Limb Joint Angles Research Articles

Kinetics and distal limb kinematics of the forelimb of 3 jumping horses at landing after a jump: effects of the fence’s height

Landing after a jump is the most strenuous phase for the forelimbs of jumping horses. However quantifying forces between the hooves and the ground, or measuring limb joint angles, at landing, has b...

Reliability and validity of the Kinect V2 for the assessment of lower extremity rehabilitation exercises

BackgroundBesides its initial use as a video gaming system the Kinect might also be suitable to capture human movements in the clinical context. However, the system’s reliability and validity to capture rehabilitation exercises is unclear. Research questionThe purpose of this study was to evaluate the test-retest reliability of lower extremity kinematics during squat, hip abduction and lunge exercises captured by the Kinect and to evaluate the agreement to a reference 3D camera-based motion system. MethodsTwenty-one healthy individuals performed five repetitions of each lower limb exercise on two different days. Movements were simultaneously assessed by the Kinect and the reference 3D motion system. Joint angles and positions of the lower limb were calculated for sagittal and frontal plane. For the inter-session reliability and the agreement between the two systems standard error of measurement (SEM), bias with limits of agreement (LoA) and Pearson Correlation Coefficient (r) were calculated. ResultsParameters indicated varying reliability for the assessed joint angles and positions and decreasing reliability with increasing task complexity. Across all exercises, measurement deviations were shown especially for small movement amplitudes. Variability was acceptable for joint angles and positions during the squat, partially acceptable during the hip abduction and predominately inacceptable during the lunge. The agreement between systems was characterized by systematic errors. Overestimations by the Kinect were apparent for hip flexion during the squat and hip abduction/adduction during the hip abduction exercise as well as for the knee positions during the lunge. Knee and hip flexion during hip abduction and lunge were underestimated by the Kinect. SignificanceThe Kinect system can reliably assess lower limb joint angles and positions during simple exercises. The validity of the system is however restricted. An application in the field of early orthopedic rehabilitation without further development of post-processing techniques seems so far limited.

Leaving hip rotation out of a conventional 3D gait model improves discrimination of pathological gait in cerebral palsy: A novel neural network analysis

BackgroundComplex clinical gait analysis results can be expressed as single number gait deviations by applying multivariate processing methods. The original Movement Deviation Profile (MDP) quantifies the deviation of abnormal gait using the most trusted nine dynamic joint angles of lower limbs. Research questionWhich subset of joint angles maximises the ability of the MDP to separate abnormal gait from normality? What is the effect of using the best subset in a large group of patients, and in individuals? MethodsA self-organising neural network was trained using normal gait data from 166 controls, and then the MDP of 1923 patients with cerebral palsy (3846 legs) was calculated. The same procedure was repeated with 511 combinations of the nine joint angles. The standardised distances of abnormal gait from normality were then calculated as log-transformed Z-scores to select the best combination. A mixed design ANOVA was used to assess how removing the least discriminating angle improved the separation of patients from controls. The effect of using the optimal subset of angles was also quantified for each individual leg by comparing the change in MDP to the independent FAQ levels of patients. ResultsRemoval of hip rotation significantly (p<0.0005) increased the separation of the patient group from normality (ΔZ-score 0.24) and also at FAQ levels 7-10 (ΔZ-score 0.38, 0.27, 0.22, 0.14). The MDP of individual patients changed in a wider range of -4.65 to 1.12 Z-scores and their change matched their independent FAQ scores, with less functional patients moving further from, and more functional patients moving closer to normality. SignificanceIn existing gait databases we recommend excluding hip rotation from data used to calculate the MDP. Alternatively, the calculation of hip rotation can be improved by post-hoc correction, but the ultimate solution is to use more accurate and reliable models of hip rotation.

The effect of joint translation constraint on within-participant variability of kinematics and kinetics during running in cerebral palsy

BackgroundBiomechanical data in cerebral palsy are inherently variable but no optimal model of translational joint constraint has been identified. The primary aim of this study was to determine which model of translational joint constraint resulted in the lowest within-participant variability of lower limb joint angles and moments. The secondary aim was to determine which model best distinguished known functional groups in Cerebral Palsy. MethodsThree models (three degrees of freedom, six degrees of freedom and six degrees of freedom with specified joint translation constraint) were applied to data from running trials of 40 children with cerebral palsy. FindingsJoint angle standard deviations were largest using the six degrees of freedom model and smallest using the constrained six degrees of freedom model (p < 0.050). For all joints in all planes of motion, joint moment standard deviations were largest using the six degrees of freedom model and smallest using the constrained six degrees of freedom model; standard deviations using the constrained model were smaller than the three degrees of freedom model by 10–30% of moment magnitude (0.01–0.03 Nm/kg; p < 0.001). The six degrees of freedom models distinguished functional subgroups with larger effect size than the three degrees of freedom model only for hip power generation in swing. InterpretationA model with specified joint constraint minimized within-participant variability during running and was useful for detecting differences in functional capacity in cerebral palsy.

Improvement of rolling performance in crawl stroke for the swimming humanoid robot

In the previous study, an experimental system to measure propulsive force during swimming using the humanoid robot SWUMANOID was constructed. However, the recovery motion of crawl stroke was not appropriate because of the earlier timing of the rolling motion, which was caused by attaching device to SWUMANOID. The objective of this study was to find better stroke which can improve the rolling performance during measuring propulsive force of crawl stroke by using the constructed experimental system. First, a simulation model which reproduced the experimental system was constructed. The better stroke was obtained by using the optimization method with Particle Swarm Optimization (PSO) and SWUM. In this method, the design variables were the joint angles of the left upper limbs for three degrees-of-freedom at the shoulder joint and two degrees-of-freedom at the elbow joint. The objective function was to minimize the difference of roll motion compared to the standard crawl. As a result, the difference of roll angle became 73% smaller than that of the previous motion and the timing of roll motion became late, resulting in the successful recovery motion.

Biomechanical and neuromuscular strategies on backward somersault landing in artistic gymnastics: A case study.

Landing is a crucial factor in gymnastics competitions, but the underlying biomechanical and neuromuscular strategies remains unclear. This study aimed to investigate the biomechanical characteristics and neuromuscular strategies of landing for backward somersault. A 19-segment human model was developed and bilateral lower-limb joint loadings were estimated using computer stimulation. Bilateral lower-limb joint angles, vertical ground reaction force (vGRF), impulse, joint reaction force, joint torque, power, work, stiffness and electromyogram (EMG) of the rectus femoris, biceps femoris, tibialis anterior, and lateral gastrocnemius were presented during initial (touchdown to peak vGRF) and terminal impact-phases of landing (peak vGRF to vGRF equaling to body weight). The hip, knee, and ankle joints were rapidly flexed (8º, 20º, and 18º, respectively) during initial impact-phase and maintained at around 90º, 120º, and 60º, respectively terminal impact-phase. Flexor and extensor torques were demonstrated for lower-limb joints during initial and terminal impact-phases, respectively. The stiffness of lower limb joints and the EMGs amplitude of all examined muscles during terminal impact-phase were several times larger than that during initial impact-phase. The absolute symmetry indexes were less than 10% for lower limb joint angles and larger than 10% for the kinetics and muscle activation. The findings demonstrated symmetrical motion for lower limb joints with flexing rapidly at initial impact-phase and maintaining unchanged at terminal impact-phase and asymmetry in joint loading and muscle activation during landing.

Knee joint moment estimation using lower limb joint angle without using ground reaction force

Knee joint moment estimation using lower limb joint angle without using ground reaction force

A Continuous Estimation Model of Upper Limb Joint Angles by Using Surface Electromyography and Deep Learning Method

The continuous control of rehabilitation robots based on surface electromyography (sEMG) is a natural control strategy that can ensure human safety and ease the discomfort of human-machine coupling. However, current models for estimating movement of the upper limb focus on two dimensions movement, and models of three dimensions movement are too complex. In this paper, a simple-structure temporal information-based model for upper limb motion was proposed. An experiment of the multijoint motion of the upper limb was carried out. We studied the touching motion and the compound task motion of the upper limbs. The touch motor task consists of three tasks, namely, shoulder abduction, shoulder forward bend and finger-nose. The compound tasks include driving and fetching objects. Three-dimensional upper limb movement data and sEMG signals of seven upper limb muscles were recorded from seven healthy subjects. Model training was carried out after data preprocessing and feature extraction. Then, 120 s of upper limb motion data was used to verify the performance of the model proposed in this paper. The estimated accuracy of the model for the touch tasks was 0.9171, and it was 0.8109 for compound tasks. Compared to the multilayer perception (MLP) model, a 13.57% reduction in the root-mean-square error (RSME) was observed. The results show that the model has good accuracy for estimating the angular motion of the upper limb and that it has the potential to be applied for three-dimensional motion control in an upper limb mirror-image therapy rehabilitation robot.

Assessment of the measurement accuracy of inertial sensors during different tasks of daily living

The low cost and ease of use of inertial measurement units (IMUs) make them an attractive option for motion analysis tasks that cannot be easily measured in a laboratory. To date, only a limited amount of research has been conducted comparing commercial IMU systems to optoelectronic systems, the gold standard, for everyday tasks like stair climbing and inclined walking. In this paper, the 3D joint angles of the lower limbs are determined using both an IMU system and an optoelectronic system for twelve participants during stair ascent and descent, and inclined, declined and level walking. Three different datasets based on different hardware and anatomical models were collected for the same movement in an effort to determine the cause and quantify the errors involved with the analysis. Firstly, to calculate software errors, two different anatomical models were compared for one hardware system. Secondly, to calculate hardware errors, results were compared between two different measurement systems using the same anatomical model. Finally, the overall error between both systems with their native anatomical models was calculated. Statistical analysis was performed using statistical parametric mapping. When both systems were evaluated based on the same anatomical model, the number of trials with significant differences decreased markedly. Thus, the differences in joint angle measurement can mainly be attributed to the variability in the anatomical models used for calculations and not to the IMU hardware.

Lower limb joint angle variability and dimensionality are different in stairmill climbing and treadmill walking

The present study tested if the quadratic relationship which exists between stepping frequency and gait dynamics in walking can be generalized to stairmill climbing. To accomplish this, we investigated the joint angle dynamics and variability during continuous stairmill climbing at stepping frequencies both above and below the preferred stepping frequency (PSF). Nine subjects performed stairmill climbing at 80, 90, 100, 110 and 120% PSF and treadmill walking at preferred walking speed during which sagittal hip, knee and ankle angles were extracted. Joint angle dynamics were quantified by the largest Lyapunov exponent (LyE) and correlation dimension (CoD). Joint angle variability was estimated by the mean ensemble standard deviation (meanSD). MeanSD and CoD for all joints were significantly higher during stairmill climbing but there were no task differences in LyE. Changes in stepping frequency had only limited effect on joint angle variability and did not affect joint angle dynamics. Thus, we concluded that the quadratic relationship between stepping frequency and gait dynamics observed in walking is not present in stairmill climbing based on the investigated parameters.

Initial balance in human standing postures: Roles of the joint mechanisms.

The static initial postures of standing before applying perturbations may affect the maintenance of postural balance. The goal of this article was to find the stable set of postures and then determine the roles of joint mechanisms. The set of posture was defined in a biomechanical model based on three joint angles of the lower limbs. Optimized inverse dynamics method was used to solve for muscle forces in a precise model of the human musculoskeletal system posed in 4096 static sets of posture using AnyBody software. Results showed that the overall body muscular activity in standing is reduced by knee flexion. Moderate knee angles between 20° and 60° provided safer postures against possible perturbations because of higher collaboration levels of the joint mechanisms. About 36% of the overall postural infeasibilities were attributed to the inability of the ankle muscles to more sustain the exerted loads. Although the roles of the joint mechanisms were closely dependent on the postures, there was no direct relation between the joint kinematics and activation levels of their supporting muscles. Lower extremity muscle groups collaborate to maintain the balance in a considerable number of static postures.

Kinematic differences between neutral and flat feet with and without symptoms as measured by the Oxford foot model

BackgroundFlatfoot is a common presentation in children. It is usually asymptomatic, though a small number of children experience pain. Foot function during flatfoot walking is rarely considered, yet as an activity that places significant demands on the feet, this could explain the differences in terms of symptoms. Research questionThis paper investigates walking patterns in neutral and flat feet, with and without symptoms, to determine which kinematic parameters are associated with symptomatic flat feet. MethodsThis is a retrospective study in which one hundred and six children between five and 18 years old were assessed by a physiotherapist for foot posture. Each foot was classified into one of four groups, giving 98 asymptomatic neutral, 47 asymptomatic mild flat, 29 asymptomatic flat, and 38 symptomatic flat feet with complete data for analysis. Using Plug-In-Gait and Oxford-Foot-Model markers, walking kinematics were measured, along with ground reaction forces. Median values of 14 lower limb joint angles were calculated at foot strike, midstance, and foot off. Each foot was treated as an independent sample. ANOVA and ANCOVA (with the speed-related variable relative stride length as the covariate) and post-hoc tests were used to assess whether angles differed between groups. ResultsThe symptomatic flat feet showed significant differences from asymptomatic groups (most commonly the neutral feet) in terms of hip flexion, knee flexion and varus, hindfoot inversion-eversion, and forefoot abduction-adduction. Increased forefoot abduction occurred throughout stance phase in symptomatic flatfooted participants compared to all asymptomatic groups. SignificanceThe results suggest that foot motion in the transverse plane is closely associated with the presence of symptoms in flat feet and that this is accompanied by changes in the kinematics of the ankle, knee, and hip.

Ulnar ostectomy decreases the stability of canine cadaver carpi as assessed with stress radiography.

Distal ulnar ostectomy may be performed palliatively in patients with distal ulnar osteosarcoma. Concurrent arthrodesis of the carpus has been proposed to counteract joint instability following transection of carpal ligaments associated with removal of the distal ulna. The objective of this prospective one group pretest, posttest study was to assess stability of the carpus following distal ulnar ostectomy using pre- and postoperative stress radiographic views in a group of canine cadaver limbs. Seven thoracic limbs from six canine cadavers weighing more than 20kg were obtained. Lateral and dorsopalmar, extended lateral, medial stress, and lateral stress radiographs were made before and after distal ulnar ostectomy. Presurgical canine cadaver carpal angle measurements were as follows (mean ± standard deviation): extension 205.9° ± 5.4; medial stress 25.1° ± 5.7; and lateral stress 13.3° ± 5.2°. Cadaver limb joint angles exceeded those previously reported in live dogs. A significant increase in carpal angle was noted following ulnar ostectomy. The mean increases in carpal angle were as follows: (mean ± standard deviation (95% confidence interval)): extension 6.2° ± 4.9 (2.6-9.8) (P=0.007); medial stress 3.2° ± 3.0 (1.0-5.5) (P=0.015); lateral stress 6.2° ± 5.2 (2.4-10.1) (P=0.010). Findings from this cadaver study support the use of supplementary stabilization for clinical patients undergoing distal ulnar ostectomy. Future studies are needed in clinical patients to evaluate changes in limb positioning and gait associated with distal ulnar ostectomy.

Visualization of walking speed variation-induced synchronized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles with a newly developed gait analysis system.

To evaluate a newly developed system for dynamic analysis of gait kinematics and muscle activity. We recruited 10 healthy men into this study. Analyses of three-dimensional motion and wireless surface electromyogram (EMG) were integrated to achieve synchronous measurement. The participants walked continuously for 10 min under two conditions: comfortable and quick pace. Outcome measures were joint angles of the lower limbs determined from reflective markers and myoelectric activity of trunk and lower limbs determined from EMG sensors, comparing comfortable and quick gait pace. Lower limb joint angle was significantly greater at the quick pace (maximum flexion of the hip joint: 4.1°, maximum extension of hip joint: 2.3°, and maximum flexion of the knee joint while standing: 7.4°). The period of maximum flexion of the ankle joint during a walking cycle was 2.5% longer at a quick pace. EMG amplitudes of all trunk muscles significantly increased during the period of support by two legs (cervical paraspinal: 55.1%, latissimus dorsi: 31.3%, and erector spinae: 32.6%). EMG amplitudes of quadriceps, femoral biceps, and tibialis anterior increased significantly by 223%, 60.9%, and 67.4%, respectively, between the periods of heel contact and loading response. EMG amplitude of the gastrocnemius significantly increased by 102% during the heel-off period. Our gait analysis synchronizing three-dimensional motion and wireless surface EMG successfully visualized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles induced by various walking speeds.

An Experimental Analysis of Stability in Human Walking

Biped locomotion has excellent environment adaptability due to natural selection and evolution over hundreds of millions years. However, the biped walking stability mechanism is still not clear. In this paper, an experimental analysis of walking stability in human walking is carried out by using a motion capture system. A new stability analysis method is proposed based on Zero Moment Point (ZMP) and Sliding Time Window (STW). The influences of ground friction coefficient, ground slope angle and contact area of support polygon on human walking stability are investigated. The experiment is carried out with 12 healthy subjects, and 53 passive reflective markers are pasted to each subject to obtain moving trajectory and to calculate lower limb joint variation during walking. Experimental results show that ground friction coefficient, ground slope angle and contact area have significant effects on the stride length, step height, gait cycle and lower limb joint angles. When walking with small stability margin, subjects modulate gait to improve the stability, such as shortening stride length, reducing step height, and increasing the gait cycle. These results provide insights into the stability mechanism of human walking, which is beneficial for locomotion control of biped robots.

A kinematics analysis of the lower limb during running with different sports shoes

The study aimed to investigate the differences in lower limb joint angles during running with three different sports shoes: basketball shoes, football shoes, and running shoes. Fifteen male subjects (age: 25 ± 2.2 years, height: 1.79 ± 0.05 m, and mass: 70.8 ± 3.4 kg) were asked to run on a treadmill at their preferred running speed. The Vicon 3D motion analysis system was used to capture the kinematics of the lower extremity during running. A one-way analysis of variance was used to determine whether any statistical significance existed between the three types of shoes (α &lt; 0.05). Significant differences existed in the lower limb joints between the three sports shoes, particularly at the knee joint. Running shoes presented more knee flexion than basketball shoes and football shoes. In the frontal plane, basketball shoes showed less knee abduction than running shoes and football shoes. No significant difference occurred in ankle external rotation between basketball shoes and football shoes, and both of them presented greater range of motion of the ankle and knee than running shoes.

Apps for smartphone available through distribution platforms and validated for goniometric measurement: A systematic review

The use of smartphones for medical purposes is increasing due to the steadily growing number of downloadable applications (apps) that transform the mobile phone into a medical device. Apps make use of the inbuilt smartphone to obtain fast measurements useful for clinical practice, in particular for goniometry. Medical apps are an emerging technology that need to be appropriately validated to ensure their safe and effective operation. The objective of this review was to provide a systematic review of apps validated for goniometry available through distribution platforms, relevant to physical medicine and rehabilitation (PMR) practitioners. A literature search was conducted by two independent reviewers on relevant articles indexed by PubMed before April, 2017. We selected only research papers published in English. Papers dealing with apps not relevant to PMR or unavailable on the market were excluded. We analyzed the following information for all apps: target population, object of the measure, body segment evaluated, modality of use, operating platform system, and validation results. The literature search produced 91 papers, 39 of which met the inclusion criteria. The included papers featured 20 different apps: 13 exclusively for upper/lower limb joint angles, 4 for spine, and 3 for both limbs and spine measurement. The 20 apps used the inbuilt smartphone magnetometer, accelerometer or camera to produce angle measurements. The overwhelming majority of the selected apps are available in the App Store for iOS. No goniometric app has been validated in dynamic conditions. Our report highlights the availability—for angle measurement of diverse body segments—of a large body of validated goniometer apps that physiatrists and other healthcare practitioners can use with confidence in research and clinical practice. There is a need for validation studies on apps focused on goniometric measurement in dynamic conditions, such as during gait or during performance of therapeutic exercises.

Generalized Lower Limb Joint Angular Phase Space Analysis of Subject Specific Normal and Modified Gait.

This study presents and applies generalized angular phase space analysis to lower limb joint angles of specific subject during normal and modified gait for discrimination of gait and joint angular movements. Case study of an adult healthy male in-vivo and noninvasive kinematic assessment of skin surface adhesive markers at lower limb was performed at human movement lab during normal gait, stiff knee gait and slow running. Musculoskeletal modeling was performed using AnyGait v.0.92 morphing Twente Lower Extremity Model (TLEM) to match the size and joint morphology of the stick-figure model. Inverse kinematics was performed obtaining hip, knee and ankle joint flexion-extension angular displacements, velocities and accelerations. Generalized phase space analysis was applied to lower limb joint angular displacements, velocities and accelerations. Directional statistics was applied to generalized phase planes with mean direction, resultant length and circular standard deviation assessment. Rayleigh test was employed for directional concentration and coordination assessment, and Watson's $\mathrm{U^{2$ goodness of fit test applied to the von Mises distribution. Results point for the importance of subject specific study, generalized joint angular phase space analysis, comparing results with other normalization methods and validation of applied methods with qualitative clinical analysis.

Criterion validity of wearable sensors in lower limb joint angle estimation: A systematic review

Motion capture systems are extensively used to measure human joint kinematics. These systems, however, lack portability and can only be used in laboratory settings. Recently, portable and wireless systems, such as inertial measurement units (IMU), have been developed and are seen as an alternative to quantify human movement outside of the laboratory. Several studies have established their psychometric properties. However, the variety of systems used and joints evaluated make it difficult to conclude on the validity of the different systems available. The aim of this systematic review is to determine the criterion validity of IMUs for the evaluation of lower limb kinematics when compared to motion capture systems. Five different databases were screened (Pubmed, Cinhal, Embase, Ergonomic abstract and Compendex). Included articles had to report on criterion validity of IMUs (vs. motion capture systems) of at least one joint in healthy adults. Only articles published after 2005 were considered. Pairs of raters conducted data extraction and critical appraisal using structured tools, and consensus had to be reached. A total of ten articles was included. Quality ratings of 30% of the studies reviewed were characterized as high, and 70% as moderated (interrater reliability: ICC = 0.7). Knee and trunk movements showed moderate to good criterion validity, while hip and ankle movements were characterized as having poor to good validity. IMU systems are valid to evaluate knee and trunk kinematics. For the hip and ankle, however, the validity varies according to movement studied. The measurement of hip flexion/extension, abduction/adduction and ankle plantar flexion/dorsiflexion with IMU can be considered as valid. For ankle inversion/eversion and hip internal/external rotation, the validity is poor. More studies are therefore needed to optimize the use of IMU for these movements (e.g. different calibration or biomechanical models).

Lower limb angular velocity during walking at various speeds

BackgroundAlthough it is well established that lower limb joint angles adapt to walking at various speeds, limited research has examined the modifications in joint angular velocity. There is currently no normative dataset for joint angular velocity during walking, which would be useful to allow comparisons for patient cohorts. Additionally, understanding normal joint angular velocity may assist clinical assessment and treatment procedures to incorporate methods that replicate the movement speed of the lower limb joints during walking. Research QuestionThis study aimed to examine lower limb joint angles and angular velocities in a healthy population walking at various gait speeds. MethodsThirty-six healthy adult participants underwent three-dimensional gait analysis while walking at various speeds during habitual and slowed walking. The peak joint angles and angular velocities during important phases of the gait cycle were examined for the hip, knee and ankle in the sagittal plane. Data were grouped in 0.2 m/s increments from a walking speed of 0.4 m/s to 1.6 m/s to represent the range of walking speeds reported in studies of people with gait impairments. ResultsFor joint angles and angular velocities, the shape of the gait traces were consistent regardless of the walking speed. However as walking speed increased, so did the peak joint angles and angular velocities for the hip, knee and ankle. The largest angular velocity occurred when the knee joint extended at the terminal swing phase of gait. For the ankle and hip joints, the largest angular velocity occurred during the push-off phase. SignificanceThis study examined how lower limb joint angular velocities change with various walking speeds. These data can be used as a comparator for data from clinical cohorts, and has the potential to be used to match clinical assessment and treatment methods to joint angular velocity during walking.