Elbow Angle Research Articles

Bayesian inference in arm posture perception.

To configure our limbs in space the brain must compute their position based on sensory information provided by mechanoreceptors in the skin, muscles, and joints. Because this information is corrupted by noise, the brain is thought to process it probabilistically, and integrate it with prior belief about arm posture, following Bayes' rule. Here, we combined computational modeling with behavioral experimentation to test this hypothesis. The model conceives the perception of arm posture as the combination of a probabilistic kinematic chain composed by the shoulder, elbow, and wrist angles, compromised with additive Gaussian noise, with a Gaussian prior about these joint angles. We tested whether the model explains errors in a VR-based posture matching task better than a model that assumes a uniform prior. Human participants were required to align their unseen right arm to a target posture, presented as a visual configuration of the arm in the horizontal plane. Results show idiosyncratic biases in how participants matched their unseen arm to the target posture. We used maximum likelihood estimation to fit the Bayesian model to these observations and estimate key parameters including the prior means and its variance-covariance structure. The Bayesian model including a Gaussian prior explained the response biases and variance much better than a model with a uniform prior. The prior varied across participants, consistent with the idiosyncrasies in arm posture perception, and in alignment with previous behavioral research. Our work clarifies the biases in arm posture perception within a new perspective on the nature of proprioceptive computations.

Inducing ipsilateral motor-evoked potentials in the biceps brachii muscle in healthy humans.

To assess reticulospinal tract excitability, high-intensity transcranial magnetic stimulation (TMS) has been used to elicit ipsilateral motor-evoked potentials (iMEPs). However, there is no consensus on robust and valid methods for use in human studies. The present study proposes a standardized method for eliciting and analysing iMEPs in the biceps brachii. Twenty-four healthy young adults participated in this study. Electromyography (EMG) electrodes recorded contralateral MEPs (cMEPs) from the right and iMEPs from the left biceps brachii. A dynamic preacher curl task was used with ~15% of the subject's one-repetition maximum load. The protocol included maximal compound action potential (M-max) determination of the right biceps brachii muscle, TMS hotspot determination, and four sets of five repetitions where 100% stimulator output was delivered at an elbow angle of 110° of flexion. We normalized cMEP amplitude by M-max (% M-max) and iMEP by cMEP amplitude ratio (ICAR). Clear iMEPs above background EMG were observed in 21 subjects (88%, ICAR = .31 ± .19). Good-to-excellent agreement (intraclass correlation coefficient [ICC] = .795-1.000) and low bias (.01-.08 mV and .60-1.11 ms) were demonstrated when comparing two different analysis methods (i.e. fixed time-window vs. manual onset detection) to determine the cMEP and iMEP amplitude and latency, respectively. Most subjects demonstrated clear iMEPs above background EMG triggered at a pre-determined joint angle during a light-load dynamic preacher curl exercise. Similar results were obtained when comparing a single-trial manual identification of iMEP and a semi-automated time-window data analysis approach.

EMG and SSVEP-based bimodal estimation of elbow angle trajectory

Detecting intentions and estimating movement trajectories in a human–machine interface (HMI) using electromyogram (EMG) signals is particularly challenging, especially for individuals with movement impairments. Therefore, incorporating additional information from other biological sources, potential discrete information in the movement, and the EMG signal can be practical. This study combined EMG and target information to enhance estimation performance during reaching movements. EMG activity of the shoulder and arm muscles, elbow angle, and the electroencephalogram signals of ten healthy subjects were recorded while they reached blinking targets. The reaching target was recognized by steady-state visual evoked potential (SSVEP). The selected target’s final angle and EMG were then mapped to the elbow angle trajectory. The proposed bimodal structure, which integrates EMG and final elbow angle information, outperformed the EMG-based decoder. Even under conditions of higher fatigue, the proposed structure provided better performance than the EMG decoder. Including additional information about the recognized reaching target in the trajectory model improved the estimation of the reaching profile. Consequently, this study’s findings suggest that bimodal decoders are highly beneficial for enhancing assistive robotic devices and prostheses, especially for real-time upper limb rehabilitation.

Evaluating Joint Angle Data for Clinical Assessment Using Multidimensional Inverse Kinematics with Average Segment Morphometry.

Movement analysis is a critical tool in understanding and addressing various disabilities associated with movement deficits. By analyzing movement patterns, healthcare professionals can identify the root causes of these alterations, which is essential for preventing, diagnosing, and rehabilitating a broad spectrum of medical conditions, disabilities, and injuries. With the advent of affordable motion capture technologies, quantitative data on patient movement is more accessible to clinicians, enhancing the quality of care. Nonetheless, it is crucial that these technologies undergo rigorous validation to ensure their accuracy in collecting and monitoring patient movements, particularly for remote healthcare services where direct patient observation is not possible. In this study, motion capture technology was used to track upper extremity movements during a reaching task presented in virtual reality. Kinematic data was then calculated for each participant using a scaled dynamic inertial model. The goal was to evaluate the accuracy of joint angle calculations using inverse kinematics from motion capture relative to the typical movement redundancy. Shoulder, elbow, radioulnar, and wrist joint angles were calculated with models scaled using either direct measurements of each individual's arm segment lengths or those lengths were calculated from individual height using published average proportions. The errors in joint angle trajectories calculated using the two methods of model scaling were compared to the inter-trial variability of those trajectories. The variance of this error was primarily within the normal range of variability between repetitions of the same movements. This suggests that arm joint angles can be inferred with good enough accuracy from motion capture data and individual height to be useful for the clinical assessment of motor deficits.

The relationship between smartphone usage position, pain, smartphone addiction, and hand function.

The hand is the most frequently used part of the body during daily life activities. Any musculoskeletal problem that may occur in the hand can lead to loss of function. This study examined the relationship between the wrist and elbow position adapted during smartphone use, pain and discomfort, smartphone addiction, and hand function. Pain and discomfort were evaluated with the visual analog scale, wrist and elbow angle during phone use were evaluated with a universal goniometer, smartphone addiction was evaluated with the Smartphone Addiction Scale-Short Version, and functional status of the hand was evaluated with the Michigan Hand Outcomes Questionnaire. A total of 120 university students (female: n= 60), with an average age of 22.71 ± 2.7years, were included in this cross-sectional study. A relationship was found between the angle of the wrist and elbow during smartphone use and pain/discomfort (r= 0.692, p= 0.001), smartphone addiction (r= 0.575, p= 0.001), and hand function parameters (r= 0.20-0.55, p⩽ 0.05). Due to the increased use of smartphones in today's environment, a preventive program should be developed in which texting for extended periods is avoided, along with frequent breaks to rest the hands, and stretching exercises for the upper extremities during rest.

The Kinematics of 3D Arm Movements in Sub-Acute Stroke: Impaired Inter-Joint Coordination is Attributable to Both Weakness and Flexor Synergy Intrusion

Background It has long been of interest to characterize the components of the motor abnormality in the arm after stroke. One approach has been to decompose the hemiparesis phenotype into negative signs, such as weakness, and positive signs, such as intrusion of synergies. We sought to identify the contributions of weakness and flexor synergy to motor deficits in sub-acute stroke. Methods Thirty-three sub-acute post-stroke participants and 16 healthy controls performed two functional arm movements; one within flexor synergy (shoulder and elbow flexion), and the other outside flexor synergy (shoulder flexion and elbow extension). We analyzed upper limb 3D kinematics to assess both overall task performance and intrusion of pathological synergies. Weakness and spasticity were also measured. Results Both tasks produced similar impairments compared to controls. Analysis of elbow and shoulder multi-joint coordination patterns revealed intrusion of synergies in the out-of-synergy reaching task based on the time spent within a flexion-flexion pattern and the correlation between shoulder and elbow angles. Regression analysis indicated that both weakness and synergy intrusion contributed to motor impairment in the out-of-synergy reaching task. Notably, the Fugl-Meyer Assessment (FMA) was abnormal even when only weakness caused the impairment, cautioning that it is not a pure synergy scale. Conclusions Weakness and synergy intrusion contribute to motor deficits in the sub-acute post-stroke period. An abnormal FMA score cannot be assumed to be due to synergy intrusion. Careful kinematic analysis of naturalistic movements is required to better characterize the contribution of negative and positive signs to upper limb impairment after stroke.

Comparing the efficiency of recurrent neural networks to EMG-based continuous estimation of the elbow angle

Comparing the efficiency of recurrent neural networks to EMG-based continuous estimation of the elbow angle

Characterizing the Sensing Response of Carbon Nanocomposite-Based Wearable Sensors on Elbow Joint Using an End Point Robot and Virtual Reality.

Physical therapy is often essential for complete recovery after injury. However, a significant population of patients fail to adhere to prescribed exercise regimens. Lack of motivation and inconsistent in-person visits to physical therapy are major contributing factors to suboptimal exercise adherence, slowing the recovery process. With the advancement of virtual reality (VR), researchers have developed remote virtual rehabilitation systems with sensors such as inertial measurement units. A functional garment with an integrated wearable sensor can also be used for real-time sensory feedback in VR-based therapeutic exercise and offers affordable remote rehabilitation to patients. Sensors integrated into wearable garments offer the potential for a quantitative range of motion measurements during VR rehabilitation. In this research, we developed and validated a carbon nanocomposite-coated knit fabric-based sensor worn on a compression sleeve that can be integrated with upper-extremity virtual rehabilitation systems. The sensor was created by coating a commercially available weft knitted fabric consisting of polyester, nylon, and elastane fibers. A thin carbon nanotube composite coating applied to the fibers makes the fabric electrically conductive and functions as a piezoresistive sensor. The nanocomposite sensor, which is soft to the touch and breathable, demonstrated high sensitivity to stretching deformations, with an average gauge factor of ~35 in the warp direction of the fabric sensor. Multiple tests are performed with a Kinarm end point robot to validate the sensor for repeatable response with a change in elbow joint angle. A task was also created in a VR environment and replicated by the Kinarm. The wearable sensor can measure the change in elbow angle with more than 90% accuracy while performing these tasks, and the sensor shows a proportional resistance change with varying joint angles while performing different exercises. The potential use of wearable sensors in at-home virtual therapy/exercise was demonstrated using a Meta Quest 2 VR system with a virtual exercise program to show the potential for at-home measurements.

CFD Modelling of Swirling Device to Study Bend Erosion Rate at Different Bend Angles in Pneumatic Conveying System

Bend Erosion problems were found mostly common in pneumatic conveying plants. Swirling of particles before striking the bend has been noted as the best solution to minimize bend erosion rate. CFD k-w model in Ansys was applied to analyze mild steel bend erosion in the pipeline by pneumatically conveyed particles with a motor-operated swirling device. A part of the pipe before the bend is rotated at different velocities in different elbow geometries from 15° to 90° elbows. A combination of Eulerian and Lagrangian methods were utilized to track particles. Mathematical modelling of the swirling of particles on bent surfaces is taken into consideration with different elbow angle. The bend erosion rate was mitigated due to the swirling of particles. Different velocities and parameters are taken to evaluate the results. At different bend angles erosion rate is different and the swirling device minimizes the bend erosion rate.

Muscle Changes during Direct Attack under Different Conditions in Elite Wheelchair Fencing.

The main objective of this study was to measure the speed and muscular participation of a direct attack gesture with and without fatigue in a sample of elite wheelchair fencers. The maximal isometric force, gestural speed, and resistance to gestural velocity were estimated in 10 elite performed direct fencers. The results revealed that sitting height and wingspan were important factors in achieving the highest speed, especially in women (r = 0.9; p = 0.07). Other factors, such as the elbow angle where the closed position was better, affected muscle contraction in both categories of athletes (p = 0.01). The onset of fatigue was earlier in category B than in category A, with greater variation in direct attack movement. The results highlight the importance of analyzing direct attacks for the best application of quick force, speed, and muscle participation, as well as identifying the onset of technical deterioration to devise a competitive strategy. These parameters may allow for precise design of conditioning sessions for elite wheelchair shooters.

Shoulder External Over Internal Rotation Ratio Is Related to Biomechanics in Collegiate Baseball Pitching.

Altering baseball pitching mechanics affects both performance and the risk of injury. The purpose of this study is to investigate the relationships of shoulder external over internal rotation ratio (SEIR) and other shoulder rotational properties during physical exam and biomechanics of pitching for 177 collegiate baseball pitchers. The shoulder range of motion was quantitatively measured using a custom-made wireless device. Pitching motion data were collected at 240Hz, and a custom program was created to calculate the throwing arm motion and loading during baseball pitching. Linear regression and analysis of variance tests were performed to investigate the relationships between the shoulder physical exam outcomes and throwing arm biomechanics. SEIR had significant correlations with shoulder horizontal adduction angle at foot contact, maximum shoulder external rotation angle, maximum shoulder linear velocity, and elbow angle at ball release. SEIR groups had significant differences in shoulder proximal force, adduction torque, internal rotation torque, and horizontal adduction torque, and in elbow medial force and varus torque. Glenohumeral internal rotation deficit and total rotational motion deficit had no relationships with throwing arm motions or joint loadings. Shoulder health should be monitored to improve understanding of pitching mechanics in collegiate baseball pitchers.

Comparing the posture and comfort of anaesthesiologists during laryngoscopy and tracheal intubation in the head-elevated laryngoscopy position in supine position and with a 25° backup: A randomised clinical crossover trial.

The head-elevated laryngoscopy position (HELP) and a 25° backup have been proposed to enhance glottic visualisation, yet concerns about ergonomic discomfort hinder their widespread adoption. This study compares the comfort and posture adopted by anaesthesiologists while performing laryngoscopy and tracheal intubation with patients in HELP while in a supine position or with 25° backup. The study included 48 patients aged 18-60 years with normal airways and 12 experienced anaesthesiologists. Patients were randomised into two groups using permuted block randomisation. Anaesthesiologists performed laryngoscopy and intubation in supine HELP and 25° backup HELP positions. Anaesthesiologist's posture was determined by measuring the angles of neck, wrist, elbow, back and knee joints, which were compared using Student's t-test, and subjective comfort assessed on a Likert scale was compared using the Chi-square test. As mentioned by the anaesthesiologist, Cormack- Lehane grading was also noted and compared using a Chi-square test between groups, taking a P value <0.05 as significant. Both positions demonstrated comparable anaesthesiologist posture (P = 0.919) and comfort (P = 0.644). However, the 25° backup HELP positions significantly improved Cormack-Lehane grades, with 68% achieving grade 1 compared to 31% in the supine HELP group (P = 0.012). Haemodynamic stability and tracheal intubation time showed no significant differences between the groups (P = 0.475 and 0.117, respectively), and no complications were reported in either group. Anaesthesiologists' posture and comfort during laryngoscopy and tracheal intubation are similar between supine and 25° backup in patients with easy airways.

Difference in Stiffness between Biceps Brachii Muscle Bellies Using Shear Wave Elastography

The Shear Wave Elastography of muscles can provide real-time information on the stiffness of muscles; however, the difference in stiffness between biceps brachii muscle bellies requires more research. Understanding the variables that affect muscle stiffness will assist in the development of Shear Wave Elastography as a diagnostic tool for muscle stiffness pathologies. This study’s aim is to determine the Shear Wave Velocity of the short and long head of biceps brachii and the change in stiffness with elbow flexion to create a reliable protocol for pathological muscle assessment. The muscle belly of the short and long heads of bilateral biceps brachii of 38 healthy participants were scanned supine with the arm at full extension and at 30° and 60° elbow flexion. A log transform of the SWV was used as the response variable in the regression analysis, and the intraclass correlation coefficient was determined for reliability. The Shear Wave Velocity of the short head was lower than the long head on average. By fitting Bayesian mixed effect regression models to the data, the estimated posterior predictive mean velocities for the short head at full extension, 30°, and 60° were 3.14 m/s, 2.65 m/s, and 2.62 m/s, respectively; and 3.91 m/s, 3.02 m/s, and 3.15 m/s, respectively, for the long head of the biceps brachii. The intraclass correlation coefficients (0.64–0.92) were good to excellent. Shear Wave Elastography can detect the consistent difference in the stiffness of the two muscle bellies of the biceps brachii at multiple elbow angles. The assessment of muscle stiffness with Shear Wave Elastography should consider the morphology of the muscles.

Normal Elbow Angles in Saudi Population: Radiographic Study

Background: In this study, we aimed to measure normal elbow radiographic angles in the Saudi population and compare the normal range of elbow angles between Saudi males and females, as well as those previously measured in other populations. Methods: Anteroposterior and lateral plain radiographs of 304 normal elbows from 153 females and 151 males from the Saudi population, aged &gt; 18 years, were assessed. Radiographs, 174 right elbows, and 130 left elbows were studied retrospectively, between 2018 and 2023 in our institute. Only normal elbow radiographs with acceptable quality were included. The standard radiographic elbow measurements were collected. Data analysis was conducted with Student’s t-test for parametric data and Wilcoxon Mann–Whitney U test for nonparametric data. Two certified orthopedic surgeons performed the measurements independently. Interobserver and intraobserver errors were measured. Results: All the radiographic elbow measurements in Saudis did not show any significant sexual dimorphism or difference between sides. The radiographic angles obtained on the anteroposterior view appeared more reliable than lateral view angles. Unlike carrying angle (CA), measurements of radiographic elbow angles in Saudis were inconsistent with previously published values. Conclusions: The elbow radiographic anatomical parameters of the Saudi population were not consistent with previously published values except for CA. The presence of a significant impact of geographical or racial variation on elbow radiographic anatomy requires additional investigations.

Outcome of Plyometric Training on the Performance of Female Badminton Players of the Islamia University of Bahawalpur

This research determined the differences between two groups of female badminton players. The participants were an experimental (group = 20 and a control group =20). The variables were obtained speed, flexibility, agility, standing jump, sit-ups, push-ups, body mass, height, anthropometric measures, and forehand services. Captured videos of the badminton serves were analyzed to obtain the kinematics measure. The experimental group followed a 6-week plyometric training and the control group continued with the same pattern of badminton practice. Factorial ANOVA with repeated measures was applied for statistical analysis. Findings showed the experimental group players were considerably greater in post-measurements in calf circumference, toe-to-toe distance stance, toe-to-toe distance connect shuttle, right elbow angle, and badminton performances. Therefore, it is concluded that the experimental groups significantly improved in physical fitness and badminton performance. It is suggested that female badminton players should follow plyometric training to enhance their fitness and badminton performance.

Distributed sensing along fibers for smart clothing.

Textile sensors transform our everyday clothing into a means to track movement and biosignals in a completely unobtrusive way. One major hindrance to the adoption of "smart" clothing is the difficulty encountered with connections and space when scaling up the number of sensors. There is a lack of research addressing a key limitation in wearable electronics: Connections between rigid and textile elements are often unreliable, and they require interfacing sensors in a way incompatible with textile mass production methods. We introduce a prototype garment, compact readout circuit, and algorithm to measure localized strain along multiple regions of a fiber. We use a helical auxetic yarn sensor with tunable sensitivity along its length to selectively respond to strain signals. We demonstrate distributed sensing in clothing, monitoring arm joint angles from a single continuous fiber. Compared to optical motion capture, we achieve around five degrees error in reconstructing shoulder, elbow, and wrist joint angles.

The relationship between explosive power, elbow angle, and jump height with smash accuracy in volleyball games; correlational studies

Background. Smash is synonymous with powerful punches and swift dives. Accuracy stands as the primary factor that holds significant importance.&#x0D; Purpose. The purpose of this study is to investigate the relationship between the independent variables, namely explosive power, elbow angle, and jump height, and the dependent variable, which is smash accuracy.&#x0D; Methods. Descriptive research design with correlational methods. This research involved a group of 15 male student athletes, whose age (M ± SD = 21.27 ± 1.163 years) and height (M ± SD = 167.67 ± 1.877 cm) were recorded. The sampling technique used purposive sampling, with certain criteria. Prerequisite tests such as normality test and linearity test were conducted, followed by hypothesis testing. The data was analyzed using SPSS 26.0.&#x0D; The results. The results demonstrate a significant and simultaneous asscosiation between the independent variable and the dependent variable, as indicated by the observed significance value of 0.015 &lt;0.05. The data output reveals a simultaneous correlation coefficient of R = 0.776, with a determination coefficient of Rsquare = 0.601, indicating that 60.1% of the variation in the dependent variable can be explained by the independent variables. The remaining 39.9% is attributed to and explained by factors other than the independent variables.&#x0D; Conclusions. The findings and discussion of the research demonstrate a noteworthy association between explosive power, elbow angle, and jump height, and the accuracy of smashes in volleyball. As a result, this study presents substantial evidence supporting the significant contributions of explosive power, elbow angle, and jump height to smash accuracy.

Influence and optimization of swirler parameters on elbow wear of deep coal fluidization pipeline transportation system

Elbow wear is a major threat to the multiphase pipeline transportation industry, which has a negative impact on the stable operation of the transportation system. In order to find the wear reduction methods of elbows in the fluidization pipeline transportation system for 2000-meter-deep coal resources, the swirler was installed upstream of the elbows, and wear simulations and tests of three kinds of elbows were carried out. The results showed that the maximum wear rate (MWR) of elbows increased and then decreased along the elbow angle. Due to the different directions of gravity, the heavy wear position (HWP) of the horizontal-vertical (H-V) elbow was in front of the vertical-horizontal (V-H) elbow. Because the downstream portion of the horizontal-horizontal (H-H) elbow was still a horizontal pipe, the HWP of the H-H elbow almost covered the whole elbow. The swirler placed upstream of the elbows could make the particles at the elbow move to the intrados of the elbows, resulting in less collision between the particles and the extrados of the elbows, thus reducing the wear of the elbows. The wear reduction effects of swirlers on three different elbows were favorably connected with the guide vane angle (GVA) and negatively correlated with the guide vane length (GVL), decreased first and then increased as the guide vane height (GVH) increased, and were little affected by the guide vane number (GVN) and the guide vane thickness (GVT). The mathematical models between the MWR of the elbows and guide vane parameters were established. By bench tests, the wear reduction effect of three kinds of elbows under the optimal guide vane parameters was 58.4%, 76.9%, and 78.6%, respectively. The errors between the bench test results and the simulation results were around 10%.

Upper limb motor dysfunction is associated with fragmented kinetics after brain injury

BackgroundCharacterization of motor deficits after brain injury is important for rehabilitation personalization. While studies reported abnormalities in the kinematics of paretic and non-paretic elbow extension for patients with brain injuries, kinematic analysis is not sufficient to explore how patients deal with musculoskeletal redundancy and the energetic aspect of movement execution. Conversely, interarticular coordination and movement kinetics can reflect patients' motor strategies. This study investigates motor strategies of paretic and non-paretic upper limb after brain injury to highlight motor deficits or compensation strategies. Methods26 brain-injured hemiplegic patients and 24 healthy controls performed active elbow extensions in the horizontal plane, with both upper limbs for patients and, with the dominant upper limb for controls. Elbow and shoulder kinematics, interarticular coordination, net joint kinetics were quantified. FindingsResults show alterations in kinematics, and a strong correlation between elbow and shoulder angles, as well as time to reach elbow and shoulder peak angular velocity in both upper limbs of patients. Net joint kinetics were lower for paretic limb and highlighted a fragmented motor strategy with increased number of transitions between concentric and eccentric phases. InterpretationIn complement to kinematic results, our kinetic results confirmed patients' difficulties to manage both spatially and temporally the joint degrees of freedom redundancy but revealed a fragmented compensatory motor strategy allowing patients upper limb extension despite quality alteration and decrease in energy efficiency. Motor rehabilitation should improve the management of this fragmentation strategy to improve the performance and the efficiency of active movement after brain injury.

Relationship between pectoralis major stiffness and shoulder extension range of motion.

This study aimed to investigate the correlation between the passive muscle stiffness of the pectoralis major muscle pars clavicularis (PMc) and shoulder extension range of motion (ROM) in both male and female participants. Thirty-nine (23 male/16 female) physically active and healthy participants volunteered in this study. After a standardized warm-up, the PMc stiffness was tested via shear wave elastography at a slightly stretched position (long muscle length) and in a non-stretched position (short muscle length). Additionally, a custom-made device and 3D motion capture assessed the active shoulder extension ROM. We found a significant moderate and negative relationship between shoulder extension ROM and PMc stiffness at long muscle length (rs = -0.33; p = 0.04) but not at short muscle length (r = -0.23; p = 0.17). Additionally, there was no significant difference between male and female participants in the correlation analyses at both elbow angles. The moderate correlation between PMc stiffness at a slightly stretched position and shoulder extension ROM suggests that additionally, other structures such as nerves/fascia stiffness or even stretch tolerance might be factors that can be related to shoulder extension ROM.