Force redevelopment and decay rates. (A and B) Rate constants (s⁻¹) from a double exponential (k₁ and k₂) fit across relative forces in slow-twitch (A; black; n = 5) and fast-twitch (B; blue; n = 4) fibers. Values for k₁ were highly dependent on Ca²⁺ activation levels, while k₂ values were similar over the entire range of Ca²⁺ activation levels in both fiber types. Values for k₁ at ∼75% and ∼100% relative force were significantly different from all other values in both fiber types. (C) t_1/2 was Ca²⁺ activation dependent in a manner qualitatively similar to the k₁ rate constant. In slow-twitch fibers, the t_1/2 at ∼25% and ∼50% relative force was significantly different from all other values. In fast-twitch fibers, the t_1/2 at ∼100% relative force was significantly greater than all other values. *, P < 0.05 slow-twitch fibers versus fast-twitch fibers.