title: Individuals with chronic ankle instability compensate for their ankle deficits using proximal musculature to maintain reduced postural sway while kicking a ball.
abstract: The aim of this study was to investigate anticipatory (APA), simultaneous (SPA) and compensatory (CPA) postural adjustments in individuals with and without chronic ankle instability (CAI) as they kicked a ball while standing in a single-leg stance on a stable and unstable surface. Electromyographic activity (EMG) of postural muscles and center of pressure (COP) displacements were calculated and their magnitudes analyzed during the postural adjustment intervals. Additionally, the COP area of sway was calculated over the duration of the whole task. The activities of postural muscles were also studied using principal component analysis (PCA) to identify between-group differences in patterns of muscle activation. The individuals with CAI showed reduced magnitude of EMG at the muscles around the ankle while around the hip the activity was increased. These were associated with a reduction in balance sway across the entire task, as compared with the control group. The PCA revealed that CAI participants assemble different sets of muscle activation to compensate for their ankle instability, primarily activating hip/spine muscles. These results set up potential investigations to examine whether balance control interventions enhance these adaptations or revert them to a normal pattern as well as if any of these changes proactively address recurrent ankle sprain conditions.
authors.affiliation: Department of Physical Therapy, Center of Health Sciences and Sport, Santa Catarina State University, Rua Pascoal Simoni, 358, Florianopolis, SC 88080-350, Brazil.
authors.forename: Jaqueline Lourdes
authors.initials: JL
authors.lastname: Rios
authors.affiliation: Department of Physical Therapy, Center of Health Sciences and Sport, Santa Catarina State University, Rua Pascoal Simoni, 358, Florianopolis, SC 88080-350, Brazil.
authors.forename: Ana Luiza
authors.initials: AL
authors.lastname: Gorges
authors.affiliation: Department of Physical Therapy, Center of Health Sciences and Sport, Santa Catarina State University, Rua Pascoal Simoni, 358, Florianopolis, SC 88080-350, Brazil; Department of Physical Therapy and Rehabilitation Sciences, School of Health Professions, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA. Electronic address: msantos@kumc.edu.
authors.forename: Marcio José
authors.initials: MJ
authors.lastname: dos Santos
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology / Q000503:physiopathology*; D002908:Chronic Disease; D004576:Electromyography; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: Anticipatory adjustments; Compensatory; Reactive responses; Recurrent sprain; Rehabilitation