Portable electromyography: Application for understanding muscle function of daily life in older adults

O. Theou, S.H. Bruce, K. Roland, G.R. Jones, J.M. Jakobi, Portable electromyography: Application for understanding muscle function of daily life in older adults. Gerontechnology 2011; 10(3):146-156; doi:10.4017/gt.2011.10.3.003.00 Purpose: To measure arm and thigh muscle activity using electromyography (EMG) for an 8-hour typical day in community-dwelling and retirement-home residents (older women only). Methods: Twenty-two women (>75 yrs), living either in the community (n=11, 82±6 yrs) or in a retirement facility (n=11, 86±6 yrs) participated. Long term EMG was recorded from the biceps brachii, triceps brachii, vastus lateralis, and biceps femoris using portable surface EMG over a typical 8-hour day. Results of the two groups were compared at a confidence limit of 0.05. Results Portable EMG was successfully used to compare muscle activity for a typical day in retirement home residents relative to community-dwelling individuals. Retirement home residents had ~22% greater number of bursts compared to community-dwellers. Conversely, retirement home residents had ~42% lower peak amplitude than community-dwellers. In addition, number of bursts was ~34% greater in the arm muscles than the thigh muscles for both community-dwelling older adults and retirement home residents. Retirement home residents were engaged ~65% less time in instrumental activities of daily living than community-dwellers (p<0.001). Conclusions The greater number of low amplitude bursts, associated with living in a retirement home, might be sensitive to the types of tasks undertaken during a typical day and indicative of decreased muscle function, likely as a consequence of reductions in mobility and instrumental activities of daily living.