Validation of current theories of skeletal muscle contraction:experiments.

Research project (DFG SI841/17-1) in cooperation with Prof. Christian Rode (University of Rostock)

Development of a structurally motivated muscle fiber model.

Notwithstanding the numerous studies of skeletal muscle and the many applications of muscle models in biology, medicine, biomechanics, and physiology, there are still fundamental questions about the physiology and force generation of muscle.
First, muscle forces in eccentric and concentric contractions are significantly underestimated and overestimated, respectively, by classical sliding filament and cross-bridge theories (so-called history effects). On the other hand, the contraction behavior of muscle fibers at short muscle lengths has not been clarified.

In this subproject, fundamental mechanisms of force production will be analyzed in isolated single muscle fibers/myofibrils. For this purpose, muscle fibers/myofibrils will be prepared and measurements will be performed under different boundary conditions using an already validated measurement setup.
Based on the experimental data, a structurally motivated muscle fiber model will be developed in a further subproject.

The research project contributes to a quantitative understanding of the mechanisms involved in force development. This not only advances the fundamental understanding of human locomotion, but can furthermore find application in the field of movement and exercise science, medical technology, robotics and prosthetics.

Literature:

  • Weidner, S., Tomalka, A., Rode, C., & Siebert, T. (2024). Impact of lengthening velocity on the generation of eccentric force by slow-twitch muscle fibers in long stretches. doi10.1007/s00424-024-02991-4 Pflugers Arch. European Journal of Physiology.[Link]
  • Tomalka A , Heim M , Klotz A, Rode C, Siebert T, 2022. Ultrastructural and kinetic evidence support that thick filaments slide through the Z-disc. Journal of the Royal Society Interface, doi: 10.1098/rsif.2022.0642 [link]   
  • Weidner, S., Tomalka, A., Rode, C., Siebert, T., 2022. How velocity impacts eccentric force generation of fully activated skinned skeletal muscle fibers in long stretches. J Appl Physiol [ link]
  • Siebert, T., Screen, H.R.C., Rode, C., 2021. Computational modelling of muscle, tendon, and ligaments biomechanics, in: Jin, Z., Li, J., Chen, Z. (Eds.), Computational Modelling of Biomechanics and Biotribology in the Musculoskeletal System, Second Edition ed. Elsevier, Cambridge, pp. 155-186. [link] 
  • Tomalka, A., Röhrle, O., Han, J.-C., Pham T., Taberner, A.J., Siebert, T. (2019). Extensive eccentric contractions in intact cardiac trabeculae : revealing compelling differences in contractile behaviour compared to skeletal muscles. Proc Biol Sci, 286.  [link]
  • Tomalka A, Rode C, Schumacher J & Siebert T. (2017). The active force-length relationship is invisible during extensive eccentric contractions in skinned skeletal muscle fibres.  [link]
Structure and function of the muscle fiber
Structure and function of the muscle fiber
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