Now showing 1 - 10 of 16
  • Publication
    Acute ankle sprain injury alters kinematic and centre of pressure measures of postural control during single limb stance
    Background: Upright single-limb stance (SLS) is maintained via integration of visual, vestibular and somatosensory afferents. The presence of redundancies between these afferents allows the sensorimotor system to simplify a specific task within a number of strategies. Musculoskeletal injury challenges the somatosensory system to reweight distorted sensory afferents. No current investigation has supplemented kinetic analysis of eyes-open and eyes-closed SLS tasks with a kinematic profile of lower limb postural orientation in an acute lateral ankle sprain (LAS) group to assess the adaptive capacity of the sensorimotor system to injury. Objective: To compare centre of pressure (COP) and lower limb postural orientation characteristics of participants with acute LAS to non-injured participants during a SLS task. Design Cross-sectional: Setting University biomechanics laboratory. Participants: 66 participants with acute LAS completed a task of eyes-open SLS on their injured and non-injured limbs (task 1). 23 of these participants successfully completed the SLS task with their eyes closed (task 2). A non-injured control group of nineteen participants completed task 1, with 16 completing task 2. Main outcome measures: 3D kinematics of the hip, knee and ankle joints as well as associated fractal dimension (FD) of the COP path. Results: Between trial analyses of groups revealed significant differences in lower limb kinematics and FD of the COP path for task 2. Post-hoc testing revealed that non-injured control group bilaterally assumed a position of greater hip flexion compared to LAS participants (injured limb=7.41±6.1◦ vs 1.44±4.8◦; non-injured limb=9.59±8.5◦ vs 2.16±5.6◦), with a corollary of greater FD of the COP path (injured limb=1.39±0.16 vs 1.25±0.14; non-injured limb=1.37±0.21 vs 1.23±0.14). Conclusion: Acute LAS causes bilateral impairment in postural control strategies.
  • Publication
    Gait Biomechanics in Participants, Six Months after First-Time Lateral Ankle Sprain
    No research currently exists predicating a link between the injury-affiliated sensorimotor deficits of acute ankle sprain and those of chronic ankle instability during gait. This analysis evaluates participants with a 6-month history of ankle sprain injury to affirm this link. 69 participants with a 6-month history of acute first-time lateral ankle sprain were divided into subgroups (‘chronic ankle instability’ and 'coper') based on their self-reported disability and compared to 20 non-injured participants during a gait task. Lower extremity kinematic and kinetic data were collected from 200 ms pre- to 200 ms post-heel strike (period 1) and from 200 ms pre- to 200 ms post-toe off (period 2). The ‘chronic ankle instability’ subgroup (who reported greater disability) displayed increased knee flexion during period 1. During period 2, this subgroup exhibited greater total displacement at their ankle joint and greater extensor dominance at their knee. That many of these features are present, both in individuals with acute ankle sprain and those with chronic ankle instability may advocate a link between acute deficits and long-term outcome. Clinicians must be aware that the sensorimotor deficits of ankle sprain may persevere beyond the acute stage of injury and be cognizant of the capacity for impairments to pervade proximally.
      527Scopus© Citations 8
  • Publication
    Concussion is associated with altered preparatory postural adjustments during gait initiation
    Gait initiation is a useful surrogate measure of supraspinal motor control mechanisms but has never been evaluated in a cohort following concussion. The aim of this study was to quantify the preparatory postural adjustments (PPAs) of gait initiation (GI) in fifteen concussion patients (4 females, 11 males) in comparison to a group of fifteen age- and sex- matched controls. All participants completed variants of the GI task where their dominant and non-dominant limbs as the stepping and support limbs. Task performance was quantified using the centre of pressure (COP) trajectory of each foot (computed from a force plate) and the centre of mass (COM) trajectory (estimated from an inertial measurement unit placed on the sacrum). Concussed patients exhibited decreased COP excursion on their dominant foot, both when it was the stepping limb (sagittal plane: 9.71mm [95% CI: 8.14 to 11.27mm] vs 14.9mm [95%CI: 12.31 to 17.49mm]; frontal plane: 36.95mm [95% CI: 30.87 to 43.03mm] vs 54.24mm [95%CI: 46.99 to 61.50mm]) and when it was the support limb (sagittal plane: 10.43mm [95% CI: 8.73 to 12.13mm] vs 18.13mm [95%CI: 14.92 to 21.35mm]; frontal plane: 66.51mm [95% CI: 60.45 to 72.57mm] vs 88.43mm [95%CI: 78.53 to 98.32mm]). This was reflected in the trajectory of the COM, wherein concussion patients exhibited lower posterior displacement (19.67mm [95%CI: 19.65mm to 19.7mm]) compared with controls (23.62mm [95%CI: 23.6 to 23.64]). On this basis, we conclude that individuals with concussion display deficits during a GI task which are potentially indicative of supraspinal impairments in motor control.
      390Scopus© Citations 12
  • Publication
    Lower Limb Interjoint Postural Coordination One Year after First-Time Lateral Ankle Sprain
    Introduction: Longitudinal analyses of participants with a history of lateral ankle sprain are lacking. This investigation combined measures of lower limb interjoint coordination and stabilometry to evaluate static unipedal stance with the eyes open (condition 1) and closed (condition 2) in a group of participants with chronic ankle instability (CAI) compared to lateral ankle sprain ‘‘copers’’ (both recruited 12 months after sustaining an acute first-time lateral ankle sprain) and a group of noninjured controls. Methods: Twenty-eight participants with CAI, 42 lateral ankle sprain ‘‘copers,’’ and 20 noninjured controls completed three 20-s singlelimb stance trials in conditions 1 and 2. An adjusted coefficient of multiple determination statistic was used to compare stance limb threedimensional kinematic data for similarity to establish patterns of interjoint coordination. The fractal dimension of the stance limb center of pressure path was also calculated. Results: Between-group analyses revealed that participants with CAI displayed notable increases in ankle–hip linked coordination compared with both lateral ankle sprain ‘‘copers’’ (j0.52 (1.05) vs 0.28 (0.9), P = 0.007) and controls (j0.52 (1.05) vs 0.63 (0.64), P = 0.006) in condition 1 and compared with controls only (0.62 (1.92) vs 0.1 (1.0) P = 0.002) in condition 2. Participants with CAI also exhibited a decrease in the fractal dimension of the center-of-pressure path during condition 2 compared with both controls and lateral ankle sprain ‘‘copers.’’ Conclusions: Participants with CAI present with a hip-dominant strategy of eyes-open and eyes-closed static unipedal stance. This coincided with reduced complexity of the stance limb center of pressure path in the eyes-closed condition.
      374Scopus© Citations 16
  • Publication
    Quantification of postural control deficits in patients with recent concussion: An inertial-sensor based approach
    Background: The aim of this study was to quantify postural control ability in a group with concussion compared with a healthy control group. Method: Fifteen concussion patients (4 females, 11 males) and a group of fifteen age- and sex-matched controls were recruited. Participants were tested during the performance of the three stance variants (bilateral, tandem and unilateral) of the balance error scoring system standing on a force place, while wearing an inertial measurement unit placed at the posterior aspect of the sacrum. Findings: The area of postural sway was computed using the force-plate and the '95% ellipsoid volume of sway' was computed from the accelerometer data. Concussed patients exhibited increased sway area (1513 mm2 [95% CI: 935 to 2091 mm2] vs 646 mm2 [95% CI: 519 to 772 mm2]; p = 0.02) and sway volume (9.46 m3 s− 6 [95% CI: 8.02 to 19.94 m3 s− 6] vs 2.68 m3 s− 6 [95% CI: 1.81 to 3.55 m3 s− 6]; p = 0.01) in the bilateral stance position of the balance error scoring system. The sway volume metric also had excellent accuracy in identifying task 'errors' (tandem stance: 91% accuracy [95% CI: 85–96%], p < 0.001; unilateral stance: 91% accuracy [95% CI: 86–96%], p < 0.001). Interpretation: Individuals with concussion display increased postural sway during bilateral stance. The sway volume that was calculated from the accelerometer data not only differentiated a group with concussion from a healthy control group, but successfully identified when task errors had occurred. This may be of value in the development of a pitch-side assessment system for concussion.
      544Scopus© Citations 29
  • Publication
    Dynamic balance deficits in individuals with chronic ankle instability compared to ankle sprain copers 1 year after a first-time lateral ankle sprain injury
    Purpose: To quantify the dynamic balance deficits that characterise a group with chronic ankle instability compared to lateral ankle sprain copers and non-injured controls using kinematic and kinetic outcomes. Methods: Forty-two participants with chronic ankle instability and twenty-eight lateral ankle sprain copers were initially recruited within 2 weeks of sustaining a first-time, acute lateral ankle sprain and required to attend our laboratory 1 year later to complete the current study protocol. An additional group of non-injured individuals were also recruited to act as a control group. All participants completed the anterior, posterior-lateral and posterior-medial reach directions of the star excursion balance test. Sagittal plane kinematics of the lower extremity and associated fractal dimension of the centre of pressure path were also acquired. Results: Participants with chronic ankle instability displayed poorer performance in the anterior, posterior-medial and posterior-lateral reach directions compared with controls bilaterally, and in the posterior-lateral direction compared with lateral ankle sprain copers on their ‘involved’ limb only. These performance deficits in the posterior-lateral and posterior-medial directions were associated with reduced flexion and dorsiflexion displacements at the hip, knee and ankle at the point of maximum reach, and coincided with reduced complexity of the centre of pressure path. Conclusion: In comparison with lateral ankle sprain copers and controls, participants with chronic ankle instability were characterised by dynamic balance deficits as measured using the SEBT. This was attested to reduced sagittal plane motions at the hip, knee and ankle joints, and reduced capacity of the stance limb to avail of its supporting base.
      1488Scopus© Citations 65
  • Publication
    Locomotive biomechanics in persons with chronic ankle instabilityand lateral ankle sprain copers
    Objectives: To compare the locomotive biomechanics of participants with chronic ankle instability (CAI) to those of lateral ankle sprain (LAS) copers. Design: Cross-sectional study. Methods: Twenty-eight participants with CAI and 42 LAS copers each performed 5 self-selected paced gait trials. 3-D lower extremity temporal kinematic and kinetic data were collected for these participants from 200 ms pre- to 200 ms post-heel strike (period 1) and from 200 ms pre- to 200 ms post-toe off (period 2). Results: The CAI group displayed increased hip flexion bilaterally during period 1 compared to LAS copers. During period 2, CAI participants exhibited reduced hip extension bilaterally, increased knee flexion bilaterally and increased ankle inversion on the ‘involved’ limb. They also displayed a bilateral decrease in the flexor moment pattern at the knee. Conclusions: Considering that all of the features which distinguished CAI participants from LAS copers were also evident in our previously published research (within 2-weeks following acute first-time LAS); these findings establish a potential link between these features and long-term outcome following first-time LAS. Clinicians must be cognizant of the capacity for these movement and motor control impairments to cascade proximally from the injured joint up the kinetic chain and recognise the value that gait re-training may have in rehabilitation planning to prevent CAI.
      781Scopus© Citations 27
  • Publication
    Lower extremity function during gait in participants with first time acute lateral ankle sprain compared to controls
    Laboratory analyses of chronic ankle instability populations during gait have elucidated a number of anomalous movement patterns. No current research exists analysing these movement patterns in a group in the acute phase of lateral ankle sprain (LAS) injury. It is possible that participants with an acute LAS display movement patterns continuous with their chronically impaired counterparts. Sixty eight participants with acute LAS and nineteen non-injured participants completed five gait trials. 3D lower extremity temporal kinematic and kinetic data were collected from 200ms pre- to 200ms post-heel strike (period 1) and from 200ms pre- to 200ms post-toe off (period 2). During period 1, the LAS group displayed increased knee flexion with increased net extensor pattern at the knee joint, increased ankle inversion with a greater inversion moment, and reduced ankle plantar flexion, compared to the non-injured control group. During period 2, the LAS group displayed decreased hip extension with a decrease in the flexor moment at the hip, and decreased ankle plantar flexion with a decrease in the net plantar flexion moment, compared to the non-injured control group. These results indicate that participants with acute LAS display coordination strategies which may play a role in the onset of chronicity or recovery.
      725Scopus© Citations 23
  • Publication
    Single-leg drop landing movement strategies 6 months following first-time acute lateral ankle sprain injury
    No research exists predicating a link between acute ankle sprain injury-affiliated movement patterns and those of chronic ankle instability (CAI) populations. The aim of the current study was to perform a biomechanical analysis of participants, 6 months after they sustained a first-time acute lateral ankle sprain (LAS) injury to establish this link. Fifty-seven participants with a 6-month history of first-time LAS and 20 noninjured participants completed a single-leg drop landing task on both limbs. Three-dimensional kinematic (angular displacement) and sagittal plane kinetic (moment of force) data were acquired for the joints of the lower extremity, from 200 ms pre-initial contact (IC) to 200 ms post-IC. Individual joint stiffnesses and the peak magnitude of the vertical component of the ground reaction force (GRF) were also computed. LAS participants displayed increases in hip flexion and ankle inversion on their injured limb (P < 0.05); this coincided with a reduction in the net flexion-extension moment at the hip joint, with an increase in its stiffness (P < 0.05). There was no difference in the magnitude of the peak vertical GRF for either limb compared with controls. These results demonstrate that altered movement strategies persist in participants, 6 months following acute LAS, which may precipitate the onset of CAI.
      701Scopus© Citations 36
  • Publication
    Recovery From a First-Time Lateral Ankle Sprain and the Predictors of Chronic Ankle Instability: A Prospective Cohort Analysis
    Background: Impairments in motor control may predicate the paradigm of chronic ankle instability (CAI) that can develop in the year after an acute lateral ankle sprain (LAS) injury. No prospective analysis is currently available identifying the mechanisms by which these impairments develop and contribute to long-term outcome after LAS. Purpose: To identify the motor control deficits predicating CAI outcome after a first-time LAS injury. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Eighty-two individuals were recruited after sustaining a first-time LAS injury. Several biomechanical analyses were performed for these individuals, who completed 5 movement tasks at 3 time points: (1) 2 weeks, (2) 6 months, and (3) 12 months after LAS occurrence. A logistic regression analysis of several "salient" biomechanical parameters identified from the movement tasks, in addition to scores from the Cumberland Ankle Instability Tool and the Foot and Ankle Ability Measure (FAAM) recorded at the 2-week and 6-month time points, were used as predictors of 12-month outcome. Results: At the 2-week time point, an inability to complete 2 of the movement tasks (a single-leg drop landing and a drop vertical jump) was predictive of CAI outcome and correctly classified 67.6% of cases (sensitivity, 83%; specificity, 55%; P = .004). At the 6-month time point, several deficits exhibited by the CAI group during 1 of the movement tasks (reach distances and sagittal plane joint positions at the hip, knee and ankle during the posterior reach directions of the Star Excursion Balance Test) and their scores on the activities of daily living subscale of the FAAM were predictive of outcome and correctly classified 84.8% of cases (sensitivity, 75%; specificity, 91%; P < .001). Conclusion: An inability to complete jumping and landing tasks within 2 weeks of a first-time LAS and poorer dynamic postural control and lower self-reported function 6 months after a first-time LAS were predictive of eventual CAI outcome.
      1831Scopus© Citations 195