title: Force steadiness in the lower extremities as an independent predictor of functional performance in older women.
abstract: The relationship between isometric force control and functional performance is unknown. Submaximal steadiness and accuracy were measured during a constant force-matching task at 50% of maximal isometric voluntary contraction (MVC) of the knee extensors in 19 older women (70-89 years). Other variables included MVC, rate of torque development, and EMG activity. Functional performance was assessed during maximal performance of walking endurance, chair rising, and stair climbing. Isometric steadiness (but not accuracy) was found to independently predict chair-rise time and stair-climbing power and explained more variance in these tasks than any other variable. Walking endurance was related to muscle strength but not steadiness. These results suggest that steadiness is an independent predictor of brief, stressful functional-performance tasks in older women with mild functional impairment. Thus, improving steadiness might help reduce functional limitations or disability in older adults.
authors.affiliation: Centre for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Cheshire, UK.
authors.forename: Olivier
authors.initials: O
authors.lastname: Seynnes
authors.forename: Olivier A
authors.initials: OA
authors.lastname: Hue
authors.forename: Frédéric
authors.initials: F
authors.lastname: Garrandes
authors.forename: Serge S
authors.initials: SS
authors.lastname: Colson
authors.forename: Pierre L
authors.initials: PL
authors.lastname: Bernard
authors.forename: Patrick
authors.initials: P
authors.lastname: Legros
authors.forename: Maria A
authors.initials: MA
authors.lastname: Fiatarone Singh
mesh_terms: D000203:Activities of Daily Living; D000367:Age Factors; D000368:Aged; D001696:Biomechanical Phenomena; D004576:Electromyography; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D035002:Lower Extremity; D018908:Muscle Weakness / Q000175:diagnosis; D018482:Muscle, Skeletal / Q000503:physiopathology*; D004856:Postural Balance; D011237:Predictive Value of Tests; D013647:Task Performance and Analysis