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Tuesday, June 6, 2023

Effect of Knee Joint Mobilization on Quadriceps Muscle Strength

Brent Brookbush

Brent Brookbush


Research Review: Knee Joint Mobilizations Improve Quadriceps Muscle Activation

By Nicholas Rolnick PT, DPT, MS, CSCS

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

Original Citation: Ghanbari A. and Kamalgharibi S. (2013). Effect of knee joint mobilization on quadriceps muscle strength. International Journal of Health and Rehabilitation Sciences. 2(4): 186-191. FULL ARTICLE

Why the Study is Relevant: Research has demonstrated altered activity/strength in muscles that cross the hip and thoracic spine immediately post mobilizations/manipulations (1-4). Whether a similar pattern exists in the muscles crossing the knee had not been investigated prior to this 2013 study from Iran. Researchers investigated the effect of grade 4 posterior-anterior tibiofemoral (knee) joint mobilizations on quadriceps muscle strength in 35 healthy women, demonstrating similar increases in muscle strength as seen in studies on other body regions. The findings suggest, human movement professionals should perform knee joint mobilizations (when necessary) prior to activation and strengthening exercises for the quadriceps .

The Brookbush Institute's recommended self-administered knee joint mobilization encourages anterior tibial glide, which is similar to the mobilization goal in this study. Image courtesy of BrentBrookbush.com

Study Summary

Study DesignQuasi-experimental repeated measures
Level of EvidenceIIB: Evidence from at least one other type of quasi-experimental study
Subject Characteristics
  • Number: 35
  • Gender: Female
  • Age: 22.14 ± 2.39 years old
  • Height: 160.43± 5.773 cm
  • Mass: 54.44±7.439 kg

Inclusion Criteria:

  • Between 18-30 years' old
  • No acute or chronic knee joint issues

Exclusion Criteria:

  • A history of trauma, surgery, disease or pathology
  • Prior to the intervention, the maximum voluntary isometric contraction (MVIC) of the dominant-leg quadriceps was measured with a digital strain dynamometer.
    • Each participant was positioned in 90° of hip and knee flexion with a strap attached to the distal lower leg.
    • Contractions were held for 5 seconds, with 10-second rest intervals.
    • The average of three contractions was used to calculate baseline quadriceps strength.

  • The intervention consisted of 3 minutes of grade 4 posterior-anterior mobilizations applied to the tibiofemoral (knee) joint with the participant seated with hip and knee bent to 90° of flexion.
  • Following the intervention and 30-minutes later, each participant underwent quadriceps MVIC testing with the digital strain dynamometer.
    • Participants remained still between measurements.

Data Collection and Analysis
  • One-way repeated-measures analysis of variance (ANOVA) compared the quadriceps MVIC pre- and post-intervention.
    • If a significant difference was detected, a post-hoc pair-wise comparison was performed.

Outcome Measures
  • Mean Maximum Voluntary Isometric Contraction (MVIC) of the quadriceps before, immediately after and 30-minutes post-mobilization.
  • Percent change in quadriceps MVIC between conditions
Results Quadriceps MVIC - Mean (± Standard Deviation) (in Newtons, N):
  • Pre-Intervention (PI): 119.00 ± 40.17 N
  • Immediately Following Intervention (IFI): 141.26 ± 44.94 N
  • 30-Minutes Following Intervention (30I): 147.13 ± 44.70 N

Percent Change Between Conditions:

  • Between PI and IFI: 18.7%, p = 0.0001*
  • Between PI and 30I: 23.6%, p = 0.0001*
  • Between IFI and 30I: 4.2%, p = 0.088

*  = statistically significant difference

Our Conclusions

The results provide additional support for a the hypothesis that the human movement system is a holistic system. That is, techniques intended to address a tissue type or structure will also affect other proximal tissues and structures. Further, this study may provide evidence that supports including joint mobilizations in an integrated treatment approach.

Specifically, this study supports performing knee joint mobilizations (when necessary) prior to muscle activation/strengthening techniques on individuals who exhibit quadriceps muscle under-activity/weakness.

Researchers' Conclusions

Quadriceps muscle activation improves for at least 30 minutes following posterior-anterior grade 4 joint mobilizations. Joint mobilizations may be effective adjuncts to rehabilitation and strengthening programs.

Knees Bow-In detected in the Overhead Squat Assessment is an indication of Vastus Medialis Obliquus under-activity. - Image courtesy of BrentBrookbush.com

Review & Commentary:

To our knowledge, this study was the first to investigate the immediate effects of knee joint mobilization on quadriceps  muscle strength. The findings add to the growing body of research on the acute effects of joint mobilization/manipulation on muscle activity/strength.

The study had many methodological strengths, including:

  • The mobilization that was performed is a common treatment technique in clinical practice. This increases the practicality of the study.
  • The findings filled a gap in the body of research. Prior to this study, it was unknown whether knee joint mobilization could improve quadriceps muscle strength.
  • Although not enough to imply carry-over, the additional measurement of muscle strength 30 minutes post intervention demonstrates that the effect will last at least the duration of an appointment/treatment session.

Weaknesses that should be noted prior to clinical integration include:

  • The reliability of the clinician's grading (applied force) during joint mobilizations was not determined.
  • The determination of maximum isometric voluntary contraction of the quadriceps  post-intervention may have improved due to participants' familiarity of the testing procedure. Future studies should include electromyography to help differentiate between muscle strength and muscle activation levels following joint mobilizations.
  • The lack of follow-up and the design of the study do not permit speculation on the long-term effects of knee joint mobilizations on quadriceps  strength.
  • The participants were asymptomatic. It is unknown whether individuals with pain would exhibit similar effects.

How This Study is Important:

This study adds to a growing body of research that suggests joint mobilizations have an effect on proximal muscle recruitment, activity and strength. This relationship implies that joint mobilizations may be an important component of an integrated approach.

How the Findings Apply to Practice:

Human movement professionals should consider incorporating knee joint mobilizations  (when assessment implies stiffness) into a program that includes a goal of increased quadriceps muscle strength. Based on the results of this study and additional studies on other body regions (1-4), the Brookbush Institute recommends joint mobilizations should be performed prior to activation techniques .

How does it relate to Brookbush Institute Content?

The findings of this study support the Brookbush Institute’s (BI) integrated approach and order of treatment for individuals exhibiting lower extremity dysfunction (LED) . In LED , vastus medialis obliquus (VMO) is classified as long/underactive. Based on the results of this study, mobilizing the knee joint prior to VMO activation techniques may enhance quadriceps force production. In conjunction with the BI's approach to addressing postural dysfunction, release techniques performed on the biceps femoris and vastus lateralis before knee joint mobilization may provide additional increases in quadriceps activity.

Human movement professionals should add self-administered knee joint mobilizaitons to programs designed to improve clients' quadriceps strength. While the self-administered mobilization currently recommended by the BI does not resemble the one performed in this study, both facilitate relative anterior glide of the tibia on the femur. Human movement professionals who have a scope of practice that includes joint-based approaches (DO’s, DPTs, DCs, ATCs) may consider manual joint mobilizations prior to activation techniques. Future videos will cover manual joint mobilization and manipulation.

The following videos illustrate a sample of techniques related to knee mobilization (independent variable) and quadriceps strength (dependent variable):

Manual Knee Joint Mobilization

Self-Administered Knee Joint Mobilization

VMO Activation

VMO Activation Progressions


  1. Liebler EJ, Tufano-Coors L, Douris P, Makofsky HW, McKenna R, Michels C, Rattray S. The effect on thoracic spine mobilization on lower trapezius strength testing. J Manual manipulative Ther. 2001; 9(4): 207-212.
  2. Cleland J, Selleck B, Stowell T, Brown L, Alberini S, St. Cyr H, Caron T. Short-term effects of thoracic manipulation on lower trapezius muscle strength. Journal of Manual & Manipulative Therapy. 2004; 12(2): 82-90.
  3. Yerys, S., Makofsky, H., Byrd, C., Pennachio, J., & Cinkay, J. (2002). Effect of mobilization of the anterior hip capsule on gluteus maximus strength. Journal of Manual & Manipulative Therapy10(4), 218-224.
  4. Makofsky, H., Panicker, S., Abbruzzese, J., Aridas, C., Camp, M., Drakes, J., … & Sileo, R. (2007). Immediate effect of grade IV inferior hip joint mobilization on hip abductor torque: a pilot study. Journal of Manual & Manipulative Therapy15(2), 103-110.

© 2017 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -