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Visual Input Affects Force Steadiness And Accuracy Among Chronic Ankle Instability Patients, Ankle Sprain Copers, And Healthy Controls

2020; Lippincott Williams & Wilkins; Volume: 52; Issue: 7S Linguagem: Inglês

10.1249/01.mss.0000671044.83654.be

1530-0315

Hyunwook Lee, Seunguk Han, S. Jun Son, Hyunsoo Kim, Ty Hopkins,

Orthopedic Surgery and Rehabilitation

Chronic ankle instability (CAI) patients have demonstrated impairments of the sensorimotor system. The sensorimotor system plays an important role in steadily generating fine forces to control balance and functional movement. Submaximal force steadiness measures sensory, motor, and visual function via feedback mechanisms, which helps researchers and clinicians to comprehend sensorimotor deficits associated with CAI. PURPOSE: This study aimed to identify effects of stroboscopic glasses on force steadiness and accuracy among CAI patients, ankle sprain copers, and healthy controls. METHODS: Twenty CAI patients (M=10, F=10; 23±3 yrs, 174±11 cm, 76±17), 20 copers (M=10, F=10; 22±2 yrs, 176±10 cm, 69±10 kg), and 20 controls (M=10, F=10; 22±3 yrs, 174±7 cm, 80±24 kg) participated in this study. Subjects performed a maximal voluntary isometric contraction (MVIC) of eversion, inversion, and hip abduction. Two days after MVIC tests, subjects performed 2 practices, followed by 3 testing trials of 10% and 20% of their MVIC for 15 seconds for submaximal force steadiness and accuracy measures with and without the stroboscopic glasses. The central 10-sec (20-80% of the total time) of three testing trials was analyzed. Main outcome measures were force steadiness, which was one standard deviation (SD), and force accuracy was a root mean square across the 10-sec data. Force steadiness and accuracy were analyzed by 3 (groups) x 2 (visual conditions) ANOVAs. RESULTS: The CAI and coper subjects exhibited greater errors than controls in 20% eversion MVIC in force steadiness (p<.0001 and p=.01, respectively). CAI subjects demonstrated less steadiness in 20% eversion and hip abduction under strobe vision (SC) compared with eyes open (EO) (p=.02, both). Additionally, CAI subjects showed less accuracy than copers and controls in 20% eversion MVIC (p=.0001 and p<.0001, respectively). CAI subjects demonstrated less accuracy in 20% eversion under SC compared with EO (p=.002). CONCLUSIONS: Individuals with a history of a lateral ankle sprain (LAS) showed reduced force steadiness than healthy controls. Only CAI patients relied more on visual input during force steadiness and accuracy tasks. A LAS injury (coper) reduced the ability to control fine force, but recurrence of LASs (CAI) altered reliance on visual input.