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Medicina dello Sport 2020 December;73(4):689-702

DOI: 10.23736/S0025-7826.20.03726-6

Copyright © 2020 EDIZIONI MINERVA MEDICA

language: English, Italian

Effects of knee middle position instruction on knee joint biomechanics during single-leg landing

Xiao SHI ^{1, 2}, Huifang CHEN ³, Jianhong QI ¹, Xiaoming LI ¹, Haibin LIU ¹, Haimei WANG ¹, Bin MA ¹, Di XIE ¹ ✉

¹ Institute of Sports Medicine, Shandong First Medical University and Shandong Academy of Medical Sciences, Taian, China; ² Unit of Training Injury Prevention and Research, Department of Health Maintenance, NCO School of PLA, Army Medical University, Shijiazhuang, China; ³ School of Nursing, Shandong First Medical University and Shandong Academy of Medical Sciences, Taian, China

BACKGROUND: For reducing the high prevalence of anterior cruciate ligament (ACL) injuries, the sports instruction by changing biomechanical indices may be effectively. This study aimed to investigate the effect of knee middle position instruction (KMPI) on knee biomechanics during a landing task. Action guidance can prevent ACL injury by changing the biomechanical index of knee joint
METHODS: Seventeen female collegiate volleyball athletes were recruited to the study. Kinematic, kinetic, and electromyography data were collected during single leg landing and compared before and after KMPI. The associations among the alteration in knee angle, knee torque, and muscle activity during the preactivity and postcontact phases were statistically analyzed.
RESULTS: After KMPI, the participants had: 1) a reduced knee abduction angle at initial ground contact time (mean =-1.2°, P<0.05); 2) decreased maximum knee abduction torque (mean =0.1 Nm.kg-1.m-1, P<0.05); and 3) an increased maximum knee flexion angle (mean =5.4°, P<0.05). After KMPI, quadriceps preactivity alteration and hamstrings activity alteration were correlated with knee extension torque alteration (r=0.72, P<0.01 and r=-0.50, P<0.05, respectively).
CONCLUSIONS: KMPI was designed to correct the knee alignment during the single leg landing, which may decrease the ACL injury risk.

KEY WORDS: Anterior cruciate ligament; Knee; Biomechanical phenomena; Wounds and injuries