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Cited by 101Muscle activation and electromyography studiesLower Extremity Biomechanics and PathologiesKnee injuries and reconstruction techniques

Electromyographic Analysis of the Squat Performed in Self-Selected Lower Extremity Neutral Rotation and 30° of Lower Extremity Turn-Out From the Self-Selected Neutral Position

Ninos, Joel C., Irrgang, James J., Burdett, Ray, Weiss, Jeffery R.·1997·Journal of Orthopaedic & Sports Physical Therapy
DOI 10.2519/jospt.1997.25.5.307
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Abstract

Little research is available on the muscle activity patterns of the lower extremity muscles during dynamic closed chain squatting activities. The purpose of this study was to examine the effect of lower extremity position during an Olympic squat on the muscle activity patterns of the vastus medialis, vastus lateralis, semimembranosus/semitendinosus, and biceps femoris. Twenty-five healthy, untrained subjects, 18-35 years old, were randomly assigned initial squatting positions of either self-selected neutral or 30 degrees of lower extremity turn-out from the self-selected neutral position. Surface electromyography and motion analysis data were collected simultaneously in 10 degrees intervals and analyzed from 10-60 degrees of knee flexion in both the ascending and descending phases of the squat. A four-way analysis of variance indicated that the main effect of lower extremity position and the interaction of extremity position and knee joint angles were not found to cause significant changes in muscle activity patterns. Significant changes in muscle activity did occur with changes in knee flexion angles in the vastus medialis and vastus lateralis but not in the semimembranosus/semitendinosus or biceps femoris.

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Crossref · 10.2519/jospt.1997.25.5.307

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  • Attainment of a forward trunk position using lumbar spine flexion results in decreased tolerance to compressive loads and lumbar spine anterior shear forces compared to when forward trunk inclination is achieved with a neutral spine position.

    “Attainment of a forward trunk position using lumbar spine flexion (Figure 2A) results in decreased tolerance to compressive loads14 and lumber spine anterior shear forces as compared to when forward trunk inclination is achieved with a neutral spine position (Figure 2B).15”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [14]

  • Maintaining a neutral spine position increases the moment arm for the spinal extensors, thereby allowing better control of compressive loads and shear forces.

    “Maintaining a neutral spine position increases the moment arm for the spinal extensors thereby allowing better control of compressive loads and shear forces.14,15”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [14]

  • Compressive and shear forces occur at the lumbar spine during squatting when posterior pelvic tilt is coupled with lumbar spine flexion.

    “Given that posterior pelvic tilt is coupled with lumbar spine flexion,37,38 compressive and shear forces occur at the lumbar spine.14,15,39”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [14]

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Authors
Ninos, J. C., Irrgang, J. J., Burdett, R., & Weiss, J. R.
Affiliations
University of Pittsburgh (US)
ORCID
Irrgang, James J.
Venue
Journal of Orthopaedic & Sports Physical Therapy
Publisher
Journal of Orthopaedic & Sports Physical Therapy (JOSPT)
Published
1997-05
Volume
25
Issue
5
Pages
307-315
ISSN
  • 0190-6011 (ISSN-L)
  • 1938-1344
DOI
10.2519/jospt.1997.25.5.307
OpenAlex
W1976000623
Cited by
101
References
9
Citations by year
2024: 2 · 2023: 1 · 2022: 2 · 2021: 2 · 2020: 3 · 2019: 3 · 2018: 3 · 2017: 2 · 2016: 5 · 2015: 8 · 2014: 4 · 2013: 6 · 2012: 5
FWCI
2.76
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 › Muscle activation and electromyography studies
  • Physical Sciences › Engineering › Biomedical Engineering › Lower Extremity Biomechanics and Pathologies
  • Health Sciences › Medicine › Surgery › Knee injuries and reconstruction techniques
Keywords
squatting, knee flexion angle, muscle activation patterns, vastus medialis, vastus lateralis, semimembranosus, semitendinosus, biceps femoris, closed kinetic chain exercises, knee joint angle
MeSH terms
Adolescent, Adult, Analysis of Variance, Electromyography, Female, Humans, Kinetics, Knee Joint, Leg, Male, Posture, Reference Values, Exercise, Muscle, Skeletal

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