The effects of isolated hip abductor and external rotator muscle strengthening on pain, health status, and hip strength in females with patellofemoral pain: a randomized controlled trial

J Orthop Sports Phys Ther. 2012 Jan;42(1):22-9. doi: 10.2519/jospt.2012.3704. Epub 2011 Oct 25.

Abstract

Study design: Randomized controlled trial.

Objectives: To examine the effectiveness of isolated hip abductor and external rotator strengthening on pain, health status, and hip strength in females with patellofemoral pain (PFP).

Background: Altered hip kinematics resulting from hip muscle weakness has been proposed as a contributing factor in the development of PFP. To date, no study has examined clinical outcomes associated with isolated hip muscle strengthening in those with PFP.

Methods: Twenty-eight females with PFP were sequentially assigned to an exercise (n = 14) or a no-exercise control group (n = 14). The exercise group completed bilateral hip abductor and external rotator strengthening 3 times per week for 8 weeks. Pain (visual analog scale), health status (WOMAC), and hip strength (handheld dynamometer) were assessed at baseline and postintervention. Pain and health status were also evaluated at 6 months postintervention in the exercise group. Two-factor mixed-model analyses of variance were used to determine the effects of the intervention on each outcome variable.

Results: Significant group-by-time interactions were observed for each variable of interest. Post hoc testing revealed that pain, health status, and bilateral hip strength improved in the exercise group following the 8-week intervention but did not change in the control group. Improvements in pain and health status were sustained at 6-month follow-up in the exercise group.

Conclusion: A program of isolated hip abductor and external rotator strengthening was effective in improving pain and health status in females with PFP compared to a no-exercise control group. The incorporation of hip-strengthening exercises should be considered when designing a rehabilitation program for females with PFP.

Level of evidence: Therapy, level 2b.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Activities of Daily Living
  • Adult
  • Analysis of Variance
  • Biomechanical Phenomena
  • Confidence Intervals
  • Exercise Therapy
  • Female
  • Health Status
  • Hip Joint / diagnostic imaging
  • Hip Joint / pathology*
  • Humans
  • Isometric Contraction / physiology
  • Muscle Strength / physiology*
  • Muscle Strength Dynamometer
  • Muscle Weakness
  • Pain Measurement
  • Patellofemoral Pain Syndrome / rehabilitation*
  • Physical Therapy Modalities*
  • Radiography
  • Self Report
  • Time Factors
  • Treatment Outcome