Postural control strategies during single limb stance following acute lateral ankle sprain.
BACKGROUND
Single-limb stance is maintained via the integration of visual, vestibular and somatosensory afferents. Musculoskeletal injury challenges the somatosensory system to reweight distorted sensory afferents. This investigation supplements kinetic analysis of eyes-open and eyes-closed single-limb stance tasks with a kinematic profile of lower limb postural orientation in an acute lateral ankle sprain group to assess the adaptive capacity of the sensorimotor system to injury.


METHODS
Sixty-six participants with first-time acute lateral ankle sprain completed a 20-second eyes-open single-limb stance task on their injured and non-injured limbs (task 1). Twenty-three of these participants successfully completed the same 20-second single-limb stance task with their eyes closed (task 2). A non-injured control group of 19 participants completed task 1, with 16 completing task 2. 3-dimensional kinematics of the hip, knee and ankle joints, as well as associated fractal dimension of the center-of-pressure path were determined for each limb during these tasks.


RESULTS
Between trial analyses revealed significant differences in stance limb kinematics and fractal dimension of the center-of-pressure path for task 2 only. The control group bilaterally assumed a position of greater hip flexion compared to injured participants on their side-matched "involved"(7.41 [6.1°] vs 1.44 [4.8]°; η(2)=.34) and "uninvolved" (9.59 [8.5°] vs 2.16 [5.6°]; η(2)=.31) limbs, with a greater fractal dimension of the center-of-pressure path (involved limb=1.39 [0.16°] vs 1.25 [0.14°]; uninvolved limb=1.37 [0.21°] vs 1.23 [0.14°]).


CONCLUSIONS
Bilateral impairment in postural control strategies present following a first time acute lateral ankle sprain.
School of Public Health, Physiotherapy and Population Science, University College Dublin, Dublin, Ireland. Electronic address: cailbhe.doherty@ucdconnect.ie.
Cailbhe
C
Doherty
Sport and Exercise Sciences Research Institute, Ulster Sports Academy, University of Ulster, Newtownabbey, Co. Antrim, Northern Ireland, United Kingdom.
Chris
C
Bleakley
Department of Kinesiology, University of Virginia, Charlottesville, VA, United States.
Jay
J
Hertel
School of Public Health, Physiotherapy and Population Science, University College Dublin, Dublin, Ireland.
Brian
B
Caulfield
St. Vincent's University Hospital, Dublin, Ireland.
John
J
Ryan
School of Public Health, Physiotherapy and Population Science, University College Dublin, Dublin, Ireland; Institute for Sport and Health, University College Dublin, Dublin, Ireland.
Eamonn
E
Delahunt
D000328:Adult; D016512:Ankle Injuries / Q000503:physiopathology*; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D013180:Sprains and Strains / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult
Ankle joint [MEsH]; Biomechanics [MEsH]; Kinematics [MEsH]; Kinetics [MEsH]; Postural balance [MEsH]