Effectiveness of pelvic stabilization exercises on knee valgus, muscle activity, and strength in individuals with dynamic knee valgus

Pelvic instability is often associated with angular deviations of lower limb and often causes valgus shift of the knee joint under load. In addition, non-contact ACL tears during sport activity are often caused by muscle weakness around the pelvis. Therefore, reinforcing the pelvic stabilizing muscles may counterbalance dynamic knee valgus (DKV). The aim of this research is to increase the activity of the pelvic stabilizing muscles through a specific exercise program and to investigate its effect of DKV after six-week pelvic stabilization training. Twenty-two subjects (male/female: 15/7) participated in the study. They performed pelvic stabilization program for six-weeks. Before and after the training, DKV was determined on both sides by performing ten single leg squats using a Kinect camera, the Gluteus maximus, medius and vastus medialis muscles activity and strength were measured by EMG system and wireless dynamometer. DKV decreased from 3.15% to 1.03% for the left knee and from 3.89% to 1.26% for the right knee, the magnitude of change was significant (p < 0.001). Maximal Isometric Force increased significantly in all tested muscles, including the gluteus maximus, gluteus medius, and biceps femoris (all p < 0.05 or p < 0.001). This functional improvement was supported by neuromuscular changes, with EMG amplitudes increasing considerably in all assessed muscles (gluteus maximus, gluteus medius, and vastus medialis obliquus), with all six sides showing significant change (all p < 0.001). Strengthening the pelvic stabilization muscles induced a substantial improvement in knee valgus, and thus reduced the risk of developing cruciate ligament injuries. This study provides a direct link between an easy diagnosed predisposing factor a common sports injury, and offers a simple countermeasure in the form of specific exercises, that may be included against ACL injuries.