Gait Initiation Research Articles

Initiation gait variability is higher in the morning in elderly inpatients.

Although elderly inpatients are known to experience decreased physical activity in the morning, falls occur frequently during this time. Gait variability is an evaluation of gait instability and a risk factor for falls. Gait initiation requires complex processes, and it is important to evaluate gait variability not only during steady-state gait but also during gait initiation. However, the effect of the diurnal pattern on variability in gait characteristics is still unknown. The aim of this study was to investigate the effect of the diurnal pattern on initiation and steady-state gait variability in elderly inpatients. Thirty-seven elderly inpatients (28 women; mean age, 79.7 ± 9.5 years) who could walk without support were sampled in this study. The quantitative measure of gait variability was evaluated using the coefficient of variation (CV) based on four consecutive stride durations determined using triaxial accelerometers. Gait characteristics were evaluated during initiation and steady-state gait and defined as initiation CV and steady-state CV, respectively. This measurement was performed at two time points, morning and daytime. There was no significant difference between initiation and steady-state gait characteristics in the daytime condition. However, in the morning condition, the initiation CV was higher than the steady-state CV. Furthermore, the initiation CV was higher in the morning than during daytime (p < 0.01). Our study revealed that the variability of initiation gait is higher in the morning. It may be important to assess the risk of falls, including initiation gait, in the morning.

Gait in Elderly Glaucoma: Impact of Lighting Conditions, Changes in Lighting, and Fear of Falling.

PurposeThe purpose of this study was to characterize the impact of lighting changes on gait in elderly patients with glaucoma and evaluate whether associations are mediated by fear of falling (FOF).MethodsGait initiation and parameters measured with the GAITRite Electronic Walkway were captured in normal indoor light, then in dim light, and again in normal light (normal post dim [NPD]). Participants’ right and left eye visual fields (VFs) were merged into integrated VF (IVF) sensitivities. FOF was evaluated using a Rasch-analyzed questionnaire. Multivariable regression models evaluated whether IVF sensitivity was associated with lighting-dependent gait changes and if this relationship was mediated by FOF.ResultsIn 213 participants (mean age = 71.4 years), gait initiation in dim light took longer with more VF damage (P = 0.02). Greater VF damage was associated with slower gait in dim (P < 0.001) and NPD (P = 0.003) lighting, as well as shorter strides (P = 0.02), broader stance (P = 0.003), and more variable stride velocity and length in all lighting (all P < 0.03). When moving from normal to dim lighting, those with more VF damage slowed gait and cadence, shortened stride length, and lengthened double support time (all P < 0.001). Velocity, cadence, and double support time did not return to baseline in NPD lighting (all P < 0.05). Fear of falling did not appear to mediate the relationship between IVF sensitivity and lighting-dependent gait changes.ConclusionsPatients with more VF damage demonstrate gait degradation in extreme or changing lighting, which is not mediated by FOF.Translational RelevanceQuantitative spatiotemporal gait evaluation reveals lighting-associated impairment, supporting patient-reported difficulty with nonideal lighting and equipping providers to advise patients about limitations.

Development of temporal and spatial characteristics of anticipatory postural adjustments during gait initiation in children aged 3-10years.

This study aimed to analyze the development of direction specificities of temporal and spatial control and the coordination pattern of anticipatory postural adjustment (APA) along the anteroposterior (AP) and mediolateral (ML) directions during gait initiation (GI) in children aged 3-10years. This study included 72 healthy children aged 3-10years and 14 young adults. The child population was divided into four groups by age: 3-4, 5-6, 7-8, and 9-10years. The GI task included GI using the dominant limb. The peak center of feet pressure (COP) shifts during APAs (APApeak), initiation time of COP shifts (APAonset), and the COP vectors in the horizontal plane were calculated to evaluate the direction specificity of spatial, temporal, and coordination control, respectively. A difference in direction specificity development was found for the APApeak. The APApeak in the mediolateral axis, but not in the anteroposterior axis, was significantly higher in the 7-8years age group than in other groups. Although APAonset was not found for direction specificity, a significant difference between the adult and children groups (5-6years, 7-8years, and 9-10years) was observed in the direction of the COP vector. In conclusion, the developmental process of the spatial, temporal, and coordination control of APAs during GI varied with age. Furthermore, the spatial control and coordination pattern of APAs was found to be direction specific. All components of APAs, namely temporal and spatial control, coordination pattern, and direction specificities, should be analyzed to capture the developmental process of anticipatory postural control.

Deep Brain Stimulation for Stroke: Continuous Stimulation of the Pedunculopontine Tegmental Nucleus has no Impact on Skilled Walking in Rats After Photothrombotic Stroke.

Gait impairment after stroke is considered as a loss of cerebral function but is also the result of dysfunctional cerebral signals travelling to the spinal motor centres. A therapeutic option to restore disturbed cerebral network activity is deep brain stimulation (DBS). A promising target for neuromodulation might be the pedunculopontine tegmental nucleus (PPTg), which contributes to the initiation and control of gait. To test this hypothesis, we trained eighteen rats to cross a horizontal ladder and a wooden beam before inflicting a photothrombosis in the right sensorimotor cortex and implanting a stimulating electrode in the ipsilateral PPTg. Continuous high-frequency DBS (130 Hz; amplitude 55 ± 5 μA) of rats for 10 days yielded no significant improvement of skilled walking when examined with the ladder rung walking test and beam walking test compared to sham-stimulation. In contrast to DBS of the cuneiform nucleus, PPTg-stimulation improves neither control of gait nor balance after stroke.

A systematic review of center of pressure measures to quantify gait changes in older adults.

Measures of gait center of pressure (COP) can be recorded using simple available technologies in clinical settings and thus can be used to characterize gait quality in older adults and its relationship to falls. The aim of this systematic review was to investigate the association between measures of gait COP and aging and falls. A comprehensive search of electronic databases including MEDLINE, Embase, Cochrane Central Register of Controlled Trials, CINAHL (EBSCO), Ageline (EBSCO) and Scopus was performed. The initial search yielded 2809 papers. After removing duplicates and applying study inclusion/exclusion criteria, 34 papers were included in the review. Gait COP has been examined during three tasks: normal walking, gait initiation, and obstacle negotiation. The majority of studies examined mean COP position and velocity as outcome measures. Overall, gait in older adults was characterized by more medial COP trajectory in normal walking and lower average anterior-posterior and medio-lateral COP displacements and velocity in both gait initiation and obstacle crossing. Moreover, findings suggest that Tai chi training can enhance older adults' balance control during gait initiation as demonstrated by greater COP backward, medial and forward shift in all three phases of gait initiation. These findings should be interpreted cautiously due to inadequacy of evidence as well as methodological limitations of the studies such as small sample size, limited numbers of 'fallers', lack of a control group, and lack of interpretation of COP outcomes with respect to fall risk. COP measures can be adopted to assess fall-related gait changes in older adults but more complex measures of COP that reveal the dynamic nature of COP behavior in step-to-step variations are needed to adequately characterize gait changes in older adults.

Can google glass™ technology improve freezing of gait in parkinsonism? A pilot study

Purpose Freezing of gait (FOG) is a disabling phenomenon defined by the periodic absence or reduction of forward progression of the feet despite the intention to walk. We sought to understand whether Google Glass (GG), a lightweight wearable device that provides simultaneous visual-auditory cues, might improve FOG in parkinsonism. Methods Patients with parkinsonism and FOG utilized GG custom-made auditory-visual cue applications: “Walk With Me” and “Unfreeze Me” in a single session intervention. We recorded ambulation time with and without GG under multiple conditions including 25 feet straight walk, dual task of performing serial 7’s while straight walking, 180 degree turn after walking 25 feet, and walking through a doorway. FOG and patient experience questionnaires were administered. Results Using the GG “Walk With Me” program, improvements were noted in the following: average 25 feet straight walk by 0.32 s (SD 2.12); average dual task of serial 7’s and 25 feet straight walk by 1.79 s (SD 2.91); and average walk through doorway by 0.59 s (SD 0.81). Average 180 degree turn after 25 feet walk worsened by 1.89 s (SD 10.66). Using the “Unfreeze Me” program, only the average dual task of serial 7’s and 25 feet straight walk improved (better by 0.82 s (SD 3.08 sec). All other tasks had worse performance in terms of speed of completion. Conclusion This feasibility study provides preliminary data suggesting that some walking tasks may improve with GG, which uses various musical dance programs to provide visual and auditory cueing for patients with FOG. IMPLICATIONS FOR REHABILITATION Freezing of gait in parkinsonian syndromes is a disabling motor block described by patients as having their feet stuck to the floor leading to difficulty in initiation of gait and increased risk for falls. Wearable assistive devices such as Google Glass™ use visual and auditory cueing that may improve gait pattern in patients with freezing of gait. Augmented reality programs using wearable assistive devices are a home-based therapy, with the potential for reinforcing physical therapy techniques; this is especially meaningful during the COVID-19 pandemic when access to both medical and rehabilitative care has been curtailed.

Can dual-task paradigms predict Falls better than single task? – A systematic literature review

With about one third of adults aged 65 years and older being reported worldwide to fall each year, and an even higher prevalence with advancing age, aged-related falls and the associated disabilities and mortality are a major public health concern. In this context, identification of fall risk in healthy older adults is a key component of fall prevention. Since dual-task outcomes rely on the interaction between cognition and motor control, some studies have demonstrated the role of dual-task walking performance or costs in predicting future fallers. However, based on previous reviews on the topic, (1) discriminative and (2) predictive powers of dual tasks involving gait and a concurrent task are still a matter of debate, as is (3) their superiority over single tasks in terms of fall-risk prediction. Moreover, less attention has been paid to dual tasks involving postural control and transfers (such as gait initiation and turns) as motor tasks. In the present paper, we therefore systematically reviewed recent literature over the last 7 years in order to answer the three above mentioned questions regarding the future of lab-based dual tasks (involving posture, gait initiation, gait and turning) as easily applicable tests for identifying healthy older adult fallers. Despite great heterogeneity among included studies, we emphasized, among other things, the promising added value of dual tasks including turns and other transfers, such as in the Timed Up and Go test, for prediction of falls. Further investigation of these is thus warranted.

Changes in motion patterns among pregnant women turning while carrying an object after rising from a chair

During pregnancy, changes in physical function, such as increases in the mass and volume of the abdomen, affect spinal alignment and the postural control system. Pregnant women often experience changes in motion patterns, as well as an increased risk of falling, during routine tasks such as rising from a chair and carrying objects. The present study aimed to analyze changes in motion patterns among pregnant women when performing a motion task involving rising from a chair, picking up plates, and walking forward while carrying the plates after turning. The study participants were nine pregnant and seven nulliparous women. The pregnant women were examined between the 16th and 18th, 24th and 25th and 32nd and 33rd weeks of gestation. The nulliparous women were examined on one occasion. Reflective markers were attached to anatomical landmarks on the participants, after which, their motion was captured using a three-dimensional motion analysis system and force plates. During a series of motions, displacement and velocity of the center of pressure (COP) coordinates and ground reaction forces (GRFs) were calculated.Differences in the COP displacement for anticipatory postural adjustments, variation in the COP velocity, and second peak value of vertical GRF during gait initiation were observed between pregnant and nulliparous women. In pregnant women, changes in strategies involving changing direction were observed at gait initiation. These findings suggest that, to reduce the risk of falls, instruction regarding motion in consideration of environmental factors during pregnancy is needed, as are interventions for the postural control system.

P.236 Tobacco use in pregnant women with bipolar disorder: a cohort study

To investigate anticipatory postural adjustments (APAs) during the transitional movement task of gait initiation (GI) in individuals acutely after a concussion.Cohort study.University research center.A population-based sample of participants (N=84) divided into 2 equal groups of acutely postconcussion and healthy student athletes.Participants were tested on 2 occasions: a preinjury baseline test and then the concussion group was retested acutely postconcussion and the healthy student athlete group again at a similar time. All participants completed 5 trials of GI on 4 forceplates.The dependent variables were the displacement and velocity of the center of pressure (COP) during the APA phase and initial step kinematics. Comparisons were made with a 2 (group) × 2 (time) repeated-measures analysis of variance.There was a significant interaction for COP posterior displacement (P<.001) and lateral displacement (P<.001). Posteriorly, post hoc testing identified a significant reduction in the concussion group (pretest: 5.7±1.6cm; posttest: 2.6±2.1cm; P<.001), but no difference in the healthy student athlete group (pretest: 4.0±1.6cm; posttest: 4.0±2.5cm; P=.921). Laterally, post hoc testing identified a significant reduction in the concussion group (pretest: 5.8±2.1cm; posttest: 3.8±1.8cm; P<.001), but no difference in the healthy student athlete group (pretest: 5.0±2.5cm; posttest: 5.2±2.4cm; P=.485).The results of this study suggest difficulty in the planning and execution of GI acutely postconcussion, and posterior APA displacement and velocity are highly effective measures of impaired postural control. Finally, the APA phase is linked to the supplementary motor area, which suggests a supraspinal contribution to postconcussion impaired postural control.

Pre-Movement Cortico-Muscular Dynamics Underlying Improved Parkinson Gait Initiation after Instructed Arm Swing.

Background:The supplementary motor area (SMA) is implicated in both motor initiation and stereotypic multi-limb movements such as walking with arm swing. Gait in Parkinson’s disease exhibits starting difficulties and reduced arm swing, consistent with reduced SMA activity.Objective:We tested whether enhanced arm swing could improve Parkinson gait initiation and assessed whether increased SMA activity during preparation might facilitate such improvement.Methods:Effects of instructed arm swing on cortical activity, muscle activity and kinematics were assessed by ambulant EEG, EMG, accelerometers and video in 17 Parkinson patients and 19 controls. At baseline, all participants repeatedly started walking after a simple auditory cue. Next, patients started walking at this cue, which now meant starting with enhanced arm swing. EEG changes over the putative SMA and leg motor cortex were assessed by event related spectral perturbation (ERSP) analysis of recordings at Fz and Cz.Results:Over the putative SMA location (Fz), natural PD gait initiation showed enhanced alpha/theta synchronization around the auditory cue, and reduced alpha/beta desynchronization during gait preparation and movement onset, compared to controls. Leg muscle activity in patients was reduced during preparation and movement onset, while the latter was delayed compared to controls. When starting with enhanced arm swing, these group differences virtually disappeared.Conclusion:Instructed arm swing improves Parkinson gait initiation. ERSP normalization around the cue indicates that the attributed information may serve as a semi-internal cue, recruiting an internalized motor program to overcome initiation difficulties.

Age differences in anticipatory and executory mechanisms of gait initiation following unexpected balance perturbations

PurposeAn age-related decline in anticipatory postural mechanisms has been reported during gait initiation; however, it is unclear whether such decline may jeopardize whole-body stability following unexpected balance perturbations. This study aimed to compare young and older individuals’ ability to generate postural responses and preserve stability in response to external waist perturbations delivered within gait initiation.MethodsTen young and ten older participants performed 10 gait initiation trials followed by 48 unperturbed and 12 perturbed trials in a random order. A stereophotogrammetric system and three force platforms were used to quantify mechanical parameters from the preparatory phase (e.g., timing and amplitude of postural adjustments) and from the stepping phase (e.g., step characteristics and dynamic stability). Activation patterns of lower leg muscles were determined by surface electromyography.ResultsOlder participants responded to perturbation with lower increase in both magnitude (p < 0.001; η2p = 0.62) and duration (p = 0.001; η2p = 0.39) of preparatory parameters and soleus muscle activity (p < 0.001; η2p = 0.55), causing shorter (p < 0.001; η2p = 0.59) and lower (p < 0.001; η2p = 0.43) stepping, compared to young participants. Interestingly, young participants showed greater correlations between preparatory phase parameters and dynamic stability of the first step than older participants (average r of − 0.40 and − 0.06, respectively).ConclusionThe results suggest that young participants took more time than older to adjust the anticipatory biomechanical response to perturbation attempting to preserve balance during stepping. In contrast, older adults were unable to modify their anticipatory adjustments in response to perturbation and mainly relied on compensatory mechanisms attempting to preserve stability via a more cautious stepping strategy.

Analysis of sloped gait: How many steps are needed to reach steady-state walking speed after gait initiation?

BackgroundGait initiation in level walking is suggested to take three steps before reaching steady-state walking speed. In sloped gait, it is not clear if the general recommendation of level gait can be used. Research questionThe aim of this study was to investigate (1) if steady-state walking speed is reached within four steps in sloped gait, and (2) to what extent the number of initial steps cause differences in step length, cadence and ground reaction force (GRF). MethodsFourteen healthy participants walked on an instrumented ramp at inclinations of 0°, ±6°, ±12°, and ±18°, covering slight (clinical application) to steep (hiking and mountaineering) slopes. The starting position on the ramp was adjusted to collect each of the first to fourth step using a 12 infrared-camera motion capture system and two force plates. For each slope condition steady-state walking speed was determined using the ratio of the braking and propulsion impulse (ratio pap;pbrakingppropulsion) and the resultant Centre of Mass (CoM) speed (velCoM). Statistical differences between steps were calculated by using a Friedman ANOVA and pairwise post-hoc Wilcoxon tests. ResultsIn all inclinations, ≥90 % (uphill) and ≥95 % (downhill) of steady-state speed regarding ratio pap and maximum velCoM was reached with the 3rd step. In the level and uphill condition the 4th step showed a slight decrease in velCoM. In uphill and downhill condition, the acceleration was mainly generated due to the increase in cadence with significant increases between the 1st and 2nd step as well as between the 2nd and 3rd step. A significant increase in step length was only observed in the uphill conditions. SignificanceSteady-state walking speed was reached with the 3rd step and thus, walkways which allow for two initial steps seem to be appropriate for uphill and downhill gait analysis for inclinations up to ±18°.

Evaluation of Gait and Quality of Movement Analysis in Children With Developmental Coordination Disorder

A Child with developmental coordination disorder will have a higher incidence of movement difficulties and challenges to participate in activities of daily living. There is no exploration of the Gait pattern and the quality of movement exhibited by children’s of developmental coordination disorder in Tamilnadu context. Children's of age 5 to 10 years were included, and after baseline screening with Diagnostic and statistical manual for mental disorder-5 criteria, children were allowed for further examination. MABC-2 and DCDQ were used to screen and rate the movement skill. Of the total sample of 100, 80% exhibited difficulties in Gait initiation, progression and integration of motor skills. Results proved that sensory integration difficulties experienced by the children with DCD were not related to motor coordination. One hundred children included in the study experiences difficulties in participation with a peer group, awareness of body position sense, balance, and activity integration and planning. The current study concludes and adds evidence that each child with DCD is unique but presented with difficulties in gait initiation and integration.

Understanding Human Neural Control of Short-term Gait Adaptation to the Split-belt Treadmill

Many studies of split-belt treadmill adaptation have been focused on the biomechanical changes that occur in response to walking on belts at different speeds. This process of adaptation, and the ensuing aftereffects that are present when participants return to typical treadmill walking, have inspired the potential use of the split-belt treadmill as a rehabilitation tool. However, a full systematic review of the current split-belt treadmill literature has not yet been published to consolidate what is known about how the human central nervous system (CNS) controls adaptation to this type of symmetry perturbation. A systematic literature search identified 55 studies that investigated the neural control of human gait adaptation to a split-belt treadmill. Studies of infants and manipulated sensory feedback in healthy adults suggest that the initial gait adjustments to split-belt walking are reliant on proprioceptive feedback to inform central pattern generators to modify lower limb muscle activation patterns appropriately. Simultaneously, this literature suggested that proprioceptive and visual feedback inform supraspinal centres for motor planning and motor output to adapt and store a new and efficient gait pattern to walk on belts at different speeds. However, evidence from participants with brain injury (post-stroke, cerebellar lesions) suggest that injury impedes, but does not completely take away, the ability to adjust and adapt aspects of the gait pattern to split-belts. The model proposed from this review provides the overarching roles of the CNS in the adaptation process, specifically in short-term, and potential sites of focus within the human CNS for future rehabilitation-based work.

Modification‐based periodic gait planning for a 3‐D bipedal robot with two underactuated DOFs

AbstractThis work considers the periodic gait planning of a 3‐D bipedal robot with two underactuated DOFs. Instead of planning a periodic gait by a traditional direct parameter optimization search, which is usually time‐consuming, we present a novel modification‐based periodic motion planning method, which consists of two steps. Firstly, an initial gait is obtained by relaxing the periodicity constraints in the optimization search. Then, the initial gait is modified to be a periodic one. To achieve a successful gait modification, the gait modification theory is firstly presented, and a gait modification strategy is then proposed. Finally, the presented method is illustrated on the underactuated 3‐D biped, and a comparative simulation study is provided. It is shown that, compared with the traditional method, the time cost in the presented method is significantly reduced.

Action observation improves sit-to-walk in patients with Parkinson's disease and freezing of gait. Biomechanical analysis of performance

IntroductionFreezing of gait (FoG) is one of the most disabling gait disorders in Parkinson's disease (PD), reflecting motor and cognitive impairments, mainly related to dopamine deficiency. Recent studies investigating kinematic and kinetic factors affecting gait in these patients showed a postural instability characterized by disturbed weight-shifting, inappropriate anticipatory postural adjustment, worse reactive postural control, and a difficulty executing complex motor tasks (i.e. sit-to-walk). These symptoms are difficult to alleviate and not very responsive to Levodopa. For this reason, additional therapeutic actions based on specific therapeutic protocols may help patients with their daily lives. We conducted a randomized control trial aimed to test if two clinical protocols for PD patients with FoG were effective to improve postural control. MethodsRehabilitation protocols, conceived to improve gait, were based on learning motor exercises with the Action Observation plus Sonification (AOS) technique, or by the use of external sensory cues. We collected biomechanical data (Center of Mass COM, Center of Pressure COP, and moving timings), using the sit-to-walk task as a measure of motor and gait performance. ResultsKinetic and kinematic data showed that when treatment effects consolidate, patients treated with AOS protocol are more efficient in merging subsequent motor tasks (sit-to-stand and gait initiation), and diminished the total moving time and the area of the COP positions. ConclusionWe demonstrated for the first time that PD patients with FoG treated with an AOS protocol aimed at relearning appropriate gait patterns increased balance control and re-acquired more efficient postural control.

The effects of light touch cue on gait initiation in patients with Parkinson's disease

IntroductionOne of the common impairments in patients with Parkinson's disease (PD) is disturbance of gait initiation. A light touch cue improves postural stability in patients with PD. Little is known about the effects of a light touch cue on gait initiation. This study investigated the effects of a light touch on gait initiation in patients with PD. MethodsThis study was a cross-sectional study design. Sixteen patients with PD (Hoehn & Yahr stage 2–3) participated in the study and were evaluated two gait conditions (no touch (NT) and light touch (LT) conditions). Gait initiation was divided into 5 events including event A, B, C, D, and E. Outcome measures included maximum center of pressure (COP) displacement and velocity in anteroposterior (AP) and mediolateral (ML) directions, and the first step time. ResultsParticipants with LT had greater COP displacement compared with the NT condition in all events of gait initiation except COP-AP displacement in event D. Additionally, the COP velocity in LT condition was faster than the NT condition in COP-ML velocity in event A, COP-AP velocity in event B, COP-AP velocity and COP-ML velocity in event C. Moreover, participants with LT presented significantly shorter the first step time than the NT condition. ConclusionsThese findings demonstrated that a light touch cue improved gait initiation in patients with PD by increased weight shifting to initial stance limb, increased postural stability of stance limb, increased velocity of weight transfer toward stance limb, and a shortened first step time.

Obesity-related alterations in anticipatory postural mechanisms associated with gait initiation.

Obesity is known to have a detrimental effect on balance and motor performance during daily motor tasks. However, it remains unclear whether these obesity-related impairments are due to deficient anticipatory postural adjustments (APA) that precede voluntary movement. The objective of this study was to examine the effects of obesity on APA and the impacts related on motor performance and mediolateral postural stability during gait initiation. Fifteen obese and ten normal-weight young participants performed a series of gait initiation at their preferred speed. Our results showed that the durations and amplitudes of APA along both anteroposterior and mediolateral directions did not differ between the two groups (P > 0.05). In contrast, compared to normal-weight participants, mechanical effectiveness of APA was reduced in obese participants (P < 0.05). As a result, we observed a decreased motor performance (P < 0.05), in terms of peak anteroposterior center-of-mass velocity at the end of the first step, and a reduced mediolateral stability at swing foot contact in obese participants compared to normal-weight participants (P < 0.05). These findings suggest that APA effectiveness during gait initiation is reduced in obese adults, resulting in a decrease of both mediolateral stability and motor performance compared to their lean counterparts.

Gait initiation and lateral wedge insole for individuals with early knee osteoarthritis

BackgroundPeople with knee osteoarthritis are at higher risk of postural deficits and locomotor adaptations which could be manifested in transient tasks like gait initiation. To better understand the effect of early knee osteoarthritis on gait initiation, we measured the gait initiation in two groups of early knee osteoarthritis and healthy age-matched controls and assessed the effect of lateral wedge insole in knee osteoarthritis group. MethodsTwenty-one individuals with early knee osteoarthritis, mean (SD) age = 53.1 (7.4, years), and 19 age- and sex-matched asymptomatic healthy individuals, mean (SD) age = 47.5 (11.2, years), participated. Centre of pressure trajectories were used to quantify the two phases of gait initiation in barefoot condition: anticipatory postural adjustment, and locomotor phase. The immediate and four-week effect of lateral wedge insole and shod condition were also compared for individuals in knee osteoarthritis group. FindingsLonger duration of anticipatory postural adjustment phase (P = 0.046), locomotor phase (P = 0.049), and total duration of gait initiation (P = 0.035) with lower length and velocity of the center of pressure trajectories in anticipatory postural adjustment phase (P = 0.002, and 0.008, respectively) were observed in knee osteoarthritis group compared to controls. Lateral wedge insole could increase the length and velocity of the centre of pressure in locomotor phase compared to barefoot condition (P = 0.001, and 0.002, respectively). InterpretationOur study outlined that people with early knee osteoarthritis adopt different gait initiation strategies mainly in postural preparation phase. The potential effect of lateral wedge insole was shown with better performance of the locomotor phase. Clinical trial registry numberIRCT2016060628310N1.

Impairments in Dynamic Postural Control across Concussion Clinical Milestones.

The aim of this study was to assess gait initiation (GI) performance longitudinally across clinical concussion recovery milestones through return to participation (RTP). We recruited 54 collegiate student-athletes, 27 with concussions and 27 matched controls (15 female and 12 male per group). Participants performed five trials of GI at baseline and again at five post-concussion clinical milestones: 1) Acute, the day clinical tests achieved baseline values on the 2) Balance Error Scoring System (BESS), 3) Immediate Post-Concussion Assessment and Cognitive Test ImPACT, 4) Asymptomatic, and 5) RTP Day. GI performance on six outcome measures (anterior/posterior and medial/lateral center of pressure displacements and velocities during the anticipatory postural adjustment [APA] phase and initial step length and velocity) with repeated-measures mixed model and pair-wise post hoc. A reliable change index (RCI) was calculated, and post-concussion participant's performance was compared to the RCI at milestones. There were significant interactions for APA posterior and lateral displacement, APA posterior velocity, step length, and step velocity. The post-hoc tests identified significant deficits across clinical milestones and at RTP for APA posterior and lateral displacement, step length, and step velocity. There were no post-hoc differences for any outcome measure in the control group. At RTP, 85.2-88.9% of concussion participants had at least one outcome measure which exceeded the 80% or 95% RCI. The primary finding of this study was persistent impairments in dynamic postural control, suggesting ongoing neurophysiological impairment despite clinical recovery. These results suggest that collegiate student-athletes may be RTP before neurophysiological recovery and potentially exposing themselves to elevated risk of recurrent concussion or subsequent musculoskeletal injury.