How Does a Standing Exercise Programme Focusing on Hip-Abduction Strength Affect Anterior Knee Pain in Runners?

Abstract

Outline: Anterior Knee Pain (AKP) is the most prevalent injury in running. Growing evidence suggests that hip muscle imbalance plays a role in the development of AKP. Gluteus Medius (GMed) is the main abductor of the hip and also stabilises the pelvis during gait. Studies show that hip-abduction strength is decreased in populations with AKP. This relates to increased hip-adduction, hip internal rotation and knee abduction, which are associated with higher patellofemoral contact pressures. Objective: The main aim of this study is to determine whether a standing exercise programme will improve hip-abductor strength. The second aim of the study is to determine whether there will be a decrease in running-related pain after completing a six-week standing exercise programme.

Design: Within-participant pre-test/post-test comparative trial.

Setting: The Sport’s Clinic at the Malta Football Association. Ta Qali National Stadium (Malta).

Main outcome measures: GMed torque was measured using a Biodex® System 3 isokinetic dynamometer as demonstrated by Brent et al (2013). The Numerical Rating Scale was used to measure pain related to running.

Results: Pre-test torque scores were higher on the affected side. Scores on the affected side improved by 22.81% from a mean baseline average of 96.00Nm/kg to 117.86Nm/kg, (p-value 0.013). Scores on the unaffected side improved by 27.97% from a mean baseline average of 90.14Nm/kg to 115.29Nm/kg (p-value 0.031). Post-test scores were more balanced between limbs. Pain scores decreased from 5.29 as measured on the NRS to 1.00 (p-value 0.000).

Conclusion: Standing exercises aimed at strengthening the hip-abductors may prove to be a valid intervention for prevention and rehabilitation of AKP. However, better quality studies are needed in order to validate this.