Comparison of the effect of Neb versus the effect of Tpm (in the presence of the troponin complex and Ca²⁺) on active tension and the kinetic constants. The ratio (after:before Neb or Tpm addition) of the parameters indicated are plotted (left ordinate). The right ordinate is log₁₀ of the ratio. Active tension for Neb⁻ fibers was corrected for the thin-filament length difference before the ratio was taken. Errors are propagated. K₅ is the Pi association constant, hence 1/K₅ is used to describe the Pi dissociation step 5. The data on Tpm were taken from Fujita et al. (2002).