Chronic electromyography (EMG) measures are common in occupational studies where they are used to understand work-related injuries. Recent studies have compared chronic EMG during daily life between young and old men and women (Harwood et al. 2008) and between old women across states of frailty (Theou et al., 2010). These studies demonstrated an age-related increase in low-threshold electromyography (EMG), which was reported to be greater in women compared with men, and EMG differed across states of frailty. PURPOSE: Measure upper and lower limb muscle activity using EMG in community- and retirement-dwelling older women for a 8-hour typical day. METHODS: Community- (n=9, 80±4 yrs) and retirement-dwelling (n=9, 84±6 yrs) older women participated. Surface EMG was recorded from the biceps brachii, triceps brachii, vastus lateralis, and biceps femoris of the self-reported non-dominant side for a 8-hour typical day. Signals were sampled at 1000Hz, stored on an MMC flashcard and imported into Spike 2 Version 5™ for custom script analysis. Isometric maximum voluntary exertions (MVE) were performed to normalize EMG data. An EMG burst was quantified as a period of muscle activity more than 2% of MVE for a duration longer than 0.1 sec. The number, mean duration, peak amplitude of bursts and the percentage of total recording time occupied by bursts were examined. RESULTS: The number of bursts in retirement-dwelling women was 22% greater (p=0.005) than the community-dwelling women (p<0.01). Peak burst amplitude was 42% less (p=0.005) in retirement-dwelling women compared with community-dwelling women. The burst percentage and duration were similar (p>0.05) between community (40±4.5% recording time, 1.1±0.2 sec/burst) and retirement groups (43±4.5% recording time, 1.1±0.2 sec/burst). CONCLUSIONS: Retirement dwelling older women had more bursts of lower amplitude compared with community-dwelling older women and these differences might be indicative of decreased muscle function in the former group. Supported by: NSERC