Figure 5.

Dependence of the calcium sensitivity on sarcomere length. (a) Hill-type F-pCa for sarcomere lengths (SLs) = 1.85, 1.95, 2.05, 2.15, and 2.25 µm. Forces are normalized to the maximum force measured at SL = 2.05 µm. The data do not show a change in the Hill coefficient. (b) Increase in the Ca²⁺ sensitivity (decreasing [Ca²⁺] at half-maximum) with increasing SL, measured from the position of the inflection point in the fitted Hill curves from panel a. Adapted from Dobesh et al. (2002).