@article{Danesini2024,

title = {Endomysium determines active and passive force production in muscle fibers},

author = {Paolo Carlo Danesini and Maximilian Heim and André Tomalka and Tobias Siebert and Filiz Ates},

editor = {Journal Biomechanics},

url = {https://www.sciencedirect.com/science/article/pii/S0021929024002124?via%3Dihub},

doi = {https://doi.org/10.1016/j.jbiomech.2024.112134},

year  = {2024},

date = {2024-05-03},

urldate = {2024-05-03},

journal = {Journal of Biomechanics},

volume = {Volume 168},

issue = {May 2024},

abstract = {Connective tissues can be recognized as an important structural support element in muscles. Recent studies have also highlighted its importance in active force generation and transmission between muscles, particularly through the epimysium. In the present study, we aimed to investigate the impact of the endomysium, the connective tissue surrounding muscle fibers, on both passive and active force production. Pairs of skeletal muscle fibers were extracted from the extensor digitorum longus muscles of rats and, after chemical skinning, their passive and active force–length relationships were measured under two conditions: (i) with the endomysium between muscle fibers intact, and (ii) after its dissection. We found that the dissection of the endomysium caused force to significantly decrease in both active (by 22.2 % when normalized to the maximum isometric force; p < 0.001) and passive conditions (by 25.9 % when normalized to the maximum isometric force; p = 0.034). These findings indicate that the absence of endomysium compromises muscle fiber’s not only passive but also active force production. This effect may be attributed to increased heterogeneity in sarcomere lengths, enhanced lattice spacing between myofilaments, or a diminished role of trans-sarcolemmal proteins due to dissecting the endomysium. Future investigations into the underlying mechanisms and their implications for various extracellular matrix-related diseases are warranted.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokeyd,

title = {Experiments meet simulations: Understanding skeletal muscle mechanics to address clinical problems},

author = {Filiz Ates and Oliver Roehrle},

editor = {Wiley-VCH GmbH},

url = {https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/gamm.202370012},

doi = {https://doi.org/10.1002/gamm.202370012},

year  = {2024},

date = {2024-03-15},

urldate = {2024-03-15},

journal = {GAMM Mitteilungen},

volume = {2024},

abstract = {This article aims to present some novel experimental approaches and compu- 

tational methods providing detailed insights into the mechanical behavior of 

skeletal muscles relevant to clinical problems associated with managing and 

treating musculoskeletal diseases. The mechanical characterization of skele- 

tal muscles in vivo is crucial for better understanding of, prevention of, or 

intervention in movement alterations due to exercise, aging, or pathologies 

related to neuromuscular diseases. To achieve this, we suggest an intraoperative 

experimental method including direct measurements of human muscle forces 

supported by computational methodologies. A set of intraoperative experiments 

indicated the major role of extracellular matrix (ECM) in spastic cerebral palsy. 

The force data linked to joint function are invaluable and irreplaceable for eval- 

uating individual muscles however, they are not feasible in many situations. 

Three-dimensional, continuum-mechanical models provide a way to predict the 

exerted muscle forces. To obtain, however, realistic predictions, it is important 

to investigate the muscle not by itself, but embedded within the respective mus- 

culoskeletal system, for example, a 6-muscle upper arm model, and the ability 

to obtain non-invasively, or at least, minimally invasively material parameters 

for continuum-mechanical skeletal muscle models, for example, by presently 

proposed homogenization methodologies. Botulinum toxin administration as a 

treatment option for spasticity is exemplified by combining experiments with 

modeling to find out the mechanical outcomes of altered ECM and the contro- 

versial effects of the toxin. The potentials and limitations of both experimental 

and modeling approaches and how they need each other are discussed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Keles2022,

title = {Botulinum Toxin Intervention in Cerebral Palsy-Induced Spasticity Management: Projected and Contradictory Effects on Skeletal Muscles},

author = {Cemre Su Kaya Keles and Filiz Ates},

editor = {Toxins},

url = {https://www.mdpi.com/2072-6651/14/11/772},

doi = {https://doi.org/10.3390/toxins14110772},

year  = {2022},

date = {2022-11-08},

urldate = {2022-11-08},

journal = {Toxins},

volume = {14},

issue = {11},

pages = {772},

abstract = {Spasticity, following the neurological disorder of cerebral palsy (CP), describes a pathological condition, the central feature of which is involuntary and prolonged muscle contraction. The persistent resistance of spastic muscles to stretching is often followed by structural and mechanical changes in musculature. This leads to functional limitations at the respective joint. Focal injection of botulinum toxin type-A (BTX-A) is effectively used to manage spasticity and improve the quality of life of the patients. By blocking acetylcholine release at the neuromuscular junction and causing temporary muscle paralysis, BTX-A aims to reduce spasticity and hereby improve joint function. However, recent studies have indicated some contradictory effects such as increased muscle stiffness or a narrower range of active force production. The potential of these toxin- and atrophy-related alterations in worsening the condition of spastic muscles that are already subjected to changes should be further investigated and quantified. By focusing on the effects of BTX-A on muscle biomechanics and overall function in children with CP, this review deals with which of these goals have been achieved and to what extent, and what can await us in the future.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{klotz2021investigating,

title = {Investigating the spatial resolution of EMG and MMG based on a systemic multi-scale model},

author = {Thomas Klotz and Leonardo Gizzi and Oliver Röhrle},

editor = {Springer},

url = {https://link.springer.com/article/10.1007/s10237-022-01572-7 

https://rdcu.be/dpxtQ},

doi = {https://doi.org/10.48550/arXiv.2108.05046},

year  = {2022},

date = {2022-04-20},

urldate = {2022-01-01},

journal = {Biomechanics and Modeling in Mechanobiology},

volume = {21},

pages = {983-997},

abstract = {While electromyography (EMG) and magnetomyography (MMG) are both methods to measure the electrical activity of skeletal muscles, no systematic comparison between both signals exists. Within this work, we propose a systemic in silico model for EMG and MMG and test the hypothesis that MMG surpasses EMG in terms of spatial selectivity. The results show that MMG provides a slightly better spatial selectivity than EMG when recorded directly on the muscle surface. However, there is a remarkable difference in spatial selectivity for non-invasive surface measurements. The spatial selectivity of the MMG 

components aligned with the muscle fibres and normal to the body surface outperforms the spatial selectivity of surface EMG. Particularly, for the MMG's normal-to-the-surface component the influence of subcutaneous fat is minimal. Further, for the first time, we analyse the contribution of different structural components, i.e., muscle fibres from different motor units and the extracellular space, to the measurable biomagnetic field. Notably, the simulations show that the normal-to-the-surface MMG component, the contribution from volume currents in the extracellular space and in surrounding inactive 

tissues is negligible. Further, our model predicts a surprisingly high contribution of the passive muscle fibres to the observable magnetic field.},

note = {cite arxiv:2108.05046Comment: Preprint, Submitted to Biomechanics and Modeling in Mechanobiology},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hessenthaler2022time,

title = {Time-periodic steady-state solution of fluid-structure interaction and cardiac flow problems through multigrid-reduction-in-time},

author = {Andreas Hessenthaler and Robert D Falgout and Jacob B Schroder and Adelaide Vecchi and David Nordsletten and Oliver Röhrle},

doi = {https://doi.org/10.1016/j.cma.2021.114368},

year  = {2022},

date = {2022-01-01},

urldate = {2022-01-01},

journal = {Computer Methods in Applied Mechanics and Engineering},

volume = {389},

pages = {114368},

publisher = {Elsevier},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bleiler2021,

title = {Tangent second-order homogenisation estimates for incompressible hyperelastic composites with fibrous microstructures and anisotropic phases},

author = {Christian Bleiler and Pedro Ponte Castañeda and Oliver Röhrle},

url = {https://doi.org/10.1016/j.jmps.2020.104251},

doi = {10.1016/j.jmps.2020.104251},

issn = {0022-5096},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Journal of the Mechanics and Physics of Solids},

volume = {147},

pages = {104251},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{gizzi2021editorial,

title = {Editorial: Somatosensory Integration in Human Movement: Perspectives for Neuromechanics, Modelling and Rehabilitation},

author = {Leonardo Gizzi and Ivan Vujaklija and Massimo Sartori and Oliver Röhrle and Giacomo Severini},

url = {https://doi.org/10.3389%2Ffbioe.2021.725603},

doi = {10.3389/fbioe.2021.725603},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Front. Bioengineering and Biotechnology, Sec. Bionics and Biomimetics},

volume = {9},

publisher = {Frontiers Media SA},

keywords = {},

pubstate = {published},

tppubtype = {article}

}