Figure 4. Simulated components of enthalpy (indexed as cross‐bridge‐dependent ATP hydrolysis) of isometric and work‐loop contractions as functions of relative afterload.

A, enthalpy; B, work; C, heat (the difference between enthalpy and work; Eqn (1)); D, shortening heat (the difference of heat output between work‐loop and isometric contractions, calculated at each relative afterload).