TY - JOUR A1 - Auer, Simon A1 - Schiebl, Jonas A1 - Iversen, Kristoffer A1 - Subhash Chander, Divyaksh A1 - Damsgaard, Michael A1 - Dendorfer, Sebastian T1 - Biomechanical assessment of the design and efficiency of occupational exoskeletons with the AnyBody Modeling System JF - Zeitschrift für Arbeitswissenschaften N2 - Exoskeletons were invented over 100 years ago but have only become popular in the last two decades, especially in the working industry as they can decrease work-related loads significantly. The most often used exoskeletons are for the lower back and shoulder since these are commonly affected body regions. All devices have in common that their purpose is to reduce internal loads of vulnerable body regions. Nevertheless, there is still little understanding on how biomechanical loading in the human body changes when exoskeletons are used. Therefore, further analyses are needed. A promising candidate for these are musculoskeletal models, which are based on an inverse dynamics approach and can calculate external parameters such as ground reaction forces or other interaction forces as well as internal parameters such as joint reaction forces or muscle activities. The various examples in the literature show that these models are increasingly used for assessing the biomechanical effects of exoskeletons on the human body. Furthermore, musculoskeletal models can calculate biomechanical loadings of humans with and without exoskeletons for all kinds of applications and allow an evaluation of their purpose. Practical Relevance: This article highlights the possibilities of musculoskeletal models for assessing the design and efficiency of occupational exoskeletons. Several practical use cases are described along with distinct descriptions of common implications of musculoskeletal and exoskeleton modeling. KW - Biomechanics KW - Ergonomics KW - Motion capture KW - Inverse dynamics Y1 - 2022 U6 - https://doi.org/10.1007/s41449-022-00336-4 N1 - Corresponding author: Sebastian Dendorfer VL - 76 IS - 4 SP - 440 EP - 449 PB - Springer Nature ER - TY - GEN A1 - Auer, Simon A1 - Niebler, Michael A1 - Eiglsperger, Josef A1 - Kubowitsch, Simone A1 - Renkawitz, Tobias A1 - Achenbach, Leonard A1 - Krutsch, Werner A1 - Dendorfer, Sebastian T1 - Cognitive stress increases muscle forces in dynamic football specific movements T2 - European Society of Biomechanics meeting 2019, Vienna, Austria Y1 - 2019 UR - https://owncloud.tuwien.ac.at/index.php/s/dovqqcj02VeZHze ER - TY - GEN A1 - Auer, Simon A1 - Reinker, Lukas A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Comparing calculated and measured muscle activity of thigh muscles in dynamic motion. 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 - 640 ER - TY - JOUR A1 - Morag, Sarah A1 - Kieninger, Martin A1 - Eissnert, Christoph A1 - Auer, Simon A1 - Dendorfer, Sebastian A1 - Popp, Daniel A1 - Hoffmann, Johannes A1 - Kieninger, Bärbel T1 - Comparison of different techniques for prehospital cervical spine immobilization: Biomechanical measurements with a wireless motion capture system JF - PLOS ONE Y1 - 2023 U6 - https://doi.org/10.1371/journal.pone.0292300 VL - 18 IS - 11 SP - 1 EP - 14 PB - PLOS CY - San Francisco, California ER - TY - CHAP A1 - Auer, Simon A1 - Kubowitsch, Simone A1 - Krutsch, Werner A1 - Renkawitz, Tobias A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Effect of mental demand on knee forces in professional youth soccer players T2 - ISBS Proceedings Archive N2 - Soccer is one of the most popular sports all around the world. It is an injurious type of sport with a focus on lower extremities and high psychological pressure during matches. The stressor is linked with injuries and an increased musculoskeletal loading. This study investigates the influence of cognitive stress on the load profile of the knee joint. Twelve professional youth soccer players performed highly dynamic runs with and without additional cognitive stress. The runs were analysed with a musculoskeletal simulation software. The data analysis shows no difference in knee joint reaction loading under additional mental stress compared to the baseline. Yet running times are significantly lower in the baseline. While there is no increase in the joint loads, the running times indicate an altered movement behaviour when the subjects are exposed to additional mental demand. KW - Kniegelenk KW - Körperliche Belastung KW - Stress KW - Computersimulation Y1 - 2020 UR - https://commons.nmu.edu/isbs/vol38/iss1/28 VL - 38 IS - 1, Art. 28 ER - TY - GEN A1 - Auer, Simon A1 - Krutsch, Werner A1 - Renkawitz, Tobias A1 - Kubowitsch, Simone A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Effect of mental demand on leg loading in highly dynamic motion T2 - AnyBody online Webinar, Oct 2020 N2 - Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury. Y1 - 2020 ER - TY - GEN A1 - Auer, Simon A1 - Reinker, Lukas A1 - Dendorfer, Sebastian T1 - Evaluation of muscle recruitment and muscle models in musculoskeletal simulation of dynamic motion T2 - 26th Congress of the European Society of Biomechanics, July 11-14, 2021, Milan, Italy N2 - Musculoskeletal simulation plays an increasingly important role in sports biomechanics. In the last years, the field of application widened from orthopaedics and ergonomics to sports [1]. A muscle recruitment algorithm with a quadratic objective function is usually used to calculate muscle activity in dynamic movements. The agreement of calculated and measured thigh muscle activity has already been investigated [2]. They found a strong agreement for sprinting and running, while the correlation decreased for side-cutting manoeuvres. Nevertheless, the influence of different muscle recruitment criteria on muscle activity in dynamic musculoskeletal simulations is currently unknown. Hence, this study aimed to analyse the effect of different muscle recruitment criteria and muscle models on the correlation of numerical and measured muscle activity in highly dynamic movements. KW - esb KW - biomechanics KW - muscle recruitment Y1 - 2021 UR - https://esbiomech.org/conference/archive/2021milan/Contribution_1719.pdf CY - Milan ER - TY - JOUR A1 - Auer, Simon A1 - Krutsch, Werner A1 - Renkawitz, Tobias A1 - Kubowitsch, Simone A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Kognitiver Stress führt zu unphysiologisch erhöhten Kniebelastungen im Profifußball JF - Sports Orthopaedics and Traumatology Y1 - 2020 U6 - https://doi.org/10.1016/j.orthtr.2020.04.122 VL - 36 IS - 2 SP - 202 EP - 203 PB - Elsevier ER - TY - JOUR A1 - Auer, Simon A1 - Kubowitsch, Simone A1 - Dendorfer, Sebastian T1 - Kombinierter Einfluss von psychologischen und biomechanischen Faktoren auf die muskulären Belastungen beim Fußballspielen JF - Die Orthopädie N2 - When mental stress and musculoskeletal loading interact, the risk for injury increases due to altered body kinematics and increased muscle tension. These changes can be detected with musculoskeletal models, and mental loading and stress must be analyzed at emotional, cognitive, and behavioral levels. To investigate these kinematic and loading changes under stress, competitive athletes were subjected to mental stress during highly dynamic movements, and musculoskeletal models were used to analyze the biomechanical loading. It was shown that under mental stress, independent of the subjective perception, a strong change in muscle forces can occur. Accordingly, competitive athletes should undergo screenings to assess individual movement patterns and promote general stress resilience. N2 - Für Fußballer:innen stellen muskuläre Verletzungen der unteren Extremitäten ein großes Problem dar. Ein Beispiel hierfür liefert die Nationalmannschaftsstürmerin Alexandra Popp, die aufgrund muskulärer Probleme das EM-Finale 2022 in Wembley kurzfristig verpasste. Oftmals stehen gerade hohe Anspannungssituationen in zeitlichem Zusammenhang mit Verletzungen, der Einfluss der psychischen Beanspruchung auf die biomechanischen Belastungen wird jedoch meist nur wenig beachtet. KW - Biologische Modelle KW - Biomechanik KW - Leistungssportler KW - Bewegung KW - Resilienz, psychologische KW - Biological models KW - Biomechanics KW - Elite athletes KW - Movement KW - Resilience, psychological Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-65113 N1 - Corresponding author: Sebastian Dendorfer VL - 52 IS - 11 SP - 1 EP - 6 PB - Springer ER - TY - JOUR A1 - Auer, Simon A1 - Kurbowitsch, Simone A1 - Süß, Franz A1 - Renkawitz, Tobias A1 - Krutsch, Werner A1 - Dendorfer, Sebastian T1 - Mental stress reduces performance and changes musculoskeletal loading in football-related movements JF - Science and Medicine in Football N2 - Purpose: Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Hence, this study investigated the musculoskeletal response of elite youth football players during highly dynamic movements under stress. The hypothesis is that mental stress reduces performance and changes the muscular forces exerted. Materials & methods: Twelve elite youth football players were subjected to mental stress while performing sports-specific change-of-direction movements. A modified version of the d2 attention test was used as stressor. The kinetics are computed using inverse dynamics. Running times and exerted forces of injury-prone muscles were analysed. Results: The stressor runs were rated more mentally demanding by the players (p = 0.006, rs = 0.37) with unchanged physical demand (p = 0.777, rs = 0.45). This resulted in 10% longer running times under stress (p < 0.001, d = −1.62). The musculoskeletal analysis revealed higher peak muscle forces under mental stress for some players but not for others. Discussion: The study shows that motion capture combined with musculoskeletal computation is suitable to analyse the effects of stress on athletes in highly dynamic movements. For the first time in football medicine, our data quantifies an association between mental stress with reduced football players’ performance and changes in muscle force. KW - Biomechanics KW - muscle injury KW - attention KW - musculoskeletal simulation Y1 - 2020 U6 - https://doi.org/10.1080/24733938.2020.1860253 VL - 5 IS - 4 SP - 323 EP - 329 PB - Taylor & Francis ER - TY - THES A1 - Auer, Simon T1 - Musculoskeletal models in highly dynamic motion: effects of model parameters and mental stress N2 - The analysis and understanding of highly dynamic movements is a fundamental part of biomechanics. Since sports injuries often involve the lower extremities and muscles, musculoskeletal models can help to prevent them. These models allow the calculation of ground and joint reaction forces as well as muscle forces and activities for individual muscle strands. One goal of this work is to use musculoskeletal models to investigate the influence of mental stress on lower extremity loading. Moreover, the models themselves are evaluated for highly dynamic movements and practical recommendations for action will be derived. For this purpose, fast movements of youth competitive and amateur athletes will be recorded using different measurement systems. Subsequently, the models calculate the target parameters using inverse dynamics. Furthermore, measured and calculated muscle activities of the lower extremities are compared and artificial balancing forces (residuals) in the models are analyzed and minimization approaches are presented. The investigation of muscle and joint loading under mental stress has shown that the response to mental stress is highly individual. Athletes may experience a significant increase in muscle and knee forces with a simultaneous decrease in performance. The comparison of measured and calculated muscle activity proved the reliability of the models also for highly dynamic movements. With the frequently used default settings in the model and optical and inertial motion capture, the muscle activities in the model could be calculated reliably. The residual forces were highest, when the model transitioned from foot-ground contact to no contact and vice versa. By adjusting the settings of the kinematic filter and the ground reaction force prediction, the residuals were reduced by up to 54%. The analysis of musculoskeletal loading under mental stress has shown that the models can make a valuable contribution to the biomechanical analysis of highly dynamic movements. Subsequently, the models have also proven to be a reliable tool for the analysis of highly dynamic movements when the calculated parameters as well as the model-specific optimization options are reviewed. With this in mind, these models can contribute to further understand highly dynamic movements and prevent muscle injuries in athletes. N2 - Die Analyse und das Verständnis hochdynamischer Bewegungen ist ein fundamentaler Bestandteil der Biomechanik. Da Sportverletzungen häufig die unteren Extremitäten und Muskeln betreffen, können muskuloskelettale Modelle dazu beitragen, sie zu vermeiden. Diese Modelle ermöglichen die Berechnung von Boden- und Gelenkreaktionskräften sowie von Muskelkräften und -aktivitäten für einzelne Muskelstränge. Ein Ziel dieser Arbeit ist es, mit Hilfe von muskuloskelettalen Modellen den Einfluss von mentalen Belastungen auf die Belastung der unteren Extremitäten zu untersuchen. Darüber hinaus werden die Modelle selbst für hochdynamische Bewegungen evaluiert und praktische Handlungsempfehlungen abgeleitet. Zu diesem Zweck werden schnelle Bewegungen von jugendlichen Leistungs- und Freizeitsportlern mit verschiedenen Messsystemen aufgezeichnet. Anschließend berechnen die Modelle mittels inverser Dynamik die Zielparameter. Weiterhin werden gemessene und berechnete Muskelaktivitäten der unteren Extremitäten verglichen sowie künstliche Ausgleichskräfte (Residuen) in den Modellen analysiert und Minimierungsansätze vorgestellt. Die Untersuchung der Muskel- und Gelenkbelastung unter mentalem Stress hat gezeigt, dass die Reaktion auf mentalen Stress sehr individuell ist. Bei einzelnen Personen kann es zu einem deutlichen Anstieg der Muskel- und Kniegelenkreaktionskräfte bei gleichzeitiger Leistungsminderung kommen. Der Vergleich von gemessener und berechneter Muskelaktivität beweist die Zuverlässigkeit der Modelle auch bei hochdynamischen Bewegungen. Mit den häufig verwendeten Standardeinstellungen im Modell und der vielseitigen Bewegungserfassung konnten die Muskelaktivitäten im Modell zuverlässig berechnet werden. Die Residualkräfte waren am höchsten, wenn das Modell von Fuß-Boden-Kontakt zu keinem Kontakt und umgekehrt überging. Durch Anpassung der Einstellungen des kinematischen Filters und der Berechnung der Bodenreaktionskraft konnten die Residualkräfte um bis zu 54% reduziert werden. Die Analyse der muskuloskelettalen Belastung unter psychischer Beanspruchung hat gezeigt, dass die Modelle einen wertvollen Beitrag zur biomechanischen Analyse von hochdynamischen Bewegungen leisten können. In der Folge haben sich die Modelle auch bei der Überprüfung der berechneten Parameter sowie der modellspezifischen Optimierungsmöglichkeiten als zuverlässiges Werkzeug für die Analyse hochdynamischer Bewegungen erwiesen. Daher können die Modelle dazu beitragen, hochdynamische Bewegungen besser zu verstehen und Muskelverletzungen bei Sportlern vorzubeugen. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:355-epub-551061 CY - Regensburg ER - TY - JOUR A1 - Benditz, Achim A1 - Auer, Simon A1 - Spörrer, J.F. A1 - Wolkerstorfer, S. A1 - Grifka, Joachim A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Regarding loads after spinal fusion, every level should be seen separately: a musculoskeletal analysis JF - European Spine Journal N2 - The number of spinal fusion surgeries is steadily increasing and biomechanical consequences are still in debate. The aim of this study is to provide biomechanical insights into the sagittal balance of the spine and to compare spinal load before and after spinal fusion. METHOD: The joint reaction forces of 52 patients were analyzed in proximo-distal and antero-posterior direction from the levels T12-L1 to L5-S1 using musculoskeletal simulations. RESULTS: In 104 simulations, pre-surgical forces were equal to post-surgical. The levels L4-L5 and T12-L1, however, showed increased spinal forces compression forces with higher sagittal displacement. Improved restauration of sagittal balance was accompanied by lower spinal load. AP shear stress, interestingly decreased with sagittal imbalance. CONCLUSION: Imbalanced spines have a risk of increased compression forces at Th12-L1. L4-L5 always has increased spinal loads. These slides can be retrieved under Electronic Supplementary Material. KW - AnyBody Modeling System KW - Musculoskeletal analysis KW - Sagittal balance KW - Spinal fusion KW - Spine biomechanics KW - Biomechanische Analyse KW - Wirbelsäulenversteifung KW - Vergleichende Anatomie Y1 - 2018 U6 - https://doi.org/10.1007/s00586-018-5476-5 VL - 27 IS - 8 SP - 1905 EP - 1910 PB - Springer-Verlag ER - TY - JOUR A1 - Kieninger, Martin A1 - Schneider, Corinna A1 - Auer, Simon A1 - Reinker, Lukas A1 - Adler, Ina A1 - Dendorfer, Sebastian A1 - Rosenberger, Johanna A1 - Popp, Daniel A1 - Eissnert, Christoph A1 - Ludsteck, Dominik A1 - Cyrus, Christopher A1 - Hoffmann, Johannes A1 - Morag, Sarah A1 - Graf, Bernhard A1 - Kieninger, Bärbel T1 - Transport von schwer verletzten Traumapatienten im Rettungswagen mit und ohne starre Halsorthese: vergleichende biomechanische Messungen JF - Die Anaesthesiologie N2 - Hintergrund: Der tatsächliche Stellenwert der prähospitalen Immobilisation der Halswirbelsäule (HWS) bei schwer verletzten Traumapatienten ist weiterhin unklar. In Anbetracht möglicher negativer Implikationen durch das Anbringen einer starren HWS-Orthese muss deren Anwendung während der gesamten prähospitalen Phase kritisch hinterfragt werden. Ziel der Arbeit: Es sollten vergleichende biomechanische Messungen zur Beweglichkeit der HWS bei Immobilisation mittels Vakuummatratze mit und ohne zusätzliches Anbringen einer starren HWS-Orthese nach Lagerung auf der Trage durchgeführt werden. Material und Methoden: Die Bewegungen der HWS beim Ein- und Ausladeprozess in einen modernen RTW sowie während der Fahrt entlang eines vordefinierten Parkours wurden mit einem Motion-Capture-System aufgezeichnet. Die Probandin, an der die Messungen durchgeführt wurden, wurde auf einer Vakuummatratze mit der Möglichkeit zur seitlichen Fixierung des Kopfes sowie Kinn- und Stirngurt auf einer elektrohydraulischen Fahrtrage immobilisiert. Bei der einen Hälfte der Versuche erfolgte die zusätzliche Immobilisation der HWS mittels starrer Orthese, bei der anderen wurde auf die Anwendung einer HWS-Orthese verzichtet. Ergebnisse: Statistisch signifikante Unterschiede ergaben sich nur bei einigen biomechanischen Parametern in der sagittalen Ebene (Flexion und Extension). Für die anderen Bewegungsrichtungen (axiale Rotation, laterale Beugung) wurden keine signifikanten Unterschiede für die gemessenen Parameter ermittelt. Generell wurden sowohl bei den Versuchen mit HWS-Orthese als auch ohne HWS-Orthese nur sehr geringe Winkelauslenkungen (im Mittel bei axialer Rotation und Flexion/Extension im Bereich von einem bis 2 Grad, bei der lateralen Beugung höchstens 3 Grad) gemessen. Schlussfolgerung: Bei einer korrekt durchgeführten Immobilisation mittels einer Vakuummatratze mit der Möglichkeit zur seitlichen Stabilisierung des Kopfes sowie Kinn- und Stirngurt auf einer elektrohydraulischen Fahrtrage mit Beladesystem ergeben sich für den Ein- und Ausladeprozess sowie während der Fahrt in einem modernen RTW mit luftgefederter Tragenlagerung und Luftfederung der Hinterachse keine relevanten Vorteile bezüglich der Einschränkung der Bewegung der HWS durch die zusätzliche Verwendung einer starren HWS-Orthese. T2 - Transport of severely injured trauma patients in an ambulance with and without a rigid neck orthosis: comparative biomechanical measurements KW - Notfallmedizin KW - Immobilisation KW - Vakuummatratze KW - Zervikalstütze · KW - Halswirbelsäule Y1 - 2024 U6 - https://doi.org/10.1007/s00101-024-01462-w VL - 73 IS - 10 SP - 668 EP - 675 PB - Springer Nature ER - TY - JOUR A1 - Auer, Simon A1 - Süß, Franz A1 - Dendorfer, Sebastian T1 - Using markerless motion capture and musculoskeletal models: An evaluation of joint kinematics JF - Technology and Health Care N2 - BACKGROUND: This study presents a comprehensive comparison between a marker-based motion capture system (MMC) and a video-based motion capture system (VMC) in the context of kinematic analysis using musculoskeletal models. OBJECTIVE: Focusing on joint angles, the study aimed to evaluate the accuracy of VMC as a viable alternative for biomechanical research. METHODS: Eighteen healthy subjects performed isolated movements with 17 joint degrees of freedom, and their kinematic data were collected using both an MMC and a VMC setup. The kinematic data were entered into the AnyBody Modelling System, which enables the calculation of joint angles. The mean absolute error (MAE) was calculated to quantify the deviations between the two systems. RESULTS: The results showed good agreement between VMC and MMC at several joint angles. In particular, the shoulder, hip and knee joints showed small deviations in kinematics with MAE values of 4.8∘, 6.8∘ and 3.5∘, respectively. However, the study revealed problems in tracking hand and elbow movements, resulting in higher MAE values of 13.7∘ and 27.7∘. Deviations were also higher for head and thoracic movements. CONCLUSION: Overall, VMC showed promising results for lower body and shoulder kinematics. However, the tracking of the wrist and pelvis still needs to be refined. The research results provide a basis for further investigations that promote the fusion of VMC and musculoskeletal models. KW - biomechanics KW - range of motion KW - musculoskeletal system KW - optical motion capture Y1 - 2024 U6 - https://doi.org/10.3233/THC-240202 SN - 0928-7329 N1 - Corresponding author der OTH Regensburg: Sebastian Dendorfer SP - 1 EP - 10 PB - IOS Press ER - TY - VIDEO A1 - Auer, Simon A1 - Reinker, Lukas A1 - Süß, Franz A1 - Kubowitsch, Simone A1 - Krutsch, Werner A1 - Weber, Markus A1 - Renkawitz, Tobias A1 - Dendorfer, Sebastian T1 - Webcast: Effect of mental demand on leg loading in highly dynamic motion N2 - Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury. KW - Webcast KW - AnyBody KW - Stress KW - Football KW - Speedcourt Y1 - 2020 UR - https://www.youtube.com/watch?v=uSc_9XlnkaA ER -