scholarly journals Sensitivity of Estimated Muscle Force in Forward Simulation of Normal Walking

2010 ◽  
Vol 26 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Ming Xiao ◽  
Jill Higginson
Keyword(s):  
Fiber Length ◽  
Muscle Force ◽  
Force Production ◽  
Muscle Group ◽  
Knee Extensors ◽  
Muscle Forces ◽  
Normal Walking ◽  
Forward Simulation ◽  
Individual Muscle ◽  
Slack Length

Generic muscle parameters are often used in muscle-driven simulations of human movement to estimate individual muscle forces and function. The results may not be valid since muscle properties vary from subject to subject. This study investigated the effect of using generic muscle parameters in a muscle-driven forward simulation on muscle force estimation. We generated a normal walking simulation in OpenSim and examined the sensitivity of individual muscle forces to perturbations in muscle parameters, including the number of muscles, maximum isometric force, optimal fiber length, and tendon slack length. We found that when changing the number of muscles included in the model, only magnitude of the estimated muscle forces was affected. Our results also suggest it is especially important to use accurate values of tendon slack length and optimal fiber length for ankle plantar flexors and knee extensors. Changes in force production by one muscle were typically compensated for by changes in force production by muscles in the same functional muscle group, or the antagonistic muscle group. Conclusions regarding muscle function based on simulations with generic musculoskeletal parameters should be interpreted with caution.

SENSITIVITY OF MODEL-PREDICTED MUSCLE FORCES OF PATIENTS WITH CEREBRAL PALSY TO VARIATIONS IN MUSCLE-TENDON PARAMETERS

2021 ◽  
Vol 21 (01) ◽  
pp. 2150008
Author(s):  
YUNUS ZIYA ARSLAN ◽  
DERYA KARABULUT
Keyword(s):  
Cerebral Palsy ◽  
Modeling And Simulation ◽  
Muscle Fiber ◽  
Fiber Length ◽  
Muscle Force ◽  
Musculoskeletal Modeling ◽  
Healthy Children ◽  
Muscle Forces ◽  
Healthy Individuals ◽  
Slack Length

Computational musculoskeletal modeling and simulation platforms are efficient tools to gain insight into the muscular coordination of patients with motor disabilities such as cerebral palsy (CP). Muscle force predictions from simulation programs are influenced by the architectural and contractile properties of muscle-tendon units. In this study, we aimed to evaluate the sensitivity of major lower limb muscle forces in patients with CP to changes in muscle-tendon parameters. Open-access datasets of children with CP ([Formula: see text]) and healthy children ([Formula: see text]) were considered. Monte Carlo analysis was executed to specify how sensitive the muscle forces to perturbations between [Formula: see text]% and [Formula: see text]% of the nominal value of the maximum isometric muscle force, optimal muscle fiber length, muscle pennation angle, tendon slack length, and maximum contraction velocity of muscle. The sensitivity analysis revealed that muscle forces of CP patients and healthy individuals were most sensitive to perturbations in the tendon slack length ([Formula: see text]), while forces of CP patients were more sensitive to tendon slack length when compared to the healthy group ([Formula: see text]). Muscle forces of patients and healthy individuals were insensitive to the other four parameters ([Formula: see text]), except for the gracilis and sartorius muscles in which the proportion of optimal muscle fiber length to tendon slack length is higher than 1; forces of these two muscles were also sensitive to the optimal muscle fiber length. The results of this study are expected to contribute to our understanding of which parameters should be personalized when conducting musculoskeletal modeling and simulation of patients with CP.

scholarly journals MM-MRE: a new technique to quantify individual muscle forces during isometric tasks of the wrist using MR elastography

2019 ◽  
Author(s):  
Andrea Zonnino ◽  
Daniel R. Smith ◽  
Peyton L. Delgorio ◽  
Curtis L. Johnson ◽  
Fabrizio Sergi
Keyword(s):  
Shear Wave ◽  
Muscle Force ◽  
Muscle Mechanics ◽  
Neuromuscular Control ◽  
Joint Torque ◽  
New Technique ◽  
Muscle Forces ◽  
Individual Muscle ◽  
Complete Set ◽  
A New Technique

AbstractNon-invasive in-vivo measurement of individual muscle force is limited by the infeasibility of placing force sensing elements in series with the musculo-tendon structures. At the same time, estimating muscle forces using EMG measurements is prone to inaccuracies, as EMG is not always measurable for the complete set of muscles acting around the joints of interest. While new methods based on shear wave elastography have been recently proposed to directly characterize muscle mechanics, they can only be used to measure muscle forces in a limited set of superficial muscles. As such, they are not suitable to study the neuromuscular control of movements that require coordinated action of multiple muscles.In this work, we present multi-muscle magnetic resonance elastography (MM-MRE), a new technique capable of quantifying individual muscle force from the complete set of muscles in the forearm, thus enabling the study of the neuromuscular control of wrist movements. MM-MRE integrates measurements of joint torque provided by an MRI-compatible instrumented handle with muscle-specific measurements of shear wave speed obtained via MRE to quantify individual muscle force using model-based estimator.A single-subject pilot experiment demonstrates the possibility of obtaining measurements from individual muscles and establishes that MM-MRE has sufficient sensitivity to detect changes in muscle mechanics following the application of isometric joint torque with self-selected intensity.

Subject-Specific Estimates of Tendon Slack Length: A Numerical Method

2004 ◽  
Vol 20 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Kurt Manal ◽  
Thomas S. Buchanan
Keyword(s):  
Numerical Method ◽  
Fiber Length ◽  
Muscle Force ◽  
Specific Input ◽  
Musculoskeletal Models ◽  
Subject Specific ◽  
Input Parameters ◽  
Slack Length

Tendon develops force proportional to the distance it is stretched beyond its slack length. Tendon slack length is an important parameter for musculoskeletal models because it can greatly affect estimations of muscle force. Unfortunately, tendon slack length is a difficult parameter to measure, and therefore values for it are not often reported in the literature. In this paper we present a numerical method for estimating tendon slack length from architectural parameters of the muscle. Specifically, tendon slack length is computed iteratively from musculotendon lengths determined when a corresponding joint is held at two angles, and from knowledge of the muscle's optimal fiber length. Idealized data generated using SIMM were used to test the tendon slack length algorithm. The method converged to within 1% of the “true” tendon slack length specified in the SIMM model. The advantage of the method outlined in this paper is that it yields subject-specific estimates of tendon slack length, given subject-specific input parameters.

A Numerical Method for Estimating Tendon Slack Length

2003 ◽  
Author(s):  
Kurt Manal ◽  
Thomas S. Buchanan
Keyword(s):  
Numerical Method ◽  
Fiber Length ◽  
Muscle Force ◽  
Isometric Force ◽  
Pennation Angle ◽  
Cross Sectional ◽  
Force Equation ◽  
Subject Specific ◽  
Maximum Isometric Force ◽  
Slack Length

Forces generated by muscle are transferred to bone via tendon. Since muscle force cannot be measured directly, computer modeling is a useful tool to enhance our understanding of normal and pathological movement. Hill-type muscle models have been used to estimate force based on information about a muscle’s architecture, activation and kinematics (Delp et al., 1995; Manal et al., 2002). Architectural parameters include optimal fiber length (lom), tendon slack length (lst), pennation angle (α), and maximum isometric force (Fmax). In addition, musculotendon length (lmt) and activation (a) are required inputs when estimating isometric muscle force (Equation I). Fm=f(lmt,lom,lst,Fmax,α,a)(1) Musculotendon length can be determined from MR images (Arnold et al., 2000), and activation recorded from EMGs (Manal, et al., 2002). Optimal fiber length and pennation angle can be measured experimentally (Murray, 2002), while Fmax can be estimated from the muscle’s physiologic cross-sectional area. Tendon slack length however cannot be measured readily, and therefore few estimates of lst can be found in the literature. In this paper we present a numerical method for estimating tendon slack from subject specific muscle parameters and musculotendon lengths. An advantage of this method is that it yields subject specific estimates of tendon slack length.

Direct Validation of Model-Predicted Muscle Forces in the Cat Hindlimb During Locomotion

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Derya Karabulut ◽  
Suzan Cansel Dogru ◽  
Yi-Chung Lin ◽  
Marcus G. Pandy ◽  
Walter Herzog ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Force ◽  
Medial Gastrocnemius ◽  
Electromyographic Activity ◽  
Muscle Forces ◽  
Static Optimization ◽  
Individual Muscle ◽  
Length Changes ◽  
Musculoskeletal Systems

Abstract Various methods are available for simulating the movement patterns of musculoskeletal systems and determining individual muscle forces, but the results obtained from these methods have not been rigorously validated against experiment. The aim of this study was to compare model predictions of muscle force derived for a cat hindlimb during locomotion against direct measurements of muscle force obtained in vivo. The cat hindlimb was represented as a 5-segment, 13-degrees-of-freedom (DOF), articulated linkage actuated by 25 Hill-type muscle-tendon units (MTUs). Individual muscle forces were determined by combining gait data with two widely used computational methods—static optimization and computed muscle control (CMC)—available in opensim, an open-source musculoskeletal modeling and simulation environment. The forces developed by the soleus, medial gastrocnemius (MG), and tibialis anterior muscles during free locomotion were measured using buckle transducers attached to the tendons. Muscle electromyographic activity and MTU length changes were also measured and compared against the corresponding data predicted by the model. Model-predicted muscle forces, activation levels, and MTU length changes were consistent with the corresponding quantities obtained from experiment. The calculated values of muscle force obtained from static optimization agreed more closely with experiment than those derived from CMC.

Predictive Neuromuscular Fatigue of the Lower Extremity Utilizing Computer Modeling

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Michael A. Samaan ◽  
Joshua T. Weinhandl ◽  
Steven A. Hans ◽  
Sebastian Y. Bawab ◽  
Stacie I. Ringleb
Keyword(s):  
Lower Extremity ◽  
Muscle Force ◽  
Cruciate Ligament ◽  
Force Production ◽  
Neuromuscular Fatigue ◽  
Lower Extremity Injury ◽  
Muscle Forces ◽  
Flexor Muscle ◽  
Lower Extremity Muscle ◽  
Muscle Force Production

This paper studies the modeling of lower extremity muscle forces and their correlation to neuromuscular fatigue. Two analytical fatigue models were combined with a musculoskeletal model to estimate the effects of hamstrings fatigue on lower extremity muscle forces during a side step cut. One of the fatigue models (Tang) used subject-specific knee flexor muscle fatigue and recovery data while the second model (Xia) used previously established fatigue and recovery parameters. Both fatigue models were able to predict hamstrings fatigue within 20% of the experimental data, with the semimembranosus and semitendinosus muscles demonstrating the largest (11%) and smallest (1%) differences, respectively. In addition, various hamstrings fatigue levels (10–90%) on lower extremity muscle force production were assessed using one of the analytical fatigue models. As hamstrings fatigue levels increased, the quadriceps muscle forces decreased by 21% (p < 0.01), while gastrocnemius muscle forces increased by 36% (p < 0.01). The results of this study validate the use of two analytical fatigue models in determining the effects of neuromuscular fatigue during a side step cut, and therefore, this model can be used to assess fatigue effects on risk of lower extremity injury during athletic maneuvers. Understanding the effects of fatigue on muscle force production may provide insight on muscle group compensations that may lead to altered lower extremity motion patterns as seen in noncontact anterior cruciate ligament (ACL) injuries.

Study of the Variation in Knee Joint Muscle Forces at Different Walking Speeds and Effectiveness of Using Knee Braces

2020 ◽  
Author(s):  
Visharath Adhikari ◽  
Paul I Ro
Keyword(s):  
Knee Joint ◽  
Muscle Force ◽  
Muscle Group ◽  
Muscle Forces ◽  
Motion Generation ◽  
Knee Brace ◽  
Emg Signal ◽  
Muscle Groups ◽  
Walking Speeds ◽  
Force Calculation

Abstract A knee assistive device can serve a large number of people to overcome muscle weakness due to aging and perform normal functional activities of the knee joint. The objective of this paper is to study the effectiveness of a knee brace to aid with normal functions and reduce muscle forces at different walking speeds. The study uses two major muscle groups, rectus femoris (RF) and biceps femoris (BF), for the muscle force study. The Electromyography (EMG) signal was recorded at 3 different walking speeds (slow, normal, fast) under both brace-assisted and normal walking conditions. EMG signals were processed and converted into muscle activation signals and finally used for muscle force calculation. The amount of assistance to each muscle group at different walking speeds was derived and analyzed to see the effectiveness of a knee brace. The knee brace was seen to have provided additional support for motion generation. However, the amount of support is found to be speed-dependent and has a different effect on different muscle groups. At slower speed, the BF muscle was seen to work against the brace, while it was not the case for the RF muscle group.

Considerations for Predicting Individual Muscle Forces in Athletic Movements

1987 ◽  
Vol 3 (2) ◽  
pp. 128-141 ◽  
Author(s):  
Walter Herzog
Keyword(s):  
Muscle Force ◽  
Load Sharing ◽  
Knee Extension ◽  
Muscle Contractions ◽  
Optimal Designs ◽  
Muscle Forces ◽  
Design Considerations ◽  
Individual Muscle ◽  
Linear And Nonlinear ◽  
Design Characteristics

Linear and nonlinear optimal designs have been used abundantly to predict the forces exerted by individual muscles for everyday movements such as walking. Individual muscle force predictions for athletic movements, those involving large ranges of motion and fast velocities of muscle contractions, are almost nonexistent. The purpose of this paper is to illustrate some of the design characteristics that must be considered for predicting individual muscle forces in athletic movements. To do this, the load sharing between two muscles, derived from nonlinear optimal designs, is considered in two ways: (a) in hypothetical experiments of muscle contractions, and (b) in real experiments of knee extension movements performed by one subject. The results suggested that additional design considerations must be made when predicting forces in athletic movements compared to everyday movements.

Use of Optimization Techniques to Predict Muscle Forces

1978 ◽  
Vol 100 (2) ◽  
pp. 88-92 ◽  
Author(s):  
R. D. Crowninshield
Keyword(s):  
Muscle Strength ◽  
Muscle Force ◽  
Optimization Techniques ◽  
Emg Activity ◽  
Muscle Action ◽  
Muscle Forces ◽  
Distribution Problem ◽  
Joint Function ◽  
Individual Muscle ◽  
Synergistic Muscle

Optimization solutions to the indeterminate distribution problem of determining muscle forces are discussed. A method of predicting muscle force during joint function is presented which encourages the prediction of synergistic muscle action with physiologically reasonable individual muscle forces. The method uses limits on muscle strength that are a set portion of the lowest muscle strength that will permit a solution at the particular joint moment. The method is shown to correlate well with recorded EMG activity.

scholarly journals Effect of habitual foot-strike pattern on the gastrocnemius medialis muscle-tendon interaction and muscle force production during running

2019 ◽  
Vol 126 (3) ◽  
pp. 708-716 ◽  
Author(s):  
Wannes Swinnen ◽  
Wouter Hoogkamer ◽  
Tijs Delabastita ◽  
Jeroen Aeles ◽  
Friedl De Groote ◽  
...  
Keyword(s):  
Energy Demand ◽  
Muscle Force ◽  
Force Production ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Ground Contact ◽  
Muscle Forces ◽  
Flexor Muscle ◽  
Contraction Velocity ◽  
Foot Strike

The interaction between gastrocnemius medialis (GM) muscle and Achilles tendon, i.e., muscle-tendon unit (MTU) interaction, plays an important role in minimizing the metabolic cost of running. Foot-strike pattern (FSP) has been suggested to alter MTU interaction and subsequently the metabolic cost of running. However, metabolic data from experimental studies on FSP are inconsistent, and a comparison of MTU interaction between FSP is still lacking. We, therefore, investigated the effect of habitual rearfoot and mid-/forefoot striking on MTU interaction, ankle joint work, and plantar flexor muscle force production while running at 10 and 14 km/h. GM muscle fascicles of 9 rearfoot and 10 mid-/forefoot strikers were tracked using dynamic ultrasonography during treadmill running. We collected kinetic and kinematic data and used musculoskeletal models to determine joint angles and calculate MTU lengths. In addition, we used dynamic optimization to assess plantar flexor muscle forces. During ground contact, GM fascicle shortening ( P = 0.02) and average contraction velocity ( P = 0.01) were 40–45% greater in rearfoot strikers than mid-/forefoot strikers. Differences in contraction velocity were especially prominent during early ground contact. Moreover, GM ( P = 0.02) muscle force was greater during early ground contact in mid-/forefoot strikers than rearfoot strikers. Interestingly, we did not find differences in stretch or recoil of the series elastic element between FSP. Our results suggest that, for the GM, the reduced muscle energy cost associated with lower fascicle contraction velocity in mid-/forefoot strikers may be counteracted by greater muscle forces during early ground contact. NEW & NOTEWORTHY Kinetic and kinematic differences between foot-strike patterns during running imply (not previously reported) altered muscle-tendon interaction. Here, we studied muscle-tendon interaction using ultrasonography. We found greater fascicle contraction velocities and lower muscle forces in rearfoot compared with mid-/forefoot strikers. Our results suggest that the higher metabolic energy demand due to greater fascicle contraction velocities might offset the lower metabolic energy demand due to lower muscle forces in rearfoot compared with mid-/forefoot strikers.

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