Variables‎ > ‎

Length-dependence

MyoSim version 2.4 and later can run simulations with parameters that depend on the prevailing half-sarcomere length.

Specifically, parameter y can be scaled from its initial value y0  by the factor r as follows
    y = y0 * (1 + r * (hsl - initial_hsl)/initial_hsl))
where hsl is the current half-sarcomere length and initial_hsl is the half-sarcomere length at the beginning of the simulation.

The r values are set for each simulation using MyoSim normal's approach for adjustable parameters. See further down this page for an example.

Thin filament parameters

ParameterLength-dependent factor
aon ld_slope_1 
aoffld_slope_2 
kplusld_slope_3 
kminus ld_slope_4 

Rate constants
You can make the parameter for a rate function length-dependent using the tag ld_rate@x@y.
Note that this modification slows down the simulations because the rate matrix has to be recalculated every iteration.

Examples
Assume:
  • the simulation was started with a half-sarcomere length of 1000 nm
  • the half-sarcomere length at the current time-step is 1100 nm
  • kminus has a default value of 10
  • rate_parameter [1][1] has a default value of 100
With these values
  • ld_slope_4 1 lin 0.5 0 3
    • will set the ld_slope_4 parameter to 1.5 (half-way between 0 and 3) and thus kminus to 1.5 * 10 = 15

  • ld_rate_1@1 1 lin 0.2 0 1
    • will set rate_parameter[1][1] to 0.2*100 = 20

Comments