title: Reduced hip strength is associated with increased hip motion during running in young adult and adolescent male long-distance runners.
abstract: METHODS
  Controlled laboratory study.
  
  
  OBJECTIVE
  Anterior knee pain is one of the most common running symptoms reported in the literature. While the exact etiology is unknown, a lack of hip strength is suggested to contribute to abnormal running mechanics. The purpose of this research study was to evaluate the association between isokinetic hip strength and 3-D running kinematics.
  
  
  METHODS
  33 male high school and collegiate cross country runners participated in this study. Peak isokinetic hip abductor and hip extensor strength were assessed. Each subject also completed a treadmill running protocol at a self-selected speed (mean = 3.8 m/s). 3-D kinematic data were collected at 240 Hz using a 10-camera motion capture system. Pearson correlation coefficients were used to determine the relationship between hip strength and hip range of motion (ROM) during the stance phase of running (p<0.05).
  
  
  RESULTS
  Peak isokinetic hip extensor torque was inversely correlated with transverse plane hip ROM (r = -.387, p = .026) but was not significantly related to sagittal plane hip ROM or frontal plane hip ROM. Peak isokinetic hip abductor torque was inversely correlated with frontal plane hip ROM (r=-.462, p=.008) but was not significantly related to either sagittal plane hip ROM or transverse plane hip ROM. Peak isokinetic hip extensor torque and peak isokinetic hip abductor torque were not significantly related to knee kinematics in any plane.
  
  
  CONCLUSIONS
  Peak isokinetic hip extensor torque and peak isokinetic hip abductor torque are associated with transverse plane and frontal plane hip kinematics, but not knee kinematics.
  
  
  METHODS
  Level 3b.
authors.affiliation: Division of Occupational Therapy & Physical Therapy, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Jeffery A
authors.initials: JA
authors.lastname: Taylor-Haas
authors.affiliation: Division of Occupational Therapy & Physical Therapy, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Hugentobler
authors.affiliation: Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: DiCesare
authors.affiliation: Division of Occupational Therapy & Physical Therapy, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Kathryn C
authors.initials: KC
authors.lastname: Hickey Lucas
authors.forename: Nathaniel A
authors.initials: NA
authors.lastname: Bates
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Myer
authors.affiliation: Department of Physical Therapy, School of Health Sciences, High Point University, High Point NC USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Ford
keywords: cross country; hip strength; isokinetic testing; running biomechanics.