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Tuesday, June 6, 2023

Hip Muscle Strength and Knee Pain in Active Females

Brent Brookbush

Brent Brookbush


Research Review: Hip Strength in Females with and without Patellofemoral Pain

By Erik Korzen, DC, NASM CES

Edited by Brent Brookbush DPT, PT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Ireland, ML., Wilson, JD., Ballantyne, BT., Davis, IM. (2003). Hip Strength in Females With and Without Patellofemoral Pain. J Orthop Sports Phys Ther 2003. 33: 671-676. FULL TEXT

Why is this relevant? Human movement professionals should be aware of the affect adjacent joint structures have on one another. Principles and concepts including the "kinetic chain", "regional interdependence" and "relative flexibility" are essential for interventions designed with the intent to optimize motion. In this study, hip muscle strength is compared in females with and without patellofemoral pain (PFP). This study adds to the growing body of evidence that correlates hip abductor and external rotator strength to knee pathology and pain (1-6).


Study Summary

Study DesignCross-Sectional
Level of Evidence Level IIA: Evidence from at least 1 controlled study without randomization
Subject Demographics
    • 30 Female subjects
      • 15 with reported patellofemoral pain (PFP)
        • pain reported for at least 3 months duration

      • 15 without patellofemoral pain (PFP)
      • All subjects reported participation in recreational/organized sports
      • Both groups were age matched
        • 15.7 years +/- 2.7 years
        • age range 12-21 years
        • weight 63.1 +/- 16.5 kg
        • weight range 43.5-93.0 kg

Outcome Measures
      • Isometric muscle strength testing for Hip Abduction and External Rotation via dynamometer
      • Hip Abduction Isometric testing
        • performed side-lying, pillows placed between legs
        • straps placed around trunk to stabilize subject to the table
        • center of force pad of handheld dynamometer placed 5.08cm proximal to lateral knee joint line
        • 3 experimental trials, 5 seconds of maximal effort with 15 seconds of rest between trials
        • peak value of 3 trials was recorded

      • Hip External Rotation Isometric testing
        • performed seated with hips and knees at 90° flexion, towel placed between legs
        • strap placed around thigh being tested to stabilize to the table
        • center of force pad of handheld dynamometer placed 5.08cm proximal to medial malleolus
        • 3 experimental trials, 5 second duration of maximal effort with 15 seconds of rest between trials
        • peak value of 3 trials was recorded

  • Isometric Muscle strength presented as % of bodyweight (kg)
    • Hip Abduction: 23.3 +/- 6.9 in PFP group
    • Hip Abduction: 31.4 +/- 6.2 in control
    • Hip ER: 10.8 +/- 4.0 in PFP group
    • Hip ER: 16.8 +/- 5.5 in control

Conclusions of the Researchers
  • Subjects with PFP exhibited significantly lower isometric strength values for both hip abduction and ER
  • On average, PFP subjects were 26% weaker in hip abduction and 36% weaker in hip external rotation
  • Female subjects with PFP have significantly lower isometric hip abduction and external rotation strength compared to those female subjects without PFP

Review & Commentary:

This study compares isometric hip abduction and external rotation strength in female subjects with and without PFP. The isometric strength discrepancies described in this study suggest that the addition of activation and strengthening techniques for hip abductors and external rotators (gluteus medius activation and gluteus maximus activation ) may be beneficial in a clinical or exercise setting for individuals with patellofemoral pain (PFP).

One limitation of the study is the possibility that reduced isometric muscle strength could have resulted from PFP lasting at least 3 months prior to the research being performed. That is, this study does not determine whether PFP was the cause of a reduction in hip abductor and external rotator strength, or if hip abductor and external rotator strength was a contributing factor in the development of PFP.

An additional limitation to this this study was the inclusion of only female subjects. Although it may be likely that the findings would be similar in a group of male subjects with similar symptoms, differences between bone and joint alignment in the lower extremity of male and female subjects decrease the generalizability of the findings in this study. A follow-up study including only male subjects, or both female and male subjects should follow.

The methodology used in the study was strong. The researchers use of age-matched individuals reduces the possibility that PFP was influenced by age-related changes, and the use of standard isometric strength tests enhances the validity and reliability of findings. Additionally, the use of 30 individuals who participated in recreational sports ensures a similar level of activity between groups, reducing the likelihood that level of activity, or a lack of activity was the difference between those with and with-out PFP.

Why is this study important?

Comparing the strength of proximal structures relative to pain/dysfunction of distal structures in an athletic population provides information that can be used to enhance rehabilitation and performance enhancement programs. The knee in particular, is a structure that has been the focus of research examining the integrated function of the lower extremity, implicating changes in both hip and ankle function may result from- , or result in- knee pathology (1-6). These findings support the inclusion of hip and ankle assessment and intervention as an integral part of a program intended for knee health and function. Females in recreational sports, seem to be particularly pre-disposed to knee dysfunction, specifically anterior cruciate ligament (ACL) injury.

How does it affect practice?

This study gives the human movement professional impetus to include hip strength testing as an integral part of an assessment protocol designed to identify the cause of knee dysfunction, and potentially the addition of activation and strengthening techniques to address weaknesses identified. Muscle strength testing does not need to include a dynamometer as was used in this study, as standard manual muscle tests (MMT) require little to no equipment. Additionally manual muscle tests are relatively quick adding little time to assessment protocols, and are not particularly complex, making learning these assessments relatively easy (Gluteus Medius MMT , Gluteus Maximus MMT ). Techniques for addressing identified weakness in hip abductors and external rotators should be the part of every human movement professionals repertoire. (Gluteus Medius Activation and Gluteus Maximus Activation )

Training Hip Musculature Results in Improved Lower Extremity Biomechanics During Running
Caption: Training Hip Musculature Results in Improved Lower Extremity Biomechanics During Running

How does it relate to Brookbush Institute Content?

The Brookbush Institute's predictive models of Lower Leg Dysfunction (LLD) and Lumbo Pelvic Hip Complex Dysfunction (LPHCD) note the potential for knee pain and similar changes in hip muscle strength as seen in this study. These models also include additional research, theory, assessment, intervention and the integration of additional joint segments to construct a more complete model of movement impairment. These predictive models have been used to enhance or modify both assessment and intervention, in the pursuit of optimal practice. The videos below are the modifications to Gluteus Medius MMT  and Gluteus Maximus MMT  (abductors and external rotators of the hip), as well as, suggested interventions (gluteus medius activation and gluteus maximus activation ) for addressing weakness/inhibition of these muscles.

Gluteus Medius Manual Muscle Testing for an Active Population:

Gluteus Maximus Manual Muscle Testing for an Active Population:

Gluteus Medius Activation:

Gluteus Medius Activation Progressions:

Gluteus Maximus Activation:

Quick Glute Activation Circuit:

Hop Down to Single Leg Touchdown to Balance:


  1. Noehren B, Hamill J, Davis I. Prospective Evidence for a Hip Etiology in Patellofemoral Pain. Medicine & Science in Sports & Exercise. 2013;45(6):1120–1124.
  2. Ramskov, D., Barton, C., Nielsen, R. O., & Rasmussen, S. (2015). High Eccentric Hip Abduction Strength Reduces the Risk of Developing Patellofemoral Pain Among Novice Runners Initiating a Self-Structured Running Program: A 1-Year Observational Study. journal of orthopaedic & sports physical therapy45(3), 153-161
  3. Padua, D. A., Bell, D. R., & Clark, M. A. (2012). Neuromuscular characteristics of individuals displaying excessive medial knee displacement. Journal of athletic training, 47(5), 525.
  4. Mauntel, T., Begalle, R., Cram, T., Frank, B., Hirth, C., Blackburn, T., & Padua, D. (2013). The effects of lower extremity muscle activation and passive range of motion on single leg squat performance. Journal Of Strength And Conditioning Research / National Strength & Conditioning Association, 27(7), 1813-1823.
  5. Bell, D. R., Oates, D. C., Clark, M. A., & Padua, D. A. (2013). Two-and 3-dimensional knee valgus are reduced after an exercise intervention in young adults with demonstrable valgus during squatting. Journal of athletic training,48(4), 442-449
  6. Snyder, K. R., Earl, J. E., O’Connor, K. M., & Ebersole, K. T. (2009). Resistance training is accompanied by increases in hip strength and changes in lower extremity biomechanics during running. Clinical Biomechanics, 24(1), 26-34

© 2015 Brent Brookbush

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