Euler and Cardan angles representation in biomechanical analysis allows straightforward description of joint rotations. However, application of Euler or Cardan angles can be problematic due to a singularity called gimbal lock. Quaternions offer an alternative way to describe rotation that avoids this problem, but they are not commonly used in biomechanics as they are complex and not inherently intuitive, specifically in dynamic models actuated by muscles. This study introduces a mathematical framework for describing muscle actions in dynamic quaternion-based musculoskeletal simulations. The proposed method estimates muscle torques in a quaternion-based musculoskeletal model. Its application is shown in a three-dimensional double-pendulum system actuated by muscle elements. Furthermore, the transformation of muscle moment arms obtained from muscle paths based on Euler or Cardan angles into a quaternion-based description is presented. The proposed method is advantageous for dynamic modeling of musculoskeletal models with complex kinematics and joints with large ranges of motion like the shoulder joint.

• Klíčová slova
• Biomechanics, Moment arm, Musculoskeletal modeling, Quaternion,
• MeSH
• biologické modely * MeSH
• biomechanika MeSH
• kosterní svaly * fyziologie   MeSH
• lidé MeSH
• počítačová simulace MeSH
• ramenní kloub * fyziologie   MeSH
• rozsah kloubních pohybů fyziologie   MeSH
• svalová kontrakce * fyziologie   MeSH
• točivý moment MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Variations observed in biomechanical studies might be attributed to errors made by operators during the construction of musculoskeletal models, rather than being solely attributed to patient-specific geometry. RESEARCH QUESTION: What is the impact of operator errors on the construction of musculoskeletal models, and how does it affect the estimation of muscle moment arms and hip joint reaction forces? METHODS: Thirteen independent operators participated in defining the muscle model, while a single operator performed 13 repetitions to define the muscle model based on 3D bone geometry. For each model, the muscle moment arms relative to the hip joint center of rotation was evaluated. Additionally, the hip joint reaction force during one-legged stance was assessed using static inverse optimization. RESULTS: The results indicated high levels of consistency, as evidenced by the intra- rater and inter-rater agreement measured by the Intraclass Correlation Coefficient (ICC), which yielded values of 0.95 and 0.99, respectively. However, the estimated muscle moment arms exhibited an error of up to 16 mm compared to the reference musculoskeletal model. It was found that muscles attached to prominent anatomical landmarks were specified with greater accuracy than those attached over larger areas. Furthermore, the variability in estimated moment arms contributed to variations of up to 12% in the hip joint reaction forces. SIGNIFICANCE: Both moment arm and muscle force demonstrated significantly lower variability when assessed by a single operator, suggesting the preference for employing a single operator in the creation of musculoskeletal models for clinical biomechanical studies.

• Klíčová slova
• Hip joint, Moment arm, Musculoskeletal model, Variability,
• MeSH
• biologické modely MeSH
• biomechanika MeSH
• kosterní svaly * fyziologie   MeSH
• kyčelní kloub * fyziologie   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Musculoskeletal research questions regarding the prevention or rehabilitation of the hand can be addressed using inverse dynamics simulations when experiments are not possible. To date, no complete human hand model implemented in a holistic human body model has been fully developed. The aim of this work was to develop, implement, and validate a fully detailed hand model using the AnyBody Modelling System (AMS) (AnyBody, Aalborg, Denmark). To achieve this, a consistent multiple cadaver dataset, including all extrinsic and intrinsic muscles, served as a basis. Various obstacle methods were implemented to obtain with the correct alignment of the muscle paths together with the full range of motion of the fingers. These included tori, cylinders, and spherical ellipsoids. The origin points of the lumbrical muscles within the tendon of the flexor digitorum profundus added a unique feature to the model. Furthermore, the possibility of an entire patient-specific scaling based on the hand length and width were implemented in the model. For model validation, experimental datasets from the literature were used, which included the comparison of numerically calculated moment arms of the wrist, thumb, and index finger muscles. In general, the results displayed good comparability of the model and experimental data. However, the extrinsic muscles showed higher accordance than the intrinsic ones. Nevertheless, the results showed, that the proposed developed inverse dynamics hand model offers opportunities in a broad field of applications, where the muscles and joint forces of the forearm play a crucial role.

• Klíčová slova
• AnyBody, Musculoskeletal, hand, inverse dynamics, moment arm,
• Publikační typ
• časopisecké články MeSH

The geometrical representation of muscles in computational models of the musculoskeletal system typically consists of a series of line segments. These muscle anatomies are based on measurements from a limited number of cadaveric studies that recently have been used as atlases for creating subject-specific models from medical images, so potentially restricting the options for personalisation and assessment of muscle geometrical models. To overcome this methodological limitation, we propose a novel, completely automated technique that, from a surface geometry of a skeletal muscle and its attachment areas, can generate an arbitrary number of lines of action (fibres) composed by a user-defined number of straight-line segments. These fibres can be included in standard musculoskeletal models and used in biomechanical simulations. This methodology was applied to the surfaces of four muscles surrounding the hip joint (iliacus, psoas, gluteus maximus and gluteus medius), segmented on magnetic resonance imaging scans from a cadaveric dataset, for which highly discretised muscle representations were created and used to simulate functional tasks. The fibres' moment arms were validated against measurements and models of the same muscles from the literature with promising outcomes. The proposed approach is expected to improve the anatomical representation of skeletal muscles in personalised biomechanical models and finite element applications.

• Klíčová slova
• Line of action, Lower limb, Moment arms, Musculoskeletal geometry, Skeletal muscle,
• MeSH
• biologické modely * MeSH
• biomechanika MeSH
• kosterní svaly * diagnostické zobrazování   fyziologie   MeSH
• kyčelní kloub * diagnostické zobrazování   fyziologie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mrtvola MeSH
• počítačová rentgenová tomografie MeSH
• počítačové modelování podle konkrétního pacienta * MeSH
• senioři nad 80 let MeSH
• Check Tag
• lidé MeSH
• senioři nad 80 let MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The purpose of this article is to review the remarkable progress in the field of musculoskeletal system gene therapy. Since the introduction of this concept 15 years much of the preclinical and clinical data have emerged. The original target, rheumatoid arthritis, has been subjected to clinical phase II efficacy protocol, and osteoarthritis gene therapy efficacy is being thoroughly investigated in various animal models. The most promising area of research in this field however, is the tissue repair, because it doesn't require prolonged period of gene expression, local delivery is reasonably simple and it avoids substantial risk associated with systemic delivery, and levels of gene expression don't need to be so finely regulated. Gene transfer is successfully being used to aid the repair and regeneration of bone, cartilage, ligament tendon, meniscus and intervertebral disc. Other potential applications of gene therapy in musculoskeletal system include osteoporosis, aseptic loosening, genetic diseases and tumors. Highly encouraging data gained from these studies have confirmed that gene therapy is a promising therapeutic solution to treat various musculoskeletal system disorders.

• MeSH
• genetická terapie * MeSH
• genetické vektory MeSH
• lidé MeSH
• muskuloskeletální nemoci terapie   MeSH
• růstové látky genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• růstové látky MeSH

PURPOSE: This study aimed to identify, through a 28-week follow-up, the association between pain and engagement in different sports among adolescents. METHODS: In total, 63 adolescents reported the occurrence of pain, which was tracked weekly. Participants were categorized into 2 groups based on their sports participation: "swimming group" and "other sports group." Researchers directly measured the time spent in different intensities during sports participation for 1 week using a heart rate monitor. For the covariates, body mass, body fatness, and whole-body lean soft tissue were assessed using a dual-energy X-ray absorptiometry scanner. Kaplan-Meier plots and risk of pain were calculated for the absence of pain during the follow-up. RESULTS: The association between the sport type and pain occurrence remained significant even after adjusting the models for potential confounders, showing that swimmers had an increased risk of reporting pain in the neck (HR = 3.33; 95% CI, 1.53-7.25), shoulders (HR = 2.21; 95% CI, 1.17-4.21), and trunk (HR = 5.60; 95% CI, 2.28-13.70). CONCLUSION: The association between the sport type and pain occurrence is evident even when controlling for confounding factors.

• Klíčová slova
• epidemiology, maturity, musculoskeletal disorder, pediatrics,
• Publikační typ
• časopisecké články MeSH

Based on electromyographic data and force measurements within the shoulder joint, there is an indication that muscle and resulting joint reaction forces keep increasing over an abduction angle of 90°. In inverse dynamics models, no single parameter could be attributed to simulate this force behaviour accordingly. The aim of this work is to implement kinematic, kinetic and muscle model modifications to an existing model of the shoulder (AnyBody™) and assess their single and combined effects during abduction up to 140° humeral elevation. The kinematics and the EMG activity of 10 test subjects were measured during humeral abduction. Six modifications were implemented in the model: alternative wrapping of the virtual deltoid muscle elements, utilization of a three element Hill model, strength scaling, motion capture driven clavicle elevation/protraction, translation of the GH joint in dependency of the acting forces and an alteration of the scapula/clavicle rhythm. From the six modifications, 16 different combinations were considered. Parameter combinations with the Hill model changed the resultant GH joint reaction force and led to an increase in force during abduction of the humerus above 90°. Under the premise of muscle activities and forces within the GH joint rising after 90° of humeral abduction, we propose that the Hill type muscle model is a crucial parameter for accurately modelling the shoulder. Furthermore, the outcome of this study indicates that the Hill model induces the co-contraction of the muscles of the shoulder without the need of an additional stability criterion for an inverse dynamics approach.

• Klíčová slova
• EMG, Glenohumeral joint reaction force, Muscle model, Musculoskeletal modelling, Shoulder joint,
• MeSH
• biomechanika MeSH
• humerus MeSH
• lidé MeSH
• lopatka MeSH
• ramenní kloub * MeSH
• rameno * MeSH
• rozsah kloubních pohybů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Musculoskeletal models of the shoulder complex are valuable research aids to investigate tears of the supraspinatus and the resulting mechanical impact during abduction of the humerus. One of the major contributors to this motion is the deltoid muscle group and for this, an accurate modeling of the lines of action is indispensable. The aim of this work was to utilize a torus obstacle wrapping approach for the deltoids of an existing shoulder model and assess the feasibility of the approach during humeral abduction. The shoulder model from the AnyBody™ modeling system was used as a platform. The size of the tori is based on a magnetic resonance imaging (MRI) approach and several kinematic couplings are implemented to determine the trajectories of the tori during abduction. To assess the model behavior, the moment arms of the virtual muscle elements and the resultant glenohumeral joint reaction force (GHJF) were compared with reference data from the literature during abduction of the humerus in the range 20°-120°. The root mean square error for the anterior, lateral and posterior part between the simulated muscle elements and reference data from the literature was 3.9, 1.7 and 5.8 mm, respectively. The largest deviation occurred on the outer elements of the muscle groups, with 12.6, 10.4 and 20.5 mm, respectively. During abduction, there is no overlapping of the muscle elements and these are in continuous contact with the torus obstacles, thus enabling a continuous force transmission. This results in a rising trend of the resultant GHJF. The torus obstacle approach as a wrapping method for the deltoid muscles provides a guided muscle pathing by simultaneously approximating the curvature of the deltoid muscle. The results from the comparison of the simulated moment arms and the resultant GHJF are in accordance with those in the literature in the range 20°-120° of abduction. Although this study shows the strength of the torus obstacle as a wrapping approach, the method of fitting the tori according to MRI data was not suitable. A cadaver study is recommended to better validate and mathematically describe the torus approach.

• Klíčová slova
• AnyBody Modeling System, MRI, Muscle trajectory, Muscoloskeletal model, Shoulder joint complex, Torus, Wrapping,
• MeSH
• biomechanika MeSH
• humerus MeSH
• musculus deltoideus * MeSH
• ramenní kloub * MeSH
• rotátorová manžeta MeSH
• rozsah kloubních pohybů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: The European Union (EU) strategy for health and safety at work underlines the need to reduce the incidence of occupational diseases (OD), but European statistics to evaluate this common goal are scarce. We aim to estimate and compare changes in incidence over time for occupational asthma, contact dermatitis, noise-induced hearing loss (NIHL), carpal tunnel syndrome (CTS) and upper limb musculoskeletal disorders across 10 European countries. METHODS: OD surveillance systems that potentially reflected nationally representative trends in incidence within Belgium, the Czech Republic, Finland, France, Italy, the Netherlands, Norway, Spain, Switzerland and the UK provided data. Case counts were analysed using a negative binomial regression model with year as the main covariate. Many systems collected data from networks of 'centres', requiring the use of a multilevel negative binomial model. Some models made allowance for changes in compensation or reporting rules. RESULTS: Reports of contact dermatitis and asthma, conditions with shorter time between exposure to causal substances and OD, were consistently declining with only a few exceptions. For OD with physical causal exposures there was more variation between countries. Reported NIHL was increasing in Belgium, Spain, Switzerland and the Netherlands and decreasing elsewhere. Trends in CTS and upper limb musculoskeletal disorders varied widely within and between countries. CONCLUSIONS: This is the first direct comparison of trends in OD within Europe and is consistent with a positive impact of European initiatives addressing exposures relevant to asthma and contact dermatitis. Taking a more flexible approach allowed comparisons of surveillance data between and within countries without harmonisation of data collection methods.

• MeSH
• horní končetina MeSH
• incidence MeSH
• kontaktní dermatitida epidemiologie   MeSH
• lidé MeSH
• muskuloskeletální nemoci epidemiologie   MeSH
• nedoslýchavost z hluku epidemiologie   MeSH
• nemoci z povolání epidemiologie   MeSH
• profesionální astma epidemiologie   MeSH
• rizikové faktory MeSH
• sběr dat metody   MeSH
• surveillance populace MeSH
• syndrom karpálního tunelu epidemiologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa epidemiologie   MeSH

Three-dimensional (3D) sonography is the next logical step in diagnostic ultrasound examination. The true value of 3D ultrasonography, however, becomes evident only if 3D structures can be assessed without preconceptions ensuing from 2D interpretations. 3D ultrasonography can greatly improve our understanding of locomotor apparatus anatomy and pathology. The authors used spatial analysis to evaluate the data obtained by examination of patients with orthopedic diagnoses. The Voluson 530 MT and SONOReal system were used for examination. The Voluson permits a choice of either a 2D or a 3D imaging program for musculoskeletal system examination. The SONOReal, owing to a positional sensor of the probe, can be attached to any ultrasound transducer. In the period from 1990 to 2004, a total of 19 000 patients were examined by ultrasonography and, in 6 500 of them, the diagnosis was verified by another method, which showed a 99 % reliability of ultrasound examination. In 350 patients 2D imaging was followed by 3D examination; in 53 of them, 3D coronal and multiplanar imaging made the diagnosis based on 2D imaging more accurate and, in 12 patients, it provided new information on the patient's diagnosis. 3D reconstructions were made in 101 patients, of these 40 had been examined by other imaging methods (magnetic resonance, computer-assisted tomography) or arthroscopy. The results of examination showed a 100% correlation. Spatial reconstruction is based on the volume rendering method. This is an extension of the planar reconstruction method. Additional image processing techniques are used for a region of interest within a 3D volume data set. 3D ultrasound revealed a spatial relationship between lesions and their surfaces. The surface mode requires that the interface between tissues with different acoustic impedances should be a start line of 3D rendering. The acoustic threshold is a condition that restricts imaging circumstances in which surface rendering will be successful. Exploring 3D reconstructions with power Doppler scanning, which is more sensitive for tracking vessels, is a unique technique that can hardly be compared with any other imaging modality. 3D-volume imaging gives the examiner freedom to generate anatomical views from an infinite number of perspectives and allows us to explore anatomic relationships in the ways not available in any conventional 2D imaging. A spatial reconstruction presents a nearly perfect anatomical model. The possibility of storing volume data is considered a further progressive trend. It greatly contributes to enhancement of the scope of follow-up examinations, permits comparisons of expert conclusions and can serve educational purposes. The digital technology offers various networking solutions and plays a role in the development of 3D telemedicine. Although the diagnostic efficacy of 3D imaging is not greatly enhanced when compared with a 2D examination done by a well-trained specialist, the features of coronary sections and spatial reconstructions represent great progress of this imaging technology.

• MeSH
• lidé MeSH
• muskuloskeletální systém diagnostické zobrazování   MeSH
• počítačové zpracování obrazu MeSH
• ultrasonografie MeSH
• zobrazování trojrozměrné * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH