Variation of rotation moment arms with hip flexion

Delp, Scott L.; Hess, William E; Hungerford, David S.; Jones, Lynne C.

doi:10.1016/s0021-9290(99)00032-9

Cited by 297 publications

(209 citation statements)

References 8 publications

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“…While bilateral weakness may have contributed to the magnitude of this difference in hip extension strength, it is also possible that an order effect from testing hip abduction prior to hip extension was a confounding factor. Because the gluteus maximus is a secondary abductor of the hip, 6,14 symptomatic subjects may have experienced greater fatigue from testing hip abduction strength with 3 maximal trials than control subjects, resulting in lower strength values during hip extension testing, with a subsequent overestimation of the difference between groups for hip extension strength normalized to body mass. In spite of these confounding factors, it is also plausible that the impairments found in hip extension strength indicate that deficits in gluteus maximus function may have a significant impact on femoral alignment in patients experiencing anterior knee pain.…”

Section: Results Dmentioning

confidence: 99%

Analysis of Hip Strength in Females Seeking Physical Therapy Treatment for Unilateral Patellofemoral Pain Syndrome

Robinson¹,

Nee²

2007

J Orthop Sports Phys Ther

259

229

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Section: Results Dmentioning

confidence: 99%

Analysis of Hip Strength in Females Seeking Physical Therapy Treatment for Unilateral Patellofemoral Pain Syndrome

Robinson¹,

Nee²

2007

J Orthop Sports Phys Ther

259

229

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“…20 Gluteus maximus (K) and medius (L) hip internal rotation moment arms are compared to a previously-published model which separated the muscles into multiple compartments and was validated by experimental measurements. 14 …”

Section: Resultsmentioning

confidence: 99%

“…Individual fiber moment arms (ma fiber ) were calculated according to the principal of virtual work, 3 ma fiber = ∂l fiber /∂θ. We compared the fiber moment arms predicted by the models with moment arms determined from anatomical measurements 6,14,20,36 and published models of the lower extremity (with series-of-line-segment representations of muscle). 6,16 We also evaluated the models by comparing the changes in shape of the 3D muscle models with changes in shape measured from the MR images we acquired with the hip extended and flexed positions.…”

Section: Evaluations Of the Modelsmentioning

confidence: 99%

Three-Dimensional Representation of Complex Muscle Architectures and Geometries

2005

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Abstract-Almost all computer models of the musculoskeletal system represent muscle geometry using a series of line segments. This simplification (i) limits the ability of models to accurately represent the paths of muscles with complex geometry and (ii) assumes that moment arms are equivalent for all fibers within a muscle (or muscle compartment). The goal of this work was to develop and evaluate a new method for creating three-dimensional (3D) finite-element models that represent complex muscle geometry and the variation in moment arms across fibers within a muscle. We created 3D models of the psoas, iliacus, gluteus maximus, and gluteus medius muscles from magnetic resonance (MR) images. Peak fiber moment arms varied substantially among fibers within each muscle (e.g., for the psoas the peak fiber hip flexion moment arms varied from 2 to 3 cm, and for the gluteus maximus the peak fiber hip extension moment arms varied from 1 to 7 cm). Moment arms from the literature were generally within the range of fiber moment arms predicted by the 3D models. The models accurately predicted changes in muscle surface geometry over a 55• range of hip flexion, as compared to changes in shape predicted from MR images (average errors between the model and measured surfaces were between 1.7 and 5.2 mm). This new framework for representing muscle will enhance the accuracy of computer models of the musculoskeletal system.

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“…In addition, posterior fibers of the gluteus medius and minimus and piriformis muscles also work as hip internal rotators at 90° of hip flexion. Delp et al 2) reported that the anterior fibers of the gluteus maximus appear to switch the rotatory action toward internal rotation at around 45° of flexion, while the same fibers display an overall external rotation MA in the anatomical position, and MA of middle and posterior fibers of the gluteus maximus decrease with hip flexion. They also reported that internal rotation MA of the anterior fibers of the gluteus medius increases as the hip flexes, and that our result of that of the posterior fibers of the gluteus medius switches from external to internal rotator at around 45° of flexion 2) .…”

Section: Discussionmentioning

confidence: 99%

“…There are no primary hip internal rotators 1) , because the internal rotation moment arm (MA) is significantly shorter than the external rotation MA 2) . Although the muscles stated above serve as hip external rotators in the anatomical position, the actions of muscles around the hip depend on hip position in other positions 1,3) .…”

Section: Introductionmentioning

confidence: 99%

Differences of Isometric Internal and External Hip Rotation Torques among Three Different Hip Flexion Positions

Uritani

Fukumoto

2012

J Phys Ther Sci

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Abstract.[Purpose] The aim of this study was to investigate isometric internal and external rotation torques of the hip at three different flexed positions of the hip.[Subjects] Twenty healthy university students.[Methods] Isometric internal and external maximum rotation torques of the hip on both sides were measured using a torque machine in the recumbent, semi-recumbent and sitting positions. Dependent variables were the isometric internal and external rotation peak torques of the hip. Independent variables were the three testing positions and each side. Measured data were analyzed using two-way analysis of variance with a post-hoc test.[Results] Mean isometric internal rotation torque was significantly higher in the sitting position than in the recumbent or semi-recumbent positions. Torque was also significantly higher in the semi-recumbent position than in the recumbent position. No interaction between testing position and leg side was found. Regarding isometric external rotation, no interaction or main effects were found among the three positions.[Conclusion] Isometric hip internal rotation torque significantly increased as the hip flexed; however, external rotation did not change significantly.

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Variation of rotation moment arms with hip flexion

Cited by 297 publications

References 8 publications

Analysis of Hip Strength in Females Seeking Physical Therapy Treatment for Unilateral Patellofemoral Pain Syndrome

Analysis of Hip Strength in Females Seeking Physical Therapy Treatment for Unilateral Patellofemoral Pain Syndrome

Three-Dimensional Representation of Complex Muscle Architectures and Geometries

Differences of Isometric Internal and External Hip Rotation Torques among Three Different Hip Flexion Positions

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