Labor Biomechanik (LBM)
Refine
Year of publication
Document Type
- conference proceeding (article) (69)
- Article (65)
- conference proceeding (presentation, abstract) (24)
- conference talk (17)
- Part of a Book (2)
- Doctoral Thesis (2)
- Moving Images (2)
- Preprint (1)
- Report (1)
Is part of the Bibliography
- no (183)
Keywords
- Biomechanik (12)
- Biomechanics (10)
- Simulation (10)
- Biomechanische Analyse (7)
- Hüftgelenkprothese (7)
- AnyBody (4)
- Bewegungsapparat (4)
- Musculoskeletal simulation (4)
- Spongiosa (4)
- biomechanics (4)
Institute
- Labor Biomechanik (LBM) (183)
- Fakultät Maschinenbau (169)
- Research Center of Biomedical Engineering - RCBE (156)
- Research Center of Health Sciences and Technology - RCHST (40)
- Labor Werkstoffprüfung und Metallographie (4)
- Labor Faserverbundtechnik (LFT) (3)
- Fakultät Elektro- und Informationstechnik (2)
- Fakultät Informatik und Mathematik (2)
- Labor Finite-Elemente-Methode (FEM) (2)
- Labor Intelligente Materialien und Strukturen (2)
Begutachtungsstatus
- peer-reviewed (57)
- begutachtet (7)
Musculoskeletal models in highly dynamic motion: effects of model parameters and mental stress
(2023)
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.
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.
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.
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.
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.
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.
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.
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.
Person-specific evaluation method for occupational exoskeletons - Biomechanical body heat map
(2025)
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.