title: Altered visual focus on sensorimotor control in people with chronic ankle instability.
abstract: The purpose of this investigation was to examine the effects of the combination of chronic ankle instability (CAI) and altered visual focus on strategies for dynamic stability during a drop-jump task. Nineteen participants with self-reported CAI and 19 healthy participants performed a drop-jump task in looking-up and looking-down conditions. For the looking-up condition, participants looked up and read a random number that flashed on a computer monitor. For the looking-down condition, participants focused their vision on the force plate. Sagittal- and frontal-plane kinematics in the hip, knee and ankle were calculated at the time points of 100 ms pre-initial foot contact to ground and at IC. The resultant vector time to stabilisation was calculated with ground reaction force data. The CAI group demonstrated less hip flexion at the point of 100 ms pre-initial contact (P < 0.01), and less hip flexion (P = 0.03) and knee flexion at initial contact (P = 0.047) compared to controls. No differences in kinematics or dynamic stability were observed in either looking-up or looking-down conditions (P > 0.05). Altered visual focus did not influence movement patterns during the drop-jump task, but the presence of CAI did. The current data suggests that centrally mediated changes associated with CAI may lead to global alterations in the sensorimotor control.
authors.affiliation: a Musculoskeletal Laboratory, Department of Rehabilitation Science , College of Health Science, University of Kentucky , Lexington , KY , USA.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Terada
authors.affiliation: b Kettering Sports Medicine Center , Kettering , OH , USA.
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Ball
authors.affiliation: c Neuromuscular Research Laboratory, Department of Exercise and Sports Science , University of North Carolina at Chapel Hill , Chapel Hill , NC , USA.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Pietrosimone
authors.affiliation: a Musculoskeletal Laboratory, Department of Rehabilitation Science , College of Health Science, University of Kentucky , Lexington , KY , USA.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Gribble
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005080:Exercise Test; D056228:Feedback, Sensory / Q000502:physiology*; D006615:Hip / Q000503:physiopathology; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology* / Q000523:psychology*; D007717:Knee / Q000503:physiopathology; D059385:Plyometric Exercise; D016059:Range of Motion, Articular; D016037:Single-Blind Method; D014785:Vision, Ocular / Q000502:physiology*; D055815:Young Adult
keywords: ankle sprain; feed-forward sensorimotor control; hip; knee; somatosensory plasticity