Repetitive Movements Research Articles

Ứng dụng tiêm Botulinum Neurotoxin dưới hướng dẫn của siêu âm và điện cơ trong điều trị loạn trương lực cơ cổ: Ca lâm sàng

Dystonia is a movement disorder characterized by persistent or intermittent muscle contractions, involuntary, creating repetitive and/or abnormal postures and movements. Dystonic movements result in characteristic twisting or tremor patterns. Dystonia often begins or worsens with intentional movements, combined with excessive muscle activation. Dystonia is classified according to the affected body regions: focal dystonia, segmental dystonia, multifocal dystonia, hemidystonia, and generalized dystonia. Anterocollis is a type of cervical dystonia, caused by persistent, repetitive contractions of neck muscle groups, leading to excessive neck flexion. Anterocollis is described in the context of movement disorders in Parkinson’s syndrome (Parkinson’s disease, multiple system atrophy, etc.). Treatment of dystonia is primarily symptomatic: medications, Botulinum Neurotoxin (BoNT) injections, surgery, and physical therapy. Among these, BoNT injections are considered the first choice for focal or segmental dystonia.Botulinum Neurotoxin acts at the neuromuscular junction, leading to muscle paralysis. BoNT injections require injection equipment, surface disinfection, and determination of the injection site based on clinical landmarks. Some deep and difficult injections require specialized techniques such as electromyography (EMG) and ultrasound. In the case of anterocollis, BoNT is often applied to both superficial and deep muscles. To achieve effectiveness and limit complications during and after injection, practitioners often use combined EMG and ultrasound techniques. We present a clinical case to illustrate the value of using BoNT injections under the simultaneous guidance of EMG and ultrasound in treating anterocollis at the Neurology Department of Hanoi Medical University Hospital.

Recommendations on the management and prevention of spinal cord injury in children following backbend dance

Spinal cord injury (SCI) is a kind of disease that indiscriminately affects all age groups, although the number of SCI cases in children is far lower than that in adults. In this paper, we discuss the appropriate diagnostic methods and prevention methods for SCI caused by repetitive hyperextension movement. Case study reports available in the published literature concerning SCI due to hyperextension movement, which were categorized using the American Spinal Injury Association (ASIA) grades, were gathered. Moreover, the age, gender, lesion length on magnetic resonance image (MRI), time of symptoms appearance, initial spinal cord atrophy region, neurological level of injury, and initial and final ASIA grades were analyzed. A total of 144 cases with SCI after backbend dance were included in our analysis, with some cases with an incubation period ranging between 15 min and 4 h showing no symptoms. Most of the collected cases were young girls of <11 years old. Early MRI showed that the pathological changes had extended toward cephalocaudal regions. In summation, the number of SCI cases, which are disabling for many children, is rapidly accumulating in China. Thus, SCI following repetitive hyperextension movements requires further research.

Risk assessment models for development of carpal tunnel syndrome: clinical, anthropometric, and neuromuscular ultrasound predictors

BackgroundCarpal tunnel syndrome (CTS) is the most common entrapment neuropathy with multifactorial etiologies. We intended in this case–control study to identify, out of a comprehensive set of risk factors, the relatively important ones and develop a quantitative risk assessment model for this disorder. It was also legitimate to define the hazard of those factors in a dose-related manner and the acceptable safe limit especially for work-related stresses.ResultsAge and female predominance were comparable between the 60 patients (89 hands with electrophysiologically confirmed CTS) and 50 controls (100 hands). Occupation of the studied sample varied between housewives only, employed housewives, and manual workers with a distribution that differed significantly between patients and controls. Significantly higher body mass index (BMI) and mean wrist depth were found in patients than controls. Wrist ratio (clinically or sonographically) was significantly squarer in patients than controls. Overall workload and number of hours spent daily performing work with repeated hand movements or awkward hand position were significantly higher among patients than controls.ROC curves were constructed for wrist measurements and occupational stresses. Cut-off points of wrist ratio and internal carpal tunnel ratio (by ultrasound) to discriminate subjects with CTS were > 0.68 and ≤ 1.854, respectively. The best cut-off value for number of hours spent daily performing work with repeated hand movements was 3 h/ day. As for working with awkward hand position or cold exposure, cut-off value was 0.6 h/day for both.Two logistic regression models were conducted to investigate nonoccupational and occupational predictors of CTS. The independent predictors concluded from the first model were BMI, positive family history of CTS, wrist ratio, and decrease grip strength. As for the occupational model, predictors were tasks requiring awkward hand position and cold exposure.ConclusionOccupational risk assessment by clinical, anthropometric, and ultrasonographic measurement should be used in professions requiring repetitive or awkward hand movements, so that in overweight persons with square wrists appropriate workplace setup measures or assistive technology at work or home could be taken to prevent or decrease the impact of work hazards or help choose individuals with low risk for appropriate jobs.

Differential components of bradykinesia in Parkinson's disease revealed by deep brain stimulation.

Bradykinesia is a term describing several manifestations of movement disruption caused by Parkinson's disease (PD), including movement slowing, amplitude reduction, and gradual decrease of speed and amplitude over multiple repetitions of the same movement. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves bradykinesia in patients with PD. We examined the effect of DBS on specific components of bradykinesia when applied at two locations within the STN, using signal processing techniques to identify the time course of amplitude and frequency of repeated hand pronation-supination movements performed by participants with and without PD. Stimulation at either location increased movement amplitude, increased frequency, and decreased variability, though not to the range observed in the control group. Amplitude and frequency showed decrement within trials, which was similar in PD and control groups and did not change with DBS. Decrement across trials, by contrast, differed between PD and control groups, and was reduced by stimulation. We conclude that DBS improves specific aspects of movement that are disrupted by PD, whereas it does not affect short-term decrement that could reflect muscular fatigue.NEW & NOTEWORTHY In this study, we examined different components of bradykinesia in patients with Parkinson's disease (PD). We identified different components through signal processing techniques and their response to deep brain stimulation (DBS). We found that some components of bradykinesia respond to stimulation, whereas others do not. This knowledge advances our understanding of brain mechanisms that control movement speed and amplitude.

Neural basis of lower-limb visual feedback therapy: an EEG study in healthy subjects

BackgroundVideo-feedback observational therapy (VOT) is an intensive rehabilitation technique based on movement repetition and visualization that has shown benefits for motor rehabilitation of the upper and lower limbs. Despite an increase in recent literature on the neurophysiological effects of VOT in the upper limb, there is little knowledge about the cortical effects of visual feedback therapies when applied to the lower limbs. The aim of our study was to better understand the neurophysiological effects of VOT. Thus, we identified and compared the EEG biomarkers of healthy subjects undergoing lower limb VOT during three tasks: passive observation, observation and motor imagery, observation and motor execution.MethodsWe recruited 38 healthy volunteers and monitored their EEG activity while they performed a right ankle dorsiflexion task in the VOT. Three graded motor tasks associated with action observation were tested: action observation alone (O), motor imagery with action observation (OI), and motor execution synchronized with action observation (OM). The alpha and beta event-related desynchronization (ERD) and event-related synchronization (or beta rebound, ERS) rhythms were used as biomarkers of cortical activation and compared between conditions with a permutation test. Changes in connectivity during the task were computed with phase locking value (PLV).ResultsDuring the task, in the alpha band, the ERD was comparable between O and OI activities across the precentral, central and parietal electrodes. OM involved the same regions but had greater ERD over the central electrodes. In the beta band, there was a gradation of ERD intensity in O, OI and OM over central electrodes. After the task, the ERS changes were weak during the O task but were strong during the OI and OM (Cz) tasks, with no differences between OI and OM.ConclusionAlpha band ERD results demonstrated the recruitment of mirror neurons during lower limb VOT due to visual feedback. Beta band ERD reflects strong recruitment of the sensorimotor cortex evoked by motor imagery and action execution. These results also emphasize the need for an active motor task, either motor imagery or motor execution task during VOT, to elicit a post-task ERS, which is absent during passive observation.Trial Registration NCT05743647

Effects of muscle fatigue on quadriceps muscle performance in healthy amateur soccer players

IntroductionQuadriceps femoris muscle (QFM) fatigue has a detrimental impact on athlete performance. Therefore, it is crucial to evaluate various performance parameters under fatigued conditions. This study aimed to assess the performance of the QFM during both concentric and eccentric contractions before and after fatigue in the lower extremities of healthy amateur soccer players. MethodTwenty-four healthy amateur soccer players performed three consecutive knee extension and flexion movements concentrically and eccentrically at a velocity of 120°/s with maximum effort, using a Biodex dynamometer. Fatigue was induced by a protocol involving repetitive concentric knee extension and flexion movements at 120°/s, with a load of 50% of maximal voluntary isometric contraction (MVIC) of the QFM until its moment declined to 50% of MVIC. Separate 2-way analyses of variance were conducted to assess the influence of contraction and fatigue on various isokinetic parameters. ResultsNo significant interaction effect between contraction and fatigue was observed for any of the parameters. There was a significant main effect of fatigue on average power for both lower extremities. However, no significant main effect of fatigue was observed for normalized peak moment, angle of peak moment, moment at 0.2s, total work, acceleration, and deceleration times. In contrast, significant main effects of contraction were noted for normalized peak moment, moment at 0.2s, average power, acceleration, and deceleration times in both lower extremities. ConclusionAverage power appeared as the most sensitive performance parameter to fatigue. To enhance QFM performance, emphasizing eccentric exercises during training and conditioning programs could be beneficial for athletes.

An Analysis of Occupational Hazards Based on the Physical Ergonomics Dimension to Improve the Occupational Health of Agricultural Workers: The Case in Mayo Valley, Mexico

The occupational health and safety of agricultural workers is a topic that has a direct impact on the agricultural sector worldwide. For this reason, investigations into ergonomic factors are relevant to the health and safety of agricultural workers. In this study, nine variables of the physical–ergonomic dimension were analyzed to determine which factors represent occupational risks for agricultural workers in Mayo Valley, Mexico. A sample of 200 people was considered. The sample was separated by gender and divided into groups according to age. A closed-ended survey was developed and validated to assess physical ergonomics variables using a five-level Likert scale. Using Principal Component Analysis, it was found that there are physical ergonomic variables that affect male agricultural workers more than female workers (the risk of carrying heavy objects, PE3, and the risk of performing repetitive movements, PE4). It was also found that certain physical ergonomic variables are not perceived as hazardous by agricultural workers (the risk of using inappropriate materials, PE9). In addition, various research findings are discussed to determine the implications and recommendations for improving the occupational health and safety of agricultural workers in Mayo Valley, Mexico.

Enhancing Awareness and Management of Carpal Tunnel Syndrome Among Medical Professionals and Athletes

Introduction and objective: The objective of this research is to enhance the awareness of carpal tunnel among medical professionals and individuals engaged in sports. The acquired knowledge will enable medical professionals to more effectively identify, treat, and prevent issues related to carpal tunnel. Additionally, individuals engaged in sports will be able to prevent the occurrence of carpal tunnel syndrome in themselves or their pupils, thereby allowing them to engage in long-term and safe physical activity. Review methods: Review and summary of research studies available in open-source format on Google Scholar, PubMed. Abbreviated description of the state of knowledge: Carpal tunnel syndrome is a disease belonging to the group of compression neuropathies. The symptoms of carpal tunnel syndrome typically manifest as an uncomfortable sensation in the thumb, index finger, and half of the ring finger. Such symptoms may include numbness and tingling. In some cases, weakness of the hand muscles may occur, and in rarer instances, atrophy of the hand muscles. The condition of carpal tunnel syndrome is primarily the result of repetitive movements of the fingers and wrist. Such activities include typing, using a mouse, riding a bicycle, or playing a musical instrument. Summary: Carpal tunnel syndrome is a prevalent condition among the general population. This condition may affect individuals who engage in regular physical activity, resulting in diminished efficiency and a notable reduction in the quality of life. The objective of this study is to examine the risk factors, symptoms, and diagnostic methods associated with carpal tunnel syndrome. In the context of sports, we will examine the mechanisms of disease development in athletes and focus on prevention. This encompasses the rehabilitation of individuals at risk of developing the disease and patient education, which will facilitate the minimisation of the appearance or recurrence of disease symptoms.

Current Clinical Concepts: Rehabilitation of Thoracic Outlet Syndrome.

Thoracic outlet syndrome (TOS) involves inconsistent symptoms, presenting a challenge for medical providers to diagnose and treat. Thoracic outlet syndrome is defined as a compression injury to the brachial plexus, subclavian artery or vein, or axillary artery or vein occurring between the cervical spine and upper extremity. Three common subcategories are now used for clinical diagnosis: neurogenic, arterial, and venous. Postural position and repetitive motions such as throwing, weightlifting, and manual labor can lead to symptoms. Generally, TOS is considered a diagnosis of exclusion for athletes due to the poor accuracy of clinical testing, including sensitivity and specificity. Thus, determining a definitive diagnosis and reporting injury is difficult. Current literature suggests there is not a gold standard diagnostic test. Rehabilitation has been shown to be a vital component in the recovery process for neurogenic TOS and for arterial TOS and venous TOS in postoperative situations.

Therapeutic Interventions for Prevention of Musculoskeletal Pain Among Orthopedic Surgeons.

Orthopedic surgery is a physically demanding specialty. The factors contributing to musculoskeletal injury among surgeons often stem from positioning the patient, using non-ergonomic instruments, maintaining static postures, and performing repetitive movements. This article focuses on exercise techniques intended to combat the most common problematic static postures held during procedures. Each exercise explained in this article is organized into "preop," "intraop," and "postop" components. Preop includes strengthening movements, intraop provides postural recommendations, and postop focuses on mobilization and recovery. This article aims for efficient body conditioning, targeting the muscular posterior chain and supporting elements. [Orthopedics. 2024;47(4):e214-e216.].

Estimation of Intrinsic And Extrinsic Hand Muscle Performance in Chronic Smartphone Users

Introduction: In recent years, smartphone use has significantly expanded, and the majority of daily tasks are now completed on them. Therefore, extended use may result in improper posture, which may result in several musculoskeletal pains. It's crucial to assess the relationship between smartphone addiction and musculoskeletal pain. The length-tension relationship between the intrinsic and extrinsic hand muscles might alter due to the repetitive movement of the hand muscles. The purpose of the study is to determine the length tension relationship of the intrinsic and extrinsic hand muscles in chronic smartphone users. Methods: The cross-sectional design of this study allowed for the selection of 80 participants based on both inclusion and exclusion criteria. The information that was gathered included demographic information, smartphone usage patterns, hand grip strength, and length-tension relationships. The subjects' pain levels were also measured using the smart phone addiction scale. The male and female scores on the smartphone addiction scale were >31 and >33, respectively. Results: The findings of this study among 80 chronic smartphone users demonstrated that 50 (62.5%) of them fell in the 25–30 age bracket, whereas 30 (12.5%) were in the 30-35 range. Amongst them, 69 (86.25%) were right-handed, while 11 (13.75%) were left-handed. Upper Limb Tension Test, Visual Analogue Scale, and Smartphone Addiction Scale mean + SD readings were 37.77 + 9.5, 5.66 + 1.47, and 0.76 + 0.42, respectively. Conclusion: According to the outcomes of this research, we established a link between smartphone use and the length-tension of the hand muscles. We can therefore draw the conclusion that among subjects who used cell phones frequently, there was a change in the length-tension relation of the hand muscles, which resulted in a reduction in hand grip strength.

Assessment of Foot In Female Kathak Dancers

Background: Kathak is the art of storytelling and conveying it to the audience in a different way. Now a days kathak is spreading worldwide, and people are learning and chasing the challenges at top level for this the kathak dancers are focusing more and more over the riyaz followed by intense practice. Tatkar is an important component of this dance form which is performed by foot of dancer, commonly called as footwork. The population increasingly demand the repetitive rhythmic movements at ankle joint and to maintain the ankle stability there is requirement of heavy muscle work. This study examines postural deviations in the foot of female kathak dancers. Methods: The design was quantitative descriptive study utilizing Self Made Questionnaire developed specially for the research and foot posture index scale with the navicular drop test. The questionnaire contained questions related years of practice and frequency of practice with the pain associated to lower limb. Results: Percentage of people with normal and supinated conditions for both right and left feet across the different variables. It's notable that the categories for Pronated, Highly Pronated, and Highly Supinated feet were not observed in the datasets. Conclusion: In the present study it is found out that about 80% of total population have no postural changes found out in the foot the reason behind that can be the regular warm up cool down sessions, stretching and much more postural awareness. To avoid the foot problems and postural deviation now a days institutes are taking great warm up and cool down sessions with stretching for at least 1 hour and then startup with the forceful riyaz. Further research is warranted to make standardized warm up and cool down protocols for kathak dancers. KEYWORDS: Tatkar, kathak, Riyaz, Postural changes, footwork.

Prevalence of Neck Pain in Physiotherapist

Background: Neck pain is one of the most common musculoskeletal disorders among health professionals, including physiotherapists, who are often involved in activities that include holding a posture for a longer duration and performance of repetitive movements. The increased usage of smartphones and laptops enhances bad postures, particularly bending of the neck in flexion, adding to the problems related to neck pain. Objective: The present study has been taken up to assess the prevalence of neck pain among physiotherapists and their relation with gender and age. Methods: This was a cross-sectional study conducted on 100 physiotherapists, of which 63 were females and 37 were males. Neck pain prevalence was assessed with the Neck Disability Index questionnaire. Data collection was done in person from November 2023 to February 2024. Results were statistically analyzed, with descriptive statistics shown in tabulations, graphs, and figures. Results: The overall prevalence of neck pain among the participants was 64%. In accordance with the NDI scale, the physiotherapists self-reported 39% to have mild disability; 23%, moderate disability; only 2% were severely disabled and none with complete disability. On a gender basis, females revealed a slightly higher prevalence of neck pain, 25%, compared to their male counterparts, 24%. Conclusion: In this study, a high prevalence of neck pain was found among physiotherapists, with a slightly increased occurrence in females. These findings bring out the importance of increasing awareness toward ergonomic practices and health regarding posture to decrease neck pain in physiotherapists. The modifiable risk factors identified will have an emphasis on the promotion of good postures with lifestyle modifications to aid in the prevention of neck pain in physiotherapists. Making these changes and taking up appropriate treatments form an important aspect of the management of work-related musculoskeletal disorders.

Educational Intervention for the Management of Nonspecific Lower Back Pain in Nonprofessional Caregivers (TRANSFE Program): A Quasi-Experimental Study.

Nonspecific lower back pain is one of the main health issues experienced by nonprofessional caregivers of dependent individuals. The repetitive movements and efforts made by caregivers to assist dependent individuals are associated with the onset of this lower back pain. The main objective of this study was to assess the effectiveness of an educational intervention for the management of nonspecific lower back pain in nonprofessional caregivers of dependent individuals (TRANSFE program). The secondary objectives were to (i) evaluate the effectiveness of the TRANSFE program on other variables (caregiver burden, perceived social support, and health-related quality of life), (ii) obtain the sociodemographic profile of the sample, and (iii) determine the baseline of the study variables. A quasi-experimental study with post-intervention measurements at 3 months was conducted. Thirty-six nonprofessional caregivers of dependent individuals participated in this study. The presence of lower back pain (back pain index), low back pain (visual analogue scale), disability due to low back pain (Oswestry disability index), perceived social support (Duke-UNK scale), caregiver burden (Zarit burden scale), and health-related quality of life (EuroQol-5D) were assessed. The intervention significantly improved all the studied variables related to lower back pain (p < 0.001). The intervention was effective on other variables related to nonprofessional caregiving such as caregiver burden, perceived social support, and health-related quality of life, albeit with moderate results. An educational intervention for lower back pain experienced by caregivers of dependent individuals was effective in reducing lower back pain and addressing caregiver burden, perceived social support, and health-related quality of life. This study was registered retrospectively on the Open Science Framework platform on 20 June 2024, with the registration number 10.17605/OSF.IO/K7WTE.

Effect of concurrent action observation, peripheral nerve stimulation and motor imagery on dexterity in patients after stroke: a pilot study

Research to improve and expand treatment options for motor impairment after stroke remains an important issue in rehabilitation as the reduced ability to move affected limbs is still a limiting factor in the selection of training content for stroke patients. The combination of action observation and peripheral nerve stimulation is a promising method for inducing increased excitability and plasticity in the primary motor cortex of healthy subjects. In addition, as reported in the literature, the use of action observation and motor imagery in conjunction has an advantage over the use of one or the other alone in terms of the activation of motor-related brain regions. The aim of the pilot study was thus to combine these findings into a multimodal approach and to evaluate the potential impact of the concurrent application of the three methods on dexterity in stroke patients. The paradigm developed accordingly was tested with 10 subacute patients, in whom hand dexterity, thumb-index pinch force and thumb tapping speed were measured for a baseline assessment and directly before and after the single intervention. During the 10-min session, patients were instructed to watch a repetitive thumb-index finger tapping movement displayed on a monitor and to imagine the sensations that would arise from physically performing the same motion. They were also repeatedly electrically stimulated at the wrist on the motorically more affected body side and asked to place their hand behind the monitor for the duration of the session to support integration of the displayed hand into their own body schema. The data provide a first indication of a possible immediate effect of a single application of this procedure on the dexterity in patients after stroke.

A Case of Autism Spectrum Disorder Treated with Theridion currasavicum Prescribed on the Basis of Group Approach

Abstract Background Autism spectrum disorder (ASD) is a pervasive developmental disorder of unknown aetiology. There is a growing prevalence of ASD globally. Currently, there are no specific treatment that can address the core impairments of ASD. Case Summary A 5-year male child was brought to outpatient department with complaints of irritability, restlessness, howling, repeating words spoken to him, repeating phrases, hand flapping, self-hurting and hurting others, climbing stairs repeatedly, repeated drawing of squares everywhere, poor social interaction, poor peer-play and inappropriate playing with toys. The case was diagnosed as ASD and was assessed with the autism treatment evaluation checklist (ATEC) at baseline and follow-up visits. The case was treated with Theridion currasavicum in centesimal scale. ATEC score at baseline of 118 turned to 69 at the 12th month and 42 after 24 months of treatment. The remedy was repeated during monthly visits in ascending potencies. The child improved in the domains of social interaction, communication, repetitive stereotype movements, restricted interests and general health. The likelihood of causal relationship between intervention and outcome has been discussed as per modified Naranjo criteria for homoeopathy. This case report highlights the usefulness of the group approach and aetiological prescription as one way of arriving at the similimum in children with autism.

Leg stereotypy syndrome: phenomenological and quantitative analysis.

Leg stereotypy syndrome (LSS) is a very common, yet underrecognized condition. The pathophysiology of the condition is not well understood. To evaluate and describe the visual kinematic characteristics of the repetitive leg movements in individuals with LSS. In this study, we identified and videotaped individuals diagnosed with LSS at the Parkinson's Disease Center and Movement Disorders Clinic, Baylor College of Medicine, Houston, Texas between 2000 and 2023. Only patients with LSS and without any co-morbidities were included in the study. Their medical records were carefully reviewed, and the demographic and clinical data were entered into a database. Video recordings of the repetitive leg movements were then analyzed using TremAn software. We identified 14 individuals with LSS who were videotaped at our center. The videos of the 5 cases were too brief and therefore not suitable for TremAn quantitative analysis. The remaining 9 individuals exhibited regular rhythmic oscillations of the legs. Among these, two individuals displayed rhythmic movements only in video segments where their legs were in crossed positions. The other 7 individuals had regular rhythmic oscillations, always with the toes resting on the floor with the heels raised. Frequency analysis showed values between 4.5 and 6.5Hz, fairly consistent with a variance below 0.5Hz in individual cases. The oscillation frequency changed from 5.7 Hz to 2.7 Hz while standing. In this study, 6 of 9 individuals with LSS showed 4.5-6.5Hz regular rhythmic leg movements. Studies involving a larger LSS population with additional electrophysiological evaluations are needed to obtain further insights into this common movement disorder.

Workers’ compensation injuries in aviation manufacturing in the state of Kansas, 2014–2022

IntroductionWorkers’ compensation injuries entail burdensome financial and social costs. This study’s objective was to describe cost and frequency of workplace injuries in aviation manufacturing in the state of Kansas using workers’ compensation data. Manufacturing incurs more workers’ compensation claims in Kansas than any other industry, and aviation contributes more of those claims than any other sub sector. MethodWorkers’ compensation insurance and reporting are required in the state of Kansas. Data were provided by the Kansas Department of Labor (KDOL) and included all closed workers’ compensation claims entailing indemnity and medical costs filed in the state from 2014 to 2022. Cost of claim data were normalized to 2022 U.S. dollars and data were analyzed as a function of percentage and claim cost by body part, type of injury, cause of injury, specific musculoskeletal disorder type, and as a function of age and gender injury rates. ResultsAviation claims entailed a median total cost of $26,941 and represented 8% of all closed claims filed in the state from 2014 to 2022. The grand total direct cost over the nine-year period was $75,404,147. Medical costs comprised 48.6% of all costs, indemnity 45.0%, and legal 6.4%. The most frequently injured body part was the hand/wrist (35.9%) followed by the shoulder (20.6%), and the most expensive body parts were related to the back. Overexertion (38.6%) was the most common cause followed by repetitive motion (22.8%). Work-related musculoskeletal disorders were the most common type accounting for 67.4% of all claims. Men and workers aged 55–64 incurred slightly higher claim rates than average. A sharp decrease in number of claims closed in 2021 coincided with production shutdowns the previous year related to the Covid-19 pandemic and design issues. ConclusionsAviation manufacturing is a key industry in Kansas and this study is the first known to describe costs and frequencies of workplace injuries in the sector using workers’ compensation data. Practical applicationsThis guide to the most problematic and costly injuries in aviation manufacturing helps practitioners prioritize prevention strategies to most effectively reduce workplace injury and helps safety and health practitioners in prioritizing prevention efforts to reduce the most severe and costly aviation manufacturing injuries and illnesses. It also brings attention to some special considerations when working with safety data from 2020 to 2022 related to the Covid-19 pandemic.

Effect of ergonomic aspects on single‐ and multiproduct assembly‐line balancing problems

AbstractIncorporating ergonomic considerations into an assembly‐line balancing problem (ALBP) enhances productivity and minimizes ergonomic concerns. The assembly process, characterized by repetitive motions and handling numerous components, can lead to worker overload. Consequently, the inclusion of ergonomic aspects results in an appropriate distribution of assembly operations and relative workloads. This study investigates a multi‐objective ALBP aimed at minimizing the number of workstations, overall skill level required, and variance in workers' energy expenditure across workstations. To address the ALBP while considering the ergonomic aspects, this study proposes an approach based on the non‐dominated sorting genetic algorithm II (NSGA‐II) and multi‐objective simulated annealing (MOSA) using Pareto optimality. A comparative analysis of the NSGA‐II and MOSA is conducted in single‐ and multiproduct production scenarios, and a computational study involving various factors is performed to identify the dominant algorithm. The computational analysis indicates that the runtime performance of MOSA is 73.287% better than that of NSGA‐II; therefore, MOSA outperforms NSGA‐II. This study aims at applying scientific knowledge concerning manufacturing ergonomics to assist manufacturing industries in enhancing their productivity.

Optimization of robot manipulator configuration calibration by using Zhang neural network for repetitive motion

High precision and low complexity control algorithm plays an important role in the developing of the end-effector instrumentation of different robot manipulators. In order to reduce the kinetic energy and the high-speed drift phenomenon of the repetitive motion tracking task, the robot manipulator needs to calibrate its configuration. In this paper, we formulate the configuration calibration of the robot manipulator for the repetitive motion task as a future quadratic programming optimization problem constrained with equality constraints, which is also regarded as a fundamental problem in artificial intelligence and modern control engineering. Zhang neural network, which is a canonical method, can be adopted to deal with the continuous form of the future optimization problem, named as temporally dependent quadratic programming problem with equality constraints. In order to overcome the issue of temporally dependent inverse computing, a novel Zhang neural network model and its uncertain disturbance tolerant model, which are termed as filtered reciprocal-kind Zhang neural network model and uncertain disturbance tolerant filtered reciprocal-kind Zhang neural network model, respectively, are proposed by integrating the energy-type cost function and Zhang neural network design formula for solving the temporally dependent quadratic programming problem with equality constraints in this paper. Based on the Euler discrete formula and the models, the discrete filtered reciprocal-kind Zhang neural network and the discrete uncertain disturbance tolerant filtered reciprocal-kind Zhang neural network algorithms are proposed for solving the future quadratic programming problem with equality constraints and the robot manipulator configuration calibration problem of repetitive motion. The convergence properties of the reciprocal-kind Zhang neural network model and its corresponding uncertain disturbance tolerant model are obtained by Lyapunov stability theory of nonlinear system and its corresponding perturbed system, while the convergence property of the filtered reciprocal-kind Zhang neural network model is analyzed by the limit thinking. For the repetitive motion task, three experiments for solving the configuration calibration problem of PUMA560, Kinova Jaco2, and Franka Emika Panda robot manipulators are performed to illustrate the effectiveness, robustness and superiority of our proposed discrete filtered reciprocal-kind Zhang neural network algorithms.