Fig. 3. Force–velocity (P–V) characteristics of ATP-dependent actin–myosin sliding in muscle contraction. (A) Constant velocity sliding of a skeletal muscle myosin-coated bead along actin cables under four different positive loads, expressed relative to maximum isometric force (P₀). (B) Typical example of a steady-state P–V curve of actin–myosin sliding. Reproduced from Oiwa et al. (1990).