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Tuesday, June 6, 2023

Hip Strengthening Prior to Functional Exercises Reduces Pain Sooner Than Quadriceps Strengthening in Females with Patellofemoral Pain Syndrome

Brent Brookbush

Brent Brookbush

DPT, PT, MS, CPT, HMS, IMT

Research Review: Comparing Hip Strengthening and Quadriceps Strengthening Prior to Functional Exercise in Females with Patellofemoral Pain Syndrome

By Tristan Rodik, M.AT, ATC

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

Original Citation: Dolak, K. L., Silkman, C., Medina McKeon, J., Hosey, R. G., Lattermann, C., and Uhl, T. L. (2011) Hip strengthening prior to functional exercises reduces pain sooner than quadriceps strengthening in females with patellofemoral pain syndrome: a randomized clinical trial. Journal of Orthopaedic and Sports Physical Therapy, 41(8), 560-570. ABSTRACT

Why the Study is Relevant: Patellofemoral pain syndrome (PFPS) is common in active populations and has been correlated with decreased hip abductor strength (1-7). PFPS interventions have focused on strengthening both the quadriceps and hip abductors simultaneously; although, little is known about the effectiveness of quadriceps strengthening compared to hip abductor strengthening (8, 9). This 2011 study investigated the effects of either hip abductors or quadriceps strengthening in preparation for functional activity, demonstrating that hip abductors strengthening prior to functional activity resulted in earlier and greater reductions in self-reported pain. The findings of this study support specific hip abductors strengthening exercise during the initial phase of rehabilitation in females with PFPS.

Karl Sterling, BI Presenter prepping to teach Gluteus Madius Activation
Caption: Karl Sterling, BI Presenter prepping to teach Gluteus Madius Activation

Karl Sterling, BI Presenter prepping to teach Gluteus Medius Activation

Study Design Randomized control trial
Level of Evidence IB Evidence from at least one randomized controlled trial
Subject Characteristics

Demographics

Hip abductors Strengthening Group

  • Age: 25 +/- 5 yrs
  • Gender: Female
  • Number of participants: 17
  • Height: 1.66 +/- 0.08 m
  • Body Mass Index: 24 +/- 4
  • Duration of symptoms: 36 +/- 34 months

Quadriceps Strengthening Group

  • Age: 26 +/- 6 yrs
  • Gender: Female
  • Number of participants: 16
  • Height: 1.66 +/- 0.08 m
  • Body Mass Index: 27 +/- 6
  • Duration of symptoms: 27 +/- 34 months

Inclusion Criteria:

  • Anterior or retropatellar knee pain during at least 2 of the following activities:
    • stair climbing
    • hopping
    • running
    • squatting
    • kneeling
    • prolonged sitting

  • Insidious onset of symptoms; symptoms unrelated to trauma
  • Pain with compression of the patella
  • Pain on palpation of patellar facets

Exclusion Criteria:

  • Symptoms present for less than 1 month
  • Knee pathology other than patellofemoral pain syndrome (PFPS)
  • Knee surgery within previous 12 months
  • Any other concurrent injury affecting the lower-extremity
Methodology
  • Participants were randomly assigned to the hip abductors or quadriceps strengthening groups
  • Two self-reported questionnaire's were completed during baseline and at 4- and 8-week testing periods:
    • The visual analog scale (VAS) was used to assess self-reported levels of pain over the previous week
    • The Lower Extremity Functional Scale (LEFS) was used to assess self-reported functional capacity

  • After the baseline questionnaire was completed, participants warmed up on a stationary bicycle for at least 3 minutes
  • Each group was then tested for isometric strength, and this was repeated at the 4- and 8-week testing periods. Tested muscles included:

  • Functional strength was measured using a step-down maneuver and was re-tested at the 4- and 8-week testing periods:
    • Participants performed as many repetitions as possible within 30 seconds

  • The affected extremity was tested throughout the duration of the study. For participants who had bilateral PFPS, the more severely affected extremity was tested.
  • H
  • Hip abductors or quadriceps exercises were completed for 4 weeks prior to progressing into functional exercises
    • The functional exercise phase continued for an additional 4 weeks

  • Both groups received an identical stretching protocol consisting of stretches for the hamstrings, quadriceps and triceps surae
    • Participants completed 3 sets of 30 seconds prior to strengthening exercises

  • Rehabilitative exercise was completed 3 times per week
    • 2 days at home
    • 1 day with a study investigator

Data Collection and Analysis
  • A handheld dynamometer was used for all isometric strength testing (JTech Commander PowerTrack II Muscle Dynamometer; OPS Medical, LLC, Pasadena, MD)
  • The functional step-down task used a step that was 20-cm in height
  • Group allocation consisted of a random-number generator in Microsoft Excel (Microsoft Corporation, Redwood, WA)
  • Intraclass correlation coefficients (ICCs) were used to calculate between-day reliability for isometric strength testing
  • Separate 2-way ANOVAs were performed to analyze questionnaire's, functional testing results and isometric strength testing results
  • All data were analyzed at an alpha level of 0.05
  • A Bonferonni post hoc analysis was used to measure differences from the ANOVA
  • Statistical analyses were ran using SPSS Version 17 (Chicago, IL)
Outcome Measures
  •  Outcome measures consisted of the following questionnaire's and tests conducted during baseline, 4- week and 8-week testing periods:
    • The VAS
    • The LEFS
    • Isometric strength testing
    • Functional testing using the step-down task

  • VAS and LEFS scores were also recorded during a 3-month follow-up
Results
  • 26 participants completed the study

Questionnaire Results

  • VAS scores for the hip abductors and quadriceps strengthening groups for all follow-up periods were, respectively:
    • Baseline: 4.6 +/- 2.5 and 4.2 +/- 2.3
    • 4-week:  2.4 +/- 2.0 and 4.1 +/- 2.5 (p = 0.035)
    • 8-week: (Both groups noted significant reductions in pain compared to baseline) 2.4 (p = 0.003) and 2.6 (p = 0.028)
    • 3-month: 2.1 +/- 2.5 and 2.4 +/- 2.3

  • At the 4 week follow-up, only the hip abductors group noted significant reductions in VAS scores (p = 0.001)
  • LEFS scores for the hip abductors and quadriceps strengthening groups for all follow-up periods were, respectively:
    • Baseline: 59 +/- 12 and 54 +/- 12
    • 4-week: 67 +/- 11 and 59 +/- 14
    • 8-week: 70 +/- 10 and 65 +/- 13
    • 3 month: 70 +/- 10 and 67 +/- 11

  • LEFS scores were not significantly different between groups (p = 0.65)
    • At 4 weeks all participants significantly improved from 56.5 +/- 12.2 to 63 +/- 12.7 (p = 0.006)
    • At 8 weeks all participants significantly improved compared to the 4 week follow-up (67.6 +/- 11.5, p = 0.006)

Functional Testing Results

  • Step-down data significantly improved for both groups but did not differ between groups:
    • Baseline results: 15 +/- 6
    • 4-week follow-up: 17 +/- 6 (p = 0.006)
    • 8-week follow-up: 19 +/- 5 (p < 0.001)

Isometric Strength Testing Results

  • Hip abduction strength improved for the hip strengthening group across the 8-week span (p = 0.001)
    • The quadriceps group did not significantly improve (p = 0.9)

  • Hip external rotation strength did not significantly differ between groups (p = 0.06) but both groups did significantly improve at the 8-week follow-up (p = 0.004)
  • Knee extensor strength did not significantly improve among both groups at the 8-week follow-up (p = 0.12) 
Our ConclusionsThis study adds to the growing body of research supporting the use of hip abductors strengthening exercises in clients presenting with PFPS (10, 11). The findings revealed that participants in the hip abductors strengthening group had significant reductions in self-reported pain sooner than those in the quadriceps strengthening group. Individuals presenting with Lower Extremity Dysfunction (LED) should incorporate hip strengthening exercises prior to multi-joint exercise and functional activities to reduce pain and improve functional outcomes.
Researchers' Conclusions

This study supports the use of proximal muscular strengthening in females presenting with PFPS. Hip abductors strengthening may be more appropriate than quadriceps strengthening prior to functional exercise. This may be due to hip abductors muscle retraining being less likely to exacerbate symptoms of PFPS. Both groups noted similar improvements in self-reported function, the step-down task and hip strength, but the hip strengthening group reported earlier and more significant reductions in self-reported pain.

Review and Commentary:

This study adds to the growing body of research supporting the recommendation of hip strengthening for clients presenting with patellofemoral pain syndrome (PFPS) (5, 10, 11). The researchers compared the effects of hip abductors and quadriceps strengthening prior to functional exercise in females presenting with PFPS. The findings suggest that performing hip abductors strengthening exercises prior to functional exercise results in greater and earlier reductions in pain.

This study had many methodological strengths, including:

  • The researchers mentioned that the varying presentations of PFPS may present a wide spectrum of limitations; however, The Brookbush Institute (BI) believes this may also be a strength, as PFPS patients present in variety of ways.
  • The positions used for isometric strength testing are commonly used by human movement professionals; improving applicability and replicability of the study.
  • Human movement professionals commonly use the exercises performed by both groups; again, improving applicability.
  • Randomize control trials, as well as practical comparative studies are rare in human movement science. The design of this study should be replicated in future research comparing other exercises and techniques, and for other common orthopedic issues.

Weaknesses that should be noted prior to clinical integration:

  • Examiners were not blinded which may have resulted in experimenter bias.
  • A larger number of participants may have aided in validating a trend regarding the Lower Extremity Functional Scale, hip external rotation strength and knee extensor strength between both groups, possibly providing additional support for hip strengthening prior to functional exercise.
  • A larger number of participants may have aided in determining a trend regarding the step-down task. The quadriceps strengthening group experienced greater improvements in this functional test but it was not statistically significant compared to the hip strengthening group.
  • The participants in this study were young (25 +/- 5 yrs) females, which may limit generalizability.

Why the Study is Important:

Researchers have established a relationship between hip abductors weakness and patellofemoral pain syndrome (PFPS) (1-5, 12, 13). To the authors' knowledge, this is the first randomized controlled trial to compare hip abductors or quadriceps strengthening on both subjective and objective outcomes in females presenting with PFPS. The outcomes suggest that subjective markers of improvement are better in women with PFPS when isolated hip abductor strengthening is recommended prior to functional exercise.

How the Findings Apply to Practice:

The findings of this study demonstrates that human movement professionals should prioritize assessment/intervention for hip abductor strength over the assessment/intervention for the quadriceps in individuals exhibiting signs of PFPS. Further. This study may also support the use of isolated activation exercise before multi-joint functional activities.

How this Study Relates to Brookbush Institute Content:

Individuals presenting with Lower-Extremity Dysfunction (LED), Lumbo Pelvic Hip Complex Dysfunction  (LPHCD) and/or Sacroiliac Joint Dysfunction (SIJD) most often present with gluteus medius and gluteus maximus inhibition, and the Brookbush Institute (BI) strongly recommends gluteus medius and gluteus maximus isolated activation exercise for all related diagnosis/symptoms. Patellofemoral pain syndrome (PFPS) is a common symptom/diagnosis correlated with these movement impairments. Further, this study provides support for isolated strengthening performed prior to multi-joint exercise, and the "order of intervention" recommended by the BI. Sample assessment and exercise videos below:

Manual Muscle Testing of the Gluteus Medius

Side-lying Gluteus Medius Exercises

Gluteus Medius Reactive Integration Exercises

Posterior Oblique Subsystem Integration Exercises

Lateral Subsystem Integration Exercises

Recommended Readings:

  1. Gluteus Medius Activation
  2. Panel Discussion: Core Subsystems and Clinical Integration
  3. Additional Clinical Considerations When Implementing Subsystem Integration

Bibliography:

  1. Bolgla, L. A., Malone, T. R., Umberger, B. R., and Uhl, T. L. (2011) Comparison of hip and knee strength and neuromuscular activity in subjects with and without patellofemoral pain syndrome. International Journal of Sports Physical Therapy, 6(4), 285-296.
  2. Bolgla, L. A., Malone, T. R., Umberger, B. R., and 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.
  3. Ramskov, D., Barton, C., Nielson, R. O., and 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 and Sports Physical Therapy, 45(3), 153-161.
  4. Boling, M. C., Padua, D. A., and Alexander Creighton, R. (2009) Concentric and eccentric torque of the hip musculature in individual with and without patellofemoral pain. Journal of Athletic Training, 44(1), 7-13.
  5. Ireland, M. L., Willson, J. D., Ballantyne, B. T., and Davis, I. M. (2003) Hip strength in females with and without patellofemoral pain. Journal of Orthopaedic and Sports Physical Therapy, 33(11), 671-676.
  6. Giles, L. S., Webster, K. E., McClelland, J. A. and Cook, J. (2013) Does quadriceps atrophy exist in individuals with patellofemoral pain? A systematic literature review with meta-analysis. Journal of Orthopaedic and Sports Physical Therapy, 43(11), 766-776
  7. Kooiker, L., Van De Port, I. G., Weir, A. and Moen, M. H. (2014) Effects of physical therapist-guided quadriceps-strengthening exercises for the treatment of patellofemoral pain syndrome: a systematic review. Journal of Orthopaedic and Sports Physical Therapy, 44(6), 391-B1
  8. Clark, D. I., Downing, N., Mitchell, J., Coulson, L., Syzpyrt, E. P. and Doherty, M. (2000) Physiotherapy for anterior knee pain: a randomised controlled trial. Annals of Rheumatic Disease, 59(9), 700-704
  9. Boling, M. C., Bolgla, L. A., Mattacola, C. G., Uhl, T. L. and Hosey, R. G. (2006) Outcomes of a weight-bearing rehabilitation program for clients diagnosed with patellofemoral pain syndrome. Archives of Physical Medicine and Rehabilitation, 87(11), 1428-1435
  10. Mascal, C. L., Landel, R., and Powers, C. (2003) Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports. Journal of Orthopaedic and Sports Physical Therapy, 33(11), 647-660
  11. Nakagawa, T. H., Muniz, T. B., Baldon Rde, M., Dias Maciel C., de Menezes Reiff, R. B., and Serrao, F. V. (2008) The effect of additional strengthening of hip abductor and lateral rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot study. Clinical Rehabilitation, 22(12), 1051-1060.
  12. Robinson, R. L. and Nee, R. J. (2007) Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. Journal of Orthopaedic and Sports Physical Therapy, 37(5), 232-237
  13. Piva, S. R., Goodnite, E. A., and Childs, J. D. (2005) Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome. Journal of Orthopaedic and Sports Physical Therapy, 35(12), 793-801

© 2017 Brent Brookbush

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