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Tuesday, June 6, 2023

Predictors of Excessive Hip Internal Rotation During Running

Brent Brookbush

Brent Brookbush


Predictors of Hip Internal Rotation During Running:

An Evaluation of Hip Strength and Femoral Structure in Women with and without Patellofemoral Pain

By Tristan J. Rodik, ATC, MA

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

Original Citation: Souza, R. B. & Powers, C. M. (2009) An evaluation of hip strength and femoral structure in women with and without patellofemoral pain. The American Journal of Sports Medicine, 37(3), 579-587. doi: 10.1177/0363546508326711 - ARTICLE

Why the study is relevant: Patellofemoral pain (PFP) has been correlated with lower extremity malalignment including excessive hip internal rotation and adduction (6, 8, 9). This malalignment may contribute to an increase in local compressive forces within the joint (7). Abnormal femoral structure and relative weakness of hip abductor/extenors may contribute to altered alignment in those exhibiting PFP (4, 6, 8) This 2009 study investigated the contribution of hip-muscle strength and femoral structure to internal rotation during running in woman with PFP. This study suggest that excessive internal rotation during running is strongly correlated with a decrease in gluteus medius and gluteus maximus strength and endurance, and that femur morphology is not strongly correlated.

3 Images of individuals with a functional knee valgus - excessive femoral internal rotation and adduction.
Caption: 3 Images of individuals with a functional knee valgus - excessive femoral internal rotation and adduction.

3 Images of "Functional Knee Valgus" - Excessive adduction and internal rotation of the hip.

Study Summary

Study DesignCross-sectional study
Level of EvidenceIII - evidence from non-experimental descriptive studies, such as comparative studies, correlation studies and case-control studies.
Subject Characteristics



  • Age (years): 27 (+/- 6)
  • Gender: female
  • Number: 38
  • Height (meters): 1.69 m (+/- 0.08)
  • Weight (kilograms): 64.7 kg (+/- 10.4)
  • Young and active

Inclusion Criteria: Patellofemoral (PFP) Group:

  • Physically active
  • Pain upon palpation of the patella
  • Pain (3/10 visual analog scale) reproduced during two or more of the following activities: going up/down stairs; squatting; kneeling; extended sitting; or an isometric quadriceps contraction.
  • Pain for more than 3 months at the time of enrollment

Exclusion Criteria (PFP Group):

  • History of knee surgery, patellar instability, or neurological condition effecting gait
  • Age 45+ years

Inclusion Criteria (Control Group):

  • Age matched, active controls who reported no knee pain

Exclusion Criteria (Control Group):

  • N/A
  • The 38 participants were divided into two groups of 19: PFP group and matched-control group
  • 5 participants presented with bilateral PFP, in which the more painful joint was tested. The remaining 14 participants in the PFP group underwent testing for the painful side.
  • All participants participated in 3 types of testing: kinematic evaluation during running; hip-muscle performance testing; and magnetic resonance imaging (MRI).

Kinematic Evaluation:

  • Reflective markers connected to Vicon workstation software, which was transferred into Visual3D (C-Motion, Rockville, Maryland), were used for testing.
  • Performed during a steady running velocity of 180m/min (6.7 mph) +/- 5%
  • Three trials were conducted; trials were deemed successful when the participants landed within the borders of a force plate.

Hip Muscle Performance Testing:

  • Hip muscle performance was tested via a Primus RS multimodel dynamometer (BTE Technologies, Hanover, MD) on a different day than the kinematic evaluation.
    • Standing pelvic drop (standing on affected leg, with non-affected/less painful limb unsupported)
    • Seated hip external rotation (both hip and knee at 90° of flexion)
    • Prone hip extension (hip 30° and knee 90° of flexion)
    • Side-lying hip abduction (neutral hip and knees, no extension or flexion)

  • The standing pelvic drop and prone hip extension were measured isometrically, isokinetically and isotonically.
  • Hip external rotation and side-lying hip abduction were measured isometrically.
  • All hip-muscle performance testing involved 3 trials with a 1-minute rest interval between trials and a 2-minute rest interval between positions.

MRI Testing:

  • A coronal T1-weighted image of the femur was taken to assess femoral inclination and anteversion
Data Collection and Analysis
  • Isometric and isokinetic testing peak torque values were normalized to body mass
  • Isokinetic testing calculated the average torque of 10 repetitions
  • Isotonic endurance testing involved as many repetitions as possible at the designated power output
  • Independent T-tests were used to assess differences between groups in the 3 tested parameters
  • Structural variables via MRI and average hip internal rotation were assessed with Pearson correlations
ResultsHip Kinematics When Running
  •  The PFP group demonstrated significantly greater hip internal rotation than the control group ( p < .001), with 8.2° +/- 6.6° for the PFP group and 0.3° +/- 3.6° for the control

Hip Muscle Performance Testing (measured in Nm/kg)

  • Isometric testing, the PFP group had significantly (p < 0.05) lower torque values in all testing positions:
    • Pelvic drop: 1.86 (+/- 0.48) to 2.34 ( +/- 0.35)
    • Hip external rotation: 0.56 (+/- 0.13) to 0.69 (+/- 0.11)
    • Hip extension: 1.98 (+/- 0.50) to 2.35 (+/- 0.38)
    • Side-lying abduction: 1.39 (+/- 0.41) to 1.62 (+/- 0.26)

  • Isokinetic testing, the PFP group demonstrated significantly (p <0.05) lower torque values during:
    • Ecccentric pelvic drop: 1.17 (+/- 0.40) to 1.50 (+/- 0.45);
    • Concentric hip extension: 0.78 (+/- 0.28) to 0.94 (+/- 0.15);

  • Isotonic testing, the PFP group did significantly (p <0.05) fewer repetitions:
    • Pelvic drop: 42.1 (+/- 23.3) to 68.7 (+/- 34.2)
    • Hip extension: 16.6 (+/- 7.5) to 31.9 (+/- 7.8)

  • Measurements for the concentric standing pelvic drop and eccentric prone hip extension ( p = 0.14 and 0.59, respectively) were similar in both groups.

Femoral Structure

  • The PFP group demonstrated significantly ( p < 0.05) greater femoral inclination, at 132.8° +/- 5.2°, than the control group at 128.4° + 5.0°.
  • Femoral anteversion was similar in both groups

Hip Internal Rotation Predictors When Running

  • Isotonic hip extension endurance
Our ConclusionsThis study suggest that a decrease in gluteus medius and gluteus maximus strength and endurance are correlated with excessive internal rotation during running.
Researchers' ConclusionsCorrelation analysis revealed that 3 variables were significantly associated with average hip internal rotation (during running):
  • Isometric hip extension torque (r = –.27; P =.046),
  • Hip extension endurance (r = –0.45; P = .002),
  • Average eccentric isokinetic torque during the pelvic drop test measured in total reps (r = –.30; P = .03)

Dr. Brookbush performing a Manual Muscle Test for Gluteus Maximus on a patient.
Caption: Dr. Brookbush performing a Manual Muscle Test for Gluteus Maximus on a patient.

Dr. Brookbush performing a Manual Muscle Test for Gluteus Maximus on a patient.

Review & Commentary

Prior research on individuals with patellofemoral pain syndrome (PFP) have investigated isometric strength of hip musculature, but these studies did not investigate isokinetic strength, isotonic strength, femur morphology, or correlation with excessive internal rotation during running (1, 2, 6, 10). The additional variables allowed for correlation analysis and a better understanding of factors contributing to, or resulting from PFP.

The study had many methodological strengths, including:

  • The use of isometric, isokinetic and isotonic muscle strength testing provides a more detailed account of the changes in muscle function related to PFP.
  • Measuring hip kinematics while running, hip muscle performance and femoral alignment in a single study allowed these factors to be compared for correlation analysis.
  • Using MRI (despite costs) to evaluate femoral inclination and anteversion angles provides strong evidence; MRI is the gold standard for measuring these angles. Note: their was a small but significant difference between groups for femoral inclination; however, the correlation between inclination and excessive internal rotation during running was weak. There was no difference in anteversion between groups.

Weaknesses and limitations:

  • All participants were young, active females, which may limit the generalizability of the findings.
  • Pre-testing activity was not dictated to participants, or not noted in the study's methodology; prior activity may have an impact on strength testing.
  • The use of isokinetic equipment for many of the tests makes applying methodology in practice challenging; however, it is possible to evaluate the same issues using standard clinical tests.

Why This Study is Important:

This study adds to a growing body of research investigating the altered movement patterns associated with patellofemoral pain (PFP). It is likely that the most important contribution of this study is the combined investigation of multiple strength variables, kinematics during and femur morphometry, allowing for correlation. The variables with the highest correlation (hip extension and single leg stance strength and endurance) should be the subject of more detailed investigation, and a prospective study on an intervention based on this data should be the subject future research.

How the Findings Apply to Practice:

This study suggests that hip extension strength and endurance should be assessed in those individuals with complaints associated with PFP. Further, hip extension strength and endurance, specifically eccentric strength may be important components of any program designed to address knee pain. This adds to the significant amount of research suggesting that hip abductor and external rotator strength may aid in optimizing lower extremity mechanics. Last, this study suggests that morphometry should not be used as excuse or explanation for a patient/clients PFP symptoms.

How Does it Relate to Brookbush Institute Content?

This study is congruent with the Brookbush Institute's (BI's) predictive models of Lower Extremity Dysfunction (LED) and Lumbo Pelvic Hip Complex Dysfunction (LPHCD) , both being correlated with knee pain or contributing to knee pain, and both recommending activation, integration and strengthening of the gluteus medius and gluteus maximus . A more subtle finding of this study is the small but significant difference in femur morphormetry that could not be strongly correlated with movement impairment (excessive hip internal rotation during running). The BI has continued to promote movement assessment, corrective exercise, and an integrated movement impairment approach to optimize motion in an attempt to reduce the risk of future injury. Their are a group of individuals who oppose this approach, claiming unique morphometry is the reason for individual differences in motion prior to any injury. The most popular focus of this argument is the position of the feet and knees during squatting. Due to the relatively small number of individuals exhibiting structural differences (< 7%) (12-13), and studies like this showing that small differences in morphometry do not matter, it would appear that the "anti-corrective exercise before injury" group cannot use unique morphometry to support their argument.

Below is a sampling of videos related to the findings in this study:

Gluteus Maxmimus Manual Muscle Testing

Isolated Gluteus Maximus Activation

Gluteus Maximus Activation Progression


  1. Bolgla, L. A., Malone, T. R., Umberger, B. R., & Uhl, T. L. (2008) Hip strength and hip and knee kinematics during stair descent in females with and without patellofemoral pain syndrome. Journal of Orthopaedic and Sports Physical Therapy, 38(1), 12-18
  2. Chichanowski, H. R., Schmitt, J. S., Johnson, R. J., & Niemuth, P. E. (2007) Hip strength in collegiate female athletes with patellofemoral pain. Medicine and Science in Sports and Exercise, 39, 1227-1232
  3. Creaby, M. W., Le Rossignol, S., Conway, Z. J., Ageberg, E., Sweeney, M., and Franettovich Smith, M. M. (2017) Frontal plane kinematics predict three-dimensional hip adduction during running. Physical Therapy in Sport, 27, 1-6
  4. Eckhoff, D. G., Montgomery, W. K., Kilcoyne, R. F., and Stamm, E. R. (1994) Femoral morphometry and anterior knee pain. Clinical Orthopaedics and Related Research, 302, 64-68
  5. Hall, C. M., and Brody, L. T. (2000) Therapeutic exercise: moving toward function. Philadelphia, PA: Lippincott Williams & Wilkins
  6. Ireland, M. L., Wilson, J. D., Ballantyne, B. T., & Davis, I. M. (2003) Hip strength in females with and without patellofemoral pain. Journal of Orthopaedic and Sports Physical Therapy, 33, 671-676
  7. Lee, T. Q., Morris, G., & Csintalan, R. P. (2003) The influence of tibial and femoral rotation on patellofemoral contact area and pressure. Journal of Orthopaedics and Sports Physical Therapy, 33, 686-693
  8. Powers, C. M. (2003) The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. Journal of Orthopaedic and Sports Physical Therapy, 33, 639-646
  9. Powers, C. M., Ward, S. R., Fredericson, M., Guillet, M., & Shellock, F. G. (2003) Patellofemoral kinematics during weight-bearing and non-weight-bearing knee extension in persons with lateral subluxation of the patella: a preliminary study. Journal of Orthopaedic and Sports Physical Therapy, 33, 677-685
  10. Robinson, R. L., Nee, R. J., Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. Journal of Orthopaedic and Sports Physical Therapy, 37, 232-238
  11. Willson, J. D., Kernozek, T. W., Arndt, R. L., Reznicheck, D. A., and Scott Straker, J. (2011) Gluteal muscle activation during running in females with and without patellofemoral pain syndrome. Clinical Biomechanics (Bristol, Avon), 26(7), 735-740
  12. Karimi-Mobarake, M., Kashefipour, A., Yousfnejad, Z. The prevalence of genu varum and genu valgum in primary school children in Iran 2003-2004. (2005) Journal of Medical Science 5(1). 52-54
  13. Ezoe, M., Naito, M., Inque, T. (2006). The prevalence of acetabular retroversion among various disorders of the hip. The Journal of Bone and Joint Surgery. 88A (2). 372-379

© 2017 Brent Brookbush

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