Direct comparison of in vivo Achilles tendon moment arms obtained from ultrasound and MR scans

2010 ◽  
Vol 109 (6) ◽  
pp. 1644-1652 ◽  
Author(s):  
Florian Fath ◽  
Anthony J. Blazevich ◽  
Charlie M. Waugh ◽  
Stuart C. Miller ◽  
Thomas Korff
Keyword(s):  
Achilles Tendon ◽  
Strong Relationship ◽  
Coefficient Of Determination ◽  
Moment Arm ◽  
Mr Images ◽  
Moment Arms ◽  
Musculoskeletal Models ◽  
Tendon Excursion ◽  
Differentiation Technique

Accurate and reliable estimation of muscle moment arms is a prerequisite for the development of musculoskeletal models. Numerous techniques are available to estimate the Achilles tendon moment arm in vivo. The purposes of this study were 1) to compare in vivo Achilles tendon moment arms obtained using the center of rotation (COR) and tendon excursion (TE) methods and 2) to assess the reliability of each method. For the COR method, magnetic resonance (MR) images from nine participants were obtained at ankle angles of −15°, 0°, and +15° and analyzed using Reuleaux' method. For the TE method, the movement of the gastrocnemius medialis-Achilles tendon junction was recorded using ultrasonography as the ankle was passively rotated through its range of motion. The Achilles tendon moment arm was obtained by differentiation of tendon displacement with respect to ankle angular excursion using seven different differentiation techniques. Moment arms obtained using the COR method were significantly greater than those obtained using the TE method ( P < 0.01), but results from both methods were well correlated. The coefficient of determination between moment arms derived from the COR and TE methods was highest when tendon displacement was linearly differentiated over a ±10° interval ( R2 = 0.94). The between-measurement coefficient of variation was 3.9% for the COR method and 4.5–9.7% for the TE method, depending on the differentiation technique. The high reliabilities and strong relationship between methods demonstrate that both methods are robust against their limitations. The large absolute between-method differences (∼25–30%) in moment arms have significant implications for their use in musculoskeletal models.

Estimation of Achilles Tendon Moment Arms In Vivo: A Novel Hybrid Method Using Ultrasound and Motion Analysis

2008 ◽  
Author(s):  
Justin D. Cowder ◽  
Nicole J. Chimera ◽  
Thomas S. Buchanan ◽  
Kurt T. Manal
Keyword(s):  
Achilles Tendon ◽  
Motion Capture ◽  
Moment Arm ◽  
Measurement Instruments ◽  
Center Of Rotation ◽  
Moment Arms ◽  
Rotation Methods ◽  
Hybrid Methodology ◽  
Tendon Excursion

The musculotendon moment arm (MA) is the perpendicular distance from a muscle’s line of action to the rotational center of a joint. Moment arms are important in muscle modeling [1], and thus their accuracy is of great importance. Current in vivo techniques for computing MAs include the center of rotation and tendon excursion methods [1, 2]. The tendon excursion (TE) method relates the change in musculotendon length to an angular change in joint position [3]. This requires two measurements of musculotendon length for each MA computed. Similarly, the center of rotation method requires multiple image-based geometry measurements to compute the MA for a specific joint angle. The TE and center of rotation methods are both prone to measurement error, and thus it is difficult to ascertain the accuracy of the resulting MA. In this paper we present a novel hybrid methodology combining ultrasound (US) and video-based motion capture to compute the Achilles tendon moment arm. An advantage of this approach is that data used to derive the MA are acquired using highly accurate and reliable measurement instruments (i.e, US & motion capture), which may improve the accuracy of the MA estimate. The purpose of this paper is to present the hybrid methodology and validation results based on testing the method using an animal model.

Achilles Tendon Moment Arms Computed Using Ultrasound and Motion Analysis: In Vivo Estimates for Male Subjects

2008 ◽  
Author(s):  
Justin D. Cowder ◽  
Thomas S. Buchanan ◽  
Kurt T. Manal
Keyword(s):  
Achilles Tendon ◽  
Motion Capture ◽  
Hybrid Method ◽  
Lower Limb ◽  
Muscle Force ◽  
Average Weight ◽  
Moment Arm ◽  
Moment Arms ◽  
Male Subjects

Accurate estimates for Achilles tendon moment arm (MA) are essential when computing gastroc-soleus force from the net plantarflexion moment. Errors in approximating the Achilles tendon MA will adversely affect the muscle force estimate. We have noted that Achilles tendon MAs reported by Maganaris [1] and others are significantly greater (> 1 cm) than values used by Delp et al. computed using SIMM [2]. It is important to note that the stature of Delp’s lower limb model was almost identical to the average weight and height of the subjects in a study by Maganaris. This led us to question which MA profiles were more anatomically meaningful. To address this, we calculated Achilles tendon MAs for 10 male subjects using a previously described method. The method combines ultrasound and video-based motion capture, and referred to as the hybrid method. Subjects in our study were chosen to ensure they were of a similar stature to those tested by Maganaris, thereby minimizing confounding effects of subject anthropometrics.

scholarly journals A Hybrid Method for Computing Achilles Tendon Moment Arm Using Ultrasound and Motion Analysis

2010 ◽  
Vol 26 (2) ◽  
pp. 224-228 ◽  
Author(s):  
Kurt Manal ◽  
Justin D. Cowder ◽  
Thomas S. Buchanan
Keyword(s):  
Achilles Tendon ◽  
Motion Capture ◽  
Hybrid Method ◽  
Moment Arm ◽  
Measurement Instruments ◽  
Moment Arms ◽  
Perpendicular Distance ◽  
The Moment ◽  
Joint Center

In this article, we outline a method for computing Achilles tendon moment arm. The moment arm is computed from data collected using two reliable measurement instruments: ultrasound and video-based motion capture. Ultrasound is used to measure the perpendicular distance from the surface of the skin to the midline of the tendon. Motion capture is used to determine the perpendicular distance from the bottom of the probe to the ankle joint center. The difference between these two measures is the Achilles tendon moment arm. Unlike other methods, which require an angular change in joint position to approximate the moment arm, the hybrid method can be used to compute the moment arm directly at a specific joint angle. As a result, the hybrid method involves fewer error-prone measurements and the moment arm can be computed at the limits of the joint range of motion. The method is easy to implement and uses modalities that are less costly and more accessible than MRI. Preliminary testing using a lamb shank as a surrogate for a human ankle revealed good accuracy (3.3% error). We believe the hybrid method outlined here can be used to measure subject-specific moment arms in vivo and thus will potentially benefit research projects investigating ankle mechanics.

scholarly journals Interactive Effects of Joint Angle, Contraction State and Method on Estimates of Achilles Tendon Moment Arms

2013 ◽  
Vol 29 (2) ◽  
pp. 241-244 ◽  
Author(s):  
Florian Fath ◽  
Anthony J. Blazevich ◽  
Charlie M. Waugh ◽  
Stuart C. Miller ◽  
Thomas Korff
Keyword(s):  
Achilles Tendon ◽  
Joint Angle ◽  
Input Parameter ◽  
Maximum Voluntary Contraction ◽  
Muscular Contraction ◽  
Voluntary Contraction ◽  
Interactive Effects ◽  
Moment Arm ◽  
Moment Arms ◽  
Musculoskeletal Models

The muscle-tendon moment arm is an important input parameter for musculoskeletal models. Moment arms change as a function of joint angle and contraction state and depend on the method being employed. The overall purpose was to gain insights into the interactive effects of joint angle, contraction state and method on the Achilles tendon moment arm using the center of rotation (COR) and the tendon excursion method (TE). Achilles tendon moment arms were obtained at rest (TErest, CORrest) and during a maximum voluntary contraction (CORMVC) at four angles. We found strong correlations between TErest and CORMVC for all angles (.72 ≤ r ≤ .93) with Achilles tendon moment arms using CORMVC being 33–36% greater than those obtained from TErest. The relationship between Achilles tendon moment arms and angle was similar across both methods and both levels of muscular contraction. Finally, Achilles tendon moment arms for CORMVC were 1–8% greater than for CORrest.

scholarly journals Plantarflexor Moment Arms Estimated From Tendon Excursion In Vivo Are Not Well Correlated With Geometric Measurements

2018 ◽  
Author(s):  
Josh R Baxter ◽  
Stephen J Piazza
Keyword(s):  
Magnetic Resonance ◽  
Strong Correlation ◽  
Young Male ◽  
Cost Effective ◽  
Moment Arm ◽  
Moment Arms ◽  
Study Population ◽  
The Moment ◽  
Tendon Excursion

AbstractGeometric and tendon excursion methods have both been used extensively for estimating plantarflexor muscle moment arm in vivo. Geometric measures often utilize magnetic resonance imaging, which can be costly and impractical for many investigations. Estimating moment arm from tendon excursion measured with ultrasonography may provide a cost-effective alternative to geometric measures of moment arm, but how well such measures represent geometry-based moment arms remains in question. The purpose of this study was to determine whether moment arms from tendon excursion can serve as a surrogate for moment arms measured geometrically. Magnetic resonance and ultrasound imaging were performed on 19 young male subjects to quantify plantarflexor moment arm based on geometric and tendon excursion paradigms, respectively. These measurements were only moderately correlated (R2 = 0.21, p = 0.052), and moment arm from tendon excursion under-approximated geometric moment arm by nearly 40% (p < 0.001). This moderate correlation between methods is at odds with a prior report (N = 9) of a very strong correlation (R2 = 0.94) in a similar study. Therefore, we performed 92,378 regression analyses (19 choose 9) to determine if such a strong correlation existed in our study population. We found that certain sub-populations of the current study generated similarly strong coefficients of determination (R2 = 0.92), but 84% of all analyses revealed no correlation (p > 0.05). Our results suggest that the moment arms from musculoskeletal geometry cannot be otherwise obtained by simply scaling moment arms estimated from tendon excursion.

scholarly journals Achilles tendon moment arm in humans is not affected by inversion/eversion of the foot: a short report

2018 ◽  
Vol 5 (1) ◽  
pp. 171358 ◽  
Author(s):  
Susann Wolfram ◽  
Christopher I. Morse ◽  
Keith L. Winwood ◽  
Emma Hodson-Tole ◽  
Islay M. McEwan
Keyword(s):  
Achilles Tendon ◽  
Magnetic Resonance Images ◽  
Triceps Surae ◽  
Short Report ◽  
Moment Arm ◽  
Moment Arms ◽  
Musculoskeletal Models ◽  
Rotation Method ◽  
Centre Of Rotation ◽  
Foot Position

The triceps surae primarily acts as plantarflexor of the ankle joint. However, the group also causes inversion and eversion at the subtalar joint. Despite this, the Achilles tendon moment arm is generally measured without considering the potential influence of inversion/eversion of the foot during plantarflexion. This study investigated the effect of foot inversion and eversion on the plantarflexion Achilles tendon moment arm. Achilles tendon moment arms were determined using the centre-of-rotation method in magnetic resonance images of the left ankle of 11 participants. The foot was positioned at 15° dorsiflexion, 0° or 15° plantarflexion using a Styrofoam wedge. In each of these positions, the foot was either 10° inverted, neutral or 10° everted using an additional Styrofoam wedge. Achilles tendon moment arm in neutral foot position was 47.93 ± 4.54 mm and did not differ significantly when the foot was positioned in 10° inversion and 10° eversion. Hence, inversion/eversion position of the foot may not considerably affect the length of the Achilles tendon moment arm. This information could be useful in musculoskeletal models of the human lower leg and foot and when estimating Achilles tendon forces during plantarflexion with the foot positioned in inversion or eversion.

Effect of Curvature on Sagittal Plane Moment Arms of Human Neck Muscles

2013 ◽  
Author(s):  
Bethany L. Suderman ◽  
Anita N. Vasavada
Keyword(s):  
Soft Tissues ◽  
Sagittal Plane ◽  
Neck Muscle ◽  
Moment Arm ◽  
Moment Arms ◽  
Musculoskeletal Models ◽  
Flexion Extension ◽  
Neck Rotation ◽  
Curved Paths

In musculoskeletal models of the cervical spine, muscles are often modeled as straight paths from origin to insertion [ e.g., 1]. However, muscle paths in the neck are constrained by bone and other soft tissues, and some studies have found that applying curvature to muscle paths improves anatomical accuracy [2; 3] and affects muscle parameters such as moment arm [3] and moment [4]. Currently, data available in the literature for neck muscle moment arms (MA) are sparse. In this study we estimated in-vivo moment arms using MRI-derived neck muscle paths modeled with curvature and those modeled as straight paths, for head and neck rotation in the sagittal plane (flexion-extension motion). We hypothesize that moment arm estimates for curved paths will be significantly different from estimates for straight paths.

Estimates of Achilles Tendon Moment Arm Length at Different Ankle Joint Angles: Effect of Passive Moment

2018 ◽  
pp. 1-22 ◽  
Author(s):  
Jared R. Fletcher ◽  
Brian R. MacIntosh
Keyword(s):  
Achilles Tendon ◽  
Passive Force ◽  
Moment Arm ◽  
Joint Angles ◽  
Joint Rotation ◽  
Male And Female ◽  
Moment Arms ◽  
Passive Rotation ◽  
Ankle Angle ◽  
Tendon Excursion

The length of a muscle’s moment arm can be estimated non-invasively using ultrasound, and the tendon excursion method. The main assumption with the tendon excursion method, however, is that the force acting on the tendon during passive rotation is constant. However, passive force changes through the range of motion, and moment arm is underestimated. We attempted to account for passive force on the measurement of Achilles tendon moment arm using the tendon excursion method in 8 male and female runners. Tendon excursion was measured using ultrasound while the ankle was passively rotated at 0.17 rad•s-1. Moment arm was calculated at 5° intervals as the ratio of tendon displacement to joint rotation from 70° to 115°. Passive moment (MP) was measured by a dynamometer. The displacement attributable to MP was calculated by monitoring tendon displacement during a ramp isometric maximum contraction. MP was 5.7±2.1 Nm at 70° and decreased exponentially from 70°-90°. °. This resulted in MP-corrected moment arms that were significantly larger than uncorrected moment arms at joint angles where MP was present. Further, MP-corrected moment arms did not change with ankle angle, which was not the case for uncorrected moment arms.

Estimates of Achilles Tendon Moment Arm Length at Different Ankle Joint Angles: Effect of Passive Moment

2018 ◽  
Vol 34 (3) ◽  
pp. 220-225 ◽  
Author(s):  
Jared R. Fletcher ◽  
Brian R. MacIntosh
Keyword(s):  
Achilles Tendon ◽  
Passive Force ◽  
Moment Arm ◽  
Joint Angles ◽  
Joint Rotation ◽  
Male And Female ◽  
Moment Arms ◽  
Passive Rotation ◽  
Ankle Angle ◽  
Tendon Excursion

The length of a muscle’s moment arm can be estimated noninvasively using ultrasound and the tendon excursion method. The main assumption with the tendon excursion method is that the force acting on the tendon during passive rotation is constant. However, passive force changes through the range of motion, and thus moment arm is underestimated. The authors attempted to account for passive force on the measurement of Achilles tendon moment arm using the tendon excursion method in 8 male and female runners. Tendon excursion was measured using ultrasound while the ankle was passively rotated at 0.17 rad·s−1. Moment arm was calculated at 5° intervals as the ratio of tendon displacement to joint rotation from 70° to 115°. Passive moment (MP) was measured using a dynamometer. The displacement attributable to MP was calculated by monitoring tendon displacement during a ramp isometric maximum contraction. MP was 5.7 (2.1) N·m at 70° and decreased exponentially from 70° to 90°. This resulted in MP-corrected moment arms that were significantly larger than uncorrected moment arms at joint angles where MP was present. Furthermore, MP-corrected moment arms did not change with ankle angle, which was not the case for uncorrected moment arms.

scholarly journals Shear Wave Predictions of Achilles Tendon Loading during Human Walking

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Emily M. Keuler ◽  
Isaac F. Loegering ◽  
Jack A. Martin ◽  
Joshua D. Roth ◽  
Darryl G. Thelen
Keyword(s):  
Achilles Tendon ◽  
Shear Wave ◽  
Wave Speed ◽  
Inverse Dynamics ◽  
Human Walking ◽  
Cross Sectional ◽  
Moment Arms ◽  
Subject Specific ◽  
S Peak

Abstract The evaluation of in vivo muscle-tendon loads is fundamental to understanding the actuation of normal and pathological human walking. However, conventional techniques for measuring muscle-tendon loads in the human body are too invasive for use in gait analysis. Here, we demonstrate the use of noninvasive measures of shear wave propagation as a proxy for Achilles tendon loading during walking. Twelve healthy young adults performed isometric ankle plantarflexion on a dynamometer. Achilles tendon wave speed, tendon moment arms, tendon cross-sectional area and ankle torque were measured. We first showed that the linear relationship between tendon stress and wave speed squared can be calibrated from isometric tasks. There was no significant effect of knee angle, ankle angle or loading rate on the subject-specific calibrations. Calibrated shear wave tensiometers were used to estimate Achilles tendon loading when walking at speeds ranging from 1 to 2 m/s. Peak tendon stresses during pushoff increased from 41 to 48 MPa as walking speed was increased, and were comparable to estimates from inverse dynamics. The tensiometers also detected Achilles tendon loading of 4 to 7 MPa in late swing. Late swing tendon loading was not discernible in the inverse dynamics estimates, but did coincide with passive stretch of the gastrocnemius muscle-tendon units. This study demonstrates the capacity to use calibrated shear wave tensiometers to evaluate tendon loading in locomotor tasks. Such technology could prove beneficial for identifying the muscle actions that underlie subject-specific movement patterns.

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