Figure 1.

Effects of SL on force–pCa relationship in skinned myocardium. Force-pCa relationships were measured at short (1.90 μm, •, n = 10) and long (2.25 μm, ◯, n = 10) SL. Forces at submaximal Ca²⁺ concentration ([Ca²⁺]_free) are expressed relative to the maximum force at pCa 4.5. The smooth lines were fit using the Hill equation: P/P_o = [Ca²⁺]ⁿ/(k ⁿ + [Ca²⁺]ⁿ)], where P is the force at each [Ca²⁺]_free, P_o is the force pCa 4.5, n _H is the Hill coefficient, and k is the [Ca²⁺] required for half-maximal activation. Data points are means ± SEM.