(A) Step heights and (B) step durations of cytoquake events found in 3T3 fibroblasts on different substrate stiffnesses. (C and D) show the corresponding data for different cell types, where CF = cardiac fibroblast and CMF = cardiac myofibroblast. The black lines show the means. Each cell type is compared with 3T3 fibroblasts on the corresponding substrate stiffness. (^*: P < 0.05, ^**: P < 0.01 via Kolmogorov–Smirnov test.)