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Cited by 105Lower Extremity Biomechanics and PathologiesKnee injuries and reconstruction techniquesMuscle activation and electromyography studies

Patellofemoral joint stress during weight bearing and non-weight bearing quadriceps exercises

Powers, Christopher M., Ho, Kai-Yu, Chen, Yu-Jen, Souza, Richard B., Farrokhi, Shawn·2014·Journal of Orthopaedic & Sports Physical Therapy
DOI 10.2519/jospt.2014.4936
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Abstract

STUDY DESIGN: Single-group, repeated-measures design. OBJECTIVE: To compare patellofemoral joint (PFJ) stress among weight-bearing and non-weight-bearing quadriceps exercises. BACKGROUND: An important consideration when prescribing exercises to strengthen the quadriceps in persons with patellofemoral pain is to minimize PFJ loading. Currently, there is disagreement in the literature as to which exercises and ranges of motion best accomplish this goal. METHODS: Ten healthy subjects participated. Lower extremity kinematics, kinetics, and electromyography of the knee musculature were obtained during a weight-bearing squatting exercise and 2 non-weight-bearing knee extension exercises: (1) knee extension with variable resistance, and (2) knee extension with constant resistance. A previously described biomechanical model was used to estimate PFJ stress at 0°, 15°, 30°, 45°, 60°, 75°, and 90° of knee flexion. PFJ stress was compared among the 3 exercises using a 2-way analysis of variance with repeated measures. RESULTS: Compared to the 2 non-weight-bearing exercises, the squat exercise produced significantly higher PFJ stress at 90°, 75°, and 60° of knee flexion. Conversely, the 2 non-weight-bearing exercises produced significantly higher PFJ stress at 30°, 15°, and 0° of knee flexion when compared to the squat exercise. The knee-extension-with-variable-resistance exercise produced significantly lower PFJ stress than the knee-extension-with-constant-resistance exercise at 90°, 75°, and 60° of knee flexion. CONCLUSION: To minimize PFJ stress while performing quadriceps exercises, our data suggest that the squat exercise should be performed from 45° to 0° of knee flexion and the knee-extension-with-variable-resistance exercise should be performed from 90° to 45° of knee flexion.

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  • Studies examining muscle recruitment with increasing squat depth are conflicting.

    “Apart from the influence of squat depth on hip and knee moments, studies examining muscle recruitment with increasing depth are conflicting.”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [36]

  • Some studies have reported an increase in quadriceps EMG activity with squat depth (29%), while others have not.

    “In regards to quadriceps activity, some studies have reported an increase in EMG activity with squat depth (29%),35 while others have not.1,5,36”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [36]

  • When comparing partial to deep squats, gluteus maximus activity has been reported to be higher with partial depths (absolute difference: 29% MVIC).

    “When comparing partial to deep squats, gluteus maximus activity has been reported to be higher with partial depths (absolute difference: 29% MVIC).36”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [36]

  • Studies have reported no change or a slight decrease in hamstring activation (absolute difference: 12% MVIC) with increasing squat depth.

    “Similarly, evidence related to hamstring activity also is conflicting, as studies have reported no change1,5,35 or a slight decrease in activation (absolute difference: 12% MVIC) with increasing squat depth.36”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [36]

  • There is evidence that shallow squats may be more desirable for gluteus maximus activation compared to deep squats.

    “Furthermore, there is evidence that shallow squats may be more desirable for gluteus maximus activation compared to deep squats.36”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [36]

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Authors
Powers, C. M., Ho, K.-Y., Chen, Y.-J., Souza, R. B., & Farrokhi, S.
Affiliations
University of Southern California (US)
ORCID
Venue
Journal of Orthopaedic & Sports Physical Therapy
Publisher
Journal of Orthopaedic & Sports Physical Therapy (JOSPT)
Published
2014-05
Volume
44
Issue
5
Pages
320-327
ISSN
  • 0190-6011 (ISSN-L)
  • 1938-1344
DOI
10.2519/jospt.2014.4936
OpenAlex
W1975850183
Cited by
105
References
29
Citations by year
2026: 8 · 2025: 15 · 2024: 10 · 2023: 9 · 2022: 8 · 2021: 6 · 2020: 8 · 2019: 8 · 2018: 15 · 2017: 9 · 2016: 5 · 2015: 4
FWCI
3.11
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of Orthopaedic and Sports Physical Therapy (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Lower Extremity Biomechanics and Pathologies
  • Health Sciences › Medicine › Surgery › Knee injuries and reconstruction techniques
  • Physical Sciences › Engineering › Biomedical Engineering › Muscle activation and electromyography studies
Keywords
patellofemoral joint stress, patellofemoral pain, quadriceps exercise, weight-bearing exercise, squatting, knee extension, variable resistance, constant resistance, knee flexion range of motion, exercise prescription, knee kinematics, knee kinetics
MeSH terms
Adult, Biomechanical Phenomena, Female, Humans, Male, Stress, Mechanical, Range of Motion, Articular, Weight-Bearing, Quadriceps Muscle, Muscle Strength, Resistance Training, Young Adult, Patellofemoral Joint

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