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Gait abnormalities have been described in patients after total knee arthroplasty (TKA), leading to the development of inter-joint coordination abnormalities and increased risk of falling. Such impairments have been reported to persist in the long-term, although the majority of studies assessed gait pattern especially in the first months after TKA. What are the long-term gait impairments in patients after TKA compared to healthy age-matched subjects? A systematic search was conducted on MEDLINE/PubMed, EMBASE, CENTRAL and Scopus databases. Observational studies or randomized controlled trials investigating gait spatial-temporal, kinematic and kinetics parameters in a time-window longer than 6 months in patients with TKA compared to healthy age-matched subjects were included. Methodological quality was assessed using the modified Downs and Black (D&B) checklist and participants' characteristics, surgical procedures details and outcome measures were extracted. Pooled or un-pooled findings were categorized into "6 months - 1 year" and "more than 1 year" timepoint categories. Twenty-eight studies (976 patients) were included. Overall quality was fair with a mean modified D&B score of 63.5 %. Reduced speed, stride length, cadence and longer stance phase were found in patients when compared to healthy individuals at "6 months - 1 year" follow-up. Spatial-temporal parameters deficits were also found at more than 1 year after TKA, where lower single-limb support and longer double-limb support durations were detected. These impairments occurred in concomitance with decreased knee range of motion along the sagittal and frontal planes and altered kinetic parameters. Hip kinematic and kinetic long-term impairments were also detected after TKA. These findings highlighted long-term gait pattern alterations in patients with TKA compared to age-matched healthy subjects. Future studies should identify interventions able to reduce long-term gait pattern alterations and improve function in patients after TKA. • Long-term gait impairments were found in patients after TKA. • Lower speed, stride length, cadence and longer stance phase occurred after TKA. • Hip and knee kinematic and kinetic deficits were detected after TKA. [ABSTRACT FROM AUTHOR]

Clinical gait analysis is a diagnostic tool often used for identifying and quantifying gait alterations in cerebral palsy (CP) patients. To date, 3D clinical gait analysis protocols based on motion capture systems featuring multiple infrared cameras and retroreflective markers to be attached to the subject’s skin are considered the gold standard. However, the need for fully dedicated personnel and space in addition to the inconvenient requirement of multiple markers attached on the patient’s body limit their use in the clinical practice. To shorten the time necessary to setup the patient and to limit his/her discomfort motion tracking performed using markerless technologies may offer a promising alternative to marker-based motion capture. This study aims at proposing and validating on 18 CP patients, an original markerless clinical gait analysis protocol based on a single RGB-D camera. Accuracy and reliability of the spatial-temporal parameters and sagittal lower limb joint kinematics were assessed based on a 3D marker-based clinical gait analysis protocol. The smallest percent mean absolute errors were obtained for stride duration (2%), followed by the step and stride length (2.2% and 2.5%, respectively) and by gait speed (3.1%). The average angular offset values between the two protocols were 8° for the ankle, 6° for the knee and 7° for the hip joint. The smallest root mean square error values were found for the knee joint kinematics (3.2°), followed by the hip (3.5°) and the ankle (4.5°). Both protocols showed a good-to-excellent reliability. Thus, this study demonstrated the technical validity of a markerless single-camera protocol for clinical gait analysis in CP population. The dataset containing markerless data from 10 CP patients along with the MATLAB codes have been made available.

Background Eighty-eight percent of the persons with bilateral vestibular dysfunction have reported at least one fall within the past 5 years. The apparent alternations due to the bilateral vestibular dysfunctions (BVD) are the gait characteristics, such as slower walking speed, prolonged stance phase, and shorter step length. Unexpectedly, due to the prevalence of this BVD being relatively low, attention is not obtained as same as in other vestibular disorders. Moreover, how does walking on different inclines, part of daily activities, alter the gait characteristics under the unreliable bilateral vestibular systems? Previous studies used vibration-based stimulations (VS) as a perturbation to understand the postural control during walking while the bilateral vestibular systems were perturbed. Therefore, this study attempted to extend the knowledge to understand the alternations in spatial-temporal gait characteristics under perturbed bilateral vestibular systems while walking on different inclines. Methods Nineteen healthy young adults participated in this study. Eight walking conditions were randomly assigned to each participant: 0%, 3%, 6%, and 9% grade of inclines with/without VS. The preferred walking speed was used for gait analysis. The dependent variables were stance time, double support time, step length, step time, step width, foot clearance, and respective variabilities. All dependent variables were defined by two critical gait events: heel-strike and toe-off. Pre-Hoc paired comparisons with Bonferroni corrections were used to prioritize the dependent variables. A two-way repeated measure was used to investigate the effect of VS and the effect of inclines on the selected dependent variables from Pre-Hoc analysis. Post-Hoc comparisons were also corrected by the Bonferroni method. Results The step length, step time, foot clearance, and foot clearance variability were selected by the Pre-Hoc analysis because the corrected paired t-test demonstrated a significant VS effect (p < 0.05) on these gait parameters at least one of four inclines. The significant interaction between the effect of VS and the effect of inclines was found in step length (p = 0.005), step time (p = 0.028), and foot clearance variability (p = 0.003). The results revealed that implementing a VS increased step length and step time when walking on 0%, 3%, and 9% of grade inclines. In particular, the foot clearance variability was found when walking on 9% of grade inclines. Conclusion The observations in the current study suggested that VS increased the step length, step time, foot clearance, and foot clearance variability while walking on inclines. These results suggested that these gait parameters might be promising targets for future clinical investigations in patients with BVD while walking on different inclines. Importantly, the increases in spatial-temporal gait performance under bilateral VS might be an indicator of gait improvement while walking on different inclines. [ABSTRACT FROM AUTHOR]

Most of the visual inertial positioning accuracy is constrained by the calibration accuracy of the sensor, however, there are few navigation systems that take the time offset and extrinsic parameters into account at the same time. In this paper, an iterative-optimization-based calibration framework for VIO (visual-inertial odometry) with limited prior conditions is proposed. In particular, a three-stage calibration method is presented, which includes the time offset estimation stage, the extrinsic and intrinsic parameters calibration stage, and global temporal and IMU parameter optimization stage. In the first stage, the time offset calibration model is proposed, which estimates the time delay by iteratively optimizing the orientation residual equation. In the second stage, based on the assumption of constant angle velocity and linear velocity between two continuous keyframes, an iterative-based coarse-to-fine calibration strategy is presented to calibrate the initial extrinsic and IMU intrinsic parameters. In the third stage, a global optimization-based algorithm is introduced to obtain a more accurate time offset value and IMU intrinsic parameters. What’s more worth mentioning is that the proposed method does not require any prior parameters, which greatly improves the universality of the navigation system. To evaluate the effectiveness and accuracy of the proposed algorithm, the method is tested on both simulation and public dataset, and also compared with classical systems. Abundant experimental results illustrate that the proposed method can effectively estimate the time offset, the IMU intrinsic and extrinsic parameters. [ABSTRACT FROM AUTHOR]

Pubalgic syndrome is a growing disease with an incidence of 10% -13% of all injuries suffered during a competitive year in 2011. Once installed, it has negative repercussions on the spatial-temporal parameters, eliminating them from the competitive activity and implicitly having a negative effect on the socio-economic situation of the athlete, but also on the capital of the club where he operates. The study was conducted on a batch of football players affected by the pubalgic syndrome (pubis osteitis). All study participants were evaluated both initially and finally. Between the two evaluations, they benefited from a kinetic treatment protocol. At the end of the initial evaluation, the data obtained were compared and processed using statistical programs. Both in comparison of the results and their processing with the help of the statistical programs showed that the treatment protocol had positive effects on the symptomatology generated by the pubalgic syndrome, but also to the socio-economic situation of the athlete. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effect of different percentages of body weight support (BWS) on spatiotemporal step characteristics during running. 26 endurance runners (age: 37 ± 9 years) completed a running treadmill protocol consisting of 6 different conditions (BWS combinations: 0-50%), with velocity maintained at 12 km/h. Each condition lasted 1 minute. Step angle, ground contact time (CT), flight time (FT), step length (SL) and frequency (SF), and duration of phases during stance time (phase1: initial contact; phase2: midstance; phase3: propulsion) were measured for every step during the test using a photoelectric cell system. Compared with the baseline condition (100% BW), FT was longer, CT was shorter, SL was longer, SF was lower, and the step angle was higher with each increase in BWS (p < 0.05). Also, some changes were observed in the duration of phases during stance time: phase1 did not experience changes across experimental conditions (p = 0.096), phase2 decreased and phase3 increased as BW was supported (p < 0.05). These results indicate that as BW was supported, runners showed longer FT and SL, shorter CT, lower SF, and greater step angle as well as some changes in the phases during the ground contact. Therefore, this study highlights the effect of different percentages of BWS on spatiotemporal parameters. [ABSTRACT FROM AUTHOR]

Owing to the nonlinearity in visual-inertial state estimation, sufficiently accurate initial states, especially the spatial and temporal parameters between IMU (Inertial Measurement Unit) and camera, should be provided to avoid divergence. Moreover, these parameters are required to be calibrated online since they are likely to vary once the mechanical configuration slightly changes. Recently, direct approaches have gained popularity for their better performance than feature-based approaches in little-texture or low-illumination environments, taking advantage of tracking pixels directly. Based on these considerations, we perform a direct version of monocular VIO (Visual-inertial Odometry), and propose a novel approach to initialize the spatial-temporal parameters and estimate them with all other variables of interest (IMU pose, point inverse depth, etc.). We highlight that our approach is able to perform robust and accurate initialization and online calibration for the spatial and temporal parameters without utilizing any prior information, and also achieves high-precision estimates even when large temporal offset occurs. The performance of the proposed approach was verified through the public UAV (Unmanned Aerial Vehicle) dataset.

Abnormal excess or lack of body mass can influence gait patterns, but in some cases such differences are subtle and not easy to detect, even with quantitative techniques for movement analysis. In these situations, the study of trunk accelerations may represent an effective way to detecting gait anomalies in terms of symmetry through the calculation of Harmonic Ratio (HR), a parameter obtained by processing trunk accelerations in the frequency domain. In the present study we used this technique to assess the existence of differences in HR during gait in a cohort of 75 healthy children and early adolescents (aged 7−14 years) stratified into 3 equally-sized age and gender-matched groups (Underweight: UW; Normal Weight: NW; Overweight: OW). The accelerometric signal, acquired using a single wearable inertial sensor, was processed to calculate stride length, speed, cadence and HR in antero-posterior, vertical and medio-lateral directions. No differences in spatio-temporal parameters were found among groups, while the HR in the medio-lateral direction was found significantly lower in UW children, while OW exhibited the highest values. On the basis of the results obtained, HR appears capable of discriminating gait symmetry in children with different body mass even when conventional gait parameters are unchanged.

Background: Eighty-eight percent of the persons with bilateral vestibular dysfunction have reported at least one fall within the past 5 years. The apparent alternations due to the bilateral vestibular dysfunctions (BVD) are the gait characteristics, such as slower walking speed, prolonged stance phase, and shorter step length. Unexpectedly, due to the prevalence of this BVD being relatively low, attention is not obtained as same as in other vestibular disorders. Moreover, how does walking on different inclines, part of daily activities, alter the gait characteristics under the unreliable bilateral vestibular systems? Previous studies used vibration-based stimulations (VS) as a perturbation to understand the postural control during walking while the bilateral vestibular systems were perturbed. Therefore, this study attempted to extend the knowledge to understand the alternations in spatial-temporal gait characteristics under perturbed bilateral vestibular systems while walking on different inclines., Methods: Nineteen healthy young adults participated in this study. Eight walking conditions were randomly assigned to each participant: 0%, 3%, 6%, and 9% grade of inclines with/without VS. The preferred walking speed was used for gait analysis. The dependent variables were stance time, double support time, step length, step time, step width, foot clearance, and respective variabilities. All dependent variables were defined by two critical gait events: heel-strike and toe-off. Pre-Hoc paired comparisons with Bonferroni corrections were used to prioritize the dependent variables. A two-way repeated measure was used to investigate the effect of VS and the effect of inclines on the selected dependent variables from Pre-Hoc analysis. Post-Hoc comparisons were also corrected by the Bonferroni method., Results: The step length, step time, foot clearance, and foot clearance variability were selected by the Pre-Hoc analysis because the corrected paired t-test demonstrated a significant VS effect ( p < 0.05) on these gait parameters at least one of four inclines. The significant interaction between the effect of VS and the effect of inclines was found in step length ( p = 0.005), step time ( p = 0.028), and foot clearance variability ( p = 0.003). The results revealed that implementing a VS increased step length and step time when walking on 0%, 3%, and 9% of grade inclines. In particular, the foot clearance variability was found when walking on 9% of grade inclines., Conclusion: The observations in the current study suggested that VS increased the step length, step time, foot clearance, and foot clearance variability while walking on inclines. These results suggested that these gait parameters might be promising targets for future clinical investigations in patients with BVD while walking on different inclines. Importantly, the increases in spatial-temporal gait performance under bilateral VS might be an indicator of gait improvement while walking on different inclines., Competing Interests: Jung H Chien is an independent researcher and is not employed by any companies. Yuxiao Sun and Dongqi Zhu are physical therapy students in University of Nebraska Medical Center. Huiyan Song is an employee of West China Hospital in China. All authors declare that they have no competing interests., (© 2023 Sun et al.)

One of the most critical functions of an intelligent transportation system (ITS) is to provide accurate and real-time prediction of traffic condition. This paper develops a short-term traffic condition prediction model based on the k-nearest neighbor algorithm. In the prediction model, the time-varying and continuous characteristic of traffic flow is considered, and the multi-time-step prediction model is proposed based on the single-time-step model. To test the accuracy of the proposed multi-time-step prediction model, GPS data of taxis in Foshan city, China, are used. The results show that the multi-time-step prediction model with spatial-temporal parameters provides a good performance compared with the support vector machine (SVM) model, artificial neural network (ANN) model, real-time-data model, and history-data model. The results also appear to indicate that the proposed k-nearest neighbor model is an effective approach in predicting the short-term traffic condition. [ABSTRACT FROM AUTHOR]

Purpose: Spastic diplegia is the most common form of cerebral palsy. It presents with symmetric involvement of the lower limbs and upper limbs. Children with spastic diplegia frequently experience problems with motor control, spasticity, and balance which lead to gait abnormalities. The aim of this study is twofold. Firstly, to determine the differences in spatial-temporal gait parameters and magnitude of plantar pressure distribution between children with spastic diplegia (CP) and typical children. Secondly, to compare and evaluate main changes of plantar pressure and spatial-temporal gait parameters instead of data between spastic diplegia children with prescribed ankle - solid foot orthosis (AFOs) and without using AFOs. Methods: The evaluation was carried out on 20 spastic diplegia children and 10 agematched children as a control group aged 6-15 years. Twenty children with spastic diplegia CP were divided into two groups: ten subjects with prescribed AFOs and ten subjects without use of assistive device. Patients used the AFOs orthosis for one year. Measurements included in-shoe plantar pressure distribution and spatial-temporal gait parameters. Results: Spatial-temporal gait parameters showed meaningful difference between study groups in velocity, stride length, step length and cadence (p < 0.05). However no significant differences between patients with and without AFOs were found (p > 0.05). Significant differences between typical and spastic diplegia children with AFOs were observed in the magnitude of plantar pressure under the toes, the metatarsal heads, the medial arch, and the heel (p < 0.05). For typical subjects, the highest pressure amplitudes were found under the heel and the metatarsal heads, while the lowest pressure distribution was under the medial arch. In CP patients the lateral arch was strongly unloaded. The peak pressure under heel was shifted inside. Conclusions: Collected data and calculated scores present a state of the gait in test groups, showed the difference and could be valuable for physicians in decision making by choosing qualitative therapy. Furthermore, it allows predicting probability of further possible changes in gait of spastic diplegia patients with AFOs and without it. In conclusion, our current results showed that the use of AFOs, prescribed on a clinical basis by doctors improves gait patterns and gait stability in children with spastic cerebral palsy. [ABSTRACT FROM AUTHOR]

Body weight support (BWS) has become a typical strategy for gait training, in special with children with cerebral palsy (CP). Although several findings have been reported in the literature, it remains uncertain how different types of surfaces and gradual amount of BWS can facilitate the mobility of children with CP. The aim of this study was to investigate gait kinematic parameters of children with CP by manipulating BWS and two different types of ground surfaces. Ten children (7.7 ± 2.1 years old) diagnosed with spastic CP and GMFCS classification between levels II and IV were asked to walk on a treadmill and over the ground. In both conditions, BWS was manipulated to minimize gravitational effects and spatial–temporal gait parameters and lower limb joints were analyzed. The results revealed that the type of ground surface causes greater impact on the gait pattern of children with CP as compared to body weight unloading. This finding may provide new insights into the behavioral heterogeneity of children with CP, and offers critical information to be considered on interventional programs specifically designed to improve mobility on this population. [ABSTRACT FROM AUTHOR]

In people with Multiple Sclerosis (pwMS) with little or no signs of disability, early detection of walking impairments represents a challenging issue, as simple gait metrics (e.g. speed, cadence, stride length, etc.) may not significantly differ from those of healthy individuals. In this study, we aimed to assess the existence of possible differences in spatial-temporal parameters and smoothness of gait measures (assessed through Harmonic Ratio, HR) obtained from trunk accelerations between 50pwMS without disability (Expanded Disability Status Scale score =1) and 50 age-matched healthy controls. The results show no differences in terms of gait velocity, stride length, stance/swing and double support phases duration, while HR in the direction of motion was significantly lower in pwMS (2.92 vs. 3.67, p<0.001), thus indicating a less smooth gait. The study of trunk accelerations through calculation of HR represents a fast, non-intrusive technique that allows early identification of anomalies in gait patterns of pwMS in absence of disability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Establishing a relationship between posture and gait is essential for PD rehabilitation. • There was correlation between postural control and gait domains in PD. • Stance and double support time, and step width were related to body sway parameters. • Posture and gait were relatively dependent domains of mobility in PD. Establishing a relationship between gait and posture in patients with Parkinson's disease (PD) is essential for PD treatment and rehabilitation. While previous studies have indicated that gait and posture are independent domains in PD, shared neuromechanisms related to gait and posture control and previous studies investigating the relationship between gait and posture parameters in stroke survivors and neurologically healthy older adults have shown a correlated domain. Thus, this study analyzed the relationship of gait and posture domains, primarily through gait temporal sub-phases (i.e., double support and stance phases) and step width. We analyzed the spatial-temporal gait parameters at the self-selected velocity and center of pressure (CoP) during quiet standing of 22 idiopathic PD participants under and without dopaminergic medication conditions. The association between quiet standing and gait variables was assessed through the Spearman test, controlled by age, disease duration, NFoG-Q, and levodopa dosage. In ON medication, CoP area showed a significant correlation with stance phase and total double support; and RMS ML CoP showed a significant correlation with stance phase, total double support, and step width. In OFF medication, CoP area, RMS AP CoP, RMS ML CoP, and ML CoP velocity significantly correlated with stance phase and total double support. By showing the relationship between gait and posture domains in PD, our study adds novel knowledge about the shared gait-posture control, which could collaborate with new approaches during mobility treatment and assessment. [ABSTRACT FROM AUTHOR]

Owing to the nonlinearity in visual-inertial state estimation, sufficiently accurate initial states, especially the spatial and temporal parameters between IMU (Inertial Measurement Unit) and camera, should be provided to avoid divergence. Moreover, these parameters are required to be calibrated online since they are likely to vary once the mechanical configuration slightly changes. Recently, direct approaches have gained popularity for their better performance than feature-based approaches in little-texture or low-illumination environments, taking advantage of tracking pixels directly. Based on these considerations, we perform a direct version of monocular VIO (Visual-inertial Odometry), and propose a novel approach to initialize the spatial-temporal parameters and estimate them with all other variables of interest (IMU pose, point inverse depth, etc.). We highlight that our approach is able to perform robust and accurate initialization and online calibration for the spatial and temporal parameters without utilizing any prior information, and also achieves high-precision estimates even when large temporal offset occurs. The performance of the proposed approach was verified through the public UAV (Unmanned Aerial Vehicle) dataset. [ABSTRACT FROM AUTHOR]

Abnormal excess or lack of body mass can influence gait patterns, but in some cases such differences are subtle and not easy to detect, even with quantitative techniques for movement analysis. In these situations, the study of trunk accelerations may represent an effective way to detecting gait anomalies in terms of symmetry through the calculation of Harmonic Ratio (HR), a parameter obtained by processing trunk accelerations in the frequency domain. In the present study we used this technique to assess the existence of differences in HR during gait in a cohort of 75 healthy children and early adolescents (aged 7–14 years) stratified into 3 equally-sized age and gender-matched groups (Underweight: UW; Normal Weight: NW; Overweight: OW). The accelerometric signal, acquired using a single wearable inertial sensor, was processed to calculate stride length, speed, cadence and HR in antero-posterior, vertical and medio-lateral directions. No differences in spatio-temporal parameters were found among groups, while the HR in the medio-lateral direction was found significantly lower in UW children, while OW exhibited the highest values. On the basis of the results obtained, HR appears capable of discriminating gait symmetry in children with different body mass even when conventional gait parameters are unchanged. [ABSTRACT FROM AUTHOR]