Step Width Research Articles

Scattering-Free and Fast Response Polymer Brush-Stabilized Liquid Crystals Beam Steering Using Surface-Initiated Polymerization Technique.

Nonmechanical fast response optical beam steering technology is increasingly essential for telecommunications, imaging systems, optical sensing, displays, and military applications. Polymer network liquid crystal (PNLC) beam steering can achieve submillisecond response times but faces limitations due to scattering issues arising from the refractive index mismatch between the polymer network and the liquid crystals (LCs). In this article, we demonstrate a scattering-free, fast-response LC beam steering by using polymer brushes to stabilize the gradient refractive index. First, the initiator is incorporated into the alignment layer and the monomer is mixed into the LC layer. Surface-initiated polymerization (SIP) is then employed to grow the polymer brushes exclusively on the substrate's surface, thus confining the polymer network's growth to the LC bulk and reducing interfacial scattering. For polymer brush stabilized liquid crystal (PBSLC) beam steering device with a period size of 225 μm and a cell gap of 7.2 μm, the average transmission rate reaches 88% in the visible light spectrum with a haze value of only 6.91. The steering angle is 0.16, and the diffraction efficiency is 80.3%. When a voltage of 35 Vrms is applied, the primary energy can be tuned to the zeroth order, with a response time close to 1 ms. By cascading two PBSLC beam steering devices with opposite steering directions, the primary energy of the beam can be adjusted between zeroth, +1, and -1 order. This method requires only a UV light source, a precision displacement stage, a power supply, and a mask, avoiding the need for expensive equipment and complex electrode fabrication. By adjustment of the phase change period, step width, and number of steps during fabrication, the steering angles and diffraction efficiency of the PBSLC beam steering device can be easily controlled, highlighting its significant potential for industrial production.

Influence of Physical Characteristics of Obstacles on the Locomotor Pattern of Older Adults at Higher Risk of Falling

ObjectiveThis study aimed to investigate the locomotor behavior of older adults with and without a history of falls as they avoided obstacles with different physical characteristics. MethodsTwenty-one older adults participated in this study. The group was divided into higher risk of falling (n = 10) and lower risk of falling (n = 11). The following conditions were carried out: (1) walking and avoiding a solid obstacle and (2) walking and avoiding a fragile obstacle. ResultsOlder adults at higher risk of falling had worse performance during the obstacle approach phase. Both groups performed worse when avoiding the fragile obstacle than when avoiding the solid obstacle. Older adults at higher risk of falling had their feet closer when avoiding the obstacle, and both groups raised their limbs higher to avoid a fragile obstacle. Older adults at higher risk of falling were closer to obstacles after avoiding them. ConclusionFor the participants in this study, the physical characteristics of the obstacle did not interfere with the locomotor performance of older adults during obstacle avoidance. This study found that older adults at higher risk of falls modulated their locomotor pattern before avoiding the obstacles, presenting lower velocity, shorter step length, and greater step width compared with older adults at lower risk of falling.

Effects of frequency mixing on Shapiro-step formations in sliding charge-density-waves

A one-dimensional charge-density wave (CDW) is driven to slide by a dc electric field, carrying an electric current. In an additional ac field with frequency ωex, it is known that the sliding CDW can be synchronized to ωex, leading to the occurrence of Shapiro steps in the I–V characteristics. Motivated by a recent experiment where ac fields with two frequencies ωex and ωex′ are simultaneously applied, we theoretically investigate the effects of frequency mixing on the Shapiro-step formation. Based on the Fukuyama–Lee–Rice model, we show that in addition to the main steps induced by ωex, satellite steps characterized by ωex′ emerge. It is also found that with increasing the ac-field strength for ωex′, each step width first exhibits a damped oscillation as in the one-frequency case and then exhibits a non-monotonic behavior. The origin of these behaviors and the relevance to the associated experiment are also discussed.

The effect of age and proprioceptive illusion susceptibility on gait

ObjectiveAge-related gait decline has been associated with impaired proprioception, one's internal awareness of spatial location and movement. Although impaired proprioception has further been linked to greater susceptibility to proprioceptive illusions, it is unclear the impact such susceptibility has on gait and its interaction with age. The purpose of this study was to address these uncertainties. MethodsWe measured proprioceptive illusions induced by muscle spindle manipulation and gait in young and older adults. We also compared illusory measures with traditionally used joint position matching to examine if illusory susceptibility can reveal proprioceptive impairments. ResultsWe found no effect of age on proprioceptive illusion susceptibility or joint position matching error. Compared to non-perceivers, illusion perceivers across both age groups showed greater joint matching error, suggesting reduced proprioceptive acuity. Consistent with previous studies, older adults had reduced cadence, gait velocity, and step length compared to young adults in both single- and dual-task walking. Interestingly, illusion perceivers, regardless of age, showed reduced cadence and step width compared to non-perceivers. ConclusionsOur results suggest that gait impairments observed in those who perceive these proprioceptive illusions are age-independent, potentially rooted in deteriorated proprioception. SignificanceThis is the first study to examine these relations.

Microstructure and mechanical properties of Ti60–Ti2AlNb functionally graded materials fabricated by laser directed energy deposition

The increasing demands for materials that service under high temperature environments in advanced aero-engines with high thrust-to-weight ratios have led to the exploration of functionally graded materials, which can offer unique advantages for addressing these challenges, such as the ability to achieve multiple properties at different positions of the components. In this study, Ti60–Ti2AlNb functionally graded materials were fabricated via laser directed energy deposition (L-DED) with 20% compositional step and various step widths in the transition zone. The distribution of chemical composition, microstructure, and microhardness in the transition zone of functionally graded materials with different compositional paths along the deposition direction were investigated. Meanwhile, the mechanical properties and fracture mechanisms were also evaluated. Smooth composition transition has been achieved in the joint zone between Ti60 and Ti2AlNb. By decreasing the width of each composition zone in the transition area or removing the Ti60-60% Ti2AlNb zone, the precipitation of the hard and brittle α2 phase can be effectively suppressed, thereby enhancing the tensile strength of the graded material. Through this approach, Ti60–Ti2AlNb functionally graded material with a tensile strength of 1030.9 MPa and elongation of 2.0% was fabricated.

Effect of mediolateral leg perturbations on walking balance in people with chronic stroke: A randomized controlled trial.

Many people with chronic stroke (PwCS) exhibit deficits in step width modulation, an important strategy for walking balance. A single exposure to swing leg perturbations can temporarily strengthen this modulation. The objective of this parallel, double-blinded, randomized controlled trial was to investigate whether repeated perturbations cause sustained increases in step modulation (NCT02964039; funded by the VA). 54 PwCS at the Medical University of South Carolina were randomly assigned to one of three intervention groups: Control (n = 18), with minimal forces; Assistive (n = 18), pushing the swing leg toward a mechanically appropriate location; Perturbing (n = 18), pushing the swing leg away from a mechanically appropriate location. All intervention groups included 24 training sessions over 12-weeks with up to 30-minutes of treadmill walking while interfaced with a novel force-field and a 12-week follow-up period, with five interspersed assessment sessions. Our primary outcome measure was paretic step width modulation, the partial correlation between step width and pelvis displacement (ρSW). Secondarily, we quantified swing and stance leg contributions to step modulation, clinical assessments of walking balance and confidence, and real-world falls. Outcomes were analyzed for participants who completed all assessment sessions (n = 44). Only the Perturbing group exhibited significant increases in paretic ρSW, which were present after 4-weeks of training and sustained through follow-up (t = 2.42-3.17). These changes were due to improved control of paretic swing leg positioning. However, perturbation-induced changes in step modulation were not always significantly greater than those in the Control group, and clinical assessments were similar across intervention groups. Participants in the Perturbing group experienced a lower fall rate than those in the Control group (incidence rate ratio = 0.53), although our small sample size warrants caution. The present results indicate that perturbations can cause sustained modifications of targeted biomechanical characteristics of post-stroke gait, although such changes alone may be insufficient to change more complex clinical assessments.

Influence of Walking Modification Strategies on Frontal Plane Hip Joint Moment and Gait Naturalness in Healthy Adults

OBJECTIVE: To evaluate the effects of lateral trunk lean and step width modification on hip adduction moment in healthy participants and examine their influence on walking naturalness. METHODS: Ten healthy participants underwent gait analysis under 4 walking conditions: natural walking, large trunk lean, doubled step width, and combined modification with slight trunk lean and 1.5 times step width. Early stance and late stance hip adduction moment were analyzed and compared using repeated-measures analysis of variance. Subjective naturalness of gait was also recorded. RESULTS: We observed a significant effect of walking condition on the hip adduction moment during early stance (F3,36 = 6.665, P = .001) and gait naturalness (F3,36 = 30.519, P<.001), but not hip adduction moment during late stance ( P = .733). Pairwise comparison indicated significantly reduced hip adduction moment during early stance with large trunk lean when compared to natural walking (36.7% less, P = .002, Cohen’s d = −1.41). Both combined and doubled step width modifications did not yield the expected hip adduction moment reduction ( P>.296). The perceived naturalness of the doubled step width modification was most comparable to natural walking ( P = .529), while the trunk lean modification was significantly less natural than natural walking and the least natural modification overall (81.1% less, P<.001, Cohen’s d = −4.34). CONCLUSION: Although trunk lean modification effectively reduces hip joint loading, it is perceived as the least natural pattern. Step width was more challenging to modify than trunk lean. JOSPT Open 2024;2(4):306-314. Epub 7 August 2024. doi:10.2519/josptopen.2024.0463

Effects of interval treadmill training on spatiotemporal parameters in children with cerebral palsy: A machine learning approach

Quantifying individualized rehabilitation responses and optimizing therapy for each person is challenging. For interventions like treadmill training, there are multiple parameters, such as speed or incline, that can be adjusted throughout sessions. This study evaluates if causal modeling and Bayesian Additive Regression Trees (BART) can be used to accurately track the direct effects of treadmill training on gait. We developed a Directed Acyclic Graph (DAG) to specify the assumed relationship between training input parameters and spatiotemporal outcomes during Short Burst Locomotor Treadmill Training (SBLTT), a therapy designed specifically for children with cerebral palsy (CP). We evaluated outcomes after 24 sessions of SBLTT for simulated datasets of 150 virtual participants and experimental data from four children with CP, ages 4–13 years old. Individual BART models were created from treadmill data of each step. Simulated datasets demonstrated that BART could accurately identify specified responses to training, including strong correlations for step length progression (R2 = 0.73) and plateaus (R2 = 0.87). Model fit was stronger for participants with less step-to-step variability but did not impact model accuracy. For experimental data, participants’ step lengths increased by 26 ± 13 % after 24 sessions. Using BART to control for speed or incline, we found that step length increased for three participants (direct effect: 13.5 ± 4.5 %), while one participant decreased step length (−11.6 %). SBLTT had minimal effects on step length asymmetry and step width. Tools such as BART can leverage step-by-step data collected during training for researchers and clinicians to monitor progression, optimize rehabilitation protocols, and inform the causal mechanisms driving individual responses.

A model of task-level human stepping regulation yields semistable walking.

A simple lateral dynamic walker, with swing leg dynamics and three adjustable input parameters, is used to study how motor regulation affects frontal-plane stepping. Motivated by experimental observations and phenomenological models, we imposed task-level multi-objective regulation targeting the walker's optimal lateral foot placement at each step. The regulator prioritizes achieving step width and lateral body position goals to varying degrees by choosing a mixture parameter. Our model thus integrates a lateral mechanical template, which captures the fundamental mechanics of frontal-plane walking, with a lateral motor regulation template, an empirically verified model of how humans manipulate lateral foot placements in a goal-directed manner. The model captures experimentally observed stepping fluctuation statistics and demonstrates how linear empirical models of stepping dynamics can emerge from first-principles nonlinear mechanics. We find that task-level regulation gives rise to a goal-equivalent manifold in the system's extended state space of mechanical states and inputs, a subset of which contains a continuum of period-1 gaits forming a semistable set: perturbations off of any of its gaits result in transients that return to the set, though typically to different gaits.

Linear jerk variability evaluation in measurements of motor control trainability: Could kinematic variables encompass information about strength and dynamic balance?

As the natural conclusion of talent identification in sports, talent development is the process that involves improving biomechanical capacities and bio-motor abilities. The development progress can be objectively assessed and monitored through measurements of trainability. This study introduces a practical methodology to assess motor control as a trainable factor using kinematic data. The study focused on establishing the relationship between kinematic data and changes in muscle strength and dynamic balance. It illustrates how wearable technology can assess trainability during a functional training programme. Twenty-six female university students were selected and divided into intervention and control groups to investigate motor control trainability. The intervention group performed step aerobics exercises for 24 sessions. A single inertial measurement unit (IMU) mounted on S1 captured the oscillatory motion profiles of the centre of mass during these rhythmic exercises. Analysis revealed that the amplitude of linear jerk variability in different anatomical planes could reflect core and lower limb muscle strengthening caused by training. Furthermore, the results indicated that the dynamic balance adaptation to the changing tempo throughout the training programme was dictated primarily by step width. The mediolateral linear jerk variability reflected this adaptation. The minimum instrumentation approach proposed by this study could prove very practical for the talent development monitoring. The methodology illustrates how the recorded kinematic data from an appropriately placed single IMU could become an information-rich source for the coach to monitor, assess and quantify the trainee's progress during long-term athletic development.

Effects of chronic ankle instability after grade I ankle sprain on the post-traumatic osteoarthritis

BackgroundUntreated acute ankle sprains often result in chronic ankle instability (CAI) and can ultimately lead to the development of post-traumatic osteoarthritis (PTOA). At present, a typical animal model of ankle instability in mice is established by transecting the ligaments around the ankle joint. This study aimed to establish a grade I acute ankle sprain animal model by rapid stretching of peri-ankle joint ligaments. Furthermore, we tried to explore the pathophysiological mechanism of ankle osteoarthritis.MethodsIn all, 18 male C57BL/6 J mice (7 weeks) were randomly divided into three groups: calcaneofibular ligament (CFL) laxity group, deltoid ligament (DL) laxity group, and SHAM group. One week after the surgical procedure, all mice were trained to run in the mouse rotation fatigue machine daily. The mice were tested on the balance beam before surgery and three days, 4 weeks, 8 weeks, and 12 weeks after surgery. Footprint analyses were performed on each mouse before surgery and 12 weeks after surgery. Micro-CT scanning was then performed to evaluate the degeneration of ankle joints and histological staining was performed to analyze and evaluate PTOA caused by ankle joint instability.ResultsAfter surgery, the mice in the CFL and DL laxity groups took longer to cross the balance beam and slipped more often than those in the SHAM group (p < 0.05). The step length and width in the CFL and DL laxity groups were significantly shorter and smaller than those in the SHAM group 12 weeks after surgery (p < 0.05). There was a significant increase in the bone volume fraction (BV/TV) in the CFL and DL laxity groups compared with the SHAM group (p < 0.05). Histological staining results suggested obvious signs of PTOA in the CFL and DL laxity groups.ConclusionsBased on CFL and DL laxity in a mouse ankle instability model, this study suggests that grade I ankle sprain can contribute to chronic ankle instability, impair motor coordination and balance, and eventually lead to PTOA of ankle with significant degeneration of its adjacent joints.

Randomized controlled trial on ankle biomechanics in the treatment of functional ankle instability with joint mobilization

Functional ankle instability (FAI) patients often experience restricted ankle dorsiflexion, increased inversion angle, and elevated ground reaction forces during walking, all related to altered kinematics of the talocrural and subtalar joints. This study aimed to investigate the potential positive impact of joint mobilization on FAI patients from a biomechanical perspective. The experimental group (EG, n = 17; Age: 20.06 ± 1.34 years; Height: 1.74 ± 0.07 m; Weight: 69.79 ± 11.20 kg; BMI:22.88 ± 2.63 kg/m2; CAIT:15.59 ± 2.58; M/F: 15/2) received joint mobilization + routine rehabilitation training, while the control group (CG, n = 16; Age: 20.50 ± 0.73 years; Height: 1.73 ± 0.09 m; Weight: 64.59 ± 7.21 kg; BMI: 21.65 ± 2.47 kg/m2; CAIT: 16.75 ± 2.21; M/F: 14/2) only received regular rehabilitation training. Biomechanical tests were performed in both groups after the 4-week intervention. The spatial parameters during walking (including step length, stride length, step width, step time, cadence, step speed, support time, and swing time), ankle flexion and dorsiflexion angle, inversion, and eversion angles, internal and external rotation angles, ankle torque, as well as the vertical ground reaction force were measured before and after the intervention. The results of the two-way ANOVA showed that the main effect of time was significant for step length (P < 0.001), stride length (P = 0.008), step speed (P < 0.001), the sagittal plane angle at touchdown (P < 0.001), maximum dorsiflexion angle (P = 0.005), sagittal plane toe off-ground angle (P < 0.001), peak flexion-dorsiflexion torque (P = 0.033), the first peak vGRF (P = 0.013), and second peak vGRF (P = 0.011). The main effect of Time * Group was significant for step speed (P = 0.044). The EG demonstrated significant improvements in step speed (P = 0.047), maximum dorsiflexion angle (P = 0.047), and the first peak vGRF (P = 0.028) compared to the CG. This study reveals that joint mobilization intervention enhances gait spatiotemporal parameters, kinematics, and kinetics, particularly in step speed, maximum dorsiflexion angle, and the first vGRF peak for the EG compared to the CG. Therefore, the rehabilitation strategy for patients with functional ankle instability should appropriately increase the use of joint movement to promote the functional recovery of FAI patients.

Metronome-Guided Balance Exercises to Aid in Dynamic Balance and Postural Control in a Novel Genetic Presentation of Niemann–Pick Disease Type C: A Case Report

Abstract Niemann–Pick disease type C is a rare progressive lysosomal lipid storage disorder. The disorder is characterized by a range of neurological consequences and complications at different points of its progression including spasticity, incoordination, ataxia, supranuclear gaze palsy, asthenia, and balance impairment, with a higher risk of falls. Among various approaches to managing such a debilitating condition, the role of physical therapy in managing the symptoms of such patients is often limited or underreported in the literature. A combination of spasticity and ataxia leads to impaired timing of agonist–antagonist control. Therefore, balance loss and falls are the most prevalent symptoms. We advocated a 12-week metronome-guided balance training program. Niemann–Pick type C disease is a rare genetic phenomenon that often presents with multi-system changes at structural and functional levels for the patient. Metronome-guided balance training is beneficial for improving dynamic balance variables, including movement velocity, center of gravity sway velocity, and step width.

Two-step deep-learning identification of heel keypoints from video-recorded gait.

Accurate and fast extraction of step parameters from video recordings of gait allows for richer information to be obtained from clinical tests such as Timed Up and Go. Current deep-learning methods are promising, but lack in accuracy for many clinical use cases. Extracting step parameters will often depend on extracted landmarks (keypoints) on the feet. We hypothesize that such keypoints can be determined with an accuracy relevant for clinical practice from video recordings by combining an existing general-purpose pose estimation method (OpenPose) with custom convolutional neural networks (convnets) specifically trained to identify keypoints on the heel. The combined method finds keypoints on the posterior and lateral aspects of the heel of the foot in side-view and frontal-view images from which step length and step width can be determined for calibrated cameras. Six different candidate convnets were evaluated, combining three different standard architectures as networks for feature extraction (backbone), and with two different networks for predicting keypoints on the heel (head networks). Using transfer learning, the backbone networks were pre-trained on the ImageNet dataset, and the combined networks (backbone + head) were fine-tuned on data from 184 trials of older, unimpaired adults. The data was recorded at three different locations and consisted of 193 k side-view images and 110 k frontal-view images. We evaluated the six different models using the absolute distance on the floor between predicted keypoints and manually labelled keypoints. For the best-performing convnet, the median error was 0.55 cm and the 75% quartile was below 1.26 cm using data from the side-view camera. The predictions are overall accurate, but show some outliers. The results indicate potential for future clinical use by automating a key step in marker-less gait parameter extraction.

Gait pathology presented with developmental dysplasia of the hip: a control case study

A well-known and long-term complication of developmental dysplasia of the hip (DDH) is improper gait pattern, early regressive joint disorder, and permanent pain. It can affect the family's psychological, social, and functional parts. This study planned to resolve foot posture and gait analysis across patients with developmental hip dysplasia and correlate it with the control group. Case-control studies determine the main results. We correlated the gait analysis results on the Zebris FDM platform. The case included candidates with DDH under conservative treatment with an abduction brace and a control group with healthy participants. This study was conducted at King Abdullah Specialized Children Hospital, Riyadh, in the Kingdom of Saudi Arabia. This research enclosed 445 outcomes with DDH and 168 for the control category. The Sign test presented a significant diversity in Zebris FDM outcomes between DDH and the control group, especially in left foot external rotation with a p-value of 0.01 (left hip mean of 4.53, n=445, SD 8.78). A significant variation was present in step width, stance phase on both legs, single support, load response, swing phase, pre-swing, and a double support p-value of 0.00 (p&lt;0.05). W-sitting was preferred in 256 (n=445, 58%) of the DDH results and by 61 (n=168, 36%) from the control group. This study's outcomes presented a greater risk of pronation on the left foot and gait alteration on the right lower limb. The gait investigation presented a clear description of its patterns in paediatrics with DDH. Analyzing the gait among the DDH and the control group demonstrated a variation in each gait outcome from Zebris FDM platform software. DDH has a negative response on the gait pattern and foot posture, this is a great consequence presented in connection with Saudi applicants. Keywords: FDM, DDH, gait, control group, Kingdom of Saudi Arabia

Walking on different inclines affects gait symmetry differently in the anterior-posterior and vertical directions: implication for future sensorimotor training

A symmetric gait pattern in humans reflects near-identical movement in bilateral limbs during walking. However, little is known about how gait symmetry changes on different inclines. This study aimed to address this knowledge gap using the central pattern generator and internal model hypotheses. Eighteen healthy young adults underwent five 2-minute walking trials (inclines of +15%, +8%, 0%, −8%, and −15%). Dependent variables included step time, step length, step width, maximum heel clearance, time to peaks of maximum heel clearance, their corresponding coefficients of variation (CV), and respective symmetry indices (SI). Significant differences were observed in SI of step length (p = .022), step length variability (p &lt; .001), step width variability (p =.001), maximum heel clearance (p &lt; .001), and maximum heel clearance variability (p = .049). Compared to level walking, walking at −8% and −15% inclines increased SI of step length (p = .011, p = .039 respectively) but decreased SI of maximum heel clearance (p = .025, p = .019 respectively). These observations suggested that incline walking affected gait symmetry differently, possibly due to varied internal models used in locomotion. Downhill walking improved vertical gait symmetry but reduced anterior-posterior symmetry compared to level walking. Downhill walking may be a preferable rehabilitation protocol for enhancing gait symmetry, as it activates internal model controls. Even slight downhill inclines could increase active control loading, beneficial for the elderly and those with impaired gait.

Gait assessment in a female rat Sprague Dawley model of disc-associated low back pain

ABSTRACT Purpose Gait disturbances are common in human low back pain (LBP) patients, suggesting potential applicability to rodent LBP models. This study aims to assess the influence of disc-associated LBP on gait in female Sprague Dawley rats and explore the utility of the open-source Gait Analysis Instrumentation and Technology Optimized for Rodents (GAITOR) suite as a potential alternative tool for spontaneous pain assessment in a previously established LBP model. Materials and Methods Disc degeneration was surgically induced using a one-level disc scrape injury method, and microcomputed tomography was used to assess disc volume loss. After disc injury, axial hypersensitivity was evaluated using the grip strength assay, and an open field test was used to detect spontaneous pain-like behavior. Results Results demonstrated that injured animals exhibit a significant loss in disc volume and reduced grip strength. Open field test did not detect significant differences in distance traveled between sham and injured animals. Concurrently, animals with injured discs did not display significant gait abnormalities in stance time imbalance, temporal symmetry, spatial symmetry, step width, stride length, and duty factor compared to sham. However, comparisons with reference values of normal gait reported in prior literature reveal that injured animals exhibit mild deviations in forelimb and hindlimb stance time imbalance, forelimb temporal symmetry, and hindlimb spatial symmetry at some time points. Conclusions This study concludes that the disc injury may have very mild effects on gait in female rats within 9 weeks post-injury and recommends future in depth dynamic gait analysis and longer studies beyond 9 weeks to potentially detect gait.

Comparison of spatiotemporal gait parameter measurements across various emulated foot strike patterns between the Tekscan® Strideway™ pressure sensitive walkway and gold-standard marker-based motion capture

Spatiotemporal gait parameters are commonly used to quantify physical functioning including in populations with atypical foot strike patterns. The current gold standard measurement system for gait analysis is marker-based motion capture and floor-mounted force plates, but it can be expensive and cumbersome to set up. Pressure sensitive walkways are more affordable, quicker to set up, and more portable. Currently available walkways have not been compared to marker-based motion capture when measuring atypical foot strike patterns. The recently developed Tekscan® Strideway pressure sensitive walkway system has not been compared to any gold standard. This study compared measurements of step width, step length, and step time from the Strideway™ system against a gold standard marker-based motion capture (Vicon® Vantage™) and floor-mounted force plate (AMTI®) system. Ten typically ambulating adults, free of injury, emulated five different foot strike patterns recording two-hundred footsteps for each. Results indicate that the Strideway™ compares well to the gold standard especially under typical foot strike patterns. The errors were highest for step width and near-zero for step time. However, the user needs to be aware that errors can substantially increase with certain foot strike patterns such as when the heel does not make contact with the walkway. The results of this study will help inform users about potential limitations when using a pressure sensitive walkway like the Strideway™ for testing populations with typical and atypical strike patterns.

Comparison of gait analysis before and after unilateral total knee arthroplasty for knee osteoarthritis

BackgroundGait ability can be objectively assessed using gait analysis. Three-dimensional gait analysis, the most commonly used analytical method, has limitations, such as a prolonged examination, high system costs, and inconsistently reported gait symmetry in patients with knee osteoarthritis (OA). Therefore, we aimed to evaluate the gait symmetry and changes before and after unilateral total knee arthroplasty (TKA) using the Walkway analyzer, a sheet-type gait analyzer.MethodsThe healthy group included 38 participants from the Locomotor Frailty and Sarcopenia Registry study with lower limb pain or Kellgren–Lawrence classification grade 3 or 4 OA. The OA group included 34 participants from the registry study who underwent unilateral TKA. The walking speed, step length, step width, cadence, stride time, stance time, swing phase time, double-limb support phase time, stride, step length, and step width were analyzed per side using the Walkway gait analyzer.ResultsNo significant differences between the right and left sides were observed in the healthy group. In the OA group, the time indices and stance phase (p = 0.011) and the double-limb support phase time (p = 0.039) were longer on the contralateral side and the swing phase was longer on the affected side (p = 0.004) pre-operatively. However, these differences disappeared post-operatively. There were no significant differences in the spatial indices. Thus, this study revealed that patients undergoing unilateral TKA had an asymmetric gait pre-operatively, with a time index compensating for the painful side, and an improved symmetric gait post-operatively.ConclusionsThe Walkway analyzer employs a simple test that requires only walking; hence, it is expected to be used for objective evaluation in actual clinical practice.

Exploring the effects of increased socket-residual limb coupling integrity via vacuum assisted suspension on prosthetic control: a preliminary study in transtibial prosthesis users.

The prosthetic socket provides the critical interface between prosthesis and residuum. The purpose of this pilot study was to explore the effect of altering socket-residuum coupling integrity on limb and body control, through the use of vacuum-assisted suspension. A secondary purpose was to explore the potential use of two measurement tools designed to assess mobility in a clinical context. Individuals with unilateral transtibial amputation performed intentional sway (n = 7) and treadmill walking (n = 6) tasks at three vacuum levels. Sway deviation from a straight-line path to peripheral targets was measured using an instrumented balance platform. Step width variability and targeting accuracy were measured using an augmented reality treadmill. There was a significant difference in intentional sway performance toward the target on the anterior diagonal toward the prosthetic side (p = 0.036); higher vacuum levels tended toward less deviation from a straight-line path. We found no group differences between total intentional sway deviation, step width variability or stepping accuracy across vacuum levels. Improved socket-residuum coupling integrity via vacuum may have measurable effects on functional control that warrant further investigation. We highlight limitations of the clinical testing paradigms to inform future work.Implications for rehabilitationThe fit of the socket is a critical factor in the success of lower limb prosthesis use.Vacuum-assisted suspension modifies the coupling between the residuum and socket.Changes in socket-residuum coupling may lead to measurable differences in control; however, these may be activity and person-specific.Clinically intended instrumented tests of movement function derived for an intact anatomy should be used with caution when assessing prosthesis users.