Hip strengthening program improved single leg squatting mechanics

Willy RW. J Orthop Sports Phys Ther. doi:10.2519/jospt.2011.3470.

A strengthening and movement program that targeted the hip abductors and hip external rotators did not alter abnormal running mechanics, according to results of a block randomized controlled trial.

“Abnormal movement patterns during running and single leg squatting have been associated with a number of running related injuries in females,” the authors wrote. Typically, hip strengthening is used to correct these aberrant movements. While strengthening improves symptoms, it is unclear if the underlying mechanics during functional movements are changed.

Richard W. Willy, PT, PhD, OCS, and his colleague Irene S. Davis, PT, PhD, FAPTA, of the University of Delaware, Newark, Del., recruited 20 healthy women with excessive hip adduction during running, which was by measured with instrumented gait analysis. The researchers matched the runners based on age and running distance and randomized them to a training or control group.

Three days a week for 6 weeks, the training group performed a hip strengthening and movement education program. They also completed a single leg squat training program with neuromuscular reeducation, which included verbal feedback on proper mechanics. The control group received no intervention but maintained their running distance.

Before and after the strengthening program, the researchers used a handheld dynamometer and standard motion capture procedures to compare hip strength, running and single leg squat mechanics.

Hip abductor and external rotation strength increased significantly in the training group; however, there was no significant change in hip or knee mechanics during running. During the single leg squat, researchers saw a significant decrease in hip adduction, hip internal rotation and contralateral pelvic drop. At 6 weeks, the control group demonstrated no changes in hip strength or in single leg squat or running mechanics.