Comparison of Electromyographic Characteristics of Volleyball Players in Stop-jumps: An Analysis at Different Speeds

Abstract

The stop-jump is a crucial skill in volleyball, and analyzing its motion can greatly benefit the training of volleyball players. This paper analyzed 30 players from the volleyball team at Chongqing Normal University. To study the impact of running speed on lower limb muscle activity during stop-jumps, the players were randomly assigned the low-speed running group, the medium-speed running group, and the high-speed running group. Surface electromyography sensors were employed to collect electromyographic signals from the rectus femoris, vastus lateralis, and gastrocnemius muscles of the players during the execution of the stop-jump. The electromyographic indicators were calculated using the surface electromyography system’s built-in program, including the root-mean-square (RMS) electromyographic value and integral electromyographic (IEMG) value. The former represents the effective discharge value of motor units, which depends on the electromyographic amplitude and is related to the number of recruited motor units. The latter represents the discharge capacity of motor units involved in muscle activity per unit of time, reflecting the degree of muscle activation during exercise. Then, statistical analysis was performed on these calculated indicators using SPSS software. It was found that the stop-jump comprised three distinct stages: stop, jump, and flight. Regardless of the stage, the results indicated that the higher the speed of running, the greater the electromyographic indexes of the muscle groups. Additionally, when comparing electromyographic indexes across different stages, it was observed that the index values gradually decreased with the progression of each stage.