Walking Velocity Research Articles

Patient-specific gait pattern in individuals with patellofemoral instability reduces knee joint loads

AbstractPatellofemoral instability is influenced by morphological factors and associated with compensational alterations in gait pattern. Recent simulation studies investigated the impact of knee morphology on the stability and loading of the patellofemoral joint but neglected the patient-specific gait pattern. The aim of this study was to investigate the impact of patient-specific gait pattern on muscle forces and joint loading in individuals with patellofemoral instability. Musculoskeletal simulations with a model including a twelve degrees of freedom knee joint were performed based on three-dimensional motion capture data of 21 individuals with chronic patellofemoral instability and 17 healthy control participants. The patellofemoral instability group walked with a less flexed knee joint and reduced knee flexion and abduction moments compared to the control group, which required less quadriceps muscle forces. Lower quadriceps muscle forces resulted in a reduction of tibiofemoral and patellofemoral joint contact forces despite similar walking velocities between both groups. Furthermore, we observed decreased lateralizing patella forces in subjects with patella instability, which could potentially reduce the risk of patella dislocation. Our findings highlight the importance of accounting for the patient-specific gait pattern when analysing knee loads in individuals with patellofemoral instability.

7785 Muscle Strength and Physical Performance Are Closely Related to Muscle Quality Regardless of Muscle Mass or Diabetes Status

Abstract Disclosure: J. Seo: None. I. Jung: None. S. Park: None. D. Lee: None. J. Yu: None. H. Cho: None. K. Kim: None. E. Song: None. K. Kim: None. N. Kim: None. H. Yoo: None. S. Kim: None. K. Choi: None. N. Kim: None. C. Shin: None. Weakness or slowness is essential to define sarcopenia rather than less muscle mass. Myosteatosis is associated with low muscle strength and poor physical performance, and ectopic fat deposition is a characteristic of diabetes (DM). We investigated the association between muscle strength/physical performance and myosteatosis by considering DM status and muscle mass in community-dwelling older adults. A total of 982 subjects (447 men and 535 women) aged 54-83 years in 8th examination of the Korean Genome and Epidemiology Study Ansan cohort participated in this study. Handgrip strength (HSG), 4-m walking velocity (VEL) and 30-Seconds Sit-to-Stand Test (STST) were checked, appendicular skeletal muscle mass (ASM) and total muscle mass (TMM) by DXA were measured. In midthigh CT image, total muscle area (TMA) was measured and categorized into 3 components using Hounsfield Unit (HU): normal-attenuation muscle area (NAMA, 35-100HU), low-attenuation muscle area (LAMA, 0-34HU), and inter/intramuscular adipose tissue (IMAT) area. As muscle quality indices, the NAMA index, LAMA index, and IMAT index were defined by dividing each parameter by TMA. DM was diagnosed by fasting glucose ≥126 mg/dL, 2hr-OGTT glucose ≥200 mg/dL, HbA1c ≥6.5% or anti-diabetic medication. Subjects with DM (38% of total subjects) had higher age and body mass index (BMI) compared to non-DM subjects. Prevalence of low muscle mass (M:<7.0kg/m2, F:<5.4kg/m2 of ASM/height2) was not statistically different by the presence of DM (DM vs non-DM, 11.7% vs 9.7% in men, 3.6% vs 7.6% in women). However, prevalence of low HGS (M:<28kg, F:<18kg) and slow VEL (<1.0m/sec) was higher in DM subjects than non-DM subjects (DM vs non-DM, low HSG: 18.3% vs 5.6% in men, 28.0% vs 17.3% in women, slow VEL: 40.6% vs 30.7% in men, 61.7% vs 46.2% in women). After adjusting for age and BMI, men with DM had lower muscle mass (ASM, ASM/height2,), TMA and NAMA index but higher LAMA index and IMAT index compared to men without DM. Also, men with DM had lower HGS (p=0.001) and poor STST (p=0.008) than men without DM. In women, muscle mass and muscle quality indices were not significantly different with or without DM, but women with DM had worse STST than women without DM (p=0.013). Age and sex adjusted HSG, but not VEL and STST, was positively associated with muscle mass (ASM, ASM/height2, ASM/BMI, and TMM). Age and sex adjusted HSG, VEL, and STST were positively associated with NAMA index and negatively associated with LAMA index and IMAT index regardless of DM. Linear regression analysis revealed that both ASM and NAMA (or LAMA) indices were independent association factors for HGS. Subjects with DM showed a more pronounced decrease in physical performance and muscle strength than a decrease in muscle mass. In this population-based cohort, less myosteatosis was associated with greater muscle strength and better physical performance, regardless of muscle mass or DM status. Presentation: 6/2/2024

The effect of ankle-foot orthoses on gait characteristics in people with Charcot-Marie-Tooth disease: A systematic review and meta-analysis.

Ankle-foot orthoses (AFOs) are commonly prescribed for people with Charcot-Marie-Tooth disease (CMT) to improve gait efficiency and reduce the occurrence of tripping and falls. The aim of this study was to systematically review evidence on the effects of AFOs on gait kinematics and kinetics and postural stability/balance in people with CMT. Studies were identified from electronic databases and screened for inclusion online using Rayyan. Data from all eligible studies were extracted into a standardised Excel spreadsheet. Methodological quality was assessed using the Joanna Briggs Institute Critical Appraisal Checklists. Where available, continuous outcomes were pooled to estimate standardised mean differences in random-effects meta-analyses. A total of 15 studies were included with variable methodological quality. Sample sizes ranged from 1 to 32 with significant variability in participant characteristics, AFO designs and testing procedures. Data from eight studies were available for meta-analysis. Although AFOs impacted walking velocity, stride length, step length, cadence, ankle dorsiflexion, plantarflexion, knee and hip flexion and ankle plantarflexion and dorsiflexion moments, the effect sizes were small-to-moderate and non-significant. There were insufficient data available for pooled analyses of outcomes related to postural stability/balance. Although AFOs positively affect a number of gait and balance parameters, the small participant numbers, variability in participant characteristics, AFO designs and testing procedures adopted by the available studies resulted in the absence of statistically significant effects when data were pooled. The results from this review also highlight the importance of device customisation based on the individual needs of people with CMT and their degree of gait impairment.

Feasibility of Stationary Cycling with Pedal Force Visual Feedback Post-Total Knee Arthroplasty: Implications for Inter-Limb Deficits in Knee Joint Biomechanics

The purpose of this study was to assess the biomechanical adaptations prompted by stationary cycling paired with visual feedback of vertical pedal reaction forces during both stationary cycling and overground walking for patients who underwent a total knee arthroplasty (TKA). Specifically, an emphasis on the inter-limb deficits in knee joint biomechanics were examined. Ten patients who underwent a TKA took part in an acute intervention with pre- and post-testing measurements of kinematics (240 Hz) and kinetics (1200 Hz) during stationary cycling and overground walking. The intervention phase consisted of six cycling sessions during which participants were provided with visual feedback of their bilateral peak vertical pedal reaction force, with instructions to maintain a symmetrical loading between limbs. A 2 × 2 (work rate/speed × time) repeated measures ANOVA (α = 0.05) was conducted on key outcome variables. Peak knee extension moment asymmetry during stationary cycling significantly improved (p = 0.038, η2p = 0.610) following the acute intervention. Walking velocities for both preferred (p = 0.001, d = 0.583) and fast (p = 0.002, d = 0.613) walking speeds displayed improvements from pre- to post-testing. Significant improvements in the total score (p = 0.009, d = 0.492) and ADL subscale score (p = 0.041, d = 0.270) for the Knee Injury and Osteoarthritis Outcome Score were present following the acute intervention. Stationary cycling with visual feedback may be beneficial post-TKA; however, further investigation is merited.

Comparative study of multidirectional pedestrian flows: Insights and dynamics

This study investigates multidirectional pedestrian flow by examining walking characteristics and behavioral factors impacting pedestrian dynamics. Parameters such as mean walking velocities, distance covered, and time taken by pedestrians were analyzed. Contrary to the expected inverse relationship between velocity and density, our findings revealed an increase in mean velocities in certain scenarios, attributed to conditions where the pedestrian density had not reached its maximum possible level and unpredicted pedestrian behaviors. Comparative analysis revealed that both Pakistani and Chinese pedestrians walk at nearly similar speeds. For instance, Pakistani pedestrians maintain a mean velocity of 1.36 ± 0.42 m/s at a density of 0.48 ped/m², while Chinese pedestrians maintain 1.27 ± 0.23 m/s at a density of 0.41 ped/m². Behavioral characteristics such as aggressive behavior, crowd avoidance, and waiting behavior were identified, with aggressive pedestrians exhibiting higher velocities than those avoiding crowds. A space-time diagram was utilized to categorize pedestrian flow types and behaviors, demonstrating increased stopping times with higher pedestrian numbers. Cultural factors, including side preferences, were analyzed using a binomial test, which returned a p-value of 0.968, indicating no significant preference for right-hand movement among Pakistani participants. These insights enhance the understanding of pedestrian dynamics and the influence of cultural norms on movement efficiency.

WiVelo: Fine-grained Wi-Fi Walking Velocity Estimation

Passive human tracking using Wi-Fi has been researched broadly in the past decade. Besides straightforward anchor point localization, velocity is another vital sign adopted by the existing approaches to infer user trajectory. However, state-of-the-art Wi-Fi velocity estimation relies on Doppler-Frequency-Shift (DFS), which suffers from the inevitable signal noise incurring unbounded velocity errors, further degrading the tracking accuracy. In this article, we present WiVelo, which explores new spatial-temporal signal correlation features observed from different antennas to achieve accurate velocity estimation. First, we use subcarrier shift distribution (SSD) extracted from channel state information (CSI) to define two correlation features for direction and speed estimation, separately. Then, we design a mesh model calculated by the antennas’ locations to enable a fine-grained velocity estimation with bounded direction error. Finally, with the continuously estimated velocity, we develop an end-to-end trajectory recovery algorithm to mitigate velocity outliers with the property of walking velocity continuity. We implement WiVelo on commodity Wi-Fi hardware and extensively evaluate its tracking accuracy in various environments. The experimental results show our median and 90-percentile tracking errors are 0.47 m and 1.06 m, which are half and a quarter of state-of-the-art. The datasets and source codes are published through Github ( https://github.com/research-source/code ).

Study protocol of a randomized controlled trial comparing backward walking to forward walking training on balance in multiple sclerosis: The TRAIN-MS trial

Balance impairment and accidental falls are a pervasive challenge faced by persons with multiple sclerosis (PwMS), significantly impacting their quality of life. While exercise has proven to be an effective intervention for improving mobility and functioning in PwMS, current exercise approaches predominantly emphasize forward walking (FW) and balance training, with variable improvements in balance and fall rates. Backward walking (BW) has emerged as a promising intervention modality for enhancing mobility and strength outcomes; however, significant gaps remain. Specifically, there is limited knowledge about the efficacy of BW interventions on outcomes such as static, anticipatory, and reactive balance, balance confidence, falls, and cognition. This randomized controlled trial aims to determine the feasibility, acceptability, and impact of 8-weeks of backward walking training (TRAIN-BW) as compared to forward walking training (TRAIN-FW). Ninety individuals with MS with self-reported walking dysfunction or ≥ 2 falls in the past 6 months will be randomized in blocks, stratified by sex and disease severity to either the TRAIN-BW or TRAIN-FW intervention groups. Adherence and retention rates will be used to determine feasibility and the Client Satisfaction Questionnaire will be used to assess acceptability. The primary outcomes will be static, anticipatory, and reactive balance. Secondary outcomes include walking velocity, balance confidence, concern about falling, cognition, physical activity, and fall rates measured prospectively for 6 months after post-testing. Additionally, the extent to which cognitive functioning influences response to intervention will be examined. Backward walking training may be an innovative intervention to address balance impairments and falls in persons with MS.

Dorsiflexion Specific Ankle Robotics to Enhance Motor Learning After Stroke: A Preliminary Report.

Robotics has emerged as a promising avenue for gait retraining of persons with chronic hemiparetic gait and footdrop, yet there is a gap regarding the biomechanical adaptations that occur with locomotor learning. We developed an ankle exoskeleton (AMBLE) enabling dorsiflexion assist-as-needed across gait cycle sub-events to train and study the biomechanics of motor learning stroke. This single-armed, non-controlled study investigates effects of nine hours (9 weeks × 2 sessions/week) locomotor task-specific ankle robotics training on gait biomechanics and functional mobility in persons with chronic hemiparetic gait and foot drop. Subjects include N = 16 participants (8 male, 8 female) age 53 ± 12 years with mean 11 ± 8 years since stroke. All baseline and post-training outcomes including optical motion capture for 3-D gait biomechanics are conducted during unassisted (no robot) over-ground walking conditions. Robotics training with AMBLE produced significant kinematic improvements in ankle peak dorsiflexion angular velocity (°/s, + 44 [49%], p < 0.05), heel-first foot strikes (%steps, + 14 [15%], p < 0.01) toe-off angle (°, + 83[162%], p < 0.05), and paretic knee flexion (°, + 20 [30%], p < 0.05). Improvements in gait temporal-spatial parameters include increased paretic step length (cm, + 12 [20%], p< 0.05), reduced paretic swing duration (%GC, -3[6%], p < 0.05), and trend toward improved step length symmetry (-16 [11%], p = 0.08). Functional improvements include 10-meter comfortable (m/s, + 13 [16%], p < 0.01) and fastest (m/s, + 13 [15%], p<0.01) walking velocities, 6-minute timed walk distance (m, + 16 [19%], p < 0.01) and Dynamic Gait Index scores (+15 [15%], p < 0.01). Subjects' perceived improvements surpassed the minimal clinically important difference on the Stroke Impact Scale (SIS) mobility subscale (+11 [19%], p < 0.05). AMBLE training improves paretic ankle neuromotor control, paretic knee flexion, and gait temporal-distance parameters during unassisted over-ground walking in persons with chronic stroke and foot drop. This locomotor learning indexed by an increase in volitional autonomous (non-robotic) control of paretic ankle across training translated to improvements in functional mobility outcomes. Larger randomized clinical trials are needed to investigate the effectiveness of task-specific ankle robotics, and precise training characteristics to durably improve gait, balance, and home and community-based functional mobility for persons with hemiparetic gait and foot drop. NCT04594837.

Effects Of Forward &amp; Backward Walking on Gait Parameters of Patients with Chronic Stroke: A Preliminary Trial

Background: Gait training after stroke is of paramount importance for independent living and quality of life. Objectives: The purpose of this study was to examine the effects of forward and backward walking over a firm level and a sandy surface on gait parameters among stroke patients. Methods: A total of 20 subjects randomly assigned to four groups were evaluated on various gait parameters while walking on a firm level surface and on sand. Baseline evaluation of temporal and spatial parameters of gait was conducted through stride analysis and final measurement after 3 weeks of intervention. Results: Backward walking on sand showed a statistically significant improvement in walking velocity, cadence, step/stride length, and gait symmetry among chronic stroke patients. Conclusion: The results of this study support the use of backward walking on sand as a new tool to improve functional walking among stroke patients. Such enhanced improvement can be attributed to the fact that backward walking on sand is more challenging than forward walking.

Impact of plantar flexion resistive moment of dynamic ankle foot orthosis on measures of center of pressure and clinical gait outcomes in individuals with post-stroke hemiparesis

BackgroundAn ankle-foot orthosis (AFO) with plantar flexion resistance (PFR) can improve the first rocker function during gait, but the incremental changes in the resistive moment on balance and gait have not been well identified. ObjectivesTo investigate the effect of changing the PFR moment of dynamic AFO (DAFO) on measures of the center of pressure (COP) and clinical gait outcomes in individuals with post-stroke hemiparesis. MethodIn this randomized repeated measure study of 36 stroke individuals, the customized DAFO using foot drop ankle units set in three PFR situations (low, medium, and high) was evaluated. The balance parameters for COP measures were investigated by HUMAC® Balance & Tilt System. Gait parameters and ankle kinematics were recorded using the 3D motion analysis through force platform and optoelectronic system. The comparison was made using a parametric ANOVA test and the P value was set at 0.05 for statistical significance. ResultsSignificant differences were observed for COP average velocity (1.30 ± 0.64, 1.10 ± 0.05, and 1.37 ± 0.43), COP path length (43.3 ± 4.6, 33.4 ± 4.3, and 36.3 ± 5.4), walking velocity (11.0 ± 3.1, 13.2 ± 4.4, and 9.9 ± 3.5), and cadence (31.5 ± 2.0, 33.0 ± 3.1, and 29.0 ± 1.6) respectively for low, medium and high PFR settings (P < 0.05). Except for the COP path length and cadence, posthoc multiple comparisons revealed significant differences between low and medium (P < 0.05) and medium and high (P < 0.05) PFR grades. PFR with medium resistance demonstrated near-normal maximal peak ankle dorsiflexion (mean deviation of 8 degrees, P < 0.05). ConclusionMedium PFR grade should be encouraged since it can enhance balance parameters like path length and average velocity of COP, increase cadence and average velocity during gait, and improve maximal peak ankle dorsiflexion.

The Hiking Optimization Algorithm: A novel human-based metaheuristic approach

In this paper, a novel metaheuristic called ‘The Hiking Optimization Algorithm’ (HOA) is proposed. HOA is inspired by hiking, a popular recreational activity, in recognition of the similarity between the search landscapes of optimization problems and the mountainous terrains traversed by hikers. HOA’s mathematical model is premised on Tobler’s Hiking Function (THF), which determines the walking velocity of hikers (i.e. agents) by considering the elevation of the terrain and the distance covered. THF is employed in determining hikers’ positions in the course of solving an optimization problem. HOA’s performance is demonstrated by benchmarking with 29 well-known test functions (including unimodal, multimodal, fixed-dimension multimodal, and composite functions), three engineering design problems (EDPs), (including I-beam, tension/compression spring, and gear train problems) and two N-P Hard problems (i.e. Traveling Salesman’s and Knapsack Problems). Moreover, HOA’s results are verified by comparison to 14 other metaheuristics, including Teaching Learning Based Optimization (TLBO), Genetic Algorithm (GA), Differential Evolution (DE), Particle Swarm Optimization, Grey Wolf Optimizer (GWO) as well as newly introduced algorithms such as Komodo Mlipir Algorithm (KMA), Quadratic Interpolation Optimization (QIO), and Coronavirus Optimization Algorithm (COVIDOA). In this study, we employ statistical tests such as the Wilcoxon rank sum, Friedman test, and Dunn’s post hoc test for the performance evaluation. HOA’s results are competitive and, in many instances, outperform the aforementioned well-known metaheuristics. The source codes of HOA and related metaheuristics can be accessed publicly via this link: https://github.com/DayoSun/The-Hiking-Optimization-Algorithm.

Robotic-arm assisted versus manual total knee arthroplasty: Functional gait analysis from a randomised controlled trial

The primary aim of this study was to assess whether measures of functional gait assessment were improved with robotic total knee arthroplasty (rTKA) when compared to manual TKA (mTKA). Gait analysis was performed as part of a randomised controlled trial. Walking and relaxed standing assessments were performed using an instrumented mat system. Spatiotemporal variables included gait cycle parameters, anteroposterior and lateral sway, and plantar pressure ratios. Measurements were recorded at pre-operative baseline and 12 months post-operatively. 100 patients were randomised, 50 to each group. Complete gait cycle data were available for 26 rTKA and 23 mTKA patients. Cadence and walking velocity showed overall improvements following surgery, with no difference between the two groups. In the operated limb, overall step and stride times decreased, while step and stride lengths increased. Subgroup analysis showed reduced propulsion time with rTKA, and decreased foot flat and mid stance times with mTKA. Lateral sway was decreased in the rTKA group. Plantar pressure ratios showed an overall increase in hindfoot loading on the operated limb, with no difference between the two groups. No other significant differences were identified between rTKA and mTKA at 12 months, and limitations may include statistical error. A small sample of the study cohort was followed up; analysis may represent the results of satisfied patients with well-functioning TKA. Further study could incorporate proprioceptive and 3D gait analysis techniques to analyse knee kinetics and kinematics with robotic surgery. Pressure mapping could further subdivide the plantar surfaces to explore any nuances in differential loading.

Effects of ankle–foot orthoses on gait parameters in post-stroke patients with different Brunnstrom stages of the lower limb: a single-center crossover trial

BackgroundAnkle-foot orthoses (AFO) can improve gait posture and walking ability in post-stroke patients. However, the effect of AFO on gait parameters in post-stroke patients according to the Brunnstrom stage of stroke recovery of the lower limbs remains unclear. The study aimed to investigate whether stroke patients with different Brunnstrom stages benefit from wearing AFO.MethodsTwenty-five post-stroke participants included 18 men (50 ± 13 years) and 7 women (60 ± 15 years). The patients were divided based on Brunnstrom stage III or IV of the lower limbs. All patients underwent the gait and timed up and go (TUG) test using a gait analysis system while walking barefoot or with an AFO. The spatiotemporal and asymmetric parameters were analyzed.ResultsAll 25 patients completed the study. Significant differences were observed between barefoot and AFO use in TUG time (P < 0.001) but not walking velocity (P > 0.05). The main effect of the swing time ratio was significant in both groups (P < 0.05); however, the main effects of stride length, stance time, and gait asymmetry ratio were nonsignificant (P > 0.05). For barefoot versus AFO, the main effects of stride length (P < 0.05) and swing time (P < 0.01) ratios were significant, whereas those of stance time and gait asymmetry ratio were nonsignificant (P > 0.05).ConclusionsPost-stroke patients with lower Brunnstrom stages benefitted more from AFO, particularly in gait asymmetry.

An 8-month adapted motor activity program in a young CMT1A male patient.

It is unclear whether prolonged periods of training can be well tolerated. In Charcot-Marie Tooth disease (CMT). We report the effects of an 8-month, adapted motor activity (AMA) program in a 16-years-old CMT1A male patient. The program included strength, mobility, and balance training (two sessions per week, 1h per session). Walking ability and walking velocity (Six-Minute Walking Test-6MWT, Ten Meters Walking Test-10mWT), balance (Y-Balance Test-YBT, Berg Balance Scale-BBS), functional mobility (Short Physical Performance Battery-Short physical performance battery), fatigue (Checklist Individual strength questionnaire - CIS20R), health and quality of life (Short Form Health Survey 36 questionnaire-SF-36) were evaluated in three moments: before (T0), after 5 (T1) and 8 (T2) months of adapted motor activity. Dorsal and plantar foot flexion strength (Maximal Voluntary Contraction-maximum voluntary contraction) and neuromuscular functions (Electromyography-sEMG, interpolated twitch technique-ITT) were measured at T1 and T2. Relative to T0, an amelioration of walking ability (6MWT, +9,3%) and balance (with improvements on Y-balance composite normalized mean reach of the right and left limb of 15,3% and 8,5%, respectively) was appreciable. Relative to T1, an increase in foot strength in three out of four movements (right plantar flexion, +39,3%, left plantar flexion, +22,7%, left dorsal flexion, 11,5%) was observed. Concerning voluntary muscle activation, a greater recruitment in the left, unlike right, medial gastrocnemius was observed. Results suggest the safety of an 8-month AMA program in a young patient affected by CMT1A.

A low-cost machine learning process for gait measurement using an electrostatic sensors network

Continuous in-house measurement of gait of elderly People is relevant for health professionals. To be adopted by most, the system must be low-cost and non-intrusive. In this paper we present a solution for measuring the walking velocity based on a network of 4 electric potential sensors. In our experiments, we also add PIR sensors used in our previous work for comparative purposes. A temporary Depth camera is used for training the model on walking velocity. The first results presented are obtained without machine learning. Then a machine learning regression method is tested to reduce the uncertainty of the sensors. The results show that the electric potential sensors are suitable for the in-house measurement of walking speed of elderly people. The uncertainty is lower than the target of 0.15 m s-1 known as the upper limit for detecting a reduction in speed due to illness. As for the PIR sensors, electric potential sensors consume very little energy, they are inexpensive, they can be embedded and hidden in the home which makes them less -intrusive and furthermore have better accuracy.

Morocco's population contact matrices: A crowd dynamics-based approach using aggregated literature data.

Estimation of contact patterns is often based on questionnaires and time-use data. The results obtained using these methods have been used extensively over the years and recently to predict the spread of the COVID-19 pandemic. They have also been used to test the effectiveness of non-pharmaceutical measures such as social distance. The latter is integrated into epidemiological models by multiplying contact matrices by control functions. We present a novel method that allows the integration of social distancing and other scenarios such as panic. Our method is based on a modified social force model. The model is calibrated using data relating to the movements of individuals and their interactions such as desired walking velocities and interpersonal distances as well as demographic data. We used the framework to assess contact patterns in different social contexts in Morocco. The estimated matrices are extremely assortative and exhibit patterns similar to those observed in other studies including the POLYMOD project. Our findings suggest social distancing would reduce the numbers of contacts by 95%. Further, we estimated the effect of panic on contact patterns, which indicated an increase in the number of contacts of 11%. This approach could be an alternative to questionnaire-based methods in the study of non-pharmaceutical measures and other specific scenarios such as rush hours. It also provides a substitute for estimating children's contact patterns which are typically assessed through parental proxy reporting in surveys.

Automatic Holonomic Mobile Micromanipulator for Submillimeter Objects Inspired by the Rhinoceros Beetle

Holonomic mobile micromanipulators driven by piezoelectric actuators offer precision and compact design. However, attaining both high speed and positioning repeatability with sufficient load capacity poses challenges, given that lightweight robots are susceptible to nonuniform driving surfaces and external forces. A holonomic beetle (HB) is proposed to realize a wide range, compact size, precise holonomic motion, automatic micromanipulation, and high‐speed movement simultaneously. Inspired by the biological makeup of a Rhinoceros Beetle, a length, weight, and load capacity of 8 cm, 74 g, and of 2000 g, respectively, are used. The HB is a two‐legged robot with a pseudoalternating tripod gait locomotion principle, with five piezoelectric actuators for XYθ displacement and switching of the contact leg. It achieves maximum walking velocities of 11.6 mm s−1 for translational motion and 19.3 deg s−1 for rotation, with a displacement resolution of 12 nm. Notably, under open‐loop control, the HB demonstrates high repeatability with a coefficient of variation of 0.3%. It exhibits the capability to climb 30°‐inclined surfaces, traverse flat surfaces with 0.1 mm bumps, and navigate 30 mm pits. Furthermore, the HB showcases practical automatic micromanipulation through visual servo control and machine learning, presenting potential applications in biomedical and microassembly fields.

Spatiotemporal variability after stroke reflects more than just slow walking velocity

BackgroundIncreased spatiotemporal gait variability is considered a clinical biomarker of ageing and pathology, and a predictor of future falls. Nevertheless, it is unclear whether the increased spatiotemporal variability observed in persons with stroke is directly related to the pathology or simply reflects their choice of walking velocity. Research questionDoes increased spatiotemporal gait variability directly relate to motor coordination deficits after stroke? MethodsForty persons with stroke participated in this cross-sectional study. Participants performed the lower-extremity motor coordination test (LEMOCOT) on an electronic mat equipped with force sensors. Then, participants walked for 120 s on a computerized treadmill at their comfortable walking velocity. For the LEMOCOT we used the traditional score of in-target touch count and computed the absolute and variable error around the targets. For gait variability, we extracted the standard deviation of step time, step length, step velocity, and step width. Using linear modeling, we tested the correlations of gait variability with the outcome measures from the LEMOCOT, after controlling for walking velocity. ResultsThe variability in step time, step length and step width correlated with walking velocity, while the variability in step velocity did not. After controlling for walking velocity, we observed that the LEMOCOT score correlated with the variance in step time, and the variable error in the LEMOCOT correlated with the variance in step length, in step width, and in step velocity. No significant correlation with any of the velocity-controlled step parameters was found for the absolute error in the LEMOCOT. SignificanceDecreased performance in the LEMOCOT was associated with increased spatiotemporal variability in persons with stroke, regardless of their walking velocity. Our results demonstrate the connection between lower-extremity coordination impairments and deficits in gait function.

The Effect of Postural Restoration Institute Training on Selected Kinematic Variables of Lower Limbs and Pelvis During Walking in Middle-Aged Men With Nonspecific Chronic Low Back Pain: A Prospective Observational Study

Background and Aims Concerning the effectiveness of training on people with chronic low back pain, the present study aimed to evaluate the effect of postural restoration institute (PRI) training on lower limb kinematics during walking in middle-aged subjects with discogenic low back pain. Methods In this prospective observational quasi-experimental study, 42 people participated in three groups: people without low back pain (healthy group, n=14) and people with low back pain in two groups (intervention group, n=14; and control group, n=14). Kinematic data were recorded by 7 Qualisys cameras with a frequency of 100 Hz in the pretest and post-test. Analysis of variance with repeated measures was used in SPSS software version 23 at a significance level 0.05. Results The results showed that people with low back pain in the intervention and control groups walk with a slower velocity, lower cadence, and shorter step length than healthy individuals for both right and left limbs. However, after the PRI training, the intervention group showed a significant increase in those three variables. Furthermore, there were significant differences between the healthy group and the two groups of intervention and control in the range of motion (ROM) for the pelvis in the sagittal and frontal planes, the right hip joint in the horizontal plane, the right ankle in the frontal plane, the left hip joint in the sagittal and horizontal planes as well as the left ankle in the sagittal plane. After applying PRI, the differences between the healthy and the intervention groups regarding the pelvis ROM on the sagittal plane, the right ankle ROM on the sagittal plane, the left hip joint ROM on the frontal plane, and the left knee ROM on the sagittal plane were minimized and became insignificant. Conclusion The present study’s findings confirmed the effectiveness of using PRI training in improving biomechanical indicators, such as the range of joint movements and increasing the velocity and step length of walking, to treat and manage the performance of people with discogenic chronic low back pain.

Assessing the impact of gait speed on gait stability using multi-scale entropy fused with plantar pressure signals.

Introduction: Walking speed can affect gait stability and increase the risk of falling. Methods: In this study, we design a device to measure the distribution of the plantar pressure to investigate the impact of the walking speed on the stability of the human gait and movements of the body. We fused the entropy acquired at multiple scales with signals of the plantar pressure to evaluate the effects of the walking speed on the stability of the human gait. We simultaneously collected data on the motion-induced pressure from eight plantar regions to obtain the fused regional pressure. To verify their accuracy, we obtained data on the plantar pressure during walking by using the force table of the Qualisys system. We then extracted the peak points and intervals of the human stride from pressure signals fused over three regions, and analyzed the mechanics of their regional fusion by using the regional amplitude-pressure ratio to obtain the distribution of the plantar pressure at an asynchronous walking speed. Furthermore, we introduced multi-scale entropy to quantify the complexity of the gait and evaluate its stability at different walking speeds. Results: The results of experiments showed that increasing the speed from 2 to 6km/h decreased the stability of the gait, with a 26.7% increase in the amplitude of pressure in the region of the forefoot. The hindfoot and forefoot regions were subjected to the minimal pressure at a speed of 2km/h, while the most consistent stress was observed in regions of the forefoot, midfoot, and hindfoot. Moreover, the curve of entropy at a speed of 2km/h exhibited a slow decline at a small scale and high stability at a large scale. Discussion: The multi-scale entropy increased the variation in the stability of the synchronous velocity of walking compared with the sample entropy and the analysis of regional fusion mechanics. Multi-scale entropy can thus be used to qualitatively assess the relationship between the speed and stability of the gait, and to identify the most stable gait speed that can ensure gait stability and posture control.