Fast striated muscle dynamics has been studied by many different authors. The sliding filament model was first introduced by Huxley in 1957. A comprehensive symposium at Cold Springs Harbor, 37 (1973)established many details of muscle response. Long(1973) and later Long and McIntire(1981)formulated a two compartment model of muscle response based on a nonequilibrium thermodynamic approach combined with the kinetics of Lymn and Taylor (1971) and Ashley and Moiscue (1972). This was the first integrated quantitative synthesis of the kinetics and mechanics of muscle action. It overcame the limitation noted by H.E.Huxley in the Cold Spring Harbor Symposium that complete data was not available on a single muscle type in a single specie by making the hypothesis that the same reactions would have roughly similarly rate and equilibrium constants across species in the same muscle types. Long and Phoonsiri(2006)revised the earlier model to employ a crossbridge balance approach to linking the solution chemistry to the protein lattice mechanics. It is a transition state type model which is distinct from the Huxley strain models, but which is similar to some of the so-called "thermal ratchet" models. One of the results of this model is that relative reaction rates of release of ADP from a high strain and low strain state can be computed from physiolgically macroscale mechanical experiment responses. The model gives quantitative results that have since been partially confirmed by the recent qualitative experiments reported by Nabir et al (2007). Mechanical responses depend on Ca+2 transport which depends on diffusion from the sarcoplasmic reticulum as well as reaction. Estimates of the Damkohler number and stretch experiments can be used to look in more detail at this issue. At present it appears that most of the ADP is released post-power stroke but some is release pre-power stroke.