Transient force overshoot and force redevelopment rates in permeabilized slow-twitch skeletal muscle fiber preparations before (black) and after (red) lambda phosphatase treatment as a function of Ca²⁺ activation levels. (A) Relative transient force overshoot (P_TO/P_o) was significantly decreased at low and medium (25% and 50%) Ca²⁺ activation levels following lambda phosphatase (red). (B and C) Lambda phosphatase decreased the rate constants (s⁻¹) of both the fast phase (k₁, B) and slow phase (k₂, C) of force redevelopment at all Ca²⁺ activation levels (n = 4). *, P < 0.05 using paired t test analysis.