title: Increased fall risk is associated with elevated co-contraction about the ankle during static balance challenges in older adults.
abstract: Falls are a leading contributor to disability in older adults. Increased muscle co-contraction in the lower extremities during static and dynamic balance challenges has been associated with aging, and also with a history of falling. Co-contraction during static balance challenges has not been previously linked with performance on clinical tests designed to ascertain fall risk. The purpose of this study was to investigate the relationship between co-contraction about the ankle during static balance challenges with fall risk on a commonly used dynamic balance assessment, the Four Square Step Test (FSST). Twenty-three volunteers (mean age 73 years) performed a series of five static balance challenges (Romberg eyes open/closed, Sharpened Romberg eyes open/closed, and Single Leg Standing) with continuous electromyography (EMG) of bilateral tibialis anterior and gastrocnemius muscles. Participants then completed the FSST and were categorized as 'at-risk' or 'not-at-risk' to fall based on a cutoff time of 12 s. Co-contraction was quantified with co-contraction index (CCI). CCI during narrow base conditions was positively correlated with time to complete FSST. High CCIs during all static balance challenges with the exception of Romberg stance with eyes closed were predictive of being at-risk to fall based on FSST time, odds ratio 19.3. The authors conclude that co-contraction about the ankle during static balance challenges can be predictive of performance on a dynamic balance test.
authors.affiliation: Regis University School of Physical Therapy, 3333 Regis Blvd. G-4, Denver, CO 80221, USA. enelsonw@regis.edu
authors.forename: Erika
authors.initials: E
authors.lastname: Nelson-Wong
authors.forename: Ryan
authors.initials: R
authors.lastname: Appell
authors.forename: Mike
authors.initials: M
authors.lastname: McKay
authors.forename: Hannah
authors.initials: H
authors.lastname: Nawaz
authors.forename: Joanna
authors.initials: J
authors.lastname: Roth
authors.forename: Robert
authors.initials: R
authors.lastname: Sigler
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Third
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
mesh_terms: D000058:Accidental Falls; D000367:Age Factors; D000368:Aged; D000375:Aging; D000843:Ankle Joint / Q000503:physiopathology*; D016009:Chi-Square Distribution; D003120:Colorado; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016017:Odds Ratio; D004856:Postural Balance; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors