The impact of hip strengthening and/or neuromuscular control on frontal plane knee kinematics and kinetics in females: a systematic review

Background: Physical therapists commonly treat individuals with anterior knee pain (AKP) and anterior cruciate ligament (ACL) injuries. Despite the suggestion for including hip strengthening or neuromuscular control exercises in preventative programs to change knee mechanics and reduce AKP and ACL injuries and in the treatment of AKP, no previous systematic review has addressed the impact of these exercises on frontal plane knee mechanics. Objective: The purpose of this systematic review was to determine the level of evidence associated with hip strengthening or neuromuscular control exercises as an intervention to improve frontal plane knee mechanics during dynamic activity in females. Methods: Databases searched included PubMed, CINAHL Plus with full text, and SportDiscus with full text; specific search terms were used. All studies were to include females without any current knee pain or injury. Studies had to investigate the impact of a hip strengthening or a hip neuromuscular control program or a combination of strengthening and neuromuscular control. The primary outcome measure of interest was frontal plane knee mechanics. Results: A total of 414 articles were identified. Eight additional articles were identified using other sources. Fourteen studies were ultimately included in the qualitative analysis. There was support for neuromuscular control exercises as well as neuromuscular control plus strengthening exercises to improve frontal plane knee mechanics during dynamic activity in females. Strengthening alone was not supported. Conclusion: Clinically, one should consider either a neuromuscular control program or a combined neuromuscular control plus strength training program for females to improve frontal plane knee mechanics during dynamic activity. This may be particularly relevant in prevention of ACL injuries and AKP.