Cartoon of the signal transduction pathway from the strong cross-bridge to Tn. Adapted from Swartz et al.36 Actin is represented by circles, Tm the contiguous red line, Tn the blue oblong structure, and the motor domain the dark brown, tadpole-like structure. Strong cross-bridges displace Tm into the M state. Because of Tm’s relative in-elasticity, this displacement is sensed by Tn, to favor TnI (arm-like structure projecting from Tn) dissociation from actin and binding to TnC, which favors calcium binding by TnC.