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An adaptive wheel-legged shape reconfigurable mobile robot, based on a scissor-like mechanism, is proposed for an obstacle detecting and surmounting robot, moving on complex terrain. The robot can dynamically adjust its own shape, according to the environment, realizing a transformation of wheel shape into leg shape and vice versa. Each wheel-legged mechanism has one degree of freedom, which means that only the relative motion of the inner and outer discs is needed to achieve the transformation of the shape into a wheel or a leg. First, the force analysis of the conversion process of the wheel-legged mechanism is carried out, while the relationship between the driving torque and the friction factor in the non-conversion trigger stage and in the conversion trigger stage is obtained. The results showed that the shape conversion can be better realized by increasing the friction factor of the trigger point. Next, the kinematics analysis of the robot, including climbing the obstacles, stairs and gully, is carried out. The motion of the spokes tip is obtained, in order to derive the folding ratio and the surmountable obstacle height of the wheel-legged mechanism. The parameters of the wheel-legged structure are optimized, to obtain better stability and obstacle climbing ability. Finally, a dynamic simulation model is established by ADAMS, to verify the obstacle climbing performance and gait rationality of the robot, in addition to a prototype experiment. The results showed that the surmountable obstacle height of the robot is about 3.05 times the spoke radius. The robot has the stability of a traditional wheel mechanism and the obstacle surmount performance of a leg mechanism, making it more suitable for field reconnaissance and exploration missions.

An automatic protection guard for bikes reduces the impact to the side panels, engine, and the rider's leg when the bike collides with the ground, which follows the reverse quick return mechanism. Include a tilt sensor to monitor the bike's lean angle to activate the system and a wave spring inside the hollow bars to absorb the impact. A tilt sensor will be installed and will set a lean angle to the system. When the bike crosses the calibrated lean angle, the system activates and releases the bars from the system installed onto the bike frame and will take the first contact with the ground surface. To match real-life situations, the time taken for the protection guards to move from initial position to extreme position has been calculated using solid Works motion analysis with an average time taken is 0.14 s, and to find the total deformation different loads and different spring constants have been applied using Ansys software the average deformation is 12 mm. The system helps the rider to ride the bike in a safe mode. The total design system is dynamic and varies with the bike segment but follows the same mechanism.

Study Design This is a validation study. Background Tracking limb movement with body worn sensors allows clinicians to measure limb dynamics to guide treatment for patients with movement disorders. The current gold standard, 3-dimensional optical motion capture, is costly, time-consuming, requires specific training, and is conducted in specialized laboratories. Purpose The purpose of our study was to a compare consumer-grade inertial sensor to a laboratory-grade sensor to provide additional methods for capturing limb dynamics. Methods The participants wore an Apple Watch and a laboratory-grade Xsens sensor on each wrist during 3 conditions: walk, fast-walk, and run. Acceleration data were collected simultaneously on each device per wrist for all conditions. Intraclass correlation coefficients and Bland-Altman plots were calculated to measure intra-/interdevice reliability, evaluate bias, and limits of agreement. Results Intradevice ICCs showed good reliability during walk and fast-walk (0.79-0.87) and excellent reliability during run (0.94-0.97) conditions. Inter-device ICCs yielded moderate reliability during walk (0.52 ± 0.22) and excellent reliability in fast-walk and run (0.93 ± 0.02, 1.00 ± 0.01) conditions. Bland-Altman plots showed small biases with 90% or more of the data contained within the limits of agreement. Discussion Our study demonstrates reliability and agreement between the two devices, suggesting that both can reliably capture upper extremity motion data during gait trials. Conclusion Our findings support further study of consumer-grade motion trackers to measure arm activity for clinical use. These devices are inexpensive, user-friendly, and allow for data collection outside of the laboratory.

This article is to study the system structure scheme based on Zigbee wireless transmission, and complete the overall design of the system scheme on this basis. Human motion capture systems are widely used in the creation of film and television works, motion analysis, video games, rehabilitation medicine and other fields. This article discusses the design and implementation of a human motion capture system based on MEMS sensors and Zigbee networks. The system can be installed on the human body Multiple sensor nodes in various parts obtain the movement information of the human body, and use sensor network technology to aggregate these data and upload them to the host computer. First, this article introduces the characteristics of angular velocity sensors, acceleration sensors, magneto resistive sensors and Zigbee networks. Then, this article explains the overall structure of the system, and from a theoretical point of view, explains how the system uses angular velocity sensors, acceleration sensors, magneto resistive sensors and Zigbee networks to achieve human motion capture. This part focuses on including vector observation methods and angular velocity Two posture capture methods including the integration method, and their advantages and disadvantages are analyzed. To achieve the complementary advantages of the two algorithms, a data fusion algorithm based on complementary filtering is introduced and optimized appropriately. In addition, this article also introduces the networking principles and optimization schemes of the Zigbee network in this section. After this, this article explains in detail the system hardware structure, chip selection scheme, circuit design scheme, software workflow and implementation of core programs Method. Finally, this article shows the effect of the actual work of the system, and compares it with the theory to verify the feasibility of the theory. Based on the research of MEMS sensor measurement unit and algorithm, a Zigbee-based wireless transmission test system was established. LabVIEW software with functions of data reception, attitude angle calculation, trajectory calculation, eigenvalue extraction, BP neural network recognition, display and data saving was designed and tested the whole system functions. The test results show that the wireless data transmission of Zigbee network is normal, the data detection and processing programs of the host computer are stable, and the correct identification of the human body’s motion state can be realized. The results show that compared with the existing research, our research has increased its efficiency by 10%, and its accuracy has increased by nearly 15%.

This study's purpose was to compare the kinematic demands placed on the knee and the hip during various biomechanical tests.Retrospective cross-sectional design.A university research laboratory.The study sample consisted of 70 NCAA Division I female athletes.During the performance of three test maneuvers, a drop vertical jump (DVJ), single leg cross over hop (COH) and modified T-test (AT), the hip and knee joint angles at maximum knee valgus were obtained from marker displacement data collected using a 20-camera motion analysis system. A linear mixed model was used to compare the effect of test on joint angle.A significant difference (p 0.001) in the frontal and sagittal plane position of the knee and hip was noted between the DVJ, COH, and AT tests at maximum knee valgus.The DVJ, COH, and AT maneuvers do not appear to place the same kinematic stress on the knee, supporting the need for the development of return to sport tests that mimic on field demands.

While gait termination is challenging for children with spastic cerebral palsy (CCP), few studies have quantitatively assessed this issue.What are the characteristics of center of mass (COM) and center of pressure (COP) displacement during gait termination in CCP, and how do they compare with those in children with typical development (CTD)?This cross-sectional study included 13 adults with typical development (19.85 ± 0.52 years), 12 CTD (10.41 ± 2.98 years), and 16 CCP (11.15 ± 2.71 years). Participants were instructed to immediately stop walking when a stop sign appeared on a screen, which was placed at the end of an 8-m walkway. COM and COP were determined via 3-dimensional motion analysis and force plate data. Differences between the groups were assessed using the two sample t-test or Wilcoxon rank sum test. The level of statistical significance was set at P0.05.The normalized time for stopping in CCP (4.556 ± 0.602) was higher than that in CTD (3.617 ± 0.545, P0.001). The normalized COP displacement (P0.001) and divergence between COM and COP (P0.001) in the mediolateral (ML) direction were significantly higher in CCP than CTD. However, the normalized divergence between COM and COP in the anteroposterior (AP) direction in CCP was lower than that in CTD (P = 0.034).The more minor divergence between COM and COP in the AP direction and the more significant COP displacement in the ML direction cause difficulty to exert braking force during gait termination. Thus, CCP require a longer time for gait termination. This finding may facilitate the development of interventions for improving gait in CCP.

Background/objective: There is a lack of information about relationship between physical characteristics and biomechanics of the lower extremity during the squat. Additionally, studies did not examine sex-related differences. The purpose of this study was to investigate relationships between physical characteristics and biomechanics of the lower extremity during the squat, and to determine if any sex differences are present. Methods: Fifty three participants recruited (21.82 ± 2.3 years; 75.56 ± 14.98 kg; 171.57 ± 8.38 cm) performed three squats with 75% of one repetition maximum. Femur to tibia length ratio, hip and ankle joints’ flexibilities, and relative muscular strength were measured and used as physical characteristics. Net joint torques (NJT) and flexion angles of the lower extremity were extracted as dependent variables. Multiple regression (stepwise) analysis was conducted to examine the relationships with physical characteristics being factors. Pearson correlation coefficients were calculated to determine intercorrelations among the dependent variables. Results: Relative muscular strength was related to hip NJT and knee flexion angle, and hip flexibility was related to ankle dorsiflexion. Hip and knee NJT showed moderate correlations with the corresponding flexion angles (r = 0.48-0.53; p

International audience; Introduction: This study explores the value of using motion analysis to evaluate cervical and jaw ROM on students with or without bruxism when comparing Osteopathic Manipulative Treatment (OMT) to sham in school settings. Methods: A feasibility study was run with 48 volunteer students from an osteopathic educational institution. Random sequence for allocation was generated using a 1:1 ratio and block size of four to either OMT or sham treatment (control group). The chosen motion outcomes of interest were the lateral jaw range of motion, jaw opening, cervical rotation and side-bending. ROM was measured averaging over three repeated movements at baseline, immediately after the 1st treatment, one week before the 2nd treatment, and immediately after the second treatment using video-based analysis with 15 body landmarks. Results: Repeated measures of joint motion at baseline showed high levels of reliability (ICC ranging from 0.953 to 0.985). Motion analysis detected clinically important differences between OMT and sham one-week posttreatment for jaw lateral ROM (3.3 degrees; p = 0.018) and cervical rotation ROM (12.0 degrees; p = 0.003) in participants with bruxism but not in those without. Magnitude of differences were increased for all parameters following the second treatment (lateral jaw movement; 4.8 degrees, p = 0.005; jaw opening; 5.5 degrees, p = 0.002; cervical side-bending; 9.2 degrees, p = 0.023; cervical rotation; 18.2 degrees, p < 0.001). Conclusion: Motion analysis is capable of detecting the effects of OMT on cervical and jaw ROM in students with bruxism but not without. Finally, the study showed the feasibility of introducing usual standards for clinical trials and sham treatment in an educational setting with students.

Background The conventional gait model (CGM) is commonly utilised within clinical motion analysis but has a number of inherent limitations. To overcome some of these limitations modifications have been made to the CGM and six-degrees of freedom models (6DoF) have been developed. Research Question How comparable are lower limb kinematics calculated using modified CGM and 6DoF models and what is the error associated with the output of each model during walking? Methods Ten healthy males attended two gait analysis sessions, in which they walked at a self-selected pace, while a 10-camera motion capture system recorded lower limb kinematics. Hip, knee and ankle joint kinematics in all three anatomical planes were calculated using a modified CGM, with medial anatomical markers and a three-dimensional foot added, and 6DoF. Mean absolute differences were calculated on a point-by-point basis over the walking gait cycle and interpreted relative to a 5° threshold to explore the comparability of model outputs. The standard error of the measurement (SEM) was also calculated on a point-by-point basis over the walking gait cycle for each model. Results Mean absolute differences above 5° were reported between the two model outputs in 58–86% of the walking gait cycle at the knee in the frontal plane, and over the entire walking gait cycle at the hip and knee in the transverse plane. SEM was typically larger for the modified CGM compared to the 6DoF, with the highest SEM values reported at the knee in the frontal plane, and the hip and the knee in the transverse plane. Significance Caution should be taken when looking to compare findings between studies utilising modified CGM and 6DoF outside of the sagittal plane, especially at the hip and knee. The reduced SEM associated with the 6DoF suggests this modelling approach may be preferable.

The purpose of this study was to assess the change of dynamic alignment after the short and intensive rehabilitation (SHAiR) program in patients with dropped head syndrome (DHS). Eighteen patients with DHS patients who complained of their inability to maintain horizontal gaze and underwent the SHAiR program. Patients performed level walking at a self-selected speed. Spatiotemporal, kinematic, and kinetic data were recorded using a three-dimensional motion analysis system. Statistical analysis was performed to compare these data before and after the SHAiR program. Those who underwent the SHAiR program showed a significant increase in the head angle and stride length compared to pre-treatment measurements (p 0.05). The SHAiR program modifies the malalignment of the head and neck and spatiotemporal parameters in DHS patients during level walking.

BACKGROUND CONTEXT: Radiographic evaluation in adult spinal deformity (ASD) offers no information on spinopelvic alignment and compensation during dynamic conditions. Motion analysis offers the potential to bridge the gap between static radiographic and dynamic alignment measurement, increasing our understanding on how ASD impacts function. PURPOSE: This study aimed to explore the changes in sagittal alignment and compensation strategies in ASD between upright standing and walking, compared to control subjects and within different sagittal alignment groups. Ten patients were measured pre- and six months postoperatively to explore the impact of surgical alignment correction on gait. STUDY DESIGN: Prospective study. SAMPLE SIZE: Full protocol: 58 ASD and 20 controls; Spinal kinematic analysis: 43 ASD and 18 controls; Postoperative analysis: 10 ASD. OUTCOME MEASURES: Standing and walking sagittal spinopelvic (thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvis), and lower limb kinematics, spinopelvic changes between standing and walking (∆ ie, difference between mean dynamic and static angle), lower limb kinetics, spatiotemporal parameters, balance (BESTest), patient-reported outcome scores (SRS-22r, ODI, and FES-I) and radiographic parameters. METHODS: Motion analysis was used to assess the standing and walking spinopelvic and lower limb kinematics, as well as the lower limb kinetics during walking. All parameters were compared between controls and patients with ASD, divided in three groups based on their sagittal alignment (ASD 1: decompensated sagittal malalignment; ASD 2: compensated sagittal malalignment; ASD 3: scoliosis and normal sagittal alignment). Ten patients were reassessed 6 months after spinal corrective surgery. Continuous kinematic and kinetic data were analyzed through statistical parametric mapping. RESULTS: All patient groups walked with increased forward trunk tilt (∆SVA=41.43 mm, p

BACKGROUND: Motion analysis is commonly used to evaluate joint kinetics in children with cerebral palsy who exhibit gait disorders. However, one cannot readily infer muscle-tendon forces from joint kinetics. This study investigates the use of shear wave tensiometry to characterize Achilles and patellar tendon forces during gait. RESEARCH QUESTION: How do Achilles and patellar tendon wave speed and loading modulate with walking speed in typically developing children? METHODS: Twelve typically developing children (9 to 16 years old, walked on an instrumented treadmill with shear wave tensiometers over their Achilles (n=11) and patellar (n=9) tendons. Wave speeds were recorded at five leg length-normalized walking speeds (very slow to very fast). Achilles and patella tendon moment arms were measured with synchronized ultrasound and motion capture. The tendon wave speed-load relationship was calibrated at the typical walking speed and used to estimate tendon loading at other walking speeds. RESULTS: Characteristic Achilles and patellar tendon wave speed trajectories exhibited two peaks over a gait cycle. Peak Achilles tendon force closely aligned with peak ankle plantarflexor moment during pushoff, though force exhibited less modulation with walking speed. A second peak in late swing Achilles loading, which was not evident from the ankle moment, increased significantly with walking speed (p < 0.001). The two peaks in patellar tendon loading occurred at 13 ± 1% and 68 ± 6% of the gait cycle, matching the timing of peak knee extension moment in early stance and early swing. Both peak patellar tendon loads increased significantly with walking speed (p < 0.05). SIGNIFICANCE: This is the first study to use shear wave tensiometry to characterize Achilles and patellar tendon loading during gait in children. These data could serve as a normative comparison when using tensiometry to identify abnormal tendon loading patterns in individuals who exhibit equinus and/or crouch gait.

AimThe dynamic motor control index during walking (walk-DMC) has been shown to be related to patient outcomes and there has been an increasing interest from motion analysis centers regarding using this metric in their own practice. However, the methods for computing the index reported in the literature are not consistent. Here we propose a standardized method and investigate if this leads to results that are consistent between laboratories.MethodComparisons of typically developing controls are made between three independent motion analysis centers. Comparisons are also made between the proposed and previously published methods. A program script to compute the walk-DMC was used for this study and is made freely available with this manuscript.ResultsUsing this script, results are highly consistent between three participating centers. The currently proposed method results in a wider distribution of walk-DMC values than those previously reported.InterpretationUsing consistent processing methods, synergy measures are equivalent between centers. The major differences between current and published data are attributed to the use of concatenation of several walking trials.

Asteroids are coming to be a popular topic in the areas of astrophysical studies and deep space exploration recently. However, surface dynamics of asteroids is still a difficult problem. This paper aims at the motion analysis of surface particles for different asteroids. The dynamical analysis method of particles’ movement is given for three parts: global motion trend, local motion trend and static analysis. A dimensionless parameter ζ is defined to distinguish the predominant term to determine the distribution of effective potential. Three kinds of common asteroids: spheroidal asteroid, spindle-shaped asteroid and dumbbell-shaped asteroid are all discussed for those three parts with different parameter ζ. The motion trend of particles on the surface of each kind of asteroid is given. The static analysis of surface particles for different asteroids is also illustrated. Based on them, some common rules for different shaped asteroids are revealed. This paper could not only provide a reference for asteroid exploration missions but also be meaningful for the research of morphologic evolution of asteroids.

Background/Objective Technical skill acquisition is an essential component of neurosurgical training. Educational theory suggests that optimal learning and improvement in performance depends on the provision of objective feedback. Therefore, the aim of this study was to develop a vision-based framework based on a novel representation of surgical tool motion and interactions capable of automated and objective assessment of microsurgical skill. Methods Videos were obtained from 1 expert, 6 intermediate, and 12 novice surgeons performing arachnoid dissection in a validated clinical model using a standard operating microscope. A mask region convolutional neural network framework was used to segment the tools present within the operative field in a recorded video frame. Tool motion analysis was achieved using novel triangulation metrics. Performance of the framework in classifying skill levels was evaluated using the area under the curve and accuracy. Objective measures of classifying the surgeons' skill level were also compared using the Mann–Whitney U test, and a value of P Results The area under the curve was 0.977 and the accuracy was 84.21%. A number of differences were found, which included experts having a lower median dissector velocity (P = 0.0004; 190.38 ms–1 vs. 116.38 ms–1), and a smaller inter-tool tip distance (median 46.78 vs. 75.92; P = 0.0002) compared with novices. Conclusions Automated and objective analysis of microsurgery is feasible using a mask region convolutional neural network, and a novel tool motion and interaction representation. This may support technical skills training and assessment in neurosurgery.

Objective Dynamic image analysis of carotid plaques has demonstrated that during systole and early diastole, all plaque components will move in the same direction (concordant motion) in some plaques. However, in others, different parts of the plaque will move in different directions (discordant motion). The aim of our study was (1) to determine the prevalence of discordant motion in symptomatic and asymptomatic plaques, (2) to develop a measurement of the severity of discordant motion, and (3) to determine the correlation between the severity of discordant motion and symptom prevalence. Methods A total of 200 patients with 204 plaques resulting in 50% to 99% stenosis (112 asymptomatic and 92 symptomatic plaques) had video recordings available of the plaque motion during 10 cardiac cycles. Video tracking was performed using Farneback's method, which relies on frame comparisons. In our study, these were performed at 0.1-second intervals. The maximum angular spread (MAS) of the motion vectors at 10-pixel intervals in the plaque area was measured in degrees. Plaques were classified as concordant (MAS, 120°). Results Motion was discordant in 89.1% of the symptomatic plaques but only in 17.9% of asymptomatic plaques (P < .001). The prevalence of symptoms increased with increasing MAS. For a MAS >120°, the hazard ratio for the presence of symptoms was 47.7 (95% confidence interval, 18.1-125.6) compared with the rest of the plaques after adjustment for the degree of stenosis and mean pixel motion. The area under the receiver operating characteristic curve for the prediction of the presence of symptoms using the MAS was 0.876 (95% confidence interval, 0.823-0.929). The use of the median MAS (120°) as a cutoff point classified 86% of the plaques correctly (sensitivity, 81.4%; specificity, 91.2%; positive predictive value, 90.2%; and negative predictive value, 83.0%). Conclusions The use of the MAS value to identify asymptomatic plaques at increased risk of developing symptoms and, in particular, stroke should be tested in prospective studies.

Multi-segment foot analysis is traditionally challenging to perform while subjects are wearing footwear or a foot orthosis and is difficult to apply in the clinical setting. A recently developed stretch strain sensor (STR), that is thin and highly flexible, may solve this limitation because it does not require observation using a camera and is highly portable.This study aimed to examine the reproducibility and validity of foot motion analysis using the STR during walking and running by comparing it with a conventional motion capture system.Twenty-one healthy participants were examined in this study. The STR was placed on the participant's foot in one of two locations in separate experiments (spring ligament; SL and navicular drop; ND methods). Foot kinematic data during walking and running were simultaneously recorded using the STR and a three-dimensional motion capture system. Intra-class correlation (ICC) was used to assess test-retest reproducibility of the STR method. Cross-correlation coefficient evaluated the similarity of the pattern of the signals between the two systems. Pearson and Spearman correlation analysis was used to evaluate the relationships between the STR measurement and angular excursion of the forefoot or hindfoot.The ICCs of the SL method were 0.95 and 0.96, and those of the ND method were 0.93 and 0.71 during walking and running, respectively. In the SL method, the pattern of the signals between the STR and forefoot frontal motion was strongly correlated. The STR measurement was significantly correlated with forefoot eversion excursion (walking: r=-0.67, running: r=-0.64, p 0.01 each). In the ND method, the STR signal was not associated with forefoot and hindfoot kinematics.Our results showed that the STR has acceptable reproducibility and validity of foot motion analysis. This system may enable measurement of foot motion while subjects are wearing shoes and outside the laboratory.

Background Rocker sole (RS) shoes have been linked to impaired postural control. However, which features of RS design affect balance is unclear. Research question Which RS design features affect standing balance and gait stability? Methods This study utilized an intervention and cross-over design. Twenty healthy young adults (10 males and 10 females) participated in this study. Standing balance and gait stability were measured using a single force platform and three-dimensional motion analysis system, respectively. The experimental conditions included the control shoe and five RS shoes in the combination of apex position (%) and apex angle (degree) for RS50-95, RS60-95, RS70-95, RS60-70, and RS60-110. The main outcome measures were the area surrounding the maximal rectangular amplitude, mean path length, average displacement of the center of pressure along the lateral and anterior/posterior directions, and maximal center of pressure excursion as the standing balance and lateral margin of stability as the gait stability. Statistical analyses were conducted using a two-way split-plot analysis of variance with repeated measures (with RS design as the within-subject factor and sex as the between-subject factor) and the Bonferroni post hoc test (α = .05). Results Regarding the mean path length, RS60-70 was significantly longer than the control shoe, and it showed a significantly increased lateral margin of stability. Thus, RS60-70 was shown to affect standing balance, limit of stability, and gait stability of the frontal plane during gait. Significance These results suggest that the apex angle of the RS design feature affects standing balance and gait stability, and RS60-70 is detrimental to stability. Therefore, when RS with a small apex angle is prescribed, it is necessary to consider the patient’s balance ability.

Background The human tracking algorithm called OpenPose can detect joint points and measure segment and joint angles. However, the validity of gait analysis using OpenPose has not been examined yet. Research question What is the validity of OpenPose-based gait analysis? Methods Twenty-four healthy young people participated in this study. The participants were assessed during walking and running. Pelvic segment angles, and hip, knee, and ankle joint angles during treadmill walking and running were measured using VICON. Simultaneously, images were captured using digital cameras from the right and back sides. After processing with OpenPose, the corresponding angles were measured from the estimated joint points. To validate these estimations, linear regression analysis was performed, and intraclass correlation coefficients [ICCs (2, 1)] between the data obtained by OpenPose and VICON were calculated. Furthermore, the agreement between the data obtained by OpenPose and VICON was assessed by Bland–Altman analysis. Results For most ranges of motion (ROM) in the sagittal plane, the hip, knee, and ankle joints had large coefficients of determination, without proportional biases. For most peak angles in the sagittal plane, the knee and ankle joints had large coefficients of determination without proportional biases, although the hip joint had nonsignificant coefficients of determination and proportional biases. In particular, for the hip flexion-extension ROM and peak knee flexion angle during running and the knee ROM during slow walking, the ICCs showed good to excellent agreement. However, for the parameters of the pelvis and hip joint in the frontal plane, there were nonsignificant coefficients of determination and poor ICCs with fixed and proportional biases. Significance The lower limb ROM in the sagittal plane during gait can be measured by the OpenPose-based motion analysis system. The markerless systems have the advantage of being more economical and convenient than conventional methods.

Owing to the rapid developments in space technology, there has been a substantial increase in the demand for large-diameter and low-mass space-borne deployable antennas with high geometric stability. To meet this demand, this paper presents a novel single mobility deployable ring mechanism with a high deploy/fold ratio. This mechanism is suitable for constructing large-scale satellite deployable antennas. First, a basic truss element with a low storage height is proposed, and fundamental parameters of the deployable mechanism are analyzed. Second, a general motion analysis model of the deployment process is established, and the corresponding cable-net structure is designed. Finally, a ground experimental prototype with a diameter of 5.0 m is fabricated to demonstrate the feasibility of the proposed mechanism. Based on the experimental results, the feasibility and effectiveness of the novel deployable antenna proposed herein are verified.

Lately, the Magnetic Resonance scans have struggled with its own inherent limitations, such as spatial resolution as well as long examination times. In this paper, a novel, rapid compressively-sensed magnetic resonance high resolution image resolution algorithm is presented. This technique addresses these two key issues by employing a highly-sparse sampling scheme and super-resolution reconstruction (SRR) method. Due to highly challenging requirements for the accuracy of diagnostic images registration, the presented technique exploits image priors, deblurring, parallel imaging, and a discrete dense displacement sampling for the deformable human body and motion analysis. The clinical trials as well as phantom based studied have been conducted. It has been proven that the proposed algorithm is able to enhance image spatial resolution, reduce motion artefacts and scan times.

The standard camera- and force plate-based set-up for motion analysis suffers from the disadvantage of being limited to laboratory settings. Since adaptive algorithms are able to learn the connection between known inputs and outputs and generalise this knowledge to unknown data, these algorithms can be used to leverage motion analysis outside the laboratory. In most biomechanical applications, feedforward neural networks are used, although these networks can only work on time normalised data, while recurrent neural networks can be used for real time applications. Therefore, this study compares the performance of these two kinds of neural networks on the prediction of ground reaction force and joint moments of the lower limbs during gait based on joint angles determined by optical motion capture as input data. The accuracy of both networks when generalising to new data was assessed using the normalised root-mean-squared error, the root-mean-squared error and the correlation coefficient as evaluation metrics. Both neural networks demonstrated a high performance and good capabilities to generalise to new data. The mean prediction accuracy over all parameters applying a feedforward network was higher (r = 0.963) than using a recurrent long short-term memory network (r = 0.935).

A method for performing 3D motion tracking of the shoulder joint with respect to the thorax, using MARG sensors and a data fusion algorithm, is proposed. Two tests were done: (1) qualitative and quantitative analysis of the response of the sensors, static position and during motion, with and without the proposed data fusion algorithm; (2) motion tracking of the shoulder joint with the upper arm, the thorax, and the shoulder joint respect to the thorax. Qualitative analysis of experimental results showed that despite slight variations regarding the evaluated motion, these variations did not have repercussions on the estimated orientation. Quantitative analysis showed that the estimated orientation did not exhibit significant variations, in five minutes, such as drift errors (about 0.1° in static position and less than 1.8° during motion), variations due to noise or magnetic disturbances (RMSE less than 0.04° static position and less than 1° during motion); no singularity problems were reported. The main contributions of this research are a multisensor data fusion algorithm, which combines the complementary properties of gyroscopes, accelerometers, and magnetometers in order to estimate the 3D orientation of two body segments separately and with respect to another body segment considering the spatial relationship between them; and a method for performing 3D motion tracking of two body segments, based on the estimation of their orientation, including motion compensation. The proposed method is applicable to monitoring devices based on IMU/MARG sensors; the performance was evaluated using a customized motion analysis system.

The aim of this study was to develop a general and automatic recognition framework for recognising the daily behaviours of lactating sows to save manual labour and promote smart management. The proposed framework used both image analysis techniques in still image and motion analysis techniques in spatiotemporal videos to recognise sow drinking, feeding, nursing, moving, medium active and inactive behaviours in a loose pen. The image analysis techniques, which are based on fully convolutional networks (FCNs) for high-accuracy segmentation, were used to extract spatial features that evaluated the spatial relationships between objects and the appearance of sows. The motion analysis techniques in spatiotemporal videos, which are based on optical flow analysis and changes in the animal centroid, were used to extract temporal features that evaluated the temporal motions of the animals. In the recognition process, these spatial and temporal features were input into a hierarchical classifier for behaviour recognition. The final recognition results were obtained by a temporal-correlation-based correction module for promoting the recognition rate. Testing on 26 h of videos (468,000 frames) of 3 sows, the algorithm realised the following accuracies of behavioural classification compared with the manual observations: 97.49% for drinking, 95.36% for feeding, and 88.09% for nursing. In addition, the amounts of time that the sow spent on the considered behaviours in the daytime (from 8:00 to 17:00), were as follows: 69.34% on inactive behaviours, 14.50% on nursing, 8.38% on medium activities, 4.04% on feeding, 2.26% on drinking and 1.48% on moving. Hence, the proposed method provides an effective approach for the automatic recognition of sow behaviours from video sequences, which facilitates the pig farmer in improving livestock-farming management.

Multiple Object Tracking (MOT) meets great challenges in videos captured by Unmanned Aerial Vehicles (UAVs). Different from traditional videos, due to high altitude and abrupt motion changes of UAVs, the sizes of target objects in UAVs videos are usually very small and the appearance information of target objects is unreliable. The motion analysis is meaningful to associate multiple objects in UAV videos. However, the traditional motion analysis models inevitably suffer from the autonomous motion of UAVs. In this paper, we proposed a Conditional Generative Adversarial Networks (GAN) based model to predict complex motions in UAV videos. We regard the objects motions and the UAV movement as the individual motions and global motions respectively. They are complementary with each other and are employed jointly to facilitate accurate motion prediction. Specifically, a social Long Short Term Memory network is exploited to estimate the individual motion of objects, and a Siamese network is constructed to generate the global motion to reflect the view changes from UAVs, and a conditional GAN is developed to generate the final motion affinity. Extensive experimental results are conducted on public UAV datasets contained various types of objects and 4 different kinds of object detection inputs. Robust motion prediction and improved MOT performance are achieved compared with state-of-the-art methods.

Gait abnormalities in cerebral palsy are complex and difficult to accurately characterize. Clinical gait analysis shows the prerequisite components of a clinical test to aid in the treatment planning for patients with cerebral palsy. Clinical gait analysis can be used to distinguish between different levels of impairment, can be used to monitor progress and outcomes, and is beginning to show promise for prediction of postsurgical outcomes. Clinical gait analysis can also provide important and relevant information for treatment planning, enhance the likelihood of positive outcomes, and reduce the number of negative outcomes.

Collaboration between humans and robots is an important aspect of Industry 4.0. It can be improved by incorporating human-like characteristics into robot motion planning. It is assumed that humans move optimal with respect to a certain objective or cost function. To find this function, also for a robot, we use an inverse optimal control approach identifying what linear weighted combination of physically interpretable cost functions best mimics human point-to-point motions. A bi-level optimization is used, where the upper level compares the optimal robot result of the lower level with human reference motions. Two depth cameras are combined in a setup to record these reference motions. The resulting weighted cost functions are then used to generate new motions for a seven degrees of freedom robot arm. The resulting optimized motions are compared to standard robot motions based on linear interpolation in joint or task space. The comparison is performed by means of a small experiment where preliminary observations show that humans experience these motions as more anthropomorphic and feel at least equally comfortable and safe compared to existing motion planning strategies.

Different stabilization devices have been used for treating lumbar spine disorders, including fusion, dynamic stabilization devices, flexible rods etc., which possess a different level of limitations. A simple experimental procedure is developed using a prototype lumbar spine specimen (L1-S), to evaluate the biomechanical performance of the lumbar spine. The range of motions (ROM) are tested for pedicle screw made of stainless steel (SS) fixation, using Teflon rod, ultra high molecular weight poly ethylene (UHMWPE) rod, poly ether ether ketone (PEEK) rod and SS flexible rod device (FRD). SS pedicle screw is used for fixation on the prototype lumbar spine. Experimental results are validated and compared with finite element (FE) results. It is observed that, in both flexion and extension, reduction in ROM is higher for Teflon and UHMWPE as compared to PEEK and FRD system. Differences between experimental and numerical results are found to be within an acceptable limit of 5–11%. For flexibility study, both numerical and experimental results support that PEEK rod plays an effective and important role among all the semi-rigid rods. The FRD devices are found to preserve the flexibility of the segment considerably better than PEEK rod.

In motion analysis of sport competitions, the question is often about the most convenient choice for defining the segment endpoints when no visible landmarks can be used. The purpose of the present study was to determine the location of the body centre of mass (CoM) of female high jumpers by using a high accuracy reaction board and two different segment models: Dempster, 1955, de Leva, 1996. Digitising the bony landmarks from the images of dual energy x-ray absorptiometry (DXA) and overhead digital camera were used to compare the digitising accuracy. The location of the CoM determined by a reaction board was 55.88 ± 0.52 % of subjects’ body height. The segment model of Dempster digitized from DXA images (56.66 ± 0.50 %) differed from the reference values of reaction board (p = 0.004), whereas the model of de Leva (56.06 ± 0.61 %) showed no significant difference. The model of de Leva adjusted for female subjects differed only slightly (0.32 %), thus, providing appropriate model for female high jumpers. Since the digitised bony landmarks in the DXA images are obviously very close to the correct locations, the differences in results between the segment models and reaction board is most likely due to inaccuracies in the model itself and/or generalisation of one model to different body structures. When the segment landmarks were estimated without any markers on the body, the results did not differ much from the DXA results. peerReviewed

International audience; The Dual Mobility Cup (DMC) was created in 1974 to prevent dislocation and decrease wear. However, the movement of the polyethylene liner in vivo remains unclear. The aims of this study were to visualise liner positions and quantify the accuracy of the liner plane orientation for static positions, using ultrasound imaging. DMC reconstruction and angle between cup and liner were evaluated on isolated submerged DMCs by comparing 3D laser scans and ultrasound imaging. Moreover, the abduction and anteversion angles of the liner plane relative to the pelvis orientation were calculated via combined motion analysis and 3D ultrasound imaging on four fresh post-mortem human subjects with implanted DMC. On submerged DMC, the mean angle error between ultrasound imaging and 3D scan was 1.2°. In cadaveric experiments, intra-operator repeatability proved satisfactory, with low range value (lower than 2°) and standard deviation (lower than 1°). The study demonstrates the feasibility of measuring liner orientation on submerged and ex vivo experiments using ultrasound imaging, and is a first step towards in vivo analysis of DMC movement.

Background In the field of three-dimensional motion analysis of the foot, there is little agreement on the preferred size of markers to record kinematic parameters. Although currently applied marker sizes show a considerable range, there has been no detailed investigation of the effect of marker size on the calculation of foot kinematics in the current literature. Research question The objective of this research was to determine whether marker size impacts essential parameters that describe foot biomechanics. Methods Seventeen subjects participated in this randomized repeatability study. All participants had to walk on a treadmill twice to test two sets of markers (set A: small marker, 9.5 mm, 1 g; set B: large marker, 14 mm, 2 g). Three-dimensional motion capturing was used to record the trajectories of the markers. The spatial relation of the markers, as well as vertical motion of the navicular bone and the angle of the medial longitudinal arch were calculated based on the marker trajectories. In addition to motion capturing, skin rigidity was quantified by applying an oscillatory shear force to the skin. Analysis of variance, root-mean-square error calculations and linear fit methods were applied to evaluate effects of marker size on the calculation of foot kinematics and the impact of skin rigidity. Results The estimated foot kinematics appeared to be unaffected by the size of the markers. Further, there was no evidence that skin rigidity influenced the error of the marker trajectories. Interestingly, the large markers fell off more frequently. Significance The findings will be of interest to those who use marker-based three-dimensional motion capturing, especially to analyze foot biomechanics. Although the calculation of kinematic parameters appears to be unaffected by marker size, practical aspects, like accidental marker loss, favor the application of small markers.

Muscle overactivity is a general term for pathological increases in muscle activity such as spasticity. It is caused by damage to the central nervous system at the cortical, subcortical or spinal levels, leading to an upper motor neuron syndrome. In routine clinical practice, muscle overactivity, which induces abnormal muscle tone, is usually evaluated by using the Modified Ashworth Scale or the Tardieu Scale. However, both of these scales involve testing in passive conditions that do not always reflect muscle activity during dynamic tasks such as gait or reaching. To determine appropriate treatment strategies, muscle overactivity should be evaluated by using objective measures in dynamic conditions. Instrumental motion analysis systems that include 3-D motion analysis and electromyography are very useful for this purpose. The method can be used to identify patterns of abnormal muscle activity that can be related to abnormal kinematic patterns. It allows for objective and accurate assessment of the effects of treatments to reduce muscle overactivity on the movement to be improved. The aim of this point-of-view article is to describe the utility of instrumental motion analysis and to outline both its numerous advantages in evaluating muscle overactivity and to present the current limitations for its use (e.g., cost, the need for an engineer, errors relating to marker placement and cross talk between electromyography sensors).

Visual object tracking is as a critical function for many computer vision tasks such as motion analysis, event detection and action recognition. Recently, Siamese network based trackers gained enormous popularity in the tracking field due to their favorable accuracy and efficiency. However, the distraction problem caused by semantic backgrounds and the simple modeling strategy of target templates often lead to performance degradation. In this study, we propose two modules, namely the target objectness model and the target template model, based on existing Siamese network based trackers to solve these issues. The target objectness model computes the possibility of each pixel in the search area pertaining to the tracked target based on color distributions of the foreground and background areas. The computed target likelihood map is masked on the previous response map, and subsequently adjusts the final response map to focus on the target. This practice enlarges the discrimination between the tracked target and surrounding backgrounds, thus alleviating the distraction problem. The target template model proposes a Gaussian mixed model to encode target appearance variations, where each component of the model represents a different aspect of the target, and the component weights are learned and dynamically updated. The proposed Gaussian model enhances diversity and simultaneously reduces redundancy between target samples. To validate the effectiveness of our proposed method, we perform extensive experiments on four widely used benchmarks, namely OTB100, VOT2016, TC128, and UAV123. The experimental results demonstrate that our proposed algorithm achieves favorable performance compared to many state-of-the-art trackers while maintaining real-time tracking speed.

This paper addresses the design of rigid wheels for planetary rovers in loose, granular soil. Wheel surface features, such as grousers, are known to improve tractive capability in planetary-relevant soils. However there are no comprehensive design guidelines for these wheel features. In this research, a series of intensive and extensive parametric studies were carried out in full-scale vehicle slope experiments and single-wheel tests that assess the influence of grouser count, height, orientation, and end-cap in various longitudinal and lateral slip conditions. This work also investigates the traction process of grousers based on a soil flow imaging technique. The soil motion analysis reveals that grousers reduce forward soil flow/motion resistance and increase net traction. A grouser design formula is derived from the soil flow observation, and design guidelines of rigid wheels of planetary rovers for loose soil are proposed based on these results. The proposed guidelines are applied to the modification of grouser design of the Mars Science Laboratory rover to improve tractive performance on loose terrain.

Background Clinical tests of foot posture and mobility are not strongly related to the dynamic kinematics of the foot during gait. These measures may be more directly related to foot and ankle kinetics. The supination resistance test (SRT) is a clinical test that may more directly measure forces acting on the weightbearing foot to provide clinicians with insight about the loading of foot structures. Research Question What is the relationship between the SRT in relaxed calcaneal stance and in single-leg-stance and the kinetics and kinematics of the foot and ankle during gait? Methods 10 healthy adults between the ages of 18 and 65 were recruited to participate in this study. Three-dimensional motion analysis was performed using the Oxford Foot Model during gait. The results of the SRT were compared with peak midfoot and ankle joint moments, power generation and absorption, joint angles, and peak angular velocities and accelerations. Correlation coefficients were calculated to assess the strength of relationships between these variables and the SRT. Results The SRT demonstrated significant relationships with several variables. In relaxed calcaneal stance, the SRT was inversely related to maximum midfoot pronation moments (r = −0.51), maximum midfoot plantarflexion moments (rho = −0.71), and peak midfoot power generation (r = −0.61). In single-leg-stance, the SRT was significantly related to maximum midfoot plantarflexion moments (rho = −0.55) and peak midfoot power generation (r = −0.47). Significance The SRT is significantly associated to several kinetic variables that quantify midfoot loading during gait. Interventions that decrease supination resistance may have the potential to increase midfoot power generation.

To investigate whether a three-dimensional (3-D) camera (Microsoft Kinect) and a smartphone can be used to accurately quantify the joint angular velocity and range of motion (ROM) compared to a criterion-standard 3-D motion analysis system during a lower limb spasticity assessment.Observational, criterion-standard comparison study.Large rehabilitation center.A convenience sample of 35 controls, 35 patients with a neurologic condition, and 34 rehabilitation professionals (physiotherapists and rehabilitation doctors) participated (N=104).Not applicable.The Modified Tardieu Scale was used to assess spasticity of the quadriceps, hamstrings, soleus, and gastrocnemius. Data for each trial were collected concurrently using the criterion-standard Optitrack 3-D motion analysis (3DMA) system, Microsoft Kinect, and a smartphone. Each healthy control participant was assessed by 1 health professional and each patient with a neurological condition was assessed by 3 health professionals. Spearman correlation coefficient and intraclass correlation coefficient with 95% confidence intervals were used to report the strength of the relationships investigated.The smartphone and Microsoft Kinect demonstrated excellent concurrent validity with the 3DMA system. Overall, 74.8% of the relationships investigated demonstrated a very strong (≥0.80) correlation across all of the testing parameters. The Microsoft Kinect was superior to the smartphone for measuring joint start and end angle, the smartphone was superior for measuring joint angular velocity, and the 2 systems were comparable for measuring total joint ROM.These findings provide preliminary evidence that user-friendly, low-cost technologies can be used to facilitate accurate measurements of joint angular velocity and angles during a lower limb spasticity assessment in a clinical setting.

The high prevalence of upper extremity joint injuries among manual wheelchair users is largely attributed to the high repetitive loading during propulsion. The purpose of this study was to evaluate the effects of using geared wheels for manual wheelchair mobility on shoulder joint biomechanics. Fourteen able-bodied participants performed overground propulsion and ramp ascension using standard and geared manual wheelchair wheels. Spatial temporal parameters, glenohumeral joint kinematics, and shoulder muscle activity were quantified. Findings indicated that regardless of the level of slope, the propulsion speed and stroke distance decreased significantly (p ≪ 0.001), and the stroke frequency increased significantly (p ≤ 0.025) during geared manual wheelchair propulsion. The glenohumeral joint ranges of motion in the coronal plane (p ≤ 0.005) and peak joint angles in the coronal (p ≤ 0.023) and transverse (p ≤ 0.012) planes were significantly different between standard and geared wheels usage. Shoulder muscle activity was substantially less using the geared wheels with significant findings in the pectoralis major (level floor, p ≤ 0.008) and infraspinatus (p ≤ 0.014) peak muscle activity, and the anterior deltoid (p ≤ 0.014) and pectoralis major (p ≤ 0.015) integrated muscle activity. However, the shoulder flexor normalized integrated muscle activity (muscle activity per stroke distance) was not different between the wheels.

Our aim was to assess three-dimensional kinematic motion analysis as an objective diagnostic tool for the characterization of the movement disorder of Shivers in horses. Kinematic parameters were measured in three horses with Shivers and were compared with a control group of four normal horses. Multiple parameter differences were found in the horses with Shivers at the walk, during backing, and when asked to pick up their hindlimbs. Most significant changes were a wider hindlimb stance of 0.39 ± 0.15 m and increased abduction angle of 48.7 ± 7.52° and hoof elevation (0.77 ± 0.08 m left and 0.94 ± 0.11 m right) when the horses were asked to pick up their hindlimbs. Control horses could back easily in a straight line and with symmetrical hoof separation and could maintain their center of weight when picking up their hindlimbs. In contrast, the horses with Shivers had difficulty backing straight, were slower, with a shorter stride and asymmetric hoof separation. They could not maintain their center of balance when picking up their hindlimbs. The findings of this pilot study advance the understanding of the movement disorder of Shivers and could be used as outcome measures to evaluate treatment modalities.

Objective The purpose of this study was to assess the intrarater and interrater reliability of marking 2 angles with the TEMPLO software and to provide relevant information for clinical practice. Methods A prospective test–retest study has been conducted. Four raters took measures on 2 days, with 2 weeks in between. Craniovertebral angle and trunk forward lean were drawn on 22 video frames using TEMPLO. Reliability was examined using intraclass correlation coefficients including standard errors of measurement and minimal detectable change values as measures of precision expressed in the unit of the test (°). Results Intraclass correlation coefficients for intrarater and interrater reliability ranged from 0.98 to 1.00. Standard errors of measurement and minimal detectable change values ranged from 0.4° to 0.8° and 0.8° to 2.3°, respectively. Conclusion These results indicate excellent reliability for craniovertebral angle and trunk forward lean assessed with TEMPLO software. Changes exceeding 2.3° may be expected to fall outside the test’s variability.

Since the end of the 1990s, several multisegment foot models (MSFMs) have been developed. Several models were used to describe foot and ankle kinematics in patients with foot and ankle pathologies; however, the diagnostic value for clinical practice of these models is not known. This review searched in the literature for studies describing kinematics in patients after foot and ankle trauma using an MSFM. The diagnostic value of the MSFMs in patients after foot and ankle trauma was also investigated. A search was performed on the databases PubMed/MEDLINE, Embase, and Cochrane Library. To investigate the diagnostic value of MSFMs in patients after foot and ankle trauma, studies were classified and analyzed following the diagnostic research questions formulated by Knottnerus and Buntinx. This review was based on 7 articles. All studies were published between 2010 and 2015. Five studies were retrospective studies, and 2 used an intervention. Three studies described foot and ankle kinematics in patients after fractures. Four studies described foot and ankle kinematics in patients after ankle sprain. In all included studies, altered foot and ankle kinematics were found compared with healthy subjects. No results on patient outcome using MSFMs and costs were found. Seven studies were found reporting foot and ankle kinematics in patients after foot and ankle trauma using an MSFM. Results show altered kinematics compared with healthy subjects, which cannot be seen by other diagnostic tests and add valuable data to the present literature; therefore, MSFMs seem to be promising diagnostic tools for evaluating foot and ankle kinematics. More research is needed to find the additional value for MSFMs regarding patient outcome and costs. (C) 2018 by the American College of Foot and Ankle Surgeons. All rights reserved.

Introduction Parkinson's disease (PD) is a common neurodegenerative disorder characterized by disabling motor and non-motor symptoms. For example, idiopathic hyposmia (IH), which is a reduced olfactory sensitivity, is typical in >95% of PD patients and is a preclinical marker for the pathology. Methods In this work, a wearable inertial device, named SensHand V1, was used to acquire motion data from the upper limbs during the performance of six tasks selected by MDS-UPDRS III. Three groups of people were enrolled, including 30 healthy subjects, 30 IH people, and 30 PD patients. Forty-eight parameters per side were computed by spatiotemporal and frequency data analysis. A feature array was selected as the most significant to discriminate among the different classes both in two-group and three-group classification. Multiple analyses were performed comparing three supervised learning algorithms, Support Vector Machine (SVM), Random Forest (RF), and Naive Bayes, on three different datasets. Results Excellent results were obtained for healthy vs. patients classification (F-Measure 0.95 for RF and 0.97 for SVM), and good results were achieved by including subjects with hyposmia as a separate group (0.79 accuracy, 0.80 precision with RF) within a three-group classification. Overall, RF classifiers were the best approach for this application. Conclusion The system is suitable to support an objective PD diagnosis. Further, combining motion analysis with a validated olfactory screening test, a two-step non-invasive, low-cost procedure can be defined to appropriately analyze people at risk for PD development, helping clinicians to identify also subtle changes in motor performance that characterize PD onset.

BACKGROUND: Clinical laboratory testing of locomotor disorders is challenging in patients with intellectual disability (ID). Nevertheless, also in this population gait analysis has substantial value as motor problems are common. To promote its use, adequate protocols need to be developed and the impact on clinical decision making needs to be documented. RESEARCH QUESTION: What is the clinical usefulness of instrumented motion analysis in patients with ID? METHOD: This narrative review consists of three parts. A literature review was performed to describe the gait pattern of patients with ID. Next, benefits and challenges of standard gait analysis protocols are described. Finally, a case of a girl with ID due to genetic cause showing gait abnormalities is discussed. RESULTS: The literature review resulted in 20 studies on "gait" in patients with an "ID", published since August, 1st 2013. Gait deviations were observed in all studies investigating the ID population with an underlying genetic syndrome. Observed gait deviations in the ID population might be attributed to physical characteristics, cognitive components or both. The main goal of clinical gait assessment is the identification of gait deviations and the evaluation of their progress over time, in order to optimize the treatment plan. The choice of adequate method and measurement modalities depends on the clinical goal, the available resources and the abilities of the patient. In the case report we presented, we succeeded in performing an instrumented 3D gait analysis in a girl with severe ID at the ages of 4y4m, 6y0m, 7y2m and 8y2m. Progressive gait deviations were found suggesting a crouch gait pattern was developing. Results of the gait analysis led to the prescription of rigid ankle-foot orthoses. SIGNIFICANCE: Gait analysis has substantial value for patients with ID. Gait analysis allows clinicians to objectify the relationship between physical characteristics and gait features. ispartof: GAIT & POSTURE vol:71 pages:105-115 ispartof: location:England status: published

Distance runners can approach long descents with slow cadence and long steps, or a fast cadence with shorter steps. These approaches differentially affect mechanical loading and energy demand.This study determined the cadence range in which biomechanical loads, caloric unit cost and energy cost were simultaneously minimized during downhill running (DR).Trained runners (N = 40; 25.6 ± 7.2 yr; 42.5% female) participated in this experimental study. Participants ran on an instrumented treadmill while wearing a portable gas analyzer during six conditions: control normal level running (LR) at 0 deg inclination (CON-0); control DR -6 deg inclinaton (CON-6); DR at cadences +/-5% and +/-10% different from CON-6. A motion analysis system was used to capture running motion, and an instrumented treadmill captured force data. Cardiopulmonary measures, rating of perceived exertion (RPE), and biomechanical measures (temporal spatial parameters, peak ground reaction forces [GRF], vertical average loading rate [VALR], impulses) were calculated. Caloric unit cost and energy costs were standardized per unit distance.Running at -10% cadence increased HR by 10 bpm compared to CON-6 (p 0.0001). Vertical excursion of the center of mass and step length were greatest in the cadence -10% and least in the cadence +10% conditions (both p 0.0001). RPEs were higher among all cadence conditions compared to CON-0 (p 0.0001). Caloric unit costs were lowest in CON-6, and +/5% cadence conditions compared to the CON-0 and +/-10% conditions (-2.1% to -12.3%, respectively; p 0.05). Peak GRF and VALR were not different among conditions; vertical impulses were greatest in the -10% condition compared to CON-0, CON-6 and +5% and +10% by 11.3-14.5% (p .001).Changing cadence across level and downhill stretches is likely not necessary and may actually increase perceived effort of running. Running downhill at cadences that range +/-5% of preferred simultaneously minimize caloric unit cost and impulse loading.

Background Common pediatric pathologic foot presentations include cavovarus and planovalgus feet. Flexibility of the hindfoot is established for these two clinical presentations through the Coleman block (eversion) and tiptoe tests (inversion). Research question The purposes of this study are to establish typical quantitative eversion and inversion motion of the hindfoot during Coleman block and tiptoe tests using 3-D motion capture and demonstrate feasibility of using this data to assist in making treatment decisions. Methods Segmented foot model kinematics were collected for this prospective descriptive study with a focus on coronal plane inversion and eversion of the hindfoot relative to the tibia. Typical standing hindfoot position, with the feet plantigrade, was determined prior to performing the tiptoe test. Maximum hindfoot inversion was extracted from the tiptoe test. Maximum hindfoot eversion was extracted from the Coleman block tests. Results 32 typically developing subjects (age range 5–21 years) completed this study. Hindfoot motion data showed a mean standing foot position of 1 ° eversion, 10 degrees inversion during tiptoe test and 6 degrees eversion during the Coleman block test. Significance Establishing control values for hindfoot flexibility can assist with making clinical treatment decisions for disorders of the foot. At our center, clients who present to the Motion Analysis Center with foot concerns receive segmented foot model quantitative assessment of hindfoot flexibility with Coleman block and tiptoe tests as appropriate.

Measuring three-dimensional (3D) forearm rotational motion is difficult. We aimed to develop and validate a new method for analyzing 3D forearm rotational motion. We proposed biplane fluoroscopic intensity-based 2D–3D matching, which employs automatic registration processing using the evolutionary optimization strategy. Biplane fluoroscopy was conducted for forearm rotation at 12.5 frames per second along with computed tomography (CT) at one static position. An arm phantom was embedded with eight stainless steel spheres (diameter, 1.5 mm), and forearm rotational motion measurements using the proposed method were compared with those using radiostereometric analysis, which is considered the ground truth. As for the time resolution analysis, we measured radiohumeral joint motion in a patient with posterolateral rotatory instability and compared the 2D–3D matching method with the simulated multiple CT method, which uses CTs at multiple positions and interpolates between the positions. Rotation errors of the radius and ulna between these two methods were 0.31 ± 0.35° and 0.32 ± 0.33°, respectively, translation errors were 0.43 ± 0.35 mm and 0.29 ± 0.25 mm, respectively. Although the 2D–3D method could detect joint dislocation, the multiple CT method could not detect quick motion during joint dislocation. The proposed method enabled high temporal- and spatial-resolution motion analyses with low radiation exposure. Moreover, it enabled the detection of a sudden motion, such as joint dislocation, and may contribute to 3D motion analysis, including joint dislocation, which currently cannot be analyzed using conventional methods.

In recent years, with the rapid development of computer technology and network technology, computer vision has been widely used in various scientific fields. Human motion recognition, as an important branch of computer vision, is essentially to classify human motion information in motion images correctly. It has great significance in intelligent monitoring and security, human-computer interaction, motion analysis and other fields. At present, there are still some problems in human motion recognition methods. Firstly, how to extract and characterize the motion information in images has been one of the difficulties in this field; secondly, with the appearance of kinect and other depth cameras, researchers have provided the depth information of human motion images, and how to effectively use these depth information to achieve human motion recognition and classification is also an important research issue; finally, when the amount of sample data is small, how to use the deep learning network model to achieve a higher human motion recognition rate? Based on UTD-MHAD database, this paper studies the human motion recognition of RGB image and depth image captured simultaneously by kinect, and carries out relevant discussion and analysis on the above problems, using micro-inertial sensors (MTi-G-700 developed by Xsens and Android mobile phones, tablets and other personal mobile devices come with MEMS gyroscopes and accelerometers) to correct the image to motion blur, build a new mathematical model, use the inertial data obtained by MIMU in a short time to estimate the position, attitude and speed of camera motion, correct the image pixel position, perform image de-motion blur processing, and then perform image processing such as denoising to solve the image motion blur problem. A new algorithm is developed and its science is verified by MATLAB simulation.

Magnetic and Inertial measurement units (MIMUs) have become exceedingly popular for ambulatory human motion analysis during the past two decades. However, measuring anatomically meaningful segment and joint kinematics requires virtual alignment of the MIMU frame with the anatomical frame of its corresponding segment. Therefore, this paper presents a simple calibration procedure, based on MIMU readouts, to align the inertial frame of the MIMU with the anatomical frames, as recommended by ISB. The proposed calibration includes five seconds of quiet standing in a neutral posture followed by ten consecutive hip flexions/extensions. This procedure will independently calibrate MIMUs attached to the pelvis, thigh, shank, and foot. The accuracy and repeatability of the calibration procedure and the 3D joint angle estimation were validated against the gold standard motion capture system by an experimental study with ten able-bodied participants. The procedure showed high test-retest repeatability in aligning the MIMU frame with its corresponding anatomical frame, i.e., the helical angle between the MIMU and anatomical frames did not significantly differ between the test and retest sessions (except for thigh MIMU). Compared to previously introduced procedures, this procedure attained the highest inter-participant repeatability (inter-participant coefficient of variations of the helical angle: 20.5–42.2%). Further, the proposed calibration would reduce the offset errors of the 3D joint angle estimation (up to 12.8 degrees on average) compared to joint angle estimation without calibration (up to 26.3 degrees on average). The proposed calibration enables MIMU to measure clinically meaningful gait kinematics.

Background: Spine posture, range of motion (ROM) and movement asymmetry can contribute to low back pain (LBP). These variables may have greater impact in populations required to perform repetitive spine movements, such as dancers; however, there is limited evidence to support this. Research question: What is the influence of dance and LBP on spinal kinematics? Methods: In this cross-sectional study, multi-segment spinal kinematics were examined in 60 female participants, including dancers (n = 21) and non-dancers (n = 39) with LBP (n = 33) and without LBP (n = 27). A nine-camera motion analysis system sampling at 100 Hz was used to assess standing posture, as well as ROM and movement asymmetry for side bend and trunk rotation tasks. A two-way ANOVA was performed for each of the outcome variables to detect any differences between dancers and non-dancers, or individuals with and without LBP. Results: Compared to non-dancers, dancers displayed a flatter upper lumbar angle when standing (p 0.05) or movement asymmetry (p > 0.05). There was no main effect for LBP symptoms on any kinematic measures, and no interaction effect for dance group and LBP on spinal kinematics (p > 0.05). Significance: Female dancers displayed a flatter spine posture and increased spine ROM compared to non-dancers for a select number of spine segments and movement tasks. However, the overall number of differences was small, and no relationship was observed between LBP and spinal kinematics. This suggests that these simple, static posture, ROM, and asymmetry measures often used in clinical practice can provide only limited generalisable information about the impact of dance or LBP on spinal kinematics.

Accurately measuring speed and acceleration during walking, running and sprinting has important implications for rehabilitation, planning training and talent identification in sporting and clinical populations. Light detection and ranging laser technology provides a continuous stream of distance data. It has the potential to allow rapid and precise measurement and may be advantageous compared with discrete methods of assessment, such as stopwatches and timing gates, which may be inaccurate over short distances. Therefore, the aim of this study was to assess the validity of a novel, low-cost and easy to implement laser-based system during walking and running trials.Cross-sectional study.Thirty-two healthy adults performed walking and running trials from flying and static starts while monitored concurrently with reference standard three-dimensional motion analysis and laser systems. Velocity was calculated over short (0.5m) and longer (3m) intervals using both systems. Validity was assessed using absolute agreement intraclass correlation coefficients (ICCAll intraclass correlation coefficients and correlations were excellent (ICC0.88, R0.89). For the longer interval, all mean absolute errors were0.03m/s (0.24-1.31%). Slightly higher mean absolute error values were reported for the shorter interval (3.16-5.10%), with the highest error of 0.184m/s evident for the flying start running trial.These results indicate that a low-cost and accessible laser system can be used to accurately assess walking and running speed. To aid implementation and further research, freely available hardware design descriptions and downloadable software can be accessed at www.rehabtools.org/LIDAR.