Effects of running fatigue on lower limb joint kinematics and kinetics in female genu valgum individuals : a comparative study

Abstract

Individuals with nontraumatic genu valgum (GV) may be at an increased risk of anterior cruciate ligament (ACL) injuries. This study investigates the impact of fatigue on lower limb biomechanics in individuals with GV compared to healthy controls. A total of eight female participants with GV and eight female healthy controls were recruited. All participants completed a running-induced fatigue protocol. Kinematic and kinetic data were collected, followed by statistical analysis using independent and paired-samples t-tests to compare between-group and within-group differences, respectively. The results demonstrated that compared to the control group, the fatigued GV group exhibited significantly greater hip flexion angles and hip flexion moments, hip internal rotation angles and hip internal rotation moments, knee flexion angles, knee internal rotation angles, and knee external rotation moments. Similarly, individuals with GV exhibited increased ankle plantarflexion angles, ankle dorsiflexion moments, ankle external rotation angles, and ankle external rotation moments. Moreover, the GV group displayed greater knee adduction angles, hip abduction angles, and ankle adduction angles than their healthy counterparts. Following fatigue, significant increases were observed in hip adduction angles, hip adduction moments, and hip flexion moments. Knee abduction angles, knee flexion angles, and knee abduction moments also increased, along with ankle eversion angles, ankle internal rotation angles, and ankle eversion moments. Furthermore, external rotation angles at both the hip and knee joints were notably elevated. During the stance phase of running, the fatigued GV group exhibited greater activation of the quadriceps and gastrocnemius muscles compared to the control group, whereas tibialis anterior (TA) activation decreased. Postfatigue, vastus lateralis (VL) activation further increased, whereas TA activation continued to decline relative to prefatigue levels. These findings underscore the importance of developing targeted exercise interventions to better assess the biomechanical characteristics and potential injury risks associated with GV.