. Author manuscript; available in PMC: 2022 Jun 22.

Published in final edited form as: IEEE Trans Neural Syst Rehabil Eng. 2022 Mar 28;30:748–757. doi: 10.1109/TNSRE.2022.3151637

TABLE II.

Overview of the Evaluated Model Designs

Model $M$	Interface to Physics	Force Equation	Parameters	L	S_BIC

Model 1A	Activated effective cross section	F = f_iA_eff(E_th, APL₀ ≡ 0) + ∊_ij	E_th, f_i	−15675	31363
Model IB	Activated effective cross section	F = f_iA_eff(E_th, APL_0,i) + ∊_ij	E_th, f_i, APL_0,i	−15450	30919

Model 2A	Activated effective volume	F = v_iV_eff(E_th, APL₀ ≡ 0) + ∊_ij	E_th, v_i	−16261	32536
Model 2B	Activated effective volume	F = v_iV_eff(E_th, APL_0,i) + ∊_ij	E_th, v_i, APL_0,i	−15683	31385

The models are summarized with respect to their interface to the electric field model, the implemented force equations based on the effective (i.e., with pennation and geometric conditions as formed by the field model) muscle cross section A_eff, muscle volume V_eff threshold field magnitude value E_th, individual force per cross section f_i or per volume v_i optional individual offset correction APL_0,i log. likelihood L, Schwarz information S_BIC, and allowed variability term ∊_ij for subject i as well as sample j.