@incollection{DendorferMaierHammer, author = {Dendorfer, Sebastian and Maier, Hans J{\"u}rgen and Hammer, Joachim}, title = {How do age and anisotropy affect the fatigue behaviour of cancellous bone?}, series = {Medicine Meets Engineering}, booktitle = {Medicine Meets Engineering}, publisher = {IOS Press}, pages = {68 -- 74}, abstract = {The fatigue behaviour of materials is of particular interest for the failure prediction of materials and structures exposed to cyclic loading. For trabecular bone structures only a few sets of lifetime data have been reported in the literature and structural measures are commonly not considered. The influence of load contributions not aligned with the main physiological axis remains unclear. Furthermore age effects on the fatigue behaviour are not well described. In the present study, different groups of human vertebral cancellous bone were exposed to cyclic compression. The inital modulus and therefore lifetimes were found to be highly dependent on age. The decrease in both with increasing age was much more pronounced in specimens which were not aligned with the main physiological axis. This implies that old bone is much more sensitive to (cyclic) failure loads in general but particularly to loads which are not coincident with the physiological main axis.}, subject = {Knochenbruch}, language = {en} } @article{HoelscherWeberLazarevetal., author = {H{\"o}lscher, Thomas and Weber, Tim A. and Lazarev, Igor A. and Englert, Carsten and Dendorfer, Sebastian}, title = {The influence of rotator cuff tears on glenohumeral stability during abduction tasks}, series = {Journal of Orthopaedic Research}, volume = {34}, journal = {Journal of Orthopaedic Research}, number = {9}, doi = {10.1002/jor.23161}, pages = {1628 -- 1635}, abstract = {One of the main goals in reconstructing rotator cuff tears is the restoration of glenohumeral joint stability, which is subsequently of utmost importance in order to prevent degenerative damage such as superior labral anterior posterior (SLAP) lesion, arthrosis, and malfunction. The goal of the current study was to facilitate musculoskeletal models in order to estimate glenohumeral instability introduced by muscle weakness due to cuff lesions. Inverse dynamics simulations were used to compute joint reaction forces for several static abduction tasks with different muscle weakness. Results were compared with the existing literature in order to ensure the model validity. Further arm positions taken from activities of daily living, requiring the rotator cuff muscles were modeled and their contribution to joint kinetics computed. Weakness of the superior rotator cuff muscles (supraspinatus; infraspinatus) leads to a deviation of the joint reaction force to the cranial dorsal rim of the glenoid. Massive rotator cuff defects showed higher potential for glenohumeral instability in contrast to single muscle ruptures. The teres minor muscle seems to substitute lost joint torque during several simulated muscle tears to maintain joint stability. Joint instability increases with cuff tear size. Weakness of the upper part of the rotator cuff leads to a joint reaction force closer to the upper glenoid rim. This indicates the comorbidity of cuff tears with SLAP lesions. The teres minor is crucial for maintaining joint stability in case of massive cuff defects and should be uprated in clinical decision-making.}, subject = {Rotatorenmanschettenriss}, language = {en} } @article{EnglertAngeleFierlbecketal., author = {Englert, Carsten and Angele, Peter and Fierlbeck, J. and Dendorfer, Sebastian and Schubert, T. and M{\"u}ller, R. and Lienhard, S. and Zellner, Johannes and Nerlich, Michael and Neumann, Carsten}, title = {Conductive bone substitute material with variable antibiotic delivery}, series = {Der Unfallchirurg}, volume = {110}, journal = {Der Unfallchirurg}, number = {5}, publisher = {Springer}, doi = {10.1007/s00113-007-1229-3}, pages = {408 -- 413}, abstract = {A new bone substitute, consisting of hydroxylapatite and calcium sulphate, was prepared in two formulations and analysed for its mechanical strength and antibiotic elution.The bone substitute PerOssal has osteoconductive and degradable properties. The material has a built-in capillary structure, which results in an immediate fluid uptake. Antibiotics absorbed to the bone substitute resulted in a prolonged release rate. Mechanical strength was investigated by an unconfined compression test up to failure under both wet and dry conditions for both formulations of the bone substitute. Antibiotic release was analysed microbiologically for two antibiotics, vancomycin and gentamicin, over an elution period of 10 days using the agar diffusion method.The drug release analysis resulted in a prolonged release rate of both antibiotics over 10 days. In vitro the amount of gentamicin and vancomycin eluted at day 10. From one pellet still exceeded the minimal inhibitory concentration of most aetiologically important pathogens. Formulation two of the present bone substitute is significantly harder in both wet and dry conditions when compared to formulation one. Both formulations lose strength in the wet condition relative to their performance in the dry condition. However, formulation two is as hard under wet conditions as formulation one is when dry.PerOssal is a suitable new degradable osteoconductive bone substitute that can be loaded with antibiotic solutions, which are released in effective doses over 10 days. The mechanical strength of PerOssal is sufficient to support cancellous bone defects in non-weight-bearing areas or in combination with osteosynthesis.}, subject = {Knochenersatz}, language = {en} } @misc{SaffertMelznerDendorfer, author = {Saffert, Anne-Sophie and Melzner, Maximilian and Dendorfer, Sebastian}, title = {Biomechanical Analysis of the Right Elevated Glenohumeral Joint in Violinists during Legato-Playing}, series = {Biomdlore 2021: 21-23 October 2021 Vilnius/Trakai, Lithuania}, journal = {Biomdlore 2021: 21-23 October 2021 Vilnius/Trakai, Lithuania}, doi = {10.3233/THC-219001}, abstract = {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.}, language = {en} } @article{SchaefferHerrmannSchratzenstalleretal., author = {Schaeffer, Leon and Herrmann, David and Schratzenstaller, Thomas and Dendorfer, Sebastian and B{\"o}hm, Valter}, title = {Theoretical considerations on stiffness characteristics of a 3-dimensional tensegrity joint model for the use in dynamic hand orthoses}, series = {Journal of Medical Robotics Research}, journal = {Journal of Medical Robotics Research}, publisher = {World Scientific}, doi = {10.1142/S2424905X25400069}, language = {en} } @misc{BrandtSteinhilberDendorferetal., author = {Brandt, Hanna and Steinhilber, Bernd and Dendorfer, Sebastian and Pfingsten, Andrea}, title = {Exoskelettale Unterst{\"u}tzung in der Pflege - eine Untersuchung der Muskelaktivit{\"a}t, des H{\"u}ftflexionswinkels und des subjektiven Belastungsempfinden bei einem simulierten Transfer.}, series = {Physioscience}, volume = {21}, journal = {Physioscience}, number = {S 01}, publisher = {Thieme}, doi = {10.1055/s-0045-1808226}, pages = {S61 -- S62}, abstract = {Die dargestellten Ergebnisse weisen darauf hin, dass das in der Studie verwendete passive r{\"u}ckenunterst{\"u}tzende Exoskelett die (wahrgenommene) k{\"o}rperliche Belastung beim dynamischen Transfer eines 45 kg schweren Dummys potenziell reduzieren kann und sich der maximale H{\"u}ftgelenksflexionswinkel mit Exo verkleinert. Dieses Ergebnis deckt sich mit bereits publizierten Studienergebnissen von Arbeitsaufgaben im Bereich des Hebens und Tragens von Gegenst{\"a}nden aus der Logistik}, language = {de} } @inproceedings{SchaefferSchmausserHerrmannetal., author = {Schaeffer, Leon and Schmaußer, Theresa and Herrmann, David and Lehmann, Lukas and Dendorfer, Sebastian and B{\"o}hm, Valter}, title = {Multi-Body Simulation of a Dynamic Hand Orthosis based on a Prestressed Compliant Structure Incorporating the Human Hand}, series = {2025 International Symposium on Medical Robotics (ISMR), May 14-16, 2025, Atlanta, GA, USA,}, booktitle = {2025 International Symposium on Medical Robotics (ISMR), May 14-16, 2025, Atlanta, GA, USA,}, publisher = {IEEE}, doi = {10.1109/ISMR67322.2025.11025982}, pages = {80 -- 86}, abstract = {Many dynamic hand orthoses use one degree of freedom joints, such as hinge joints. Therefore, these orthoses can only partially replicate the complex, multi-axis movement of the hand. A possible solution for this is the use of prestressed compliant structures as the basis for orthoses. Determining the joint forces in the wrist and optimizing the dynamic orthosis to influence these forces as well as acting muscle forces are important steps in the development of these orthoses. For this reason, in this work multi-body simulation models of an orthosis with human hand models are presented. Based on these theoretical investigations, more detailed orthosis models as well as initial prototypes of prestressed compliant dynamic hand orthoses can be developed.}, language = {en} } @misc{KreftingZaunsederSaeringetal., author = {Krefting, Dagmar and Zaunseder, Sebastian and S{\"a}ring, Dennis and Wittenberg, Thomas and Palm, Christoph and Schiecke, Karin and Krenkel, Lars and Hennemuth, Anja and Schnell, Susanne and Spicher, Nicolai}, title = {Blutdruck, H{\"a}modynamik und Gef{\"a}ßzustand: Innovative Erfassung und Bewertung - Schwerpunkt bildbasierte Verfahren}, series = {66. Jahrestagung der Deutschen Gesellschaft f{\"u}r Medizinische Informatik, Biometrie und Epidemiologie e. V. (GMDS), 12. Jahreskongress der Technologie- und Methodenplattform f{\"u}r die vernetzte medizinische Forschung e. V. (TMF), 26. - 30.09.2021, online}, journal = {66. Jahrestagung der Deutschen Gesellschaft f{\"u}r Medizinische Informatik, Biometrie und Epidemiologie e. V. (GMDS), 12. Jahreskongress der Technologie- und Methodenplattform f{\"u}r die vernetzte medizinische Forschung e. V. (TMF), 26. - 30.09.2021, online}, doi = {10.3205/21gmds016}, url = {http://nbn-resolving.de/urn:nbn:de:0183-21gmds0167}, abstract = {Einleitung: Blutdruck gilt als sogenannter Vitalparameter als einer der grundlegenden Indikatoren f{\"u}r den Gesundheitszustand einer Person. Sowohl zu niedriger als auch zu hoher Blutdruck kann lebensbedrohend sein, letzerer ist dar{\"u}ber hinaus ein Risikofaktor insbesondere f{\"u}r Herz-Kreislauferkrankungen, die trotz wichtiger Fortschritte in der Behandlung immer noch die h{\"a}ufigste Todesursache in Deutschland darstellen. Die H{\"a}modynamik, also die raumzeitliche Dynamik des Blutflusses, und der Gef{\"a}ßzustand sind eng verbunden mit dem Blutdruck und ebenfalls von hoher klinischer Relevanz, u.a. zur Identifikation von Durchblutungsst{\"o}rungen und ung{\"u}nstigen Druckverteilungen der Gef{\"a}ßwand. Innovationen in der Messtechnik als auch in der Datenanalyse bieten heute neue M{\"o}glichkeiten der Erfassung und Bewertung von Blutdruck, H{\"a}modynamik und Gef{\"a}ßzustand [1], [2], [3], [4]. Methodik: In einer gemeinsamen Workshopserie der AG Medizinische Bild- und Signalverarbeitung der GMDS und des Fachausschusses Biosignale der DGBMT werden wir neue Ans{\"a}tze und L{\"o}sungen f{\"u}r Mess- und Analyseverfahren zu Blutdruck und -fluss sowie zum Gef{\"a}ßzustand vorstellen und diskutieren. Dabei stehen im ersten Workshop auf der GMDS Jahrestagung Bildbasierte Verfahren im Zentrum, w{\"a}hrend der zweite Workshop auf der DGBMT Jahrestagung den Fokus auf Biosignalbasierten Verfahren legt. Es werden aktuelle Forschungsergebnisse vorgestellt und diskutiert. Es sind jeweils mehrere Vortr{\"a}ge geplant mit ausreichend Zeit zur Diskussion. Folgende Vortr{\"a}ge sind geplant (Arbeitstitel): Sebastian Zaunseder: Videobasierte Erfassung des Blutdrucks Anja Hennemuth: A Visualization Toolkit for the Analysis of Aortic Anatomy and Pressure Distribution Lars Krenkel: Numerische Analyse der Rupturwahrscheinlichkeit zerebraler Aneurysmata Susanne Schnell: Messung des Blutflusses und h{\"a}modynamischer Parameter mit 4D flow MRI: M{\"o}glichkeiten und Herausforderungen Ergebnisse: Ziel des Workshops ist die Identifikation von innovativen Ans{\"a}tzen und neuen Methoden zur qualitativen und quantitativen Bestimmung von h{\"a}modynamischen Parametern sowie deren kritische Bewertung durch die Community f{\"u}r die Eignung in der klinischen Entscheidungsunterst{\"u}tzung. Diskussion: Der Workshop leistet inhaltlich einen Beitrag zu zentralen Aspekten f{\"u}r die Herz-Kreislauf-Medizin. Er bringt dabei Expertise aus verschiedenen Bereichen zusammen und schl{\"a}gt die Br{\"u}cke zwischen Kardiologie, Medizininformatik und Medizintechnik. Schlussfolgerung: Innovative Technologien aus Medizintechnik und Informatik erm{\"o}glichen zunehmend einfache und raumzeitlich aufgel{\"o}ste Erfassung und Bewertung wichtiger Informationen zur Unterst{\"u}tzung von Diagnose und Therapieverfolgung. [1] Zaunseder S, Trumpp A, Wedekind D, Malberg H. Cardiovascular assessment by imaging photoplethysmography - a review. Biomed Tech (Berl). 2018 Oct 25;63(5):617-34. [2] Huellebrand M, Messroghli D, Tautz L, Kuehne T, Hennemuth A. An extensible software platform for interdisciplinary cardiovascular imaging research. Comput Methods Programs Biomed. 2020 Feb;184:105277. [3] Schmitter S, Adriany G, Waks M, Moeller S, Aristova M, Vali A, et al. Bilateral Multiband 4D Flow MRI of the Carotid Arteries at 7T. Magn Reson Med. 2020 Oct;84(4):1947-60. [4] Birkenmaier C, and Krenkel, L. Flow in Artificial Lungs. In: New Results in Numerical and Experimental Fluid Mechanics XIII. Contributions to the 22nd STAB/DGLR Symposium. Springer; 2021.}, subject = {Blutdruck}, language = {de} } @article{BarthelSuessDendorfer, author = {Barthel, Mareike and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Application of a transformer encoder for the prediction of intra-abdominal pressure}, series = {Computer Methods in Biomechanics and Biomedical Engineering}, journal = {Computer Methods in Biomechanics and Biomedical Engineering}, publisher = {Taylor \& Francis}, doi = {10.1080/10255842.2025.2586143}, pages = {11}, abstract = {Intra-abdominal pressure is a significant physiological parameter influencing spinal stability and pelvic floor health. This study investigates the potential of a transformer encoder model to predict IAP using motion capture data and musculoskeletal modeling. Data from 211 subjects performing walking, fast walking, and running were used to train a transformer encoder. The model showed promising results with an overall Mean Absolute Percentage Error of 13.5\% and a Pearson correlation coefficient of 0.85. Predictions for fast walking and running proved to be more challenging compared to walking, which was attributed to the greater variability and complexity of faster movements.}, language = {en} } @article{BrebantWeihererNoisseretal., author = {Br{\´e}bant, Vanessa and Weiherer, Maximilian and Noisser, Vivien and Seitz, Stephan and Prantl, Lukas and Eigenberger, Andreas}, title = {Implants Versus Lipograft: Analysis of Long-Term Results Following Congenital Breast Asymmetry Correction}, series = {Aesthetic Plastic Surgery}, volume = {46}, journal = {Aesthetic Plastic Surgery}, publisher = {Springer Nature}, doi = {10.1007/s00266-022-02843-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-32404}, pages = {2228 -- 2236}, abstract = {Aims Congenital breast asymmetry represents a particular challenge to the classic techniques of plastic surgery given the young age of patients at presentation. This study reviews and compares the long-term results of traditional breast augmentation using silicone implants and the more innovative technique of lipografting. Methods To achieve this, we not only captured subjective parameters such as satisfaction with outcome and symmetry, but also objective parameters including breast vol-ume and anthropometric measurements. The objective examination was performed manually and by using the Vectra H2 photogrammetry scanning system. Results Differences between patients undergoing either implant augmentation or lipograft were revealed not to be significant with respect to patient satisfaction with surgical outcome (p= 0.55) and symmetry (p= 0.69). Furthermore, a breast symmetry of 93 \% was reported in both groups. Likewise, no statistically significant volume difference between the left and right breasts was observed in both groups (p\0.41). However, lipograft patients needed on average 2.9 procedures to achieve the desired result, compared with 1.3 for implant augmentation. In contrast, patients treated with implant augmentation may require anumber of implant changes during their lifetime. Conclusion Both methods may be considered for patients presenting with congenital breast asymmetry.}, language = {en} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {Towards a deeper understanding of Pelvic Floor Disorders via Biomechanical Models}, language = {en} } @misc{Dendorfer, author = {Dendorfer, Sebastian}, title = {Zahlen statt Meinung - virtuelle Ganzk{\"o}rpermodelle f{\"u}r die Mensch-Fahrzeug-Interaktion}, language = {de} } @article{TroesterEcksteinKenneletal., author = {Tr{\"o}ster, Mark and Eckstein, Simon and Kennel, Paula and Kopp, Verna and Benkiser, Alina and Bihlmeier, Felicitas and Daub, Urban and Maufroy, Christophe and Dendorfer, Sebastian and Fritzsche, Lars and Schneider, Urs and Bauernhasl, Thomas}, title = {Person-specific evaluation method for occupational exoskeletons - Biomechanical body heat map}, series = {Applied Ergonomics}, volume = {132}, journal = {Applied Ergonomics}, publisher = {Elsevier}, doi = {10.1016/j.apergo.2025.104671}, pages = {30}, abstract = {Human-centred and ergonomic work design is one of the most important drivers for increasing the competitiveness of the European Union. As a flexible, person-specific occupational measure, exoskeletons promise great potential for effectively reducing individual ergonomic stress. Digital human models can provide important insights and offer great potential for systematising the effect and targeted use of exoskeletons, supporting their effective implementation in practice. In this article, digital human models are applied on two levels. Firstly, a realistic industrial logistics scenario in which boxes had to be relocated is designed with the help of a digital human model for workplace and process planning and secondly, a new biomechanical evaluation methodology to analyse intended and unintended effects on internal stress on the human body is demonstrated by applying musculoskeletal exoskeleton human models of four test subjects. Finally, the modelled biomechanical support tendencies of one exoskeleton are preliminary validated using EMG measurement data of the back muscles collected from the four male workers. The preliminary analysis of two back-support exoskeletons to demonstrate the new methodological approach confirms the expected, intended effects in the lower back and reveals unintended effects, such as e.g. changes in knee kinetics when applying a soft or hard-frame exoskeleton. Furthermore, the exemplary results to demonstrate the methodological approach expose notable differences between the test subjects, which underlines the relevance of person-specific evaluation and consideration of exoskeleton support. The preliminary validation shows a correlation between the modelled and the EMG-measured biomechanical exoskeleton support of the considered back muscles.}, language = {en} } @misc{GschossmannSuessDendorfer, author = {Gschoßmann, Lukas and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Impact of Model Parameters on Ground Reaction Force Predictions in Musculoskeletal Modelling}, series = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27-31 July, Stockholm}, journal = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27-31 July, Stockholm}, abstract = {This study evaluated how model parameters affect ground reaction force (GRF) predictions in musculoskeletal simulations. A parameter study varying contact height and velocity thresholds and marker weights was conducted. While height and velocity thresholds had minimal impact, marker weights impact prediction errors. These findings highlight the importance of carefully selecting model parameters.}, language = {en} } @misc{SteinSchmitzKretschmeretal., author = {Stein, Leonhard and Schmitz, Paul and Kretschmer, Rainer and Dendorfer, Sebastian}, title = {Gait parameter based fall risk scoring}, abstract = {This study explored the connection between subjective self-assessed gait insecurities and objective movement scores. 93 subjects answered detailed fall risk questionnaires and performed functional tests. Significantly different movement patterns between fallers and non-fallers were found.}, language = {en} } @misc{FoerstlAdlerSuessetal., author = {F{\"o}rstl, Nikolas and Adler, Ina and S{\"u}ß, Franz and Jansov{\´a}, Magdalena and Vychytil, Jan and Dendorfer, Sebastian}, title = {Evaluating the loads on the female pelvic floor during full-body activities using computational models}, abstract = {This work investigated the loads on the female pelvic floor during various full-body movements using computational models to calculate abdominal pressure and organ dynamic loads. While high-impact exercises resulted in higher loads, other movements showed lower loads, potentially indicating, which movements may be performed without risking pelvic floor overload and subsequent dysfunctions.}, language = {en} } @misc{BarthelSuessDendorfer, author = {Barthel, Mareike and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Predicting intra-abdominal pressure during walking and running}, series = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27-31. July 2025, Stockholm}, journal = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27-31. July 2025, Stockholm}, abstract = {Intra-abdominal pressure (IAP) is an important physiological parameter, which is difficult to measure during physical activity. In this study, motion capture, musculoskeletal modeling and a transformer encoder model are used to predict IAP during walking and running. The model showed promising results with an overall mean percentage error of 13.5\% and a Pearson correlation coefficient of 0.85. Minor challenges included the lower accuracy for fast walking and running and the limited amount of data. All in all, the prediction of IAP was successful, which opens up prospects for further applications.}, language = {en} } @misc{AdlerFoerstlČechovaetal., author = {Adler, Ina and F{\"o}rstl, Nikolas and Čechov{\´a}, Hana and Nov{\´a}ček, V{\´i}t and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Mechanistic analysis of pelvic floor functionality using musculoskeletal simulation}, series = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27-31 July 2025, Stockholm}, journal = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27-31 July 2025, Stockholm}, doi = {10.35096/othr/pub-8729}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-87294}, pages = {1}, abstract = {There is consensus that knowledge about the fundamentals of the pelvic floor remains incomplete, particularly regarding the sensitivity of individual pelvic floor muscles to posture variations. This study aimed to investigate the effects of variations in pelvic tilt and the point of force application induced by changes in posture on pelvic floor activity using musculoskeletal simulation. A parameter study analysed various loading cases, highlighting the coherent response of individual pelvic floor muscles to loads. Muscle activities and forces were compared across different force application points and pelvic tilt angles. A key finding was identifying peak muscle activity conditions that could help better understand the causes of pelvic floor disorders.}, language = {en} } @misc{GschossmannSchedelSuessetal., author = {Gschoßmann, Lukas and Schedel, Valentin and S{\"u}ß, Franz and Weber, Markus and Pfingsten, Andrea and Dendorfer, Sebastian}, title = {Evaluating Knee Joint Loads Across Exercises and Activities of Daily Living to Personalize TKA Rehabilitation}, series = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27.-31. July 2025, Stockholm}, journal = {ISB 2025 - The XXX Congress of the International Society of Biomechanics, 27.-31. July 2025, Stockholm}, doi = {10.35096/othr/pub-8725}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-87252}, pages = {1}, abstract = {This study assessed knee joint loading during various physiotherapy exercises and activities of daily living in 30 healthy subjects. Results showed that lunges and squats caused the highest joint forces, while gait and stair activities also imposed substantial loads. These findings support datadriven exercise selection for personalized rehabilitation after total knee arthroplasty.}, language = {en} } @article{KrausKnipferJacobetal., author = {Kraus, Richard and Knipfer, Maximilian and Jacob, Matthias and Kienninger, Baerbel and Alikhani, Jasmine and Ghamsary, Parham Heydarzadeh and Reinker, Lukas and Adler, Ina and Dendorfer, Sebastian and Kieninger, Martin}, title = {Effectiveness and safety of techniques for cervical spine immobilization in mountain rescue}, series = {Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine}, volume = {34}, journal = {Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine}, publisher = {Springer}, doi = {10.1186/s13049-025-01530-z}, pages = {10}, abstract = {Background Cervical spine injuries in alpine sports require immediate immobilization at the site of the accident to avoid possible secondary damage caused by transportation. Using special sensor technology, this study investigated whether a cervical spine orthosis (cervical collar, Stifneck collar (Laerdal Medical GmbH, Puchheim, Germany)) provides greater stability than a vacuum mattress alone. Methods Using one male test person, we simulated transporting a patient with a spinal injury in steep alpine terrain. A wireless motion capture system (Xsens Technologies, Movella™ Inc., Henderson, USA) was used to record motion in three-dimensional space within a standardized environment. All tests were performed on a set course by the Bavarian Mountain Rescue Service. The test person lay on a mountain rescue stretcher and was immobilized with a vacuum mattress, either with or without a cervical orthosis. The axes of cervical spine movements were analyzed separately. Results There were no significant differences between immobilization with and without a cervical orthosis with regard to lateral flexion (max. 3.7° compared to 3.0°) in the frontal plane and maximum excursion in flexion (max. 1.6° compared to 2.8°) or extension (max. -1.6° compared to -1.7°). There was significantly greater rotation movement around the craniocaudal axis without an orthosis (max. 2.4° compared to 1.3°). Conclusion During mountain rescues, the cervical spine can be immobilized without a rigid cervical spine orthosis. Future research should explore the fundamental benefits of cervical spine immobilization, while the findings of this work contribute to the safe care of patients by avoiding the disadvantages associated with rigid cervical orthoses.}, language = {en} } @phdthesis{Suess, author = {S{\"u}ß, Franz}, title = {The influence of mental stress on the musculoskeletal human back during static posture and trunk motion}, doi = {10.5283/epub.46055}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-460554}, pages = {106}, abstract = {The investigation of the influence of mental stress on muscle recruitment of the back and its effect on the intervertebral discs was the main focus of this work. Furthermore, the goal was to develop algorithms to use mental stress as an input parameter in musculoskeletal simulation models. In the first step, a study was designed to investigate the influence of emotional and cognitive stress without kinetic influencing factors during sitting. At the muscular level, emotional stress was found to affect the upper back, while cognitive stress elicited higher muscle activity in the upper and lower back. Using a newly developed algorithm to apply back muscle recruitment changes to static inverse kinematic simulation models, load increases at the discs of up to 189 N on average and up to 907 N at peak were found.Based on the results of the first study, a second dynamic study was designed and conducted. In this case, the focus was on the cognitive stressor and the lower back. Using a dynamometer, subject-specific loads were applied during extension and flexion of the upper back. In contrast to the first study, in the upper back, only the right m. trapezius pars descendens showed a load-induced difference in muscle activity, but the lower back did. To investigate the effects of muscle tone increase in detail, the algorithm developed in the first study was extended to the dynamic case. The use of simulation models allowed the inference of the effects of the purely stress-induced tone increase. For this purpose, the kinetic and muscular effects were isolated and simulated. The study revealed a stress increase of 47\% of the body weight in the L4L5 disc. The final numerical study focused on the general application of muscle activities to inverse kinematic simulation models. This was based on the novel simulation algorithm used in study two and the measured muscle activities. The simulation of the measured muscle activities formed the link between reality and simulation. To simulate the activities, neural networks and gradient boosting regression algorithms were investigated. The latter were found to be better suited to represent the data. However, the data is too small for a detailed statement, especially for loads below 100\%. The results of this work can help to better assess the musculoskeletal effects of psychological stress on the musculoskeletal system and, if necessary, to develop ergonomic prevention strategies. By recognizing stress-related kinematic difference, as well as subsequent prompting of trunk movement, could help prevent long-term effects. When examining any situation, the combination of machine learning and musculoskeletal simulation tools can help examine and minimize the effects of psychological stress.}, language = {en} } @phdthesis{Auer, author = {Auer, Simon}, title = {Musculoskeletal models in highly dynamic motion: effects of model parameters and mental stress}, address = {Regensburg}, doi = {10.5283/epub.55106}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:355-epub-551061}, pages = {ii, 85}, abstract = {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.}, language = {en} }