changes in muscle activity for simple isometric and anisometric contractions [3¨C5], gait [6], and discrete tasks [7] executed under experimental constraints. With the advancement of technology, portable EMG devices now offer a means to characterize muscle activity (bursts) and quiescence (gaps) over long durations outside the laboratory, enabling discrete measurement of neuromuscular control within the environmental context of daily life [8, 9]. Quantification of gaps in EMG for a discrete task and during daily life activities, in young and old adults, suggests muscle quiescence decreases in old adults and is less in women compared with men [10]. For a discrete task when the EMG is quantified through bursts, muscle activity increases in old adults relative to young adults and is also greater in women [8, 11]. Together, measurement of bursts and gaps for a discrete task, such as carrying a bag of groceries, suggests that muscles are active more often and Ħ°restĦħ less in older adults and women. Age-related remodeling [12, 13], decreased muscle strength [3, 14, 15], and greater declines in performance for fast velocity relative to slow velocity movements [16, 17] likely predispose old adults to increased bursts to
%U http://www.hindawi.com/journals/jar/2013/720246/