Limb Support Phase Research Articles

Forces required to dynamize sliding screws in gamma nail and selfdynamizable internal fixator.

Single limb support phase of the gait-cycle in patients who are treated for a pertrochanteric fracture is characterized by transversal loads acting on the lag screw, tending to block its dynamization. If the simultaneous axial force overcomes transversal loads of the sliding screw, the dynamization can still occur. Biomechanical investigation was performed for three types of dynamic implants: Gamma Nail, and two types of Selfdynamizable Internal Fixators (SIF) - SIF-7 (containing two 7mm non-cannulated sliding screws), and SIF-10 (containing one 10mm cannulated sliding screw). Contact surface between the stem and the sliding screws is larger in SIF implants than in Gamma Nail, as the stem of Gamma Nail is hollow. A special testing device was designed for this study to provide simultaneous application of a controlled sliding screws bending moment and a controlled transversal load on sliding screws (Qt) without using of weights. Using each of the implants, axial forces required to initiate sliding screws dynamization (Qa) were applied and measured using a tensile testing machine, for several values of sliding screws bending moment. Standard least-squares method was used to present the results through the linear regression model. Positive correlation between Qt and Qa was confirmed (p < 0.05). While performing higher bending moments in all the tested implants, Qa was higher than it could be provided by the body weight. It was the highest in Gamma Nail, and the lowest in SIF-10. A larger contact surface between a sliding screw and stem results in lower forces required to initiate dynamization of a sliding screw. Patients treated for a pertrochanteric fracture by a sliding screw internal fixation who have longer femoral neck or higher body weight could have different programme of early postoperative rehabilitation than lighter patients or patients with shorter femoral neck.

Dynamics of Center of Pressure Trajectory in Gait: Unilateral Transfemoral Amputees Versus Non-Disabled Individuals.

The primary goal of rehabilitation for individuals with lower limb amputation, particularly those with unilateral transfemoral amputation (uTFA), is to restore their ability to walk independently. Effective control of the center of pressure (COP) during gait is vital for maintaining balance and stability, yet it poses a significant challenge for individuals with uTFA. This study aims to study the COP during gait in individuals with uTFA and elucidate their unique compensatory strategies. This study involved 12 uTFA participants and age-matched non-disabled controls, with gait and COP trajectory data collected using an instrumented treadmill. Gait and COP parameters between the control limb (CL), prosthetic limb (PL), and intact limb (IL) were compared. Notably, the mediolateral displacement of COP in PL exhibited significant lateral displacement compared to the CL from 30% to 60% of the stance. In 20% to 45% of the stance, the COP forward speed of PL was significantly higher than that of the IL. Furthermore, during the initial 20% of the stance, the vertical ground reaction force of PL was significantly lower than that of IL. Additionally, individuals with uTFA exhibited a distinct gait pattern with altered duration of loading response, single limb support, pre-swing and swing phases, and step time. These findings indicate the adaptability of individuals with uTFA in weight transfer, balance control, and pressure distribution on gait stability. In conclusion, this study provides valuable insights into the unique gait dynamics and balance strategies of uTFA patients, highlighting the importance of optimizing prosthetic design, alignment procedures, and rehabilitation programs to enhance gait patterns and reduce the risk of injuries due to compensatory movements.

Age-related differences in lower limb muscle activation patterns and balance control strategies while walking over a compliant surface

Substantial evidence demonstrates that falls in older adults are leading causes of fatal and non-fatal injuries and lead to negative impacts on the quality of life in the aging population. Most falls in older fallers result from unrecoverable limb collapse during falling momentum control in the single limb support (SLS) phase. To understand why older adults are more likely to fall than younger adults, we investigated age-related differences in knee extensor eccentric control, lower limb muscle activation patterns, and their relation to balance control. Ten older and ten younger healthy adults were compared during balance control while walking on a compliant surface. There was a positive correlation between knee extensor eccentric work in the perturbed leg and the swinging leg’s speed and margin of stability. In comparison to younger adults, older adults demonstrated (1) less eccentric work, reduced eccentric electromyography burst duration in the perturbed leg, (2) higher postural sway during SLS, and (3) impaired swinging leg balance control. The group-specific muscle synergy showed that older adults had a prominent ankle muscle activation, while younger adults exhibited a more prominent hip muscle activation. These findings provide insight into targeted balance rehabilitation directions to improve postural stability and reduce falls in older adults.

Validation of a Wearable System for Lower Extremity Assessment.

Remote assessment and diagnosis of functional impairment caused by osteoarthritis (OA) of the knee can achieve early intervention of patients' functional impairment, prevent the deterioration of OA of the knee, and provide functional remote screening for patients with knee OA. This study introduced an inertial measurement unit (IMU) sensor-based system to assess lower extremity function and perform gait analysis. Then, we compared its accuracy to gold-standard motion capture and gait measurement systems. Nine adults were selected to participate in a comparative study of gait assessment outcomes using an IMU sensor-based wearable system, a gold-standard motion capture system, and a pressure-based gait analysis system. The subject walked on a path that incorporated all three systems. Data analysis was performed on spatiotemporal gait parameters, including velocity, cycle time, cadence, and stride length. This was followed by gait phases, including stance, swing, double stance, and single limb support phases. Data were processed using the data processing software of each system. An independent sample t-test was conducted for inter-group comparison to analyze the data. The spatiotemporal gait parameters of the systems demonstrated excellent consistency, and the gait phases showed high consistency. Compared to the gold-standard pressure-based gait analysis system (the GATERite system), the mean gait cycle time results were 1.124 s vs. 1.127 s (p = 0.404); cadence was 93.333 steps/min vs. 94.189 steps/min (p = 0.482); stance phase was 60.89% vs. 63.26% (p < 0.001); swing phase was 39.11% vs. 36.74% (p < 0.001); stride length was 1.404 m vs. 1.420 m (p = 0.743); speed was 1.093 m/s vs. 1.110 m/s (p = 0.725). Compared to the gold-standard video-based motion capture system, the root mean square error was 2.7° for the hip angle and 2.6° for the knee angle. This IMU-based wearable system delivered precise measuring results to evaluate patients with knee OA. This technology can also be used to guide rehabilitation exercises for patients with knee OA.

Contribution of Lower Limb Eccentric Control to Balance Recovery From Surface Drop Perturbations

<h3>Research Objectives</h3> To investigate age-related differences in eccentric neuromuscular control of the knee and its relationship to postural stability during balance recovery following unexpected surface drop perturbations. <h3>Design</h3> Cross sectional, comparative study. <h3>Setting</h3> General community. <h3>Participants</h3> Healthy, community dwelling, and ambulatory older (n=10, age=75.3±5.6) and younger (n=10, age=25.7±2.0) adults. <h3>Interventions</h3> N/A. <h3>Main Outcome Measures</h3> 1) Eccentric knee extension work (J/kg); 2) EMG burst duration (s) in the perturbed leg during the single limb support phase of compensatory stepping; 3) postural sway (standard deviation of center of mass acceleration, m/s2) in the anterior-posterior (A-P), medio-lateral (M-L), vertical directions; 4) margin of stability (MoS) of first compensatory step touchdown after perturbations. <h3>Results</h3> Following an 8 cm surface drop perturbation at gait initiation, older adults (OA) compared to younger adults (YA), demonstrated reduced eccentric knee extensor work (OA: 0.013±0.005 J/kg, YA: 0.020±0.007 J/kg, p=0.034), rectus femoris EMG burst duration (OA: 0.35±0.07s, YA: 0.47±0.08s, p< 0.01), MoS (OA: 68.41±14.30%, YA: 82.88±13.24%, p=0.04), and increased postural sway in all directions (A-P: OA: 2.29±1.38m/s2, YA: 1.03±0.54 m/s2, p=0.02, M-L: OA: 1.42±0.71 m/s2,YA: 0.72±0.41m/s2, p=0.02, Vertical: OA: 4.17±1.01m/s2, YA: 1.74±0.86m/s2, p< 0.01). There was a negative correlation between eccentric work and postural sway in the M-L direction (r = -0.54, p=0.012) and a positive correlation between eccentric work and MoS (r = +0.55, p=0.009). <h3>Conclusions</h3> This study is the first to demonstrate that age-related differences in eccentric control of the perturbed leg are associated with maintaining postural stability and improving compensatory stepping balance response following unexpected surface drop perturbations. Older adults demonstrated deficits in eccentric knee extensor control and this contributed to greater postural sway and unstable compensatory stepping during balance recovery. This finding provides insight into mechanisms of fall recovery and directions for lower limb strengthening exercises for aging populations. Future investigations of these mechanisms in aging populations with a disability due to neurological or musculoskeletal impairments such as Parkinson's disease, stroke, and osteoarthritis are warranted. <h3>Author(s) Disclosures</h3> The contents of this abstract were developed under a grant from NIDILRR (90AR5028).

Changes in sensory, postural stability and gait functions depending on cognitive decline, and possible markers for detection of cognitive status

BackgroundNumerous people never receive a formal dementia diagnosis. This issue can be addressed by early detection systems that utilize alternative forms of classification, such as gait, balance, and sensory function parameters. In the present study, said functions were compared between older adults with healthy cognition, older adults with low executive function, and older adults with cognitive impairment, to determine which parameters can be used to distinguish these groups.ResultsA group of cognitively healthy older men was found to have a significantly greater gait cadence than both the low executive function group (113.1 ± 6.8 vs. 108.0 ± 6.3 steps/min, p = 0.032) and the cognitively impaired group (113.1 ± 6.8 vs. 107.1 ± 7.4 steps/min, p = 0.009). The group with low executive function was found to have more gait stability than the impaired cognition group, represented by the single limb support phase (39.7 ± 1.2 vs. 38.6 ± 1.3%, p = 0.027). Additionally, the healthy cognition group had significantly greater overall postural stability than the impaired cognition group (0.6 ± 0.1 vs. 1.1 ± 0.1, p = 0.003), and the low executive function group had significantly greater mediolateral postural stability than the impaired cognition group (0.2 ± 0.1 vs. 0.6 ± 0.6, p = 0.012). The low executive function group had fewer mistakes on the sentence recognition test than the cognitively impaired (2.2 ± 3.6 vs. 5.9 ± 6.4, p = 0.005). There were no significant differences in visual capacity, however, the low executive function group displayed an overall greatest ability.ConclusionsOlder adults with low executive function showcased a lower walking pace, but their postural stability and sensory functions did not differ from those of the older adults with healthy cognition. The variables concluded as good cognitive status markers were (1) gait cadence for dividing cognitively healthy from the rest and (2) single limb support portion, mediolateral stability index, and the number of mistakes on the sentence recognition test for discerning between the low executive function and cognitive impairment groups.

Responses of stance leg muscles induced by support surface translation during gait

This study determined the presence of the muscle responses to the support surface translation in the stance leg during gait and examined the effect of the direction and time point of the translation and that of the cognitive process on the responses. The rectus femoris (RF), biceps femoris (BF), soleus (SOL), and tibialis anterior (TA) muscles in the stance leg were tested. There was no significant effect of cognitive process on the electromyographic (EMG) activity induced by the translation of the support surface. In all muscles except the SOL, the EMG amplitude increased 0–300 ​ms after the support surface translation at the initial stance (IS) or middle stance (MS) of the tested leg. This means that the EMG activity in the leg muscles other than the SOL occurs after the support surface translation at the IS or MS no matter the direction of the translation. The EMG amplitude was not changed after the translation at the late stance, indicating that the translation does not influence the EMG amplitude at the double limb support phase with the tested leg behind the other. In the SOL, the EMG amplitude increased after the backward translation at the IS and after the forward translation at the MS, but decreased after the forward translation at the IS, indicating that the support surface translation-induced change in the EMG amplitude of the SOL is dependent on its direction. The change in the EMG amplitude of the TA and RF induced by the forward translation was greatest when the translation was given at the IS. In the SOL, the decrease in the EMG amplitude after the forward translation and the increase in the amplitude after the backward translation were greatest at the IS. Taken together, the change in the EMG amplitude induced by the support surface translation is greatest when the translation is given at the IS. The increase in the EMG amplitude in the TA and RF after the forward translation was greater than that after the backward translation at the IS, indicating that the EMG activity of the frontal leg muscles after the forward translation is greater when the translation is given at the IS.

Морфофункциональная характеристика мышц коленного сустава у представителей семейства кошачьих

The article presents the morphological and functional characteristics of the knee joint muscles in representatives of the feline family. When studying the structural and functional features of the knee joint, a comprehensive methodological approach was used, including fine anatomical dissection, biomechanical modeling with subsequent analysis of the studied structures and survey radiography. The objects of research were 10 cats of both sexes in the age range from 1 to 6 years, without pathologies of the musculoskeletal system, kept at home. Based on the conducted studies, both general patterns and specific features of the anatomical organization of the knee joint muscles in representatives of the feline family have been established. The revealed specific features are expressed in cats in the specific anatomical design of the tailor's muscle, consolidated with topographically conjugated fascial formations. A semi-webbed muscle, which is characterized by uneven development of its parts, as well as a slender muscle, the aponeurosis of which is involved in the formation of the achilles. Based on the results of biomechanical modeling, it was found that the features of the anatomical design of the knee joint muscles determine their functional purpose. It is shown that the strainer of the wide fascia of the thigh, being a multi-articular muscle, bends the hip, unbends and supinates the knee joint in synergy with the semi-tendon and popliteal muscles. The biceps femoral muscle in the limb support phase participates through its cranial head in the extension of the knee joint, and the slender muscle initiates its flexion and pronation. The revealed features of the distribution of sesamoid bones in the knee joint in a domestic cat may have an applied value in the issues of objective decoding of radiographic information, as well as differential diagnosis of arthropathies of the knee joint. The obtained normative data can be used in assessing the condition of the musculoskeletal system of the studied animals, deviations in its morphogenesis and deciphering the mechanism of myopathy development.

Determination of the correlation between muscle forces obtained from OpenSim and muscle activities obtained from electromyography in the elderly.

Measurement of muscle forces related to aging can help to better identify the gait impairment mechanisms in the elderly. To this end, musculoskeletal modeling has been developed to estimate muscle forces. This study aimed to check the validity of OpenSim modeling (i.e., computed muscle control) approach in elderly subjects. Kinematic and kinetic data and Electromyography (EMG) signals for four different muscles were collected in nine healthy elderly males during walking. Dynamic simulation was done within OpenSim. Correlation analysis was performed to quantitatively compare the maximum estimated muscle forces with maximum measured muscle activities during the first double limb support, single limb support, and the second double limb support phases. The area-time plots of OpenSim and EMG data during gait cycle were obtained for qualitative assessment. In quantitative assessment, a low to moderate correlation was observed for the peak of muscle force and muscle activation of four muscles during sub phases of gait. The muscle forces pattern from OpenSim was found to be relatively similar to the muscle activity pattern from EMG especially for Gastrocnemius Medialis. A low to moderate consistency between OpenSim and EMG in the elderly can be explained by using a single mathematical estimation approach.

Assessment of Spatio-Temporal Parameters of Human Gait Using Fiber Bragg Grating Sensor-Based Devices

Gait analysis is vital from the view of its established capacity as an indicator for neuromuscular disorders. Gait analysis is carried out in order to provide a quantified assessment of human movement which may aid orthopaedic and podiatric fraternity to suggest suitable therapeutic treatment. The proposed study comprises of two wearable non-invasive devices realized using FBG sensors i.e. Knee Angle Measurement Device (KAMD) for dynamic knee angle measurement and Forefoot Load Measurement Device (FLMD) for dynamic measurement of load on the forefoot. In the present study, the assessment of locomotion is illustrated and analyzed utilizing the developed devices without any time synchronization complexity. During locomotion, the swing and the stance phase is analyzed with respect to both knee joint angle and forefoot load which further reveals the complementary nature between them. In addition, FLMD can also be utilized for the evaluation of single and double limb support phases during locomotion. Furthermore, the novel cantilever approach utilized in the FLMD design ensures to acquire the load imparted specifically over the forefoot region which facilitates FLMD to be employed for assessment of other locomotory actions such as landing phase analysis during leaps, climbing stairs, treadmill tests etc. Also, the cantilever approach helps minimize the hysteresis effects on the device.

Effects of Gait Inducing Assist for Patients with Parkinson’s Disease on Double Support Phase During Gait

Parkinson’s disease (PD) is a common progressive neurodegenerative disease that affects a wide range of motor and non-motor symptoms. Freezing of gait (FOG) is such a motor symptom of PD that frequently results in falling, and almost half of PD patients suffer from FOG. In this study, we investigated the effectiveness of a robotic assistance system called UPS-PD, which was developed to suppress FOG. The double limb support phase (DLS) in a 10-m straight-line walking task, the gait time and step counts were measured in five PD subjects. In addition, the safety of the UPS-PD in a healthy person was investigated using OpenSim, and the DLS parameters in four healthy elderly subjects were evaluated. In the experiment with the PD patients, the DLS parameters of two subjects showed an improvement. Furthermore, the step length of one subject and the step length and walking speed of the other subject were improved. Moreover, there were no problems in terms of instability of gait in both the PD patients. The UPS-PD did not adversely affect the gait of healthy elderly subjects and the walking of a healthy subject model in the simulation. Therefore, the UPS-PD is considered to be a useful device for improving walking in PD patients.

The Application Study of Specific Ankle-Foot Orthoses for Stroke Patients by 3D Printing Somos NeXt

Objective: To investigate the effects of specific ankle-foot orthoses (AFOs) fabricated by 3D printing Somos NeXt on patients with stroke. Method: The ankle and foot were scanned by Artec 3D scanner. The model was performed with finite element analysis (FEA) using the software Abaqus to optimize the structure. Based on the structural optimization, AFOs were fabricated by 3D printing technique of Somos NeXt. Gait parameters were measured using the Gait Watch system. Seven sensors were bound to the sacrum, anterior side in the middle segment of the bilateral femoral femur, the median side at the proximal end of the bilateral tibia, and dorsal part of the bilateral foot. Results: The AFOs fabricated by 3D printing Somos NeXt significantly improved the temporalspatial parameters including velocity (20.75 vs. 17.38 cm/s) and stride length (47.88 vs. 43.63 cm), as well as increased cadence (52.5 vs. 48.75 times/min), while slightly decreased gait cycle (2.57 vs. 2.80 cm) and double limb support phase (34.00 vs. 37.13%). The AFOs also improved symmetry parameters such as the step length difference (9.75 vs. 15.25 cm), step length ratio (1.87 vs. 3.98), and swing phase ratio (0.99 vs. 0.75). Conclusion: The AFOs fabricated by 3D printing Somos NeXt have a significant effect on the improvement of velocity and stride length in patients with stroke.

Walking impairments after severe tibia plateau fractures. A gait pattern analysis

PurposeTibia plateau fractures are severe knee injuries which have a great impact on the patients' lives, but in what extend is not clear yet in the literature. The purpose of this study was to investigate the short-term gait alternations after severe tibia plateau fractures treated with circular Ilizarov frame. Materials & methodsGait pattern evaluation was performed to patients who were treated with circular Ilizarov frame after severe tibia plateau fractures (Schatzker IV-VI), three to six months after the frame removal. Gait evaluation performed by using a force plate in a walking platform at self selected speeds. Data collected from two walking tasks for each limb. Demographic, clinical, radiological and quality of life questionnaire (SF-12v2) and COST data were also collected. ResultsThe gait pattern of sixteen patients (aged 48.8 ± 13.3 years), following treatment with circular Ilizarov frame for severe tibia plateau fractures (Schatzker IV-VI) was analysed. The tests were performed at an average of 10.4 months after the initial treatment. SF-12v2 Mental scores have returned to normal (mean 55.8 ± 11.9) but physical scores remained impaired (mean 40.6 ± 11.3). COST scores reached average levels (mean 54.1 ± 19.8).A one-way repeated measures ANOVA was conducted to compare the GRFs and gait timing data of the affected limb with the normal one. Single limb support interval was significantly reduced to the affected limb (p < 0.001) and terminal stance phase was prolonged for the normal limb (p = 0.05). The rest of the GRF and gait timing data did not reach significant differences. ConclusionsDuring the early stages of rehabilitation following severe tibia plateau fractures treated with circular Ilizarov frame, the gait pattern returns to normal curve morphology, but with reduced single limb support and terminal stance phases at the affected knee. Mental status returns to normal but symptoms and function remain impaired.

Additive manufacturing of specific ankle-foot orthoses for persons after stroke: A preliminary study based on gait analysis data.

The aim of present study is to investigate the feasibility of patient-specific ankle-foot orthoses fabricated using additive manufacturing (AM) techniques. Then, clinical performance of the AFOs manufactured using material PA12 was evaluated in stroke survivors based on gait analysis data. The ankle and foot were scanned by EinScan-Pro 3D scanner. The software Geomagic Studio was used for modifying the AFO model. After processing the original AFO model into the final required model, material PA12 were used to fabricate the AFOs by Multi Jet Fusion (MJF) technique. Finally, gait analysis of 12 stroke patients was conducted to compare the effects with and without AFO. It took 2 hours from processing the initial AFO model to the completion of final model, and the printing time was 8 hours. The printing thickness of the AFO was 1.2 mm. With respect to the temporal-spatial parameters, the velocity and stride length in the gait with AFO increased significantly as compared to the gait without AFO (P=0.001, P=0.002). The cadence increased, double limb support phase decreased, and the step length difference decreased in the gait with AFO; however, the difference was not statistically significant (P=0.117, P=0.075, P=0.051).This study confirmed the feasibility of patient-specific AFO fabricated by AM techniques, and demonstrated the process of modifying AFO models successfully. The specific ankle-foot orthoses fabricated by material PA12 have a significant effect on the improvement of velocity and stride length in people with stroke.

Cutaneous sensory feedback from paw pads affects lateral balance control during split-belt locomotion in the cat.

Cutaneous sensory feedback from the paw pads plays an important role in regulating body balance, especially in challenging environments like ladder or slope walking. Here, we investigated the contribution of cutaneous sensory feedback from the paw pads to balance control in cats stepping on a split-belt treadmill. Forepaws and hindpaws were anesthetized unilaterally using lidocaine injections. We evaluated body balance in intact and compromised cutaneous feedback conditions during split-belt locomotion with belt-speed ratios of 0.5, 1.0, 1.5 and 2.0. Measures of body balance included step width, relative duration of limb support phases, lateral bias of center of mass (CoM) and margins of static and dynamic stability. In the intact condition, static and dynamic balance declined with increasing belt-speed ratio as a result of a lateral shift of the CoM toward the borders of support on the slower moving belt. Anesthesia of the ipsilateral paws improved locomotor balance with increasing belt-speed ratios by reversing the CoM shift, decreasing the relative duration of the two-limb support phase, increasing the duration of four- or three-limb support phases, and increasing the hindlimb step width and static stability. We observed no changes in most balance measures in anesthetized conditions during tied-belt locomotion at 0.4 m s-1 CoM lateral displacements closely resembled those of the inverted pendulum and of human walking. We propose that unilaterally compromised cutaneous feedback from the paw pads is compensated for by improving lateral balance and by shifting the body toward the anesthetized paws to increase tactile sensation during the stance phase.

Footwear-Generated Dynamic Biomechanical Manipulation and Perturbation Training for Chronic Nonspecific Low Back Pain

BackgroundHome-based therapy optimizing biomechanics and neuromuscular control is increasingly recognized as a treatment option for chronic nonspecific low back pain (CNSLBP). However, its impact on pain, function, and gait is limited among patients in a metropolitan area. ObjectiveTo evaluate the change of pain, function, and gait parameters with home-based therapy with the use of footwear-generated biomechanical manipulation and perturbation training in a population with CNSLBP in a metropolitan area. DesignProspective observational study. SettingOutpatient rehabilitation clinic at an academic teaching hospital. ParticipantsOne hundred sixteen patients with CNSLBP for more than 6 months. InterventionSix months of home-based therapy with a biomechanical device using 4 modular elements attached to a foot-worn platform. Main Outcome MeasuresInstrumental gait analysis (gait velocity, step length, single limb support phase % of gait cycle), Numeric Rating Scale for pain, and Oswestry Disability Questionnaire Index for pain and function. ResultsOnly 43 patients (37.1%) completed the study. Among 43 patients, mean gait velocity increased from 86.6 ± 20.7 to 99.7 ± 22.1 cm/s (P < .0001) in 6 months. Mean left step length increased from 51.1 ± 8.4 to 54.8 ± 9.8 cm (P < .0001). Mean right step length increased from 51.0 ± 7.9 to 55.4 ± 9.0 cm (P < .0001). Mean single limb support increased from 36.4 ± 2.8 to 37.2 ± 2.5%, (P = .208) in the right side and from 36.6 ± 3.0 to 37.8 ± 4.4%, (P = .019) in the left side. Median Oswestry Disability Questionnaire Index score improved from 28 (18-44; interquartile range) to 17 (10-35) (P = .045). Mean Numeric Rating Scale for back pain improved from 7.7 ± 1.8 to 3.3 ± 3.1 (P < .0001). ConclusionAt 6 months, patients with CNSLBP undergoing home-based therapy with footwear-generated biomechanical manipulation and perturbation training demonstrated significant improvement of objective gait parameters, pain, and function. Level of EvidenceIV

Effects of Talocrural Mobilization with Movement on Ankle Strength, Mobility, and Weight-Bearing Ability in Hemiplegic Patients with Chronic Stroke: A Randomized Controlled Trial

In general, adequate movement of the ankle joint is known to play an important role in functional activities. Stroke survivors frequently have limited range of motion of the ankle, leading to dysfunctional weight transfer toward the paretic lower limb during standing or gait. The purpose of this study was to investigate the effects of talocrural mobilization with movement (MWM) on ankle strength, dorsiflexion passive range of motion (DF-PROM), and weight-bearing ability on the paretic limb during standing or gait in stroke patients with limited ankle dorsiflexion. Twenty-six participants with chronic hemiplegia (>6 months post stroke) were divided into 2 groups: MWM group (n = 13) and control group (n = 13). Both groups attended conventional physiotherapy sessions 3 times a week for 5 weeks. Additionally, the MWM group underwent talocrural MWM 3 times a week for 5 weeks. Isokinetic ankle strength, DF-PROM, and weight-bearing ability measures included the limit of stability (LOS); gait parameters were evaluated before and after interventions. Plantarflexors peak torque and DF-PROM significantly increased in the MWM group. In addition, forward and forward-paretic direction LOS significantly increased in the MWM group. Paretic direction LOS, single-limb support phase of the paretic limb significantly increased and double limb support phase significantly decreased within the MWM group. This study demonstrates that talocrural MWM has an augmented effect on ankle strength, mobility, and weight-bearing ability in chronic stroke patients with limited ankle motion when added to conventional therapy.

Abstract TP109: Quantitative Gait Analysis Demonstrates Significant Changes in Motor Function Post-ischemic Stroke and Simulated Intraparenchymal Therapeutic Delivery in a Porcine Model

Severity of stroke and subsequent recovery can be measured through gait changes of affected individuals. Recent failures of therapies tested in rodents to support safety and efficacy in human clinical trials has led to the development of a novel porcine ischemic stroke model with more comparable brain anatomy and physiology. Assessment of motor function changes is essential for determining the feasibility of the pig stroke model, the effect of therapies and the potential effects of modes of therapeutic delivery such as intraparenchymal injection. We hypothesized permanent occlusion of the middle cerebral artery (MCA) and the intraparenchymal injection process would lead to significant alterations in motor functions such as increased stride duration and decreased two limb support and stride swing time. Gait data was collected on 3 adult male Landrace pigs at 3 pre-stroke time points. Ischemic stroke was induced by permanent middle cerebral artery occlusion (MCAO) and pigs were evaluated at 1, 3 and 5 days post-stroke. Stride duration increased by &gt;50% and percent swing time and percent two limb support decreased by &gt;30% 1 day post-stroke. Increased stride duration and decreased relative swing time and two limb support phase persisted 3 and 5 days post-stroke. At 5 days post-stroke, pigs received PBS intraparenchymal injections and were recorded at 1 and 3 days and 1, 2, 4, 6, 9 and 12 weeks post-injection. Stride duration significantly increased between 5 days post-stroke and 1 day post-injection demonstrating injection had a negative effect on motor function. All other parameters showed no significant changes between 5 days post-stroke and 1 day post-injection. Despite significant changes in gait parameters at early time points post-stroke, by 12 weeks post-injection, pigs showed spontaneous recovery with no detectable changes in motor function as compared to pre-stoke time points. Collectively, these results demonstrate MCAO stroke and intraparenchymal injection led to gait impairments and show that gait analysis is a highly sensitive method to detect changes in motor function.

The mental representation of the human gait in young and older adults.

The link between mental representation (MREP) structures and motor performance has been evidenced for a great variety of movement skills, but not for the human gait. Therefore the present study sought to investigate the cognitive memory structures underlying the human gait in young and older adults. In a first experiment, gait parameters at comfortable gait speed (OptoGait) were compared with gait-specific MREPs (structural dimensional analysis of MREP; SDA-M) in 36 young adults. Participants were divided into a slow- and fast-walking group. The proven relationship between gait speed and executive functions such as working memory led to the hypothesis that gait pattern and MREP differ between slow- and fast-walking adults. In a second experiment, gait performance and MREPs were compared between 24 young (27.9 years) and 24 elderly (60.1 years) participants. As age-related declines in gait performance occur from the seventh decade of life onward, we hypothesized that gait parameters would not be affected until the age of 60 years accompanied by unchanged MREP. Data of experiment one revealed that gait parameters and MREPs differed significantly between slow and fast walkers. Notably, eleven previously incurred musculoskeletal injuries were documented for the slow walkers but only two injuries and one disorder for fast walkers. Experiment two revealed no age-related differences in gait parameters or MREPs between healthy young and older adults. In conclusion, the differences in gait parameters associated with lower comfortable gait speeds are reflected by differences in MREPs, whereby SDA-M data indicate that the single limb support phase may serve as a critical functional period. These differences probably resulted from previously incurred musculoskeletal injuries. Our data further indicate that the human gait and its MREP are stable until the age of 60. SDA-M may be considered as a valuable clinical tool for diagnosis of gait abnormalities and monitoring of therapeutic effectiveness.

Deviations in gait metrics in patients with chronic ankle instability: a case control study.

BackgroundGait metric alterations have been previously reported in patients suffering from chronic ankle instability (CAI). Previous studies of gait in this population have been comprised of relatively small cohorts, and the findings of these studies are not uniform. The objective of the present study was to examine spatiotemporal gait metrics in patients with CAI and examine the relationship between self-reported disease severity and the magnitude of gait abnormalities.MethodsForty-four patients with CAI were identified and compared to 53 healthy controls. Patients were evaluated with spatiotemporal gait analysis via a computerized mat and with the Short Form (SF) - 36 health survey.ResultsPatients with CAI were found to walk with approximately 16% slower walking velocity, 9% lower cadence and approximately 7% lower step length. Furthermore, the base of support, during walking, in the CAI group was approximately 43% wider, and the single limb support phase was 3.5% shorter compared to the control group.All of the SF-36 8-subscales, as well as the SF-36 physical component summary and SF-36 mental component summary, were significantly lower in patients with CAI compared to the control group. Finally, significant correlations were found between most of the objective gait measures and the SF-36 mental component summary and SF-36 physical component summary.ConclusionsThe results outline a gait profile for patients suffering from CAI. Significant differences were found in most spatiotemporal gait metrics. An important finding was a significantly wider base of support. It may be speculated that these gait alterations may reflect a strategy to deal with imbalance and pain. These findings suggest the usefulness of gait metrics, alongside with the use of self-evaluation questionnaires, in assessing disease severity of patients with CAI.