In current models of muscle force and fatigue in denervated subjects, the mechanistic understanding of the role of baseline calcium current (R0) and the voltage sensitivity (km) is inadequate. R0 and km are assumed to be scalar, which generates errors in predicting force and fatigue respectively in response to external electrical stimulation. Previous work generated experimental data that conform to the Riccati/logistic/Boltzmann equation. To extend that work, a theoretical analysis of the role of calcium current, assumed to be a Riccati-Bass growth/diffusion/decay process, is presented for fresh and fatigued paralyzed muscle. The analysis will be included in existing models of muscle force and fatigue to determine any change in predictive accuracy. An improved theoretical biophysical model of the calcium current will lead to better understanding of muscle dynamics in paralyzed subjects so that electrotherapeutic stress injuries from overstimulation may be prevented.