Table 2.

Parameter units, definitions, and values for force fatigue model (Ding et al. 2003). Parameter range values were defined by values used in the referenced paper and an associated follow-up study for simulations of skeletal muscles (Doll et al. 2017). PSO-identified values were used for all simulations unless otherwise stated. Ding et al. 2003 values used in model perturbation simulations

Free parameters for muscle activation model (Ding et al. 2003)			Range minimum	Range maximum	PSO-identified value	Ding et al. 2003 value
Parameter	Unit	Definition
A	N/ms	Scaling factor for force and shortening velocity of muscle	0.11	10	10	3.0009
Km	–	Sensitivity of strongly bound cross-bridges to Ca2+-troponin complex	0.01	0.50	0.50	0.103
τ1	ms	Time constant of force decline at the absence of strongly bound cross-bridges	2.00	200	2.00	50.957
τ2	ms	Time constant of force decline due to the extra friction between actin and myosin resulting from the presence of cross-bridges	5	100	100	100
αA	ms−2	Fatigue coefficient for force-model parameter A	1	-1	−0.51	−4.0*10−7
αKm	ms−1 N−1	Fatigue coefficient for Km	-1*10− 4	1*10− 4	9.97*10−5	1.9*10− 5
ατ1	N− 1	Fatigue coefficient for τ1	0	1*10−3	160*10−7	2.1*10−5
τfat	s	Time constant controlling recovery of force model parameters from fatigue	80	160	160	127