Model Mathematics

Component: environment

Component: parameters

Component: parameters_izakov_et_al_1991

q_v=q_1-q_2vv_maxifv0q_3otherwise v_1=v_max10

Component: force

F_CE=lambdap_vN F_muscle=F_XSE F_SE=beta_1alpha_1l_2-l_1-1 F_PE=beta_2alpha_2l_2-1 F_XSE=beta_3alpha_3l_3-1

Component: crossbridge_kinetics

M_A=AmuAmu+A_halfmu n_1=0.6l_1+0.5 L_oz=l_1+S_00.46+S_0 k_p_v=chichi_0q_vm_0G_star k_m_v=chi_0q_v1-chim_0G_star K_chi=k_p_vM_An_1L_oz1-N-k_m_vN ddtimeN=K_chi

Component: length

dl_1_dt=v ddtimel_1=dl_1_dt dl_2_dt=w ddtimel_2=dl_2_dt dl_3_dt=0ifisotonic_mode=1-wotherwise ddtimel_3=dl_3_dt

Component: CE_velocity

k_P_vis=beta_P_lengtheningalpha_P_lengtheningl_1ifdl_1_dt0beta_P_shorteningalpha_P_shorteningl_1otherwise phi_chi=lambdaK_chip_v1+alpha_Pk_P_visv2+alpha_2beta_2alpha_2l_2w1lambdaNp_prime_v1+k_P_visifisotonic_mode=1lambdaK_chip_v1+alpha_Pk_P_visv2+alpha_2beta_2alpha_2l_2+alpha_3beta_3alpha_3l_3w1lambdaNp_prime_v1+k_P_visotherwise ddtimev=phi_chi

Component: PE_velocity

k_S_vis=beta_S_lengtheningalpha_S_lengtheningl_2-l_1ifdl_2_dtdl_1_dtbeta_S_shorteningalpha_S_shorteningl_2-l_1otherwise ddtimew=k_S_visphi_chi-alpha_Sw-v2-alpha_1beta_1alpha_1l_2-l_1w-v1-alpha_2beta_2alpha_2l_2w1k_S_visifisotonic_mode=1k_S_visphi_chi-alpha_Sw-v2-alpha_1beta_1alpha_1l_2-l_1w-v1-alpha_2beta_2alpha_2l_2+alpha_3beta_3alpha_3l_3w1k_S_visotherwise

Component: average_crossbridge_force

gamma=ad_hv_1v_max23ad_h-a+1vv_max P_star=a1+vv_maxa-vv_maxifv01+d_h-d_h2aad_hgammavv_max2+a+1vv_max+ad_hotherwise G_star=1+0.6vv_maxif-v_maxvv0P_star0.4a+1avv_max+1if0<vvv_1P_star-alpha_Gv-v_1v_maxalpha_PG0.4a+1avv_max+1otherwise case_1=a0.4+0.4av_maxa+10.42 case_2=a11+0.4a+1.2vv_max+0.6vv_max2v_maxa-vv_max1+0.6vv_max2 case_3=0.4a+1av_max case_4=1v_max-alpha_Gvv_max-v_1v_maxalpha_PG0.4a+1a+alpha_Galpha_P1+0.4a+1vav_maxvv_max-v_1v_maxalpha_PG-1 p_v=P_starG_star p_prime_v=case_1phi_chiifv-v_maxcase_2phi_chiif-v_max<vv0case_3phi_chiif0<vvv_1case_4phi_chiotherwise

Component: calcium_handling

ddtimeA=dA_dt dA_dt=a_onA_tot-ACa_C-a_off-k_AApi_N_AA N_A=NL_ozA pi_N_A=1ifN_A10.02N_Aotherwise ddtimeB=dB_dt dB_dt=b_onB_tot-BCa_C-b_offB ddtimeCa_C=b_ctime1--a_ctime2-a_ctime2iftime<t_d-dA_dt-dB_dt-r_Ca-q_CaCa_CCa_Cotherwise