Fig. 2.

Model schematic illustrating population states and transition rates. The new treatment of unavailable sites is in black, while the standard 4-state crossbridge model is in grey. The new state A for unavailable binding sites is populated from unbound myosin, phosphorylated or not, by the spatially-dependent transition rate f_E(x) (see text). Re-equilibration occurs via the slow recovery rate g_E. The other populations are governed by traditional crossbridge mechanics (i.e. Mijailovich et al., 2000; Wang et al., 2008).