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Cited by 362Cerebral Palsy and Movement DisordersLower Extremity Biomechanics and PathologiesHip disorders and treatments

Variation of rotation moment arms with hip flexion

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Delp, Scott L, Hess, William E, Hungerford, David S, Jones, Lynne C·1999·Journal of Biomechanics
DOI 10.1016/s0021-9290(99)00032-9
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Abstract

Excessive flexion and internal rotation of the hip is a common gait abnormality among individuals with cerebral palsy. The purpose of this study was to examine the influence of hip flexion on the rotational moment arms of the hip muscles. We hypothesized that flexion of the hip would increase internal rotation moment arms and decrease external rotation moment arms of the primary hip rotators. To test this hypothesis we measured rotational moment arms of the gluteus maximus (six compartments), gluteus medius (four compartments), gluteus minimus (three compartments) iliopsoas, piriformis, quadratus femoris, obturator internus, and obturator externus. Moment arms were measured at hip flexion angles of 0, 20, 45, 60, and 90 degrees in four cadavers. A three-dimensional computer model of the hip muscles was developed and compared to the experimental measurements. The experimental results and the computer model showed that the internal rotation moment arms of some muscles increase with flexion; the external rotation moment arms of other muscles decrease, and some muscles switch from external rotation to internal rotation as the hip is flexed. This trend toward internal rotation with hip flexion was apparent in 15 of the 18 muscle compartments we examined, suggesting that excessive hip flexion may exacerbate internal rotation of the hip. The gluteus maximus was found to have a large capacity for external rotation. Enhancing the activation of the gluteus maximus, a muscle that is frequently underactive in persons with cerebral palsy, may help correct excessive flexion and internal rotation of the hip.

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  • FAI can result in chondrolabral damage, thereby contributing to early onset of hip osteoarthritis.

    “FAI, or abutment or impingement of the femoral neck against the acetabular labrum, can result in chondrolabral damage, thereby contributing to early onset of hip osteoarthritis.51,52”

    From A Biomechanical Review of the Squat Exercise: Implications for Clinical Practice. (2024) · cites this paper as [52]

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Authors
Delp, S. L., Hess, W. E., Hungerford, D. S., & Jones, L. C.
Affiliations
  • Stanford University (US)
  • Northwestern University (US)
  • Johns Hopkins University (US)
Corresponding author
Delp, Scott L
ORCID
Venue
Journal of Biomechanics
Publisher
Elsevier BV
Published
1999-05
Volume
32
Issue
5
Pages
493-501
ISSN
0021-9290 (ISSN-L)
DOI
10.1016/s0021-9290(99)00032-9
OpenAlex
W2162866558
Cited by
362
References
14
Citations by year
2026: 11 · 2025: 15 · 2024: 17 · 2023: 14 · 2022: 16 · 2021: 22 · 2020: 17 · 2019: 16 · 2018: 18 · 2017: 20 · 2016: 22 · 2015: 26 · 2014: 24 · 2013: 21 · 2012: 11
FWCI
2.60
Type
journal article
Language
en
Open access
Licence
Locations
  • Journal of Biomechanics (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
Funders
Eunice Kennedy Shriver National Institute of Child Health and Human Development (R01HD33929, R01HD033929)
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Cerebral Palsy and Movement Disorders
  • Physical Sciences › Engineering › Biomedical Engineering › Lower Extremity Biomechanics and Pathologies
  • Health Sciences › Medicine › Surgery › Hip disorders and treatments
Keywords
hip flexion, hip internal rotation, hip external rotation, gluteus maximus, gluteus medius, gluteus minimus, iliopsoas, piriformis, obturator muscle, quadratus femoris, cerebral palsy, gait disturbance, cadaveric measurement
MeSH terms
Biomechanical Phenomena, Buttocks, Cadaver, Cerebral Palsy, Computer Simulation, Femur, Gait, Hip Joint, Humans, Models, Biological, Muscle Contraction, Rotation, Thigh, Range of Motion, Articular, Psoas Muscles, Muscle, Skeletal

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