The knee joint is a primary mobile joint in the lower limbs, contributing the most to the height of take-off and is an important factor affecting take-off effect. Analyzing the muscle force and movement characteristics of the knee joint in athletes provides a reference for sports training and injury prevention. Through experimental methods, the study on the EMG of volleyball athletes' lower limbs during blocking showed significant differences in the impact of deep squat and shallow squat on the tibialis anterior muscle during squatting (p=0.027‹05); significant differences in the impact of deep squat and shallow squat on the tibialis anterior muscle during the landing phase (p=0.017); significant differences in the impact of deep squat and half squat on the tibialis anterior muscle (p=0.001‹05) as well as on the rectus femoris (p=0.015‹05) in the pedal-stretch phase; and significant differences in the impact of deep squat and shallow squat on the rectus femoris during the aerial phase (p=0.019). Since the rectus femoris is the primary knee-extension muscle and plays a role in buffer and immobilization, it determines the height of take-off to a certain extent. To effectively improve jump height, the force training of the rectus femoris should be enhanced, which can also help prevent sports-related injuries. The rectus femoris is a major muscle for maintaining body balance, and the medial head of gastrocnemius muscle and the lateral head of gastrocnemius muscle play critical roles in maintaining balance in the air. It is necessary to strengthen the coordinated training among these muscles to boost their work efficiency.

Shuai Geng. EMG Analysis of Volleyball Athletes in the Process of Blocking at Different Knee Take-off Angles. Frontiers in Sport Research (2024) Vol. 6, Issue 2: 9-19. https://doi.org/10.25236/FSR.2024.060202.

[1] Hua Lijun, Song Jirui. Research on Muscle Force and EMG Characteristics of Volleyball Player's Lower Limbs [J]. Journal of Shenyang Sport University, 2007 26(4)

[2] Wang Fanjia, Zhou Chenlei. Comparison of Lower Extremity Joint Kinematics and Muscle Activation between Asian Squat and Western Squat [J]. Journal of Medical Biomechanics, 2021, 36(5): 705-711.

[3] Liu Gang. Synchronous Study on Isokinetic Centripetal Flexion, Muscle Force at Extension and Myoelectric Characteristics of Knee Joint [J]. Compilation of Thesis Abstracts of the 17th National Conference on Sports Biomechanics, 2014 (9).

[4] Zhan Jianguo, Dai Xinghong. The Characteristic Analysis of Lower Limbs Electricity of Sprinter's Hip Muscle Group in Force Training [J]. Journal of Xi'an Physical Education University, 2011, 28(2) 227-232