@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} } @article{AurbachSpickaSuessetal., author = {Aurbach, Maximilian and Spicka, Jan and S{\"u}ß, Franz and Dendorfer, Sebastian}, title = {Evaluation of musculoskeletal modelling parameters of the shoulder complex during humeral abduction above 90°}, series = {Journal of Biomechanics}, volume = {106}, journal = {Journal of Biomechanics}, number = {June}, publisher = {Elsevier}, doi = {10.1016/j.jbiomech.2020.109817}, abstract = {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.}, subject = {Schultergelenk}, language = {en} }