A mechanism accounting for independence on starting length of tension increase in ramp stretches of active skeletal muscle at short half-sarcomere lengths

Olaf Till (1) , Tobias Siebert (1) , Reinhard Blickhan (1)

1 Division of Motion Science

Based on previous experimental results of independence on starting length of the tension gradient in constant-velocity contractions of a skeletal muscle stretches of active skeletal muscle at muscle lengths including the ascending limb and the plateau of the tension-length relation, a possible physiological mechanism for determining the tension increase in these contractions lengthening active muscle is discussed. Considering the sliding filament theory, it is suggested that the tension-length relation of a half-sarcomere in eccentric lengthening contractions is different from that in isometric contractions. The assumed mechanism predicts, among others, that the thick filament retains its shortened length in eccentric lengthening contractions starting from a half-sarcomere length where this filament is compressed. An example model is implemented and checked with simulations.

Mots clés: Skeletal muscle; Eccentric contraction; Muscle model; Simulation

Olaf Till, Tobias Siebert, Reinhard Blickhan. A mechanism accounting for independence on starting length of tension increase in ramp stretches of active skeletal muscle at short half-sarcomere lengths. Journal of Theoretical Biology, 2010, 266 (1), pp.117. ⟨10.1016/j.jtbi.2010.06.021⟩. ⟨hal-00613136⟩