Figure 1. . The experimental protocol included two bouts of eccentric exercise, ECC1 and ECC2. The subjects performed the exercises at an interval of 3 weeks with (Microwave condition: MW) and without (Control condition: CON) heat preconditioning by microwave exposure. # Time point for the measurement of muscle soreness using a visual analog scale (VAS). § Time point for the measurement of blood creatine kinase activity (CK). * Time point for the measurement of upper arm circumference (CIR). Time point for the measurement of range of motion (ROM). †  Time point for the measurement of maximal voluntary contraction (MVC).