A new exercise protocol to cause delayed onset muscle soreness in quadriceps femoris muscle and analyzing its effects on vertical jump height in amateur sportswomen

Delayed onset muscle soreness normally appears right after an eccentric exercise and reaches its highest level between the first 24 to 48 hours after exercise. The symptoms totally disappear after 7 to 10 days. After recovery, power and efficiency of the muscle increase and this power raise, results in improvement of a sport skill like vertical jump. The aim of this article was to study the effects of eccentric exercise of quadriceps femoris muscle on vertical jump height in nonprofessional sportswomen. This study was performed on 10 amateur sportswomen. Quadriceps femoris muscle force, one repetition maximum (1RM), height of four types of single leg squat, double leg squat, countermovement, and drop jump, and the amount of muscle soreness were examined in two test sessions (right after and 10 days after the exercise). Using SPSS software, a paired T- test was done for statistical analysis. Isometric force of the quadriceps femoris muscle and the height of vertical jump decreased right after performing the eccentric exercise. The isometric force and the 1RM of quadriceps femoris muscle increased 10 days after performing eccentric exercise (P< 0.05). The jump that was mostly affected was single leg squat jump. Performing eccentric exercise increases the muscle force and this force raise can enhance sport skill efficiency like vertical jump. The eccentric exercise protocol in this study was new and although its intensity was medium, it had positive effects on muscle force and vertical jump height.