Equilibrium fiber length with a compliant tendon

Solves the quasi-static (isometric) muscle-tendon force balance for the fiber length: the fiber active+passive force along the tendon equals the tendon force, with tendon length = MTU length - fiber length * cos(pennation).

Usage

equilibriumFiberLength(
  activation,
  mtu_length,
  optimal_fiber_length,
  tendon_slack_length,
  max_isometric_force = 1000,
  pennation = 0,
  e0t = 0.04
)

Arguments

activation

Activation in [0, 1].

mtu_length

Muscle-tendon-unit length (m).

optimal_fiber_length

Optimal fiber length (m).

tendon_slack_length

Tendon slack length (m).

max_isometric_force

Peak isometric force (N).

pennation

Pennation angle (rad).

e0t

Tendon reference strain (default 0.04).

Value

A list with fiber_length, tendon_length, norm_fiber_length, norm_tendon_length, and force (N).

Examples

equilibriumFiberLength(0.5, mtu_length = 0.30,
                       optimal_fiber_length = 0.10,
                       tendon_slack_length = 0.20)
#> $fiber_length
#> [1] 0.09373984
#> 
#> $tendon_length
#> [1] 0.2062602
#> 
#> $norm_fiber_length
#> [1] 0.9373984
#> 
#> $norm_tendon_length
#> [1] 1.031301
#> 
#> $force
#> [1] 495.6645
#>