Properties of the muscle-tendon complex

Research project (DFG SI841/2-2, 2-3, 6-1) in cooperation with Prof. Reinhard Blickhan (Chair of Human Movement Sciences, Jena)

Muscle-tendon complex properties of small mammals (DFG SI841/2-2, 2-3, 6-1)

This project will be performed in cooperation with Prof. Reinhard Blickhan (Chair Science of Motion, Jena).

Muscles have different functions during locomotion (e.g. motor, brake, spring). This study investigates whether there are adaptions in muscle properties according to these functions. For this purpose, the two rat muscles - M. gastrocnemius (Caput mediale) and M. quadriceps femoris (Vastus lateralis) - are compared experimentally as well as in simulations of muscle contractions. The latter requires a muscle model which is able to predict the history-dependence of muscle force, namely force-depression after muscle shortening and force-enhancement after muscle stretch (e.g. Rode et al. 2008). In the previous funding period we developed a physiologically motivated model which for the first time realistically predicts lengthening-induced force enhancement (Till et al. 2008, Till et al. 2010). In this period it is necessary to enhance the existing muscle model with regard to shortening-induced force depression. Using the enhanced muscle model we will perform simulations of muscle contractions to compare the muscles with respect to their functions (motor, brake, spring) during locomotion. Upon conclusion of the project a better understanding of functional muscle adaptations on the level of muscle properties will be achieved.

Vertebral skeletal muscles are embedded in an environment of other muscles, connective tissues, and bones. These structures may transfer lateral forces to the muscle belly. Lateral loading occurs also during daily activities such as sitting, carrying large loads, and wearing orthoses. The aim of this project is to examine the influence of transversal muscle loading on contraction dynamics and muscle force.

Therefore, we performed isometric experiments with and without transversal muscle loading were performed (Siebert et al. 2012a, Siebert et al. 2012b). The interaction between the muscle and the transversal load was modelled based on energy balance between the (1) work performed by the contractile component and (2) the work performed to lift the load, to stretch the series elastic structures and to deform the muscle.

Compared to the unloaded contraction, the force rate and maximal isometric force were reduced both in the experiment and in the simulation. The reduction in maximal isometric resulted from using part of the work done by the contractile component to lift the load and deform the muscle. The response of the muscle to transversal loading opens a window into the interdependence of contractile and deformation work, which can be used to specify and validate 3D-muscle models.


    • Siebert, T., Tomalka, A., Stutzig, N., Leichsenring, K., & Bol, M. (2017). Changes in three-dimensional muscle structure of rabbit gastrocnemius, flexor digitorum longus, and tibialis anterior during growth. J Mech Behav Biomed Mater, 74, 507-519. [link]
    • Siebert, T., Stutzig, N., & Rode, C. (2017). A hill-type muscle model expansion accounting for effects of varying transverse muscle load. J Biomech. [link]
    • Heidlauf, T., Klotz, T., Rode, C., Siebert, T., & Rohrle, O. (2017). A continuum-mechanical skeletal muscle model including actin-titin interaction predicts stable contractions on the descending limb of the force-length relation. PLoS Comput Biol, 13(10), e1005773. doi:10.1371/journal.pcbi.1005773 [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. Proc Biol Sci, 284. [link]
    • Heidlauf T, Klotz T, Rode C, Altan E, Bleiler C, Siebert T & Rohrle O. (2016). A multi-scale continuum model of skeletal muscle mechanics predicting force enhancement based on actin-titin interaction. Biomech Model Mechanobiol 15, 1423-1437. [link]
    • Reinhardt L, Siebert T, Leichsenring K, Blickhan R & Böl M. (2016). Intermuscular pressure between synergistic muscles correlates with muscle force. J Exp Biol 219, 2311-2319. [link]
    • Rode C, Siebert T, Tomalka A & Blickhan R. (2016). Myosin filament sliding through the Z-disc relates striated muscle fibre structure to function. Proc R Soc B., 283. [link]
    • Siebert T, Rode C, Till O, Stutzig N & Blickhan R. (2016). Force reduction induced by unidirectional transversal muscle loading is independent of local pressure. J Biomech. 49, 1156-1161. [link]
    • Siebert T, Leichsenring K, Rode C, Wick C, Stutzig N, Schubert H, Blickhan R & Bol M. (2015). Three-Dimensional Muscle Architecture and Comprehensive Dynamic Properties of Rabbit Gastrocnemius, Plantaris and Soleus: Input for Simulation Studies. PLoS ONE 10, e0130985. [link]
    • Morl F, Siebert T & Haufle D. (2015). Contraction dynamics and function of the muscle-tendon complex depend on the muscle fibre-tendon length ratio: a simulation study. Biomech Model Mechanobiol. DOI: 10.1007/s10237-015-0688-7   [link]
    • Siebert T., Till O., Stutzig N., Günther M. & Blickhan R. (2014). Muscle force depends on the amount of transversal muscle loading.  J Biomech 47, 1822-1828.  [link]
    • Till O., Siebert T., Blickhan R. (2014). Force depression decays during shortening in the medial gastrocnemius of the rat.   J Biomech  47, 1099-1103.  [link]
    • Siebert T, Till O & Blickhan R. (2014). Work partitioning of transversally loaded muscle: experimentation and simulation.  Comput Methods Biomech Biomed Engin, 17, 217-229  [link
    • Morl F, Siebert T, Schmitt S, Blickhan R & Gunther M. (2012). Electro-mechanical delay in Hill-type muscle models.  Journal of Mechanics in Medicine and Biology  12,18 pages. Doi: 10.1142/S0219519412500856.  [link]
    • Muller R, Siebert T & Blickhan R. (2012). Muscle Preactivation Control: Simulation of Ankle Joint Adjustments at Touchdown During Running on Uneven Ground.  J Appl Biomech  28, 718-725.  [link]
    • Maas R, Siebert T & Leyendecker S. (2012). On the relevance of structure preservation to simulations of muscle actuated movements.  Biomech Model Mechanobiol 11, 543-556.  [link]
    • Till O, Siebert T & Blickhan R. (2010). A mechanism accounting for independence on starting length of tension increase in ramp stretches of active skeletal muscle at short half-sarcomere lengths.  J Theor Biol  266, 117-123.  [link]
    • Rode C, Siebert T & Blickhan R. (2009). Titin-induced force enhancement and force depression: a 'sticky-spring' mechanism in muscle contractions?  J Theor Biol  259, 350-360.  [link]
    • Rode C, Siebert T, Herzog W, & Blickhan R (2009). The effects of parallel and series elastic components on the active cat soleus force-length relationship.  Journal of Mechanics in Medicine and Biology, 9(1), 105-122.  [link]
    • Till O, Siebert T, Rode C & Blickhan R. (2008). Characterization of isovelocity extension of activated muscle: a Hill-type model for eccentric contractions and a method for parameter determination.  J Theor Biol  255, 176-187.  [link]
    • Siebert T, Rode C, Herzog W, Till O, Blickhan R (2008) Nonlinearities make a difference: comparison of two common Hill-type models with real muscle.  Biol Cybern 98 (2), 133-143.  [link]
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