Table 1 Summary of reported parameter definitions for three mathematical muscle models.
Model | Parameter | Definition |
|---|---|---|
2nd Order Linear | β (Ns) | output gain [25, 33, 35] |
|  | ωn (rad/s) | natural undamped frequency [25, 33, 35] |
|  | ζ (-) | damping coefficient [25, 33, 35] |
2nd Order Nonlinear | B (N) | force gain, "maximum tetanic force" [20] |
| Â | a (1/s) | "muscle specific" rate constant [20] |
| Â | b0(1/s) | rate constant; maximum value of variable rate constant parameter, b, when b1 = zero. [20] |
| Â | b1 (-) | force feedback mechanism for variable rate constant, b; higher values = greater modulation of parameter b [20] |
| Â | n (-) | "muscle specific constant" used in static force saturation equation [20] |
| Â | k (-) | "muscle specific constant" used in static force saturation equation [20] |
Hill-Huxley Nonlinear | A (N/ms) | Force scaling factor [21, 28, 29, 31, 32, 41, 42], and scaling factor for the muscle shortening velocity [29, 31, 41, 42] |
| Â | Ï„1(ms) | Force decay time constant when CN is absent, i.e. "in absence of strongly bound cross-bridges" [21, 28-32, 41, 42] |
| Â | Ï„2(ms) | Force decay time constant when CN is present; "extra friction due to bound cross-bridges" [21, 28-32, 41, 42] |
| Â | Ï„c(ms) | Time constant controlling rise and decay of CN [21, 28-31, 41, 42] or the transient shape of CN [32] and time constant controlling the duration of force enhancement due to closely spaced pulses [30] |
| Â | km(-) | "Sensitivity of strongly bound cross-bridges to CN" [29, 31, 32, 41, 42] |
| Â | R0(-) | Magnitude of force enhancement due to closely-spaced pulses [28, 30] and/or from the following stimuli [29, 31, 41, 42] |