Fig. 4.

The reaction profile of Scheme 1 with stretch (δl > 0) that either (1) decreases the activation energy (E_α) of force-generating state A by δW, or (2) increases the activation energy ( $E_{\alpha }^{\prime }$) of the detached state B by δW, where δW = φδl, and φ is unitary force (force/cross-bridge). From this it follows that δE_α = −δW = −φδl and/or $\delta E_{\alpha }^{\prime }=+\delta W=\phi \delta l$. All equations are the same for release, except that δl < 0