Search

This article introduces a data‐driven locomotion style controller for full‐body human characters using gait cycle features. Based on gait analysis, we define a set of gait features that can represent various locomotion styles as spatio‐temporal patterns within a single gait cycle. We compute the gait features for every single gait cycle in motion capture data and use them to search for the desired motion. Our real‐time style controller provides users with visual feedback for the changing inputs, exploiting the Motion Matching algorithm. We also provide a graphical controller interface that visualizes our style representation to enable intuitive control for users. We show that the proposed method is capable of retrieving appropriate locomotions for various gait cycle features, from simple walking motions to single‐foot motions such as hopping and dragging. To validate the effectiveness of our method, we conducted a user study that compares the usability and performance of our system with those of an existing footstep animation tool. The results show that our method is preferred over the baseline method for intuitive control and fast visual feedback. [ABSTRACT FROM AUTHOR]

Balance and walking are fundamental to support common daily activities. Relatively accurate characterizations of normal and impaired gait features were attained at the kinematic and muscular levels. Conversely, the neural processes underlying gait dynamics still need to be elucidated. To shed light on gait‐related modulations of neural activity, we collected high‐density electroencephalography (hdEEG) signals and ankle acceleration data in young healthy participants during treadmill walking. We used the ankle acceleration data to segment each gait cycle in four phases: initial double support, right leg swing, final double support, left leg swing. Then, we processed hdEEG signals to extract neural oscillations in alpha, beta, and gamma bands, and examined event‐related desynchronization/synchronization (ERD/ERS) across gait phases. Our results showed that ERD/ERS modulations for alpha, beta, and gamma bands were strongest in the primary sensorimotor cortex (M1), but were also found in premotor cortex, thalamus and cerebellum. We observed a modulation of neural oscillations across gait phases in M1 and cerebellum, and an interaction between frequency band and gait phase in premotor cortex and thalamus. Furthermore, an ERD/ERS lateralization effect was present in M1 for the alpha and beta bands, and in the cerebellum for the beta and gamma bands. Overall, our findings demonstrate that an electrophysiological source imaging approach based on hdEEG can be used to investigate dynamic neural processes of gait control. Future work on the development of mobile hdEEG‐based brain–body imaging platforms may enable overground walking investigations, with potential applications in the study of gait disorders. [ABSTRACT FROM AUTHOR]

One commonly used criterion in evaluating a patients' response to knee surgery or rehabilitation is bilateral symmetry. However, the natural symmetry in uninjured healthy adult knee kinematics remains relatively unknown, making it challenging to determine if clinical treatment has adequately restored bilateral symmetry. The primary purpose of this study was to determine the typical side‐to‐side differences in 6 degree of freedom (DOF) knee kinematics over the entire gait cycle in healthy adults using biplane radiography. Six DOF tibiofemoral kinematics were measured during treadmill walking in 19 participants using a validated volumetric model‐based tracking process that matched subject‐specific bone models to biplane radiographs collected at 100 images/s. Average absolute side‐to‐side differences in knee kinematics at foot strike were 1.3 mm or less in translation and 3.8° or less in rotation. Peak side‐to‐side differences in knee kinematics occurred during the swing phase and were up to 2.2 mm in translation and 7.1° in rotation. Dominant versus non‐dominant leg differences were 0.8 mm and 2.8° or less at foot strike and reached maximum values of 0.8 mm and 7.2° over the full gait cycle. Statement of Clinical Significance: This study quantifies the inherent asymmetry of knee kinematics in healthy individuals over the entire gait cycle. The values of asymmetry presented here may serve as a guide for evaluating functional outcomes and restoration of so‐called "normal" kinematics after injury and clinical intervention. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [ABSTRACT FROM AUTHOR]

The purpose of the current study was to evaluate influences of radial tears and partial meniscectomy of lateral meniscus on the knee joint mechanics during normal walking by using computational modeling. A 3D geometry of a knee joint of a healthy patient was obtained from our previous study, whereas the data of normal walking were taken from the literature. Cartilage tissue was modeled as a fibril reinforced poroviscoelastic material, whereas meniscal tissue was modeled as a transverse isotropic elastic material. The realistic gait cycle data were implemented into the computational model and the effects of radial tears and partial meniscectemy of lateral meniscus on the knee joint mechanics were simulated. Middle, posterior, and anterior radial tears in lateral meniscus increased stresses by 300%, 430%, and 1530%, respectively, at the ends of tears compared to corresponding areas in the model with intact lateral meniscus. Meniscus tears did not alter stresses and strains at the tibial cartilage surface, whereas partial meniscectomy increased contact pressures, stresses, strains and pore pressures in the tibial cartilage by 50%, 44%, 21%, and 43%, respectively. Increased stresses and strains were observed primarily during the first ∼50% of the stance phase of the gait cycle. The present study suggests that anterior radial tear causes the highest risk for the development of total meniscal rupture, whereas partial meniscectomy increases the risk for the development of OA in lateral tibial cartilage. Highest risks for meniscus and cartilage failures are suggested to occur during the loading response and mid-stance of the gait cycle. In the future, the present modeling may be further developed to offer a clinical tool for aid in decision making of clinical interventions for patients with knee joint injuries. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1208-1217, 2013 [ABSTRACT FROM AUTHOR]

Objective: Knee kinematic asymmetries after anterior cruciate ligament reconstruction (ACLR) are correlated with poor clinical outcomes, such as the progression of knee cartilage degenerations or reinjuries. Fast walking in patients with knee conditions may exacerbate knee kinematic asymmetries, but its impact on ACLR patients is uncertain. The aim of this study is to investigate if fast walking induces more knee kinematic asymmetries in unilateral ACLR patients. Methods: This cross‐sectional study enrolled 55 patients with unilateral ACLR from January 2020 to July 2022. There were 48 males and seven females with an average age of 30.6 ± 6.4 years. Knee kinematic data were collected at three walking speeds: self‐selected, fast (150% normal), and slow (50% normal). A 3D knee kinematic analysis system measured the data, and self‐reported outcomes assessed comfort levels during walking. We used SPM1D for two‐way repeated ANOVA and posthoc paired t‐tests to analyze kinematic differences in groups. Results: In fast walking, ACLR knees exhibited more transverse kinematic asymmetries than intact knees, including greater external rotation angle (1.8°, 38%–43%; gait cycle [GC], p < 0.05 & 1.8–2.7°, 50%–61% GC, p < 0.05) and increased proximal tibial translation (2.1–2.5 mm, 2%–6% GC, p < 0.05 & 2.5–3.2 mm, 92%–96% GC, p < 0.05). Additionally, ACLR knees showed greater posterior tibial translation than intact knees (3.6–3.7 mm, 7%–8% GC, p < 0.05) during fast walking. No posterior tibial translation asymmetries were observed in slow walking compared to normal walking levels. ACLR knees have the most comfortable feelings in slow walking speed, and the most uncomfortable feelings in fast walking speed levels (29%). Conclusions: Fast walking induces additional external tibial rotation and proximal and posterior tibial translation asymmetries in ACLR patients. This raises concerns about long‐term safety and health during fast walking. Fast walking, not self‐selected speed, is beneficial for identifying postoperative gait asymmetries in ACLR patients. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the biomechanical contact characteristics of rotating hinge knee (RHK) prostheses with different motion axial systems. We performed finite element (FE) analyses to investigate and compare the peak contact stress and contact location on tibial insert and bushing during a gait cycle. The biaxial (BA) system and spherical center axial (SA) system RHK prostheses were included in this study. The comparisons between experimental tests and FE analyses were performed to verify the validation of FE models. Decreased ISO loadings were then applied to the validated FE models to investigate the peak contact stress and contact location on tibial insert and bushing. The contact areas obtained from experimental tests and FE analyses were in a good agreement. The peak contact stresses on tibial insert and bushing of BA prosthesis were higher than those of SA prosthesis. The contact locations on the superior surface of tibial insert in SA and BA prostheses were at the middle‐posterior and posterior side, while those on the rotating axial surface were at the medial and lateral sides, respectively. This study indicate that the tibial insert and bushing of an SA prosthesis have lower peak contact stresses and better contact locations than those of a BA prosthesis during a gait cycle, which may decrease the risk of long‐term complications of RHK prostheses. Future studies should be performed to confirm the relationship between the contact characteristics and wear in RHK prostheses. [ABSTRACT FROM AUTHOR]

Objective: To investigate the hip joint forces, Von Mises stress, contact pressure and micro‐motion of hip prosthesis for developmental dysplasia of the hip (DDH) patients under different hip joint centers using musculoskeletal (MSK) multi‐body dynamics and finite element analysis. Methods: Both MSK multi‐body dynamics model and finite element (FE) model were based on CT data of a young female DDH patient with total hip replacement and were developed to study the biomechanics of the S‐ROM hip prosthesis. The same offset of hip joint center along all six orientations compared with the standard position was set to predict its effects on both MSK multi‐body dynamics and contact mechanics during one gait cycle. Results: The hip joint forces in the entire walking gait cycle showed two peak values and clear differences between them under different hip joint centers. The hip joint force increased when the hip joint center moved posteriorly (2101 N) and laterally (1969 N) to the anatomical center (1848 N) at the first peak by 13.7% and 6.6%, respectively. The hip joint force increased sharply when the hip center deviated laterally (2115 N) and anteriorly (2407 N), respectively, from the standard position (1742 N) at the second peak. For the sleeve of the S‐ROM prosthesis, the maximum Von Mises stress and contact pressure of the sleeve increased if the hip joint center deviated from the anatomical center posteriorly at the first peak. However, the Von Mises stresses and contact pressure increased at anterior and lateral orientations, compared to that of the standard position at the second peak. Small changes were observed for the maximum relative sliding distance along most of the orientations at both peaks except in the lateral and medial orientations, in which an increase of 8.6% and a decrease of 13.6% were observed, respectively. Conclusion: The hip joint center obviously influenced the hip joint forces, stress, contact pressure and micro‐motion of the hip implant for this female patient. [ABSTRACT FROM AUTHOR]

Summary: In healthcare applications, gait plays a major role in identification of the normal or abnormal person in different situations. Human gait refers to the walking style of the person, and it may also refer as locomotion using human limbs. The abnormal gait has irregular patterns of stance and swing phases. Without any clinical impairment, this paper proposes a novel approach to classify the person as normal or the person as suffering from neurological disorders from the videos using their gait videos. In addition, neurological gait disorders such as Parkinson gait, hemiplegic gait, and neuropathic gait has been identified using the gait features. Many systems are designed to detect and identify gait disorders using head, hip, heel, and toe behavior analysis from the bidirectional gait videos. As motivated by previous mechanisms, this paper proposes a novel vision based algorithm to recognize the gait abnormalities using model free approaches and significant feature vector generation from complete silhouette images of one gait cycle of a person. Here, a lean angle and ramp angle are considered as distinguishing and prominent features, and the results of these features are properly classified into normal or abnormal gait through the design of an unsupervised classifier. [ABSTRACT FROM AUTHOR]

Objective: Early articular cartilage lesion (CL) is a vital sign in the onset of posttraumatic knee osteoarthritis (PTOA) in patients with anterior cruciate ligament deficiency (ACLD). Researchers have suggested that altered kinematics could accelerate CLs and, therefore, lead to the onset of PTOA. However, little is known about whether specific knee kinematics exist that lead to early CL in chronic ACLD knees. Level walking is the most frequent and relevant in vivo activity, which greatly impacts knee health. We hypothesized that the knee kinematics during level walking in chronic ACLD knees with early tibiofemoral CL would significantly differ from those of chronic ACLD knees without early tibiofemoral CL. Methods: Thirty patients with a chronic ACLD history, including 18 subjects with CLs and 12 subjects without CLs, and 35 healthy control subjects were recruited for the study from July 2020 to August 2022. The knee kinematic data during level walking were collected using a three‐dimensional motion analysis system. The kinematic differences between groups were compared using statistical parametric mapping with one dimension for One‐Way ANOVA. The cartilage statuses of the ACLD knees were assessed via MRI examination. The CLs distribution of subjects was evaluated using a modified Noyes scale and analyzed by chi‐square tests. Results: ACLD knees with CLs had significantly greater posterior tibial translation (7.7–8.0mm, 12%–18% gait cycle GC, p = 0.014) compared to ACLD knees without CLs during level walking. ACLD knees with CLs had greater posterior tibial translation (4.6–5.5mm, 0%–23% GC, p < 0.001; 5.8–8.0mm, 86%–100% GC, p < 0.001) than healthy controls during level walking. In the group of ACLD knees with CLs, CL is mainly located in the back of the tibia plateau and front of load bearing area of the medial femoral condyle (p < 0.05). Conclusion: Chronic anterior cruciate ligament deficient knees with cartilage lesions have increased posterior tibial translation compared to anterior cruciate ligament deficient knees without cartilage lesions and healthy subjects. The posterior tibial translation may play an important role in knee cartilage degeneration in ACLD knees. The increased posterior tibial translation and cartilage lesion characteristics may improve our understanding of the role of knee kinematics in cartilage degeneration and could be a helpful potential reference for anterior cruciate ligament deficient therapy, such as physical training to improve abnormal kinematic behavior. [ABSTRACT FROM AUTHOR]

Recently, human gait pattern has turned into an essential biometric feature to recognize an individual remotely. Gait as a feature becomes challenging owing to variation in appearance under different covariate conditions (eg, shoe, surface, haul, viewpoint and attire). The covariates may alter few fragment of gait while other fragment stay unaltered, leading to lower the probability of correct identification. To overcome such variation, an improved gait recognition strategy is proposed in this article by gait energy image partitioning and selection processing. Our method involves pre‐processing of raw video for silhouette extraction, gait cycle detection, segmentation into different regions, and histogram of gradients feature extraction from selected segments. In this way, the specific features across complete gait cycles are extracted precisely. Finally, recognition is done by using K‐NN. The proposed strategy has been assessed using the CASIA B gait database. Our outcomes shows a particular proposed strategy accomplishes high recognition rate and outperforms the advanced gait recognition mechanism. [ABSTRACT FROM AUTHOR]

Objective: To assess the tibio‐femoral contact forces before and after total knee arthroplasty (TKA) in patients with knee osteoarthritis (KOA) by three‐dimensional (3D) finite element analysis (FEA) models and gait analysis. Methods: Two hospitalized patients with Kellgren–Lawrence grade IV varus KOA and two healthy subjects were enrolled in this study. Both patients underwent unilateral TKA. FEA models were established based on CT and MR images of the knees of the patients with KOA and healthy subjects. Gait analysis was performed using a three‐dimensional motion capture system with a force plate. Three direction forces at the ankle joints were calculated by inverse dynamic analysis, which provided the load for the FEA models. The total contact forces of the knee joints were also calculated by inverse dynamic analysis to enable comparisons with the results from the FEA models. The total knee contact forces, maximum von Mises stress, and stress distribution of the medial plateau were compared between the patients and healthy subjects. The distributions of the medial plateau force at 2 and 6 months postoperatively were compared with the distributions of the forces preoperatively and those in the healthy subjects. Results: During static standing, the medial plateau bore the most of the total contact forces in the knees with varus KOA (90.78% for patient 1 and 93.53% for patient 2) compared with 64.75 ± 3.34% of the total force in the healthy knees. At the first and second peaks of the ground reaction force during the stance phase of a gait cycle, the medial plateau bore a much higher percentage of contact forces in patients with KOA (74.78% and 86.48%, respectively, for patient 1; 70.68% and 83.56%, respectively, for patient 2) than healthy subjects (61.06% ± 3.43% at the first peak and 72.09% ± 1.83% at the second peak). Two months after TKA, the percentages of contact forces on the medial tibial plateau were 79.65%–85.19% at the first and second peaks of ground reaction forces during the stance phase of a gait cycle, and the percentages decreased to 53.99% – 68.13% 6 months after TKA. Conclusion: FEA showed that TKA effectively restored the distribution of tibio‐femoral contact forces during static standing and walking, especially 6 months after the surgery. The changes in the gait were consistent with the changes in the contact force distribution calculated by the FEA model. [ABSTRACT FROM AUTHOR]

Objectives: To determine if adolescents with patellofemoral pain exhibit different biomechanical characteristics to asymptomatic adolescents during walking and running. Methods: Twenty‐eight adolescents with patellofemoral pain (16 male, 12 female, mean [SD] age: 14.3 [1.7] years) and 24 asymptomatic adolescents (13 male, 11 female, mean [SD] age: 14.1 [1.6] years) participated. Participants walked and ran on an instrumented treadmill in a standardized athletic shoe. Continuous hip, knee, and ankle joint angles and moments, and frontal plane pelvic motion were compared between groups using one‐dimensional statistical parametric mapping independent t‐tests (alpha <0.05). Cadence and stride length were compared between groups using independent t‐tests. Results: During walking, adolescents with patellofemoral pain had a higher hip extension moment at 7%–8% of the gait cycle (p = 0.04) and walked with a shorter stride length (mean difference [95% confidence interval] = −0.07 [−0.1, −0.01] m). There were no other differences between groups during walking. During running, adolescents with patellofemoral pain had greater knee flexion than asymptomatic adolescents at 35%–40% of the gait cycle (p = 0.04) and ran with a higher cadence (mean difference [95% confidence interval] = 5.8 [2.0, 9.5] steps/min). There were no other statistically significant differences between groups during running. Conclusions: Adolescents with patellofemoral pain demonstrate few biomechanical differences to asymptomatic adolescents during walking and running. The identified differences are likely of limited clinical importance. Biomechanical alterations which have been previously associated with patellofemoral pain in adults, may not need to be the target of management of adolescent patellofemoral pain. [ABSTRACT FROM AUTHOR]

Objectives: Diagonal‐sequence, diagonal‐couplet (DSDC) gaits have been proposed as an adaptation to travel on discontinuously arranged arboreal branches. Only a few studies have examined primate gait adjustment to support discontinuity. We analyzed the gaits of Japanese macaques walking on the "ground" and two discontinuous conditions, "circle" and "point," to better understand the advantages of DSDC gaits on discontinuous supports. Materials and Methods: Seventy‐eight vertical posts, each with a circular upper surface, were arranged in four rows at a spacing of 200 mm. The diameter of the circular upper surface was 150 mm ("circle condition") or 50 mm ("point condition"). We calculated the limb phase, duty factor, and time interval from hindlimb touchdown to ipsilateral forelimb liftoff. The supports the fore‐ and hindlimbs landed on during walking were identified in the circle and point condition. Results: The macaques predominantly used DSDC gaits in the ground and circle conditions and lateral‐sequence, diagonal‐couplet (LSDC) gaits in the point condition. The macaques usually placed their hindlimbs on the same supports as their ipsilateral forelimbs during the gait cycle. Discussion: Japanese macaques overlapped the ipsilateral fore‐ and hindlimb stance phase in all DSDC and some LSDC gaits to proximate the ipsilateral limbs on the discontinuous support, allowing the forelimb to guide the hindlimb placement to the support. The overlap duration of the ipsilateral limb stance phases may be extended by DSDC gaits longer than by LSDC gaits, allowing for a direct pass of the support being held by the prehensile hand to the prehensile foot. [ABSTRACT FROM AUTHOR]

Closed-circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean ± 1 SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individual's VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 60-80 in the gait cycle. We show how our data can assess gait data from an actual case. [ABSTRACT FROM AUTHOR]

Background: Gait phenotypes are well documented in people with Down syndrome (pwDS), but sex‐related differences are still unexplored. This study investigated the existence of possible differences in spatio‐temporal and kinematic parameters of gait between men and women with DS using quantitative three‐dimensional gait analysis. Methods: Gait patterns of 117 pwDS (53 F, 64 M) who underwent a computerised gait analysis from 2002 to 2017 were retrospectively analysed to obtain spatio‐temporal gait parameters and kinematics in the sagittal plane at hip, knee and ankle joints, as well as foot progression. Results: Overall, when considered as a single group, the gait patterns found for pwDS confirmed the findings of previous studies. However, when analysed by sex, our data revealed that women with DS exhibit a larger hip flexion at late stance (42% to 54% of the gait cycle) and reduced knee flexion at the beginning of the swing phase (61% to 69% of the gait cycle). In contrast, men are characterised by larger foot extra‐rotation angles through most of the stance phase (from 0% to 55% of the gait cycle) and at the end of the swing phase (92% to 99% of the gait cycle). No differences between men and women with DS were found concerning ankle dorsi‐ plantar‐flexion or in all spatio‐temporal parameters normalised by individuals' anthropometry, excluding cadence (higher in women). Conclusions: The findings of the present study highlight the need to investigate gait dysfunctions in pwDS by taking their sex into consideration. Such an approach may be useful not only in gaining a better understanding of the pathophysiology of gait disturbances associated with DS but also in supporting a better orientation of rehabilitative treatments. [ABSTRACT FROM AUTHOR]

Non‐invasive brain stimulation has been of interest as a therapeutic tool to modulate cortical excitability. However, there is little evidence that oscillatory brain stimulation can modulate the cortical control of muscle activities during gait, which can be assessed using coherence analysis of paired surface electromyographic (EMG) recordings. This study aimed to investigate the effects of gait‐combined transcranial alternating current stimulation (tACS) at the gait cycle frequency on the cortical control of muscle activities during gait using EMG‐EMG coherence analysis. Fourteen healthy young adults participated in this study. All participants underwent 2 test conditions (real tACS and sham stimulation over the leg area of the primary motor cortex during 10‐min treadmill walking). The average peak‐to‐peak amplitudes of the motor evoked potentials (MEPs) from the tibialis anterior (TA) and lateral gastrocnemius muscles in the sitting position and EMG‐EMG coherences in the TA muscle, triceps surae muscles, quadriceps muscles, and hamstring muscles during gait were measured before and after stimulation. Entrainment effect was significantly higher during real tACS than during sham stimulation. After real tACS, the MEP amplitude and beta band (13–33 Hz) coherence area increased in the TA muscle. The change in MEP amplitude from the TA muscle was positively correlated with the change in beta band coherence area in the TA muscle. Gait‐combined tACS can modulate the strength of descending neural drive to TA motoneurons during gait. This suggests that oscillatory brain stimulation is a useful therapeutic tool to modulate the cortical control of muscle activities during gait. [ABSTRACT FROM AUTHOR]

The present study focuses on the design and finite element analysis of a novel hip prosthesis comprising truss structures intended to equally distribute the stress along the prosthesis. The prosthesis is designed to suit three different inclination angles of 20°, 40° and 60°. The three designs were subjected to loading conditions that emulate walking, jogging, and cycling activities via finite element simulations. Using the von Mises yield criterion and Goodman relation for fatigue, it is found that the safety factor and the life cycle of the proposed prosthesis design was within the acceptable range. Furthermore, the truss structures incorporated in the prosthesis appear to reduce the stress levels in the femur. [ABSTRACT FROM AUTHOR]

Ankle arthritis is a debilitating disease marked by pain and limited function. Total ankle arthroplasty improves pain while preserving motion and offers an alternative to the traditional treatment of ankle fusion. Gait analysis and functional outcomes tools can provide an objective balanced analysis of ankle replacement for the treatment of ankle arthritis. Twenty‐nine patients with end‐stage ankle arthritis were evaluated before and after ankle arthroplasty. Multi‐segment foot and ankle kinematics were assessed annually following surgery (average 3.5 years, range 1–6 years) using the Milwaukee Foot Model and a Vicon video motion analysis system. Functional outcomes (American Orthopedic Foot and Ankle Society [AOFAS] ankle/hindfoot scale, short form 36 [SF‐36] questionnaire) and temporal‐spatial parameters were also assessed. Kinematic results were compared to findings from a previously collected group of healthy ambulators. AOFAS and SF‐36 mean scores improved postoperatively. Walking speed and stride length increased after surgery. There were significant improvements in tibial sagittal range of motion in terminal stance and hindfoot sagittal range of motion in preswing. Decreased external rotation of the tibia and increased external rotation of the hindfoot were noted throughout the gait cycle. Pain and function improved after ankle replacement as supported by better outcomes scores, increased temporal‐spatial parameters, and significant improvement in tibial sagittal range of motion during terminal stance and hindfoot sagittal range of motion during preswing. While multi‐segment foot kinematics were improved, they were not restored to control values. Statement of clinical significance: Total ankle arthroplasty does not fully normalize mutli‐segment gait kinematics despite improved patient‐reported outcomes and gait mechanics. [ABSTRACT FROM AUTHOR]

Background: Differential diagnosis between idiopathic normal pressure hydrocephalus (iNPH) associated with parkinsonism (iNPH‐P) and Parkinson's disease (PD) may prove difficult when evaluating patients with early parkinsonism. The objective of this study was to evaluate differences in mobility during standardized tasks between iNPH‐P and PD. Methods: We selected 21 iNPH‐P and 21 pharmacologically untreated PD patients. They all performed the instrumented Timed Up and Go test at the time of diagnosis. Results: Turning tasks showed longer duration and lower speed in iNPH‐P than in PD. Vertical variation in acceleration during the sit‐to‐stand phase was lower in iNPH‐P patients, whereas the duration of the stand‐to‐sit phase was longer. On walking, iNPH‐P showed smaller stride length and a longer gait cycle duration. In multivariate analysis adjusting for age and cognitive status as potential confounders, average angular speed on turning before sitting was the discriminating parameter between the two groups. Conclusions: Patients with iNPH‐P showed specific abnormal mobility performances with respect to untreated PD, specifically during the turning‐to‐sitting transition. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the contact stress and the contact area o tibial inserts and bushings with respect to different congruency designs in a spherical center axis and rotating bearing hinge knee prosthesis under gait cycle loading conditions using finite element analysis. Methods: Nine prostheses with different congruency (different degrees of tibiofemoral conformity and different distances between the spherical center and the bushing) designs were developed with the same femoral and tibial components. The models were transferred to finite element software. The peak contact stresses and contact areas on tibial inserts and bushings under the gait cycle loading conditions were investigated and compared. Results: For tibial insert, the peak contact stress was the highest in the low conformity‐long group (61.4486 MPa), and it was 1.88 times higher than that in the group with the lowest stress (moderate conformity‐short group, 32.754 MPa). The contact area was the largest in the low conformity‐long group (420.485 mm2), and it was 1.19 times larger than that in the group with the smallest area (moderate conformity‐middle group, 352.332 mm2). For bushing, the peak contact stress was the highest in the high conformity‐long group (72.8093 MPa), and it was 3.21 times higher than that in the group with the lowest stress (high conformity‐short group, 22.6928 MPa). The contact area was the largest in the low conformity‐short group (2.41 mm2), and it was 2.27 times larger than that in the group with the smallest area (high conformity‐middle group, 1.063 mm2). Conclusion: The results of our study showed that the congruency of the tibiofemoral surface and bushing surface should be considered carefully in the design of the spherical center axis and rotating bearing hinge knee prosthesis. Different levels of contact performance were observed with different congruency designs. In addition, the influence of contact stress and contact area on the polyethylene wear of rotating hinge knee prostheses should be confirmed with additional laboratory tests. [ABSTRACT FROM AUTHOR]

Modification of ongoing walking movement to fit changes in external environments requires accurate voluntary control. In cats, the motor and posterior parietal cortices have crucial roles for precisely adjusting limb trajectory during walking. In human walking, however, it remains unclear which cortical information contributes to voluntary gait modification. In this study, we investigated cortical activity changes associated with visually guided precision stepping using electroencephalography source analysis. Our results demonstrated frequency‐ and gait‐event‐dependent changes in the cortical power spectrum elicited by voluntary gait modification. The main differences between normal walking and precision stepping were as follows: (a) the alpha, beta or gamma power decrease during the swing phases in the sensorimotor, anterior cingulate and parieto‐occipital cortices, and (b) a power decrease in the theta, alpha and beta bands and increase in the gamma band throughout the gait cycle in the parieto‐occipital cortex. Based on the previous knowledge of brain functions, the former change was considered to be related to execution and planning of leg movement, while the latter change was considered to be related to multisensory integration and motor awareness. Therefore, our results suggest that the gait modification is achieved by higher cortical involvements associated with different sensorimotor‐related functions across multiple cortical regions including the sensorimotor, anterior cingulate and parieto‐occipital cortices. The results imply the critical importance of the cortical contribution to voluntary modification in human locomotion. Further, the observed cortical information related to voluntary gait modification would contribute to developing volitional control systems of brain–machine interfaces for walking rehabilitation. [ABSTRACT FROM AUTHOR]

Objective: 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. Methods: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Objective: The third generation Intelligent Device for Energy Expenditure and Activity (IDEEA3, MiniSun, CA) has been developed for clinical gait evaluation, and this study was designed to evaluate the accuracy and reliability of IDEEA3 for the gait measurement of lumbar spinal stenosis (LSS) patients. Methods: Twelve healthy volunteers were recruited to compare gait cycle, cadence, step length, velocity, and number of steps between a motion analysis system and a high‐speed video camera. Twenty hospitalized LSS patients were recruited for the comparison of the five parameters between the IDEEA3 and GoPro camera. Paired t‐test, intraclass correlation coefficient, concordance correlation coefficient, and Bland–Altman plots were used for the data analysis. Results: The ratios of GoPro camera results to motion analysis system results, and the ratios of IDEEA3 results to GoPro camera results were all around 1.00. All P‐values of paired t‐tests for gait cycle, cadence, step length, and velocity were greater than 0.05, while all the ICC and CCC results were above 0.950 with P < 0.001. Conclusions: The measurements for gait cycle, cadence, step length, velocity, and number of steps with the GoPro camera are highly consistent with the measurements with the motion analysis system. The measurements for IDEEA3 are consistent with those for the GoPro camera. IDEEA3 can be effectively used in the gait measurement of LSS patients. [ABSTRACT FROM AUTHOR]

Closed circuit television ( CCTV) footage is often available from crime scenes and may be used to compare perpetrators with suspects. Usually, the footage comprises incomplete gait cycles at different velocities, making gait pattern identification from crimes difficult. This study investigated the concurrence of joint angles throughout a gait cycle at three different velocities (3.0, 4.5, 6.0 km/h). Six datasets at each velocity were collected from 16 men. A variability range VR throughout the gait cycle at each velocity for each joint angle for each person was calculated. The joint angles at each velocity were compared pairwise, and whenever this showed values within the VR of this velocity, the case was positive. By adding the positives throughout the gait cycle, phases with high and low concurrences were located; peak concurrence was observed at mid-stance phase. Striving for the same velocity for the suspect and perpetrator is recommended. [ABSTRACT FROM AUTHOR]

Background: Cerebral small vessel disease (CSVD) is closely related to gait disorders. Previous studies have found a negative correlation between the severity of MRI white matter hyperintensities (WMH) and gait speed. However, not every individual with WMH experiences a gait disorder. Purpose: To investigate the mechanisms underlying the mismatch between the severity of MRI WMH and gait impairment, in particular in subjects with severe WMH (Fazekas 3, scale 0–3) resulting from vascular disease. Study Type: Cohort. Population: 54 subjects with severe WMH and gait disorder (WMH‐GD; 29 males) and 114 subjects with severe WMH with no gait disorder (WMH‐nGD; 60 males). Field Strength/Sequence: 3T/diffusion tensor imaging (DTI), and T1‐weighted, T2‐weighted, FLAIR, DWI, SWI. Assessment: Trace‐based spatial statistics analysis (TBSS) approach (fractional anisotropy, FA; mean diffusivity; radial diffusivity; axial diffusivity); Cognitive assessment; Conventional MRI markers of CSVD (WMH, enlarged perivascular spaces, lacunae, and cerebral microbleeds); Gait parameters (gait speed; cadence; stride length; gait cycle duration; step duration; time‐up‐and‐go test, TUG). Gait disorder was defined as a TUG time exceeding 12 sec. Statistical Tests: The t‐tests, Mann–Whitney U tests, Chi‐square tests, and partial correlation analysis (Pearson or Spearman) were used. P < 0.05 with threshold‐free cluster enhancement corrected was considered statistically significant for TBSS. Results: After adjusting for age, sex, height, and other conventional MRI markers of CSVD, the WMH‐nGD group showed significantly decreased FA values in the corpus callosum, bilateral superior longitudinal fasciculus, left corona radiata, and left posterior thalamic radiation. There was a significant association between FA values and TUG time, gait speed, and stride length in multiple WM tracts, independent of other conventional CSVD markers. Data Conclusion: This study provides evidence for microstructural damage of specific fibers in WMH‐GD subjects compared to WMH‐nGD subjects. This may explain the mismatch between WMH and gait impairment in subjects with severe WMH. Level of Evidence: 1 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

In vivo anterior cruciate ligament (ACL) bundle (anteromedial bundle [AMB] and posterolateral bundle [PLB]) relative elongation during walking and running remain unknown. In this study, we aimed to investigate in vivo ACL relative elongation over the full gait cycle during walking and running. Ten healthy volunteers walked and ran at a self‐selected pace on an instrumented treadmill while biplane radiographs of the knee were acquired at 100 Hz (walking) and 150 Hz (running). Tibiofemoral kinematics were determined using a validated model‐based tracking process. The boundaries of ACL insertions were identified using high‐resolution magnetic resonance imaging (MRI). The AMB and PLB centroid‐to‐centroid distances were calculated from the tracked bone motions, and these bundle lengths were normalized to their respective lengths on MRI to calculate relative elongation. Maximum AMB relative elongation during running (6.7 ± 2.1%) was significantly greater than walking (5.0 ± 1.7%, p = 0.043), whereas the maximum PLB relative elongation during running (1.1 ± 2.1%) was significantly smaller than walking (3.4 ± 2.3%, p = 0.014). During running, the maximum AMB relative elongation was significantly greater than the maximum PLB relative elongation (p < 0.001). ACL relative elongations were correlated with tibiofemoral six degree‐of‐freedom kinematics. The AMB and PLB demonstrate similar elongation patterns but different amounts of relative elongation during walking and running. The complex relationship observed between ACL relative elongation and knee kinematics indicates that ACL relative elongation is impacted by tibiofemoral kinematic parameters in addition to flexion/extension. These findings suggest that ACL strain is region‐specific during walking and running. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1920–1928, 2019 [ABSTRACT FROM AUTHOR]

Gait abnormalities are frequently reported in autism. The empirical literature, however, is characterized by inconsistent findings concerning which aspects of gait are affected. We conducted a meta‐analysis to summarize study findings that examined temporal and spatial (i.e., two‐dimensional) gait parameters in pediatric and adult samples comprising individuals with autism and healthy controls. After searching electronic databases, a total of 18 studies were identified and included in this review. Results from the meta‐analyses revealed autism is associated with a wider step width, slower walking speed, longer gait cycle, longer stance time and longer step time. Additionally, autism appears to be associated with greater intra‐individual variability on measures of stride length, stride time and walking speed. Meta‐regression analyses revealed cadence and gait cycle duration differences, between autism and control groups, become more pronounced with age. Overall, this review demonstrates that autism is associated with gait abnormalities. However, assessment of the methodological quality of the studies reveal, additional research is required to understand the extent that gait abnormalities are specifically linked to autism, or whether they may be secondary to other factors commonly found in this group, such as increased weight. Lay Summary: It is often noted by clinicians that individuals with autism have an awkward or unusual walking style, which is also referred to as gait. In this report, we reviewed past studies that compared gait in individuals with and without autism. Our review indicates autism is associated with an abnormal gait. However, it is not yet clear whether gait abnormalities are caused by autism, or arise due to other factors such as heavier weight, which often co‐occurs in this group. Autism Res 2021, 14: 733–747. © 2020 International Society for Autism Research and Wiley Periodicals LLC [ABSTRACT FROM AUTHOR]

High tibial osteotomy (HTO) is a well‐established treatment for medial compartment knee osteoarthritis (OA), which shifts the weight‐bearing axis from the medial to the lateral side of the knee. As the adjacent ankle joint may be directly affected by the change in biomechanics, this study aimed to evaluate the change in the intersegmental foot and ankle motion after HTO in patients with genu varum. The study included 24 patients who underwent HTO, and 48 older healthy participants as a control group. Segmental foot kinematics were evaluated using a 3D multisegment foot model, and gait data of temporal and spatial parameters were obtained. After HTO, normalized stride length significantly increased with a tendency for increases in gait speed. In hallux kinematics relative to the forefoot, the sagittal motions of both the patients and the control group were similar throughout the majority of the gait cycle. In forefoot kinematics relative to the hindfoot, the pre‐HTO state revealed significant pronation throughout the gait cycle, while the post‐HTO state showed a similar position and motion to the control group. In hindfoot kinematics relative to the tibia, coronal motions of the pre‐HTO state showed supination throughout the gait cycle, while supination during the stance phase decreased after HTO. Genu varum patients with medial compartment knee OA showed different gait parameters and intersegmental motion during gait when compared with age‐ and gender‐matched controls. The effect of HTO was demonstrated by the normalization of midfoot compensation in patients with genu varum. [ABSTRACT FROM AUTHOR]

The problem of robust control applied to adjust the configuration of an ankle prosthesis based on disturbance estimation has been addressed in this study. Active disturbance rejection control was the paradigm used for controlling the robotic prosthesis by means of a direct active estimation. Based on this active estimation, the robust controller implemented the disturbance cancellation providing a fast converge to the origin of the tracking error. The uncertainties affecting the prosthesis dynamics were identified by a high‐order extended state high gain observer. This identification was used to force the tracking between the actual position and force needed in the ankle prosthesis and some reference values obtained by a biomechanical gait cycle analysis. Therefore, the estimated states were used to implement a robust output feedback controller that was effective to reject actively the perturbations. This rejection implemented within the controller forced the trajectory tracking to a small vicinity of the origin. A strategy based on composite Lyapunov function served to prove that tracking problem for the prosthesis was successfully solved despite the switching nature of the gait cycle. The controller was implemented in numerical simulations for showing the convergence of the tracking error. The convergence of this tracking error to the region around the origin was obtained within the first second of simulation. [ABSTRACT FROM AUTHOR]

There are various walking pavements in daily life. Slip accidents will happen if required friction for safe walking is greater than available friction between the foot and ground surface. Existing researches mostly focus on horizontal or slope pavements, whereas the cross‐slope walkways are less. A self‐developed gait friction test platform was used to test friction, distribution of plantar pressure and spatiotemporal parameters of human walking under cross‐slope condition. With the increase of cross‐slope angles, the mediolateral friction increases (R2 = 0.972, P < 0.001), the anterior‐posterior friction shows no significant change (R2 = 0.758, P = 0.017), the normal pressure decreases (R2 = 0.915, P = 0.007), and the high foot is more prone to slip and fall than low foot. Therefore, plantar pressure distribution of both feet was shifted to left. The gait cycle was prolonged (P < 0.001), swing period of both feet decreased (P = 0.029) and support period increased (P = 0.015) with the increase of cross‐slope angle. [ABSTRACT FROM AUTHOR]

Background Altered gait patterns and reduced walking speed are commonly reported in adults with Down syndrome (DS). Research on the effects of DS-specific exercise programmes on adults with DS is lacking. The purpose of this quasi-experimental study was to evaluate the changes in gait deviations and walking speed in adults with DS after a DS-specific exercise programme. Methods Twenty participants underwent a 12-week, DS-specific exercise programme in a telehealth format. Before and after the intervention, gait deviations were assessed with the Ranchos Los Amigos Observational Gait Analysis form, and comfortable walking speed was evaluated with the 4-m walk test. Results We observed increased comfortable walking speed and reduced gait deviations in the whole gait cycle in adults with DS after the intervention. There were fewer gait deviations during single-leg stance and swing-limb advancement and at the hip, knee and ankle joints after the 12-week exercise programme. Conclusions Gait speed and observable gait impairments in adults with DS significantly improved following a 12-week telehealth exercise programme. [ABSTRACT FROM AUTHOR]

Aim: In schizophrenia, subjectively perceived disruptions of the sense of the Self (also referred to as "self‐disorders") seem to be intimately associated with a perturbation of the implicit awareness of one's own body. Indeed, an early impairment of the motor system, including posture and gait, is now considered a marker of schizophrenia neurodevelopmental substrate and appears more pronounced in early‐onset schizophrenia. Therefore, the present study was aimed at: (1) investigating a possible relationship between self‐disorders, symptom dimensions and postural and gait profile in schizophrenia; (2) identifying a specific motor profile in early‐onset conditions. Methods: A total of 43 schizophrenia outpatients and 38 healthy controls underwent an exhaustive investigation of posture and gait pattern. The positive and negative syndrome scale (PANSS), the examination of anomalous self experience scale (EASE) and the abnormal involuntary movement scale (AIMS) were administered to the schizophrenia group. Subsequently, schizophrenia patients were divided into early and adult‐onset subgroups and compared with respect to their motor profile. Results: We found an association between specific postural patterns (impaired sway area), a general disruption of the gait cycle and subjective bodily experiences (concerning the loss of bodily integrity, cohesion and demarcation). Only motor parameters (increased sway area and gait cadence reduction) differentiated between early and adult‐onset patients. Conclusion: The results of the present study hint at a link between motor impairment and self‐disturbances in schizophrenia and candidate a specific motor profile as a possible marker of early‐onset forms. [ABSTRACT FROM AUTHOR]

Background: Ankle fractures are common fractures in trauma surgery. Several studies have compared gait patterns between affected patients and control groups. However, no one used the Heidelberg Foot Measurement Method in combination with statistical parametric mapping of the entire gait cycle in this patient cohort. We sought to identify possible mobility deficits in the tibio-talar joint and medial arch in patients after ankle fractures as a sign of stiffness and pain that could result in a pathological gait pattern. We focused on the tibio-talar flexion as it is the main movement in the tibio-talar joint. Moreover, we examined the healing progress over time. Methods: Fourteen patients with isolated ankle fractures were included prospectively. A gait analysis using the Heidelberg Foot Measurement Method was performed 9 and 26 weeks after surgery to analyse the tibio-talar dorsal flexion, the foot tibia dorsal flexion, the subtalar inversion and the medial arch as well as the cadence, the walking speed and the ground reaction force. The American Orthopedic Foot & Ankle Society ankle hindfoot score was used to obtain clinical data. Results were compared to those from 20 healthy participants. Furthermore, correlations between the American Orthopedic Foot & Ankle Society hindfoot score and the results of the gait analysis were evaluated. Results: Statistical parametric mapping showed significant differences for the Foot Tibia Dorsal Flexion for patients after 9 weeks (53–75%: p = 0.001) and patients after 26 weeks (58–70%: p = 0.011) compared to healthy participants, respectively. Furthermore, significant differences regarding the tibio-talar dorsal flexion for patients 9 weeks after surgery (15–40%: p < 0.001; 56,5–70%: p = 0.007; 82–88%: p = 0.033; 97–98,5%: p = 0.048) as well as patients after 26 weeks (62,5–65%: p = 0.049) compared to healthy participants, respectively. There were no significant differences looking at the medial arch and the subtalar inversion. Moreover, significant differences regarding the ground reaction force were found for patients after 9 weeks (0–17%: p < 0.001; 21–37%: p < 0.001; 41–54%: p < 0.001; 60–64%: p = 0.013) as well as patients after 26 weeks (0–1,5%: p = 0.046; 5–15%: p < 0.001; 27–33%: p = 0.001; 45–49%: p = 0.005; 57–59%: p = 0.049) compared to healthy participants, respectively. In total, the range of motion in the tibio-talar joint and the medial arch was reduced in affected patients compared to healthy participants. Patients showed significant increase of the range of motion between 9 and 26 weeks. Conclusions: This study shows, that patients affected by ankle fractures show limited mobility in the tibio-talar joint and the medial arch when compared to healthy participants. Even though the limitation of motion remains at least over a period of 26 weeks, a significant increase can be recognized over time. Furthermore, if we look at the absolute values, the patients' values tend to get closer to those of the control group. Trial registration: This study is registered at the German Clinical Trials Register (DRKS00023379). [ABSTRACT FROM AUTHOR]

Background: The first metatarsophalangeal joint plays a fundamental role during the gait cycle. The Hubscher manoeuvre, which consists of passively dorsiflexing the first metatarsophalangeal joint of an individual in relaxed stance and observing the raising of the medial longitudinal arch, is a clinical test thought to examine the function of the first metatarsophalangeal joint. However, the hallux dorsiflexion achieved during this test is not related to hallux dorsiflexion during gait. On the other hand, unlike kinematic tests, results from kinetic tests have been shown to be strongly correlated with dynamic joint biomechanics. Thus, given the need for valid and reliable tests to evaluate the function of the first metatarsophalangeal joint, this study aimed to assess the reliability of a new kinetic test, namely, the first metatarsophalangeal joint dorsiflexion resistance test. Method: Thirty young adults completed two data collection sessions 1 week apart, during which the first metatarsophalangeal joint dorsiflexion resistance test was performed. Intrarater and interrater reliability were assessed using intraclass correlation coefficients (ICC), minimal detectable difference (MDD), standard error of the mean (SEM) and limits of agreements (LoA). Results: For the intrarater reliability, the ICC was 0.77 (p < 0.001), the SEM was 6.5 N, the MDD was 18.1 N and the LoA were −7.9 to 26.9 N. For the interrater reliability, the ICC was 0.86 (p < 0.001), the SEM was 6.9 N, the MDD was 19.0 N and the LoA were −6.4 to 21.8 N. Conclusion: The results of this study demonstrate good intra and interrater reliability of the first metatarsophalangeal joint dorsiflexion resistance test, which provides evidence to support its use in clinical and research contexts. Further work is required to establish the test results' relationship with joint kinetics during gait and to provide normative values in individuals with and without musculoskeletal disorders as well as among different age groups and genders to optimise its utilization in clinical and research settings. [ABSTRACT FROM AUTHOR]

Background and purpose: Stroke and small vessel disease cause gait disturbances and falls. The naturally occurring loss‐of‐function mutation in the C‐C chemokine receptor 5 gene (CCR5‐Δ32) has recently been reported as a protective factor in post‐stroke motor and cognitive recovery. We sought to examine whether it also influences gait and balance measures up to 2 years after stroke. Method: Participants were 575 survivors of first‐ever, mild–moderate ischaemic stroke or transient ischaemic attack from the TABASCO prospective study, who underwent a 3 T magnetic resonance imaging at baseline and were examined by a multi‐professional team 6, 12 and 24 months after the event, using neurological, neuropsychological and mobility examinations. Gait rhythm and the timing of the gait cycle were measured by force‐sensitive insoles. CCR5‐Δ32 status and gait measures were available for 335 patients. Results: CCR5‐Δ32 carriers (16.4%) had higher gait speed and decreased (better) stride and swing time variability 6 and 12 months after the index event compared to non‐carriers (p < 0.01 for all). The association remained significant after adjustment for age, gender, education, ethnicity and stroke severity. Conclusions: Significant associations were found between gait measurements and CCR5‐Δ32 loss‐of‐function mutation amongst stroke survivors. This is the first study showing that genetic predisposition may predict long‐term gait function after ischaemic stroke. [ABSTRACT FROM AUTHOR]

Bi‐cruciate retaining (BCR) total knee arthroplasty (TKA) design preserves both anterior and posterior cruciate ligaments with the potential to restore normal posterior femoral rollback and joint kinematics. Abnormal knee kinematics and "paradoxical" anterior femoral translation in conventional TKA designs have been suggested as potential causes of patient dissatisfaction. However, there is a paucity of data on the in vivo kinematics and articular contact behavior of BCR‐TKA. This study aimed to investigate in vivo kinematics, articular contact position, and pivot point location of the BCR‐TKA during gait. In vivo kinematics of 30 patients with unilateral BCR‐TKA during treadmill walking was determined using validated dual fluoroscopic imaging tracking technique. The BCR‐TKA exhibited less extension than the normal healthy knee between heel strike and 48% of gait cycle. Although the average external rotation trend observed for BCR TKA was similar to the normal healthy knee, the range of motion was not fully comparable. The lowest point of the medial condyle showed longer anteroposterior translation excursion than the lateral condyle, leading to a lateral‐pivoting pattern in 60% of BCR TKA patients during stance phase. BCR‐TKA demonstrated no statistical significant differences in anterior–posterior translation as well as varus rotation, when compared to normal healthy knees during the stance phase. However, sagittal plane motion and tibiofemoral articular contact characteristics including pivoting patterns were not fully restored in BCR TKA patients during gait, suggesting that BCR TKA does not restore native tibiofemoral articular contact kinematics. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1929–1937, 2019 [ABSTRACT FROM AUTHOR]

The gluteal muscles act as stabilizers of the hip joint and are important for the maintenance of hip function. Atrophy and weakness of the gluteal muscles have been identified in people with hip OA, but it is not known whether these muscles also exhibit altered activity patterns. The aim of this study was to compare gluteal muscle activity in people with hip OA and healthy older adults. Fine‐wire intramuscular electrodes were inserted into the three segments of gluteus medius (GMed) and two segments of gluteus minimus (GMin) in 20 participants with unilateral hip OA and 20 age‐ and gender‐matched controls. Electromyographic activity of these muscle segments was examined during walking along a 10 m walkway. Peak amplitude, average amplitude, and time to peak were compared between groups during the stance phase of the gait cycle. During early stance, the OA group demonstrated a higher burst of activity in posterior GMin (P = 0.02) and trends toward a higher peak in anterior GMin. Both groups displayed peak activity in anterior GMin in the early stance phase in contrast to previous reports in young adults. This early burst of muscle activity was more pronounced with increasing severity of OA. No differences were identified in GMed activity. While altered GMin activity is associated with aging, these changes were more pronounced in participants with hip OA. To reduce disability associated with hip OA, future rehabilitation programs should consider targeted gait strategies and exercises for GMin. [ABSTRACT FROM AUTHOR]

Armadillos comprise a particular group of armoured animals whose functional morphology of locomotion remains unclear. For the first time, the kinematic patterns of Dasypus novemcinctus are analysed. Eight specimens of nine‐banded armadillos were studied at a research institute in São Paulo State, Brazil. The individuals were induced to cross a horizontal corridor and each gait performed during the time each of them was kept inside this structure was recorded to a detailed analysis posteriorly performed in a computer program. Four parameters regarding speed range were considered: stride frequency (Hz) (1/stride period), stride length (m), speed (ms−1) and duty factor (%). A total of 89 strides have been analysed among symmetrical (60.6%) and asymmetrical gaits (39.4%), and six footfall patterns were here reported as follows: lateral sequences (symmetrical), transverse gallop, canter, bound, half‐bound and crutch walk (asymmetrical). This kind of analysis implements our knowledge on the locomotory aspects of these animals, hence contributing to the improvement of our knowledge on this still poorly known group. [ABSTRACT FROM AUTHOR]

Background: Prior studies investigated selected discrete sagittal‐plane outcomes (e.g., peak knee flexion) in relation to running economy, hereby discarding the potential relevance of running technique parameters during noninvestigated phases of the gait cycle and in other movement planes. Purpose: Investigate which components of running technique distinguish groups of runners with better and poorer economy and higher and lower weekly running distance using an artificial neural network (ANN) approach with layer‐wise relevance propagation. Methods: Forty‐one participants (22 males and 19 females) ran at 2.78 m∙s−1 while three‐dimensional kinematics and gas exchange data were collected. Two groups were created that differed in running economy or weekly training distance. The three‐dimensional kinematic data were used as input to an ANN to predict group allocations. Layer‐wise relevance propagation was used to determine the relevance of three‐dimensional kinematics for group classification. Results: The ANN classified runners in the correct economy or distance group with accuracies of up to 62% and 71%, respectively. Knee, hip, and ankle flexion were most relevant to both classifications. Runners with poorer running economy showed higher knee flexion during swing, more hip flexion during early stance, and more ankle extension after toe‐off. Runners with higher running distance showed less trunk rotation during swing. Conclusion: The ANN accuracy was moderate when predicting whether runners had better, or poorer running economy, or had a higher or lower weekly training distance based on their running technique. The kinematic components that contributed the most to the classification may nevertheless inform future research and training. [ABSTRACT FROM AUTHOR]

Background: Lee Silverman voice treatment (LSVT) BIG is an exercise program developed for patients with Parkinson's disease (PwPD), consisting of sets of exercises performed for 4 consecutive days a week for 4 weeks. However, the standard protocol suggests a treatment frequency difficult to follow for most patients who have difficulties reaching rehabilitation clinics. Our aim was to compare the standard LSVT BIG protocol with a modified LSVT (m‐LSVT) BIG protocol (twice a week in the clinic for 4 weeks and twice a week at home for 4 weeks). Methods: In this randomized controlled trial, 16 PwPD (aged 18–80 years, Hoehn and Yahr stages I–III) were recruited into two groups. The LSVT group received standard LSVT BIG training (four times per week for 4 weeks at the clinic). The other group was given m‐LSVT BIG exercises, but unlike the LSVT group, the m‐LSVT group exercised twice a week at the clinic and twice a week at home for 4 weeks. The Berg Balance Scale was used to assess functional balance. Biodex Balance System was used to assess laboratory balance measures. Timed Up and Go test and G‐Walk sensor system were used to assess functional mobility and spatiotemporal gait analysis. Results: Significant group‐by‐time interactions on the eyes open‐firm surface score of the modified clinical test of sensory integration of balance (F = 10.138, p =.007) and gait cycle symmetry index (F = 10.470, p =.010) were found to be in favor of the LSVT group. Additionally, post hoc analyses revealed that both groups significantly improved postural stability, gait speed, motor symptoms, and functional mobility (p <.05). Conclusion: The results revealed the beneficial effects of the modified protocol on balance and gait in PwPD, as well as the superiority of the standard LSVT BIG protocol. The m‐LSVT BIG protocol may be an effective intervention method, especially for PwPD who have difficulty adapting to the treatment frequency of the standard protocol. [ABSTRACT FROM AUTHOR]

Background: In hereditary spastic paraplegia type 4 (SPG4), subclinical gait changes might occur years before patients realize gait disturbances. The prodromal phase of neurodegenerative disease is of particular interest to halt disease progression by future interventions before impairment has manifested. Objective: The objective of this study was to identify specific movement abnormalities before the manifestation of gait impairment and quantify disease progression in the prodromal phase. Methods: Seventy subjects participated in gait assessment, including 30 prodromal SPAST pathogenic variant carriers, 17 patients with mild‐to‐moderate manifest SPG4, and 23 healthy control subjects. An infrared‐camera‐based motion capture system assessed gait to analyze features such as range of motion and continuous angle trajectories. Those features were correlated with disease severity as assessed by the Spastic Paraplegia Rating Scale, neurofilament light chain as a fluid biomarker indicating neurodegeneration, and motor‐evoked potentials. Results: Compared with healthy control subjects, we found an altered gait pattern in prodromal pathogenic variant carriers during the swing phase in the segmental angle of the foot (Dunn's post hoc test, q = 3.1) and heel ground clearance (q = 2.8). Furthermore, range of motion of segmental angle was reduced for the foot (q = 3.3). These changes occurred in prodromal pathogenic variant carriers without quantified leg spasticity in clinical examination. Gait features correlated with neurofilament light chain levels, central motor conduction times of motor‐evoked potentials, and Spastic Paraplegia Rating Scale score. Conclusions: Gait analysis can quantify changes in prodromal and mild‐to‐moderate manifest SPG4 patients. Thus, gait features constitute promising motor biomarkers characterizing the subclinical progression of spastic gait and might help to evaluate interventions in early disease stages. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society [ABSTRACT FROM AUTHOR]

Hip dysplasia is known to lead to premature osteoarthritis. Computational models of joint mechanics have documented elevated contact stresses in dysplastic hips, but elevated stress has not been directly associated with regional cartilage degeneration. The purpose of this study was to determine if a relationship exists between elevated contact stress and intra‐articular cartilage damage in patients with symptomatic dysplasia and femoroacetabular impingement. Discrete element analysis was used to compute hip contact stresses during the stance phase of walking gait for 15 patients diagnosed with acetabular dysplasia and femoral head‐neck offset deformity. Contact stresses were summed over the duration of the walking gait cycle and then scaled by patient age to obtain a measure of chronic cartilage contact stress exposure. Linear regression analysis was used to evaluate the relationship between contact stress exposure and cartilage damage in each of six acetabular subregions that had been evaluated arthroscopically for cartilage damage at the time of surgical intervention. A significant correlation (R2 = 0.423, p < 0.001) was identified between chondromalacia grade and chronic stress‐time exposure above both a 1 MPa damage threshold and a 2 MPa‐years accumulated damage threshold. Furthermore, an over‐exposure threshold of 15% regional contact area exceeding the 1 and 2 MPa‐years threshold values resulted in correct identification of cartilage damage in 83.3% (55/66) of the acetabular subregions loaded during gait. These results suggest corrective surgery to alleviate impingement and reduce chronic contact stress exposures below these damage‐inducing thresholds could mitigate further cartilage damage in patients with hip dysplasia. [ABSTRACT FROM AUTHOR]

Key points Following unexpected ipsilateral knee extension joint rotations applied during the late stance phase of the gait cycle in humans, a crossed reflex response was observed in the contralateral biceps femoris (cBF) muscle with a mean onset latency of 76 ms., Transcranial magnetic and electrical stimulation applied to the primary motor cortex revealed that a transcortical pathway probably contributes to the cBF response., We hypothesize that the cBF response signifies a preparation of the contralateral leg for early load bearing, helping the body to maintain dynamic stability during walking., This is the first study to show that a transcortical pathway contributes to an interlimb reflex in upper leg muscles. The transcortical nature of the response may allow for more adaptable responses than purely spinally mediated reflexes due to integration with other sensory information., Abstract A strong coordination between the two legs is important for maintaining a symmetric gait pattern and adapting to changes in the external environment. In humans as well as animals, receptors arising from the quadriceps muscle group influence the activation of ipsilateral muscles. Moreover, strong contralateral spinal connections arising from quadriceps and hamstring afferents have been shown in animal models. Therefore, the aims of the present study were to assess if such connections also exist in humans and to elucidate on the possible pathways. Contralateral reflex responses were investigated in the right leg following unexpected unilateral knee joint rotations during locomotion in either the flexion or extension direction. Strong reflex responses in the contralateral biceps femoris (cBF) muscle with a mean onset latency of 76 ± 6 ms were evoked only from ipsilateral knee extension joint rotations in the late stance phase. To investigate the contribution of a transcortical pathway to this response, transcranial magnetic and electrical stimulation were applied. Motor evoked potentials elicited by transcranial magnetic stimulation, but not transcranial electrical stimulation, were facilitated when elicited at the time of the cBF response to a greater extent than the algebraic sum of the cBF reflex and motor evoked potentials elicited separately, indicating that a transcortical pathway probably contributes to this interlimb reflex. The cBF reflex response may therefore be integrated with other sensory input, allowing for responses that are more flexible. We hypothesize that the cBF reflex response may be a preparation of the contralateral leg for early load bearing, slowing the forward progression of the body to maintain dynamic equilibrium during walking. [ABSTRACT FROM AUTHOR]

Key points: Gait‐related arm swing in humans supports efficient lower limb muscle activation, indicating a neural coupling between the upper and lower limbs during gait.Intermuscular coherence analyses of gait‐related electromyography from upper and lower limbs in 20 healthy participants identified significant coherence in alpha and beta/gamma bands indicating that upper and lower limbs share common subcortical and cortical drivers that coordinate the rhythmic four‐limb gait pattern.Additional directed connectivity analyses revealed that upper limb muscles drive and shape lower limb muscle activity during gait via subcortical and cortical pathways and to a lesser extent vice versa.The results provide a neural underpinning that arm swing may serve as an effective rehabilitation therapy concerning impaired gait in neurological diseases. Human gait benefits from arm swing, as it enhances efficient lower limb muscle activation in healthy participants as well as patients suffering from neurological impairment. The underlying neuronal mechanisms of such coupling between upper and lower limbs remain poorly understood. The aim of the present study was to examine this coupling by intermuscular coherence analysis during gait. Additionally, directed connectivity analysis of this coupling enabled assessment of whether gait‐related arm swing indeed drives lower limb muscles. To that end, electromyography recordings were obtained from four lower limb muscles and two upper limb muscles bilaterally, during gait, of 20 healthy participants (mean (SD) age 67 (6.8) years). Intermuscular coherence analysis revealed functional coupling between upper and lower limb muscles in the alpha and beta/gamma band during muscle specific periods of the gait cycle. These effects in the alpha and beta/gamma bands indicate involvement of subcortical and cortical sources, respectively, that commonly drive the rhythmic four‐limb gait pattern in an efficiently coordinated fashion. Directed connectivity analysis revealed that upper limb muscles drive and shape lower limb muscle activity during gait via subcortical and cortical pathways and to a lesser extent vice versa. This indicates that gait‐related arm swing reflects the recruitment of neuronal support for optimizing the cyclic movement pattern of the lower limbs. These findings thus provide a neural underpinning for arm swing to potentially serve as an effective rehabilitation therapy concerning impaired gait in neurological diseases. Key points: Gait‐related arm swing in humans supports efficient lower limb muscle activation, indicating a neural coupling between the upper and lower limbs during gait.Intermuscular coherence analyses of gait‐related electromyography from upper and lower limbs in 20 healthy participants identified significant coherence in alpha and beta/gamma bands indicating that upper and lower limbs share common subcortical and cortical drivers that coordinate the rhythmic four‐limb gait pattern.Additional directed connectivity analyses revealed that upper limb muscles drive and shape lower limb muscle activity during gait via subcortical and cortical pathways and to a lesser extent vice versa.The results provide a neural underpinning that arm swing may serve as an effective rehabilitation therapy concerning impaired gait in neurological diseases. [ABSTRACT FROM AUTHOR]

Subject-specific three-dimensional finite element models of the knee joint were created and used to study the effect of the frontal plane tibiofemoral angle on the stress and strain distribution in the knee cartilage during the stance phase of the gait cycle. Knee models of three subjects with different tibiofemoral angle and body weight were created based on magnetic resonance imaging of the knee. Loading and boundary conditions were determined from motion analysis and force platform data, in conjunction with the muscle-force reduction method. During the stance phase of walking, all subjects exhibited a valgus-varus-valgus knee moment pattern with the maximum compressive load and varus knee moment occurring at approximately 25% of the stance phase of the gait cycle. Our results demonstrated that the subject with varus alignment had the largest stresses at the medial compartment of the knee compared to the subjects with normal alignment and valgus alignment, suggesting that this subject might be most susceptible to developing medial compartment osteoarthritis (OA). In addition, the magnitude of stress and strain on the lateral cartilage of the subject with valgus alignment were found to be larger compared to subjects with normal alignment and varus alignment, suggesting that this subject might be most susceptible to developing lateral compartment knee OA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1539-1547, 2010 [ABSTRACT FROM AUTHOR]

Translational crawl and path tracking are presented for a quadruped robot, named TITAN-VIII, to walk on rough ground. The generalized and explicit formulation is derived to generate the translational crawl gait in an arbitrary direction automatically, to control the joint positions, and to estimate the robot localization in a walking environment. Compared to conventional gaits, the proposed gait is characterized by a natural and continuous transition between any successive gait cycles, by a maximized stride of the robot in each gait cycle, and by different foot trajectories corresponding to the uneven terrain. Especially, the proposed approach enables the quadruped robot to track a reference path in a complex walking environment, based on dead-reckoning localization for the robot. The effectiveness of the proposed method is demonstrated through the experimental results. © 2002 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The spatial distribution of myoelectric activity within lower limb muscles is often nonuniform and can change during different stationary tasks. Recent studies using high‐density electromyography (EMG) have suggested that spatial muscle activity may also differ among muscles during locomotion, but contrasting electrode array sizes and experimental designs have limited cross‐study comparisons. Here, we sought to determine if spatial EMG patterns differ among lower limb muscles and locomotion speeds. We recorded high‐density EMG from the vastus medialis, tibialis anterior, biceps femoris, medial gastrocnemius, and lateral gastrocnemius muscles of 11 healthy subjects while they walked (1.2 and 1.6 m/s) and ran (2.0, 3.0, 4.0, and 5.0 m/s) on a treadmill. To overcome the detrimental effects of cable, electrode, and soft tissue movements on high‐density EMG signal quality during locomotion, we applied multivariate signal cleaning methods. From these data, we computed the spatial entropy and center of gravity from the total myoelectric activity within each recording array during the stance or swing phases of the gait cycle. We found heterogeneous spatial EMG patterns evidenced by contrasting spatial entropy among lower limb muscles. As locomotion speed increased, mean entropy values decreased in four of the five recorded muscles, indicating that EMG signal amplitudes were more spatially heterogeneous, or localized, at faster speeds. The EMG center of gravity location also shifted in multiple muscles as locomotion speed increased. Contrasting myoelectric spatial distributions among muscles likely reflect differences in muscle architecture, but increasingly localized activity and spatial shifts in the center of gravity location at faster locomotion speeds could be influenced by preferential recruitment of faster motor units under greater loads. [ABSTRACT FROM AUTHOR]