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Muscle activity during functional tasks in pre-frail and frail individuals

University of British Columbia

The ability to identify the progression of frailty is essential to mitigate physical impairments associated with aging. Previous studies have indicated that stages of frailty can be identified through bursts and gaps in electromyography (EMG) for an 8-hour day. The purpose of this study was to determine whether EMG and a specific functional task, or group of functional tasks is sensitive to classify middle-aged, non-frail, pre-frail, and frail older adults. Fifteen middle-aged (49 ± 5 years), and seventy-six older adults (77 ± 8 years) participated in this study. Older adults were categorized as non-frail (n= 49), pre-frail (n=20) and frail (n= 7) based-upon gait speed and modified frailty index score. Bursts and gaps were measured in the biceps brachii, triceps brachii, vastus lateralis, and biceps femoris bilaterally during nine functional tasks: (1) Standing-up from a chair; (2) a toilet; and (3) the floor; (4) Dressing and undressing a buttoned shirt; (5) Transferring laundry between washer and dryer; (6) Carrying laundry up stairs; (7) Eating soup; (8) Preparing a light meal; and (9) Loading, carrying and unloading groceries. Bursts were greater and gaps fewer in frail compared with middle-aged and non-frail. The variable that provided the best prediction of phenotype allocation was the fewer number of gaps in the upper limbs (Λ = 0.677, χ2 (9) = 33.746, p< 0.001), and greater mean burst amplitude in lower limbs during the chair, toilet, and floor tasks (Λ = 0.764, χ2 (9) = 23.310, p< 0.001); where 80.2% and 72.5% of the original grouped cases were correctly classified in this sample. When separated by sex, the number of gaps respectively, correctly classified 100% and 81.8% of males and females. Mean burst amplitude correctly classified 77.8% and 78.2% of males and females. Burst and gap characteristics indicate that EMG differs across stages of frailty and progression is best identified with mobility tasks of rising from a chair, toilet and floor.

Text

2014-08-07

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/49939

Interdisciplinary Studies

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/