TY - CHAP A1 - Jungtäubl, Dominik A1 - Aurbach, Maximilian A1 - Melzner, Maximilian A1 - Spicka, Jan A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - EMG-Based Validation of Musculoskeletal Models Considering Crosstalk T2 - International Conference BIOMDLORE, June 28 - 30 2018, Białystok, Poland N2 - BACKGROUND: Validation and verification of multibody musculoskeletal models sEMG is a difficult process because of the reliability of sEMG data and the complex relationship of muscle force and sEMG. OBJECTIVE: This work aims at comparing experimentally recorded and simulated muscle activities considering a numerical model for crosstalk. METHODS: For providing an experimentally derived reference data set, subjects were performing elevations of the arm, where the activities of the contemplated muscle groups were measured by sEMG sensors. Computed muscle activities were further processed and transformed into an artificial electromyographical signal, which includes a numerical crosstalk model. In order to determine whether the crosstalk model provides a better agreement with the measured muscle activities, the Pearson correlation coefficient has been computed as a qualitative way of assessing the curve progression of the data sets. RESULTS: The results show an improvement in the correlation coefficient between the experimental data and the simulated muscle activities when taking crosstalk into account. CONCLUSIONS: Although the correlation coefficient increased when the crosstalk model was utilized, it is questionable if the discretization of both, the crosstalk and the musculoskeletal model, is accurate enough. KW - musculoskeletal modeling KW - validation KW - surface electromyography KW - crosstalk Y1 - 2018 U6 - https://doi.org/10.1109/BIOMDLORE.2018.8467211 ER - TY - GEN A1 - Melzner, Maximilian A1 - Ismail, Khaled A1 - Rušavý, Zdeněk A1 - Kališ, Vladimír A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Musculoskeletal Lower Back Load of Accoucheurs During Delivery T2 - 26th Congress of the European Society of Biomechanics, July 11-14, 2021, Milan, Italy N2 - With the progress in modern medicine, it was possible to significantly reduce the risks of birth for mother and child. One aspect that has received less attention so far is the risk of injury to the accoucheurs (obstetricians and midwives) during the birth process. Indeed, studies indicate that 92% of midwives suffer from musculoskeletal disorders, with the lower back being the main cause of complaints (72%). The aim of this study was to investigate two commonly used postural techniques used by accoucheurs during childbirth and to analyze the resulting load on the lower back using the AnyBodyTM musculoskeletal simulation software. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-20208 CY - Milan ER - TY - VIDEO A1 - Melzner, Maximilian A1 - Engelhardt, Lucas T1 - AnyBody Webcast - A new musculoskeletal AnyBody™ detailed hand model Y1 - 2020 UR - https://www.youtube.com/watch?v=E4xnbjRJYm8&t=631s ER - TY - GEN A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Biomechanik und muskuloskeletale Simulation T2 - Jahreskongress des ISPO Deutschland e.V., 2./3. Juni 2022, Hedelberg Y1 - 2022 ER - TY - GEN A1 - Melzner, Maximilian A1 - Pfeifer, Christian A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Muskuloskeletal analysis of elbow stability for common injury patterns T2 - 27th Congress of the European Society of Biomechanics, 26 - 29 June 2022, Porto, Portugal Y1 - 2022 UR - https://drive.google.com/uc?id=1RBguxyHZE-Wr2y6ktOWK06_3lQg2M9Rb&export=download&confirm=t SP - 654 ER - TY - GEN A1 - Melzner, Maximilian A1 - Pfeifer, Christian A1 - Alt, V. A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Änderung der Gelenkreaktionskraft bei Schädigung des medialen Bandapparates im Ellenbogen T2 - Zeitschrift fur Orthopadie und Unfallchirurgie KW - Muskuloskelettale Simulation KW - Ellenbogenstabilität Y1 - 2020 U6 - https://doi.org/10.1055/s-0040-1717270 N1 - Poster VL - 158 IS - S01 PB - Thieme ER - TY - CHAP A1 - Melzner, Maximilian A1 - Engelhardt, Lucas A1 - Havelkova, Leonard A1 - Simon, Ulrich A1 - Dendorfer, Sebastian T1 - A new musculoskeletal AnyBody detailed hand model validated by electromyography T2 - 16th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering (CMBBE) 2019, New York City, USA N2 - The AnyBody™ Modeling System (AMS) [1], is an universally used musculoskeletal simulation software using inverse dynamics. Until now, no complete human hand model is known in the AMS. Also considering other musculoskeletal software platforms, just one detailed entire hand model is recently published [2] but is only based on one subject. The aim of this work is to implement a full detailed hand model for the AMS including all extrinsic and intrinsic muscles using data by the UWB gained through an anatomical study of ten cadaver hands. Y1 - 2019 UR - https://www.researchgate.net/publication/336944957_A_NEW_MUSCULOSKELETAL_ANYBODY_DETAILED_HAND_MODEL_VALIDATED_BY_ELECTROMYOGRAPHY ER - TY - GEN A1 - Melzner, Maximilian A1 - Engelhardt, Leonard A1 - Süß, Friedrich A1 - Dendorfer, Sebastian T1 - Sensitivity evaluation of a musculoskeletal hand model using Latin hypercube sampling T2 - ESMAC 2020 Abstracts Y1 - 2020 U6 - https://doi.org/10.1016/j.gaitpost.2020.08.008 VL - 81 IS - Suppl. 1 PB - Elsevier ER - TY - GEN A1 - Engelhardt, Lucas A1 - Melzner, Maximilian A1 - Havelkova, Linda A1 - Fiala, Pavel A1 - Rybarova, Martina A1 - Christen, Patrik A1 - Dendorfer, Sebastian A1 - Simon, Ulrich T1 - A new musculoskeletal AnyBody detailed hand model T2 - European Society of Biomechanics meeting 2019, Vienna, Austria N2 - The AnyBody™ Modeling System (AMS) [1], is an universally used musculoskeletal simulation software using inverse dynamics. Until now, no complete human hand model is known in the AMS. Also considering other musculoskeletal software platforms, just one detailed entire hand model is recently published [2] but is only based on one subject. The aim of this work is to implement a full detailed hand model for the AMS including all extrinsic and intrinsic muscles using data by the UWB gained through an anatomical study of ten cadaver hands. Y1 - 2019 UR - https://owncloud.tuwien.ac.at/index.php/s/dovqqcj02VeZHze ER - TY - GEN A1 - Suess, Franz A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Towards Ergonomic working - machine learning algorithms and musculoskeletal modeling T2 - RIM 2021, 13th International Scientific Conference on Manufacturing Engineering, 29 Sept. - 1 Oct 2021, Sarajevo, Bosnia and Herzegovina Y1 - 2021 ER - TY - JOUR A1 - Dendorfer, Sebastian A1 - Melzner, Maximilian T1 - Rückenschmerzen bei Geburtshelfer:innen. Die Haltung macht's. JF - Deutsche Hebammen-Zeitschrift N2 - Für Mutter und Kind konnte das Risiko der Geburt durch die Weiterentwicklung der Medizin drastisch reduziert werden. Doch wie ist es um das Wohl derer bestellt, die die Gebärende unterstützen? Eine Studie der Ostbayerischen Technischen Hochschule Regensburg hat sich mit den muskuloskelettalen Beschwerden von Geburtshelfer:innen auseinandergesetzt Y1 - 2022 UR - https://ip.staudeverlag.de/de/profiles/c3962f735915-elwin-staude-verlag-kiosk-bc/editions/dhz-11-2022/pages/page/32 SN - 0012-026X VL - 74 IS - 11 SP - 60 EP - 62 PB - Staude CY - Hannover ER - TY - JOUR A1 - Melzner, Maximilian A1 - Ismail, Khaled A1 - Rušavy, Zdenek A1 - Kališ, Vladimír A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Musculoskeletal lower back load of accoucheurs during childbirth – A pilot and feasibility study JF - European Journal of Obstetrics & Gynecology and Reproductive Biology N2 - Introduction: Back problems represent one of the leading causes of accouchers' work-related musculoskeletal morbidities. The correct execution of birth-related maneuvers including manual perineal protection is crucial not only for the mother and child but also for obstetricians and midwives to reduce any strain on their musculoskeletal system. Therefore, the overall aim of this study was to test the feasibility of determining the effect of different accouchers' postures (standing and kneeling) on their musculoskeletal system. Methods: The biomechanical analysis is based on musculoskeletal simulations that included motion recordings of real deliveries as well as deliveries conducted on a birthing simulator. These simulations were then used to determine individual joints' loads. Results: In the kneeling posture, both a low intra-operator variability and a lower average maximum load of the lower back was observed. For the standing position the spine load was reduced by pivoting the elbow on the accouchers' thigh, which in turn was associated with a significantly greater load on the shoulder joint. Conclusion: The study demonstrated the feasibility of our technique to assess joints loads. It also provided initial data indicating that a posture that reduces spinal flexion and tilt, achieved in this study by the kneeling, can significantly reduce the strain on the practitioner's musculoskeletal system. KW - lower back load KW - Accoucheur KW - Musculoskeletal simulation Y1 - 2021 U6 - https://doi.org/10.1016/j.ejogrb.2021.07.042 IS - 264 SP - 306 EP - 313 PB - Elsevier ER - TY - JOUR A1 - Engelhardt, Lucas A1 - Melzner, Maximilian A1 - Havelkova, Linda A1 - Fiala, Pavel A1 - Christen, Patrik A1 - Dendorfer, Sebastian A1 - Simon, Ulrich T1 - A new musculoskeletal AnyBodyTM detailed hand model JF - Computer Methods in Biomechanics and Biomedical Engineering N2 - 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. KW - Musculoskeletal KW - hand KW - AnyBody KW - inverse dynamics KW - moment arm Y1 - 2020 U6 - https://doi.org/10.1080/10255842.2020.1851367 VL - 24 IS - 7 SP - 777 EP - 787 PB - Taylor & Francis ER - TY - GEN A1 - Saffert, Anne-Sophia A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Biomechanical Analysis of the Right Elevated Glenohumeral Joint in Violinists during Legato-Playing T2 - Biomdlore 2021: 21-23 October 2021 Vilnius/Trakai, Lithuania N2 - BACKGROUND: Many statistics reveal that violin players suffer most often from musculoskeletal disorders compared to musicians of other instrument groups. A common phenomenon, especially observed in violin beginners, is the tendency to elevate the right shoulder during playing the violin. This can probably lead to serious disorders in long-term practice with repetitive movements. OBJECTIVE: For this reason, this study investigated the relationship between the right shoulder elevation and the force in the right glenohumeral joint during violin playing. It was hypothesized that the forces in the right glenohumeral joint are higher during playing with the right shoulder raised compared to playing in normal posture. METHODS: Motion capture data from four experienced violinists was recorded and processed by means of musculoskeletal simulation to get the force and elevation angle while playing with raised shoulder and in normal position. RESULTS: The results indicate that the absolute values of the resulting force, as well as the forces in the mediolateral, inferosuperior, and anteroposterior directions, are higher in playing the violin with the shoulder raised than in a normal posture. CONCLUSIONS: Elevating the right shoulder while playing the violin may pose a potential problem. Y1 - 2021 U6 - https://doi.org/10.3233/THC-219001 N1 - Veröffentlicht in: Technology and Health Care, vol. 30, no. 1 (Selected Papers From the 13th International Conference BIOMDLORE 2021), pp. 177-186, 2022 ER - TY - JOUR A1 - Melzner, Maximilian A1 - Suess, Franz A1 - Dendorfer, Sebastian T1 - The impact of anatomical uncertainties on the predictions of a musculoskeletal hand model – a sensitivity study JF - Computer Methods in Biomechanics and Biomedical Engineering N2 - Outputs of musculoskeletal models should be considered probabilistic rather than deterministic as they are affected by inaccuracies and estimations associated with the development of the model. One of these uncertainties being critical for modeling arises from the determination of the muscles' line of action and the physiological cross-sectional area. Therefore, the aim of this study was to evaluate the outcome sensitivity of model predictions from a musculoskeletal hand model in comparison to the uncertainty of these input parameters. For this purpose, the kinematics and muscle activities of different hand movements (abduction of the fingers, abduction of the thumb, and flexion of the thumb) were recorded. One thousand simulations were calculated for each movement using the Latin hypercube sampling method with a corresponding variation of the muscle origin/insertion points and the cross-sectional area. Comparing the standard hand to simulations incorporating uncertainties of input parameters shows no major deviations in on- and off-set time point of muscle activities. About 60% of simulations are located within a ± 30% interval around the standard model concerning joint reaction forces. The comparison with the variation of the input data leads to the conclusion that the standard hand model is able to provide not over-scattered outcomes and, therefore, can be considered relatively stable. These results are of practical importance to the personalization of a musculoskeletal model with subject-specific bone geometries and hence changed muscle line of action. KW - Biomechanik KW - Simulation Y1 - 2021 U6 - https://doi.org/10.1080/10255842.2021.1940974 SN - 1476-8259 N1 - Corresponding author: Maximilian Melzner VL - 25 IS - 2 SP - 156 EP - 164 PB - Taylor & Francis ER - TY - JOUR A1 - Melzner, Maximilian A1 - Pfeiffer, Christian A1 - Suess, Franz A1 - Dendorfer, Sebastian T1 - Musculoskeletal simulation of elbow stability for common injury patterns JF - Journal of Orthopaedic Research N2 - Elbow stability is derived from a combination of muscular, ligamentous, and bony structures. After an elbow trauma the stability of the joint is an important decision criterion for the subsequent treatment. The decision regarding non-operative/operative care depends mostly on subjective assessments of medical experts. Therefore, the aim of this study is to use musculoskeletal simulations as an objective assessment tool to investigate the extent to which failure of different stabilizers affects the elbow stability and how these observations correspond to the assessment from clinical practice. A musculoskeletal elbow simulation model was developed for this aim. To investigate the stability of the elbow, varus/valgus moments were applied under 0°, 45°and 90° flexion while the respective cubital angle was analyzed. This was performed for nine different injury scenarios, which were also evaluated for stability by clinical experts. With the results, it can be determined by which injury pattern and under which flexion angle the elbow stability is impaired regarding varus/valgus moments. The scenario with a complete failure of the medial and lateral ligaments and a fracture of the radial head was identified as having the greatest instability. The study presented a numerical determination of elbow stability against varus/valgus moments regarding clinical injury patterns, as well as a comparison of the numerical outcome with experience gained in clinical practice. The numerical predictions agree well with the assessments of the clinical specialists. Thus, the results from musculoskeletal simulation can make an important contribution to a more objective assessment of the elbow stability. KW - AnyBody KW - musculoskeletal simulation KW - elbow stability Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-54819 SN - 1554-527X N1 - Corresponding author: Maximilian Melzner VL - 41 IS - 6 SP - 1356 EP - 1364 PB - Wiley ER - TY - JOUR A1 - Melzner, Maximilian A1 - Engelhardt, Lucas A1 - Simon, Ulrich A1 - Dendorfer, Sebastian T1 - Electromyography-Based Validation of a Musculoskeletal Hand Model JF - Journal of Biomechanical Engineering N2 - Regarding the prevention of injuries and rehabilitation of the human hand, musculoskeletal simulations using an inverse dynamics approach allow for insights of the muscle recruitment and thus acting forces on the hand. Currently, several hand models from various research groups are in use, which are mainly validated by the comparison of numerical and anatomical moment arms. In contrast to this validation and model-building technique by cadaver studies, the aim of this study is to further validate a recently published hand model [1] by analyzing numerically calculated muscle activities in comparison to experimentally measured electromyographical signals of the muscles. Therefore, the electromyographical signals of 10 hand muscles of five test subjects performing seven different hand movements were measured. The kinematics of these tasks were used as input for the hand model, and the numerical muscle activities were computed. To analyze the relationship between simulated and measured activities, the time difference of the muscle on- and off-set points was calculated, which resulted in a mean on- and off-set time difference of 0.58 s between the experimental data and the model. The largest differences were detected for movements that mainly addressed the wrist. One major issue comparing simulated and measured muscle activities of the hand is cross-talk. Nevertheless, the results show that the hand model fits the experiment quite accurately despite some limitations and is a further step toward patient-specific modeling of the upper extremity. KW - Elektromyographie KW - Biomechanik KW - Simulation KW - Electromyography KW - Muscle KW - Musculoskeletal system KW - Signals KW - Simulation Y1 - 2021 U6 - https://doi.org/10.1115/1.4052115 VL - 144 IS - 2 PB - American Society of Mechanical Engineers, ASME ER - TY - JOUR A1 - Saffert, Anne-Sophie A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Biomechanical analysis of the right elevated glenohumeral joint in violinists during legato-playing JF - Technology and Health Care N2 - BACKGROUND: Many statistics reveal that violin players suffer most often from musculoskeletal disorders compared to musicians of other instrument groups. A common phenomenon, especially observed in violin beginners, is the tendency to elevate the right shoulder during playing the violin. This can probably lead to serious disorders in long-term practice with repetitive movements. OBJECTIVE: For this reason, this study investigated the relationship between the right shoulder elevation and the force in the right glenohumeral joint during violin playing. It was hypothesized that the forces in the right glenohumeral joint are higher during playing with the right shoulder raised compared to playing in normal posture. METHODS: Motion capture data from four experienced violinists was recorded and processed by means of musculoskeletal simulation to get the force and elevation angle while playing with raised shoulder and in normal position. RESULTS: The results indicate that the absolute values of the resulting force, as well as the forces in the mediolateral, inferosuperior, and anteroposterior directions, are higher in playing the violin with the shoulder raised than in a normal posture. CONCLUSIONS: Elevating the right shoulder while playing the violin may pose a potential problem. KW - Biomechanische Analyse KW - Schultergelenk KW - Verletzung KW - Violinspiel KW - biomechanics KW - violin KW - shoulder elevation KW - shoulder joint force KW - musculoskeletal disease Y1 - 2022 U6 - https://doi.org/10.3233/THC-219001 N1 - Corresponding author: Anne-Sophie Saffert VL - 30 IS - 1 SP - 177 EP - 186 PB - IOS Press ER - TY - CHAP A1 - Suess, Franz A1 - Melzner, Maximilian A1 - Dendorfer, Sebastian T1 - Towards ergonomics working - machine learning algorithms and musculoskeletal modeling T2 - IOP Conference Series: Materials Science and Engineering N2 - Ergonomic workplaces lead to fewer work-related musculoskeletal disorders and thus fewer sick days. There are various guidelines to help avoid harmful situations. However, these recommendations are often rather crude and often neglect the complex interaction of biomechanical loading and psychological stress. This study investigates whether machine learning algorithms can be used to predict mechanical and stress-related muscle activity for a standardized motion. For this purpose, experimental data were collected for trunk movement with and without additional psychological stress. Two different algorithms (XGBoost and TensorFlow) were used to model the experimental data. XGBoost in particular predicted the results very well. By combining it with musculoskeletal models, the method shown here can be used for workplace analysis but also for the development of real-time feedback systems in real workplace environments. Y1 - 2021 U6 - https://doi.org/10.1088/1757-899X/1208/1/012001 SN - 1757-899X N1 - Corresponding author: Sebastian Dendorfer VL - 1208 PB - IOP Publishing ER -