Biomechanical Engineering Commons^™

Implicit Methods For Efficient Musculoskeletal Simulation And Optimal Control, Antonie J. Van Den Bogert, Dimitra Blana, Dieter Heinrich

Mechanical Engineering Faculty Publications

The ordinary differential equations for musculoskeletal dynamics are often numerically stiff and highly nonlinear. Consequently, simulations require small time steps, and optimal control problems are slow to solve and have poor convergence. In this paper, we present an implicit formulation of musculoskeletal dynamics, which leads to new numerical methods for simulation and optimal control, with the expectation that we can mitigate some of these problems. A first order Rosenbrock method was developed for solving forward dynamic problems using the implicit formulation. It was used to perform real-time dynamic simulation of a complex shoulder arm system with extreme dynamic stiffness. Simulations …

Personal Navigation Via High-Resolution Gait-Corrected Inertial Measurement Units, Özkan Bebek, Michael A. Suster, Srihari Rajgopal, Michael J. Fu, Xuemei Huang, M. Cenk Çavu¸So˘Glu,, Darrin J. Young, Mehran Mehregany, Antonie J. Van Den Bogert, Carlos H. Mastrangelo

Mechanical Engineering Faculty Publications

In this paper, a personal micronavigation system that uses high-resolution gait-corrected inertial measurement units is presented. The goal of this paper is to develop a navigation system that uses secondary inertial variables, such as velocity, to enable long-term precise navigation in the absence of Global Positioning System (GPS) and beacon signals. In this scheme, measured zerovelocity duration from the ground reaction sensors is used to reset the accumulated integration errors from accelerometers and gyroscopes in position calculation. With the described system, an average position error of 4 m is achieved at the end of half-hour walks.

Concurrent Muscoskeletal Dynamics And Finite Element Analysis Predicts Altered Gait Patterns To Reduce Foot Tissue Loading, Jason P. Halloran, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Current computational methods for simulating locomotion have primarily used muscle-driven multibody dynamics, in which neuromuscular control is optimized. Such simulations generally represent joints and soft tissue as simple kinematic or elastic elements for computational efficiency. These assumptions limit application in studies such as ligament injury or osteoarthritis, where local tissue loading must be predicted. Conversely, tissue can be simulated using the finite element method with assumed or measured boundary conditions, but this does not represent the effects of whole body dynamics and neuromuscular control. Coupling the two domains would overcome these limitations and allow prediction of movement strategies guided by …

Longitudinal Sex Differences During Landing In Knee Abduction In Young Athletes, Kevin R. Ford, Robert Shapiro, Gregory D. Meyer, Antonie J. Van Den Bogert, Timothy E. Hewett

Mechanical Engineering Faculty Publications

Purpose—

The objective of this study was to determine if biomechanical and neuromuscular risk factors related to abnormal movement patterns increased in females, but not males, during the adolescent growth spurt.

Methods—

315 subjects participated in two testing sessions approximately one year apart. Male and female subjects were classified based on their maturation status as pubertal or post-pubertal.Three trials of a drop vertical jump (DVJ) were collected. Maximum knee abduction angle and external moments were calculated during the DVJ deceleration phase using a 3D motion analysis system. Changes in knee abduction from the first to second year were compared among …

Optimization And Evaluation Of A Proportional Derivative Controller For Planar Arm Movement, Kathleen M. Jagodnik, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

In most clinical applications of functional electrical stimulation (FES), the timing and amplitude of electrical stimuli have been controlled by open-loop pattern generators. The control of upper extremity reaching movements, however, will require feedback control to achieve the required precision. Here we present three controllers using proportional derivative (PD) feedback to stimulate six arm muscles, using two joint angle sensors. Controllers were first optimized and then evaluated on a computational arm model that includes musculoskeletal dynamics. Feedback gains were optimized by minimizing a weighted sum of position errors and muscle forces. Generalizability of the controllers was evaluated by performing movements …

Optimality Principles For Model-Based Prediction Of Human Gait, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient's gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like …

Design And Validation Of A General Purpose Robotic Testing System For Musculoskeletal Applications, Lawrence D. Noble, Robb W. Colbrunn, Dong-Gil Lee, Antonie J. Van Den Bogert, Brian L. Davis

Mechanical Engineering Faculty Publications

Orthopaedic research on in vitro forces applied to bones, tendons, and ligaments during joint loading has been difficult to perform because of limitations with existing robotic simulators in applying full-physiological loading to the joint under investigation in real time. The objectives of the current work are as follows: (1) describe the design of a musculoskeletal simulator developed to support in vitro testing of cadaveric joint systems, (2) provide component and system-level validation results, and (3) demonstrate the simulator’s usefulness for specific applications of the foot-ankle complex and knee. The musculoskeletal simulator allows researchers to simulate a variety of loading conditions …

An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load …

Gender Dimorphic Acl Strain In Response To Combined Dynamic 3d Knee Joint Loading: Implications For Acl Injury Risk, Kiyonori Mizuno, Jack T. Andrish, Antonie J. Van Den Bogert, Scott G. Mclean

Mechanical Engineering Faculty Publications

While gender-based differences in knee joint anatomies/laxities are well documented, the potential for them to precipitate gender-dimorphic ACL loading and resultant injury risk has not been considered. To this end, we generated gender-specific models of ACL strain as a function of any six degrees of freedom (6DOF) knee joint load state via a combined cadaveric and analytical approach. Continuously varying joint forces and torques were applied to five male and five female cadaveric specimens and recorded along with synchronous knee flexion and ACL strain data. All data (~10,000 samples) were submitted to specimen-specific regression analyses, affording ACL strain predictions as …

An Elaborate Data Set Characterizing The Mechanical Response Of The Foot, Ahmet Erdemir, Pavana A. Sirimamilla, Jason P. Halloran, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Mechanical properties of the foot are responsible for its normal function and play a role in various clinical problems. Specifically, we are interested in quantification of foot mechanical properties to assist the development of computational models for movement analysis and detailed simulations of tissue deformation. Current available data are specific to a foot region and the loading scenarios are limited to a single direction. A data set that incorporates regional response, to quantify individual function of foot components, as well as the overall response, to illustrate their combined operation, does not exist. Furthermore, the combined three-dimensional loading scenarios while measuring …

Comment On "A Stochastic Biomechanical Model For Risk And Risk Factors Of Non-Contact Anterior Cruciate Ligament Injuries", Antonie J. Van Den Bogert, Scott G. Mclean

Mechanical Engineering Faculty Publications

No abstract provided.

Assessing Vaginal Surgical Skills Using Video Motion Analysis, Gouri B. Diwadkar, Antonie J. Van Den Bogert, Matthew D. Barber, J. Eric Jelovsek

Mechanical Engineering Faculty Publications

OBJECTIVE: To demonstrate the feasibility of using video motion analysis to quantitate a key step of vaginal hysterectomy and define measurable differences between novice and experienced surgical trainees during vaginal hysterectomy.

METHODS: Analyses focused on clamping, transecting, and suturing the left uterosacral ligament. Using a cutoff of 25, trainees were grouped as experienced (n=14) and novice (n=9) based on the total number of vaginal hysterectomies performed by each trainee. Contrasting-groups analysis was used to determine cutoff values that separated novices from experts.

RESULTS: Novice trainees took longer (112 seconds compared with 84 seconds) and had greater cumulative translational motion (92 …

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Mechanical Engineering Faculty Publications

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains 22 muscles …

Application Of The Actor-Critic Architecture To Functional Electrical Stimulation Control Of A Human Arm, Philip Thomas, Michael Branicky, Antonie Van Den Bogert, Kathleen Jagodnik

Mechanical Engineering Faculty Publications

Clinical tests have shown that the dynamics of a human arm, controlled using Functional Electrical Stimulation (FES), can vary significantly between and during trials. In this paper, we study the application of the actor-critic architecture, with neural networks for the both the actor and the critic, as a controller that can adapt to these changing dynamics of a human arm. Development and tests were done in simulation using a planar arm model and Hill-based muscle dynamics. We begin by training it using a Proportional Derivative (PD) controller as a supervisor. We then make clinically relevant changes to the dynamics of …

Concurrent Simulation Of Neuromuscular Control And Tissue Deformation Is Possible By Adaptive Surrogate Modeling, Jason P. Halloran, Ahmet Erdemir, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

No abstract provided.

Adaptive Surrogate Modeling For Efficient Coupling Of Musculoskeletal Control And Tissue Deformation Models, Jason P. Halloran, Ahmet Erdemir, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background

Finite element (FE) modeling and multibody dynamics have traditionally been applied separately to the domains of tissue mechanics and musculoskeletal movements, respectively. Simultaneous simulation of both domains is needed when interactions between tissue and movement are of interest, but this has remained largely impractical due to high computational cost.

Method of Approach

Here we present a method for concurrent simulation of tissue and movement, in which state of the art methods are used in each domain, and communication occurs via a surrogate modeling system based on locally weighted regression. The surrogate model only performs FE simulations when regression from …

Investigating Isolated Neuromuscular Control Contributions To Non-Contact Anterior Cruciate Ligament Injury Risk Via Computer Simulation Methods, Scott G. Mclean, Xuemei Huang, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background

Despite the ongoing evolution of anterior cruciate ligament injury prevention methods, injury rates and the associated sex-disparity remain. Strategies capable of successfully countering key control parameters existent within the injury mechanism thus remain elusive. Forward dynamics model simulations afford an expedited means to study realistic injury causing scenarios, while controlling all facets of the movement control strategy. Utilizing these methods, the current study examined the potential for perturbations in key initial contact neuromuscular parameters to injure the anterior cruciate ligament during the stance phase of sidestep cutting maneuvers.

Methods

Controlled experiments were performed on optimized and validated subject-specific forward …

A Weighted Least-Squares Method For Inverse Dynamic Analysis, Antonie J. Van Den Bogert, Anne Su

Mechanical Engineering Faculty Publications

Internal forces in the human body can be estimated from measured movements and external forces using inverse dynamic analysis. Here we present a general method of analysis which makes optimal use of all available data, and allows the use of inverse dynamic analysis in cases where external force data is incomplete. The method was evaluated for the analysis of running on a partially instrumented treadmill. It was found that results correlate well with those of a conventional analysis where all external forces are known.

Creating A Reinforcement Learning Controller For Functional Electrical Stimulation Of A Human Arm, Philip S. Thomas, Michael Branicky, Antonie Van Den Bogert, Kathleen Jagodnik

Mechanical Engineering Faculty Publications

Clinical tests have shown that the dynamics of a human arm, controlled using Functional Electrical Stimulation (FES), can vary significantly between and during trials. In this paper, we study the application of Reinforcement Learning to create a controller that can adapt to these
changing dynamics of a human arm. Development and tests were done in simulation using a two-dimensional arm model and Hill-based muscle dynamics. An actor-critic architecture is used with artificial neural networks for both the actor and the critic. We begin by training it using a Proportional Derivative (PD) controller as a supervisor. We then make clinically relevant …

Helical Axes Of Skeletal Knee Joint Motion During Running, Antonie J. Van Den Bogert, C. Reinschmidt, A. Lundberg

Mechanical Engineering Faculty Publications

The purpose of this study was to determine the changes in the axis of rotation of the knee that occur during the stance phase of running. Using intracortical pins, the three-dimensional skeletal kinematics of three subjects were measured during the stance phase of five running trials. The stance phase was divided into equal motion increments for which the position and orientation of the finite helical axes (FHA) were calculated relative to a tibial reference frame. Results were consistent within and between subjects. At the beginning of stance, the FHA was located at the midepicondylar point and during the flexion phase …

The Effect Of Tibiofemoral Loading On Proximal Tibiofibular Joint Motion, Jacob Scott, Ho Lee, Wael Barsoum, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The human proximal tibiofibular joint (PTFJ) and its relationship to overall knee joint mechanics have been largely unexplored. This study describes force/displacement data from experiments done on four human cadaveric knee specimens and general conclusions obtained with the help of a statistical modeling technique. Specimens were rigidly affixed at the tibia to a force plate and the femur was attached to a custom made device allowing for manual load application. Motion of the fibular head was tracked relative to the tibial plateau by means of reflective markers and a high speed digital camera synchronized with the force plate data stream. …

Model-Based Estimation Of Muscle Forces Exerted During Movements, Ahmet Erdemir, Scott Mclean, Walter Herzog, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Estimation of individual muscle forces during human movement can provide insight into neural control and tissue loading and can thus contribute to improved diagnosis and management of both neurological and orthopaedic conditions. Direct measurement of muscle forces is generally not feasible in a clinical setting, and non-invasive methods based on musculoskeletal modeling should therefore be considered. The current state of the art in clinical movement analysis is that resultant joint torques can be reliably estimated from motion data and external forces (inverse dynamic analysis). Static optimization methods to transform joint torques into estimates of individual muscle forces using musculoskeletal models, …

Acl Injuries: Do We Know The Mechanisms?, Antonie J. Van Den Bogert, Scott G. Mclean

Mechanical Engineering Faculty Publications

Injuries of the anterior cruciate ligament (ACL) remain a frequent occurrence in many sports activities. Recent research has identified risk factors, and prevention strategies are being developed based on these findings. There is, however, still a limited understanding of the actual injury mechanisms. In this presentation we will review the current knowledge on ACL injury mechanisms, and identify needs and opportunities for further research.

Effect Of Gender On Lower Extremity Kinematics During Rapid Direction Changes: An Integrated Analysis Of Three Sports Movements, S. G. Mclean, K. B. Walker, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Anterior cruciate ligament (ACL) injury is a common sports injury, particularly in females. Gender differences in knee kinematics have been observed for specific movements, but there is limited information on how these findings relate to other joints and other movements. Here we present an integrated analysis of hip, knee and ankle kinematics across three movements linked to non-contact ACL injury. It was hypothesised that there are gender differences in lower extremity kinematics, which are consistent across sports movements. Ten female and ten male NCAA basketball players had three-dimensional hip, knee and ankle kinematics quantified during the stance phase of sidestep, …

Association Between Lower Extremity Posture At Contact And Peak Knee Valgus Moment During Sidestepping: Implications For Acl Injury, Scott G. Mclean, Xuemei M. Huang, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background. Knee valgus load during sports movement is viewed as an important predictor of non-contact anterior cruciate ligament injury risk, particularly in females. Formulating movement strategies that can reduce valgus loading during these movements therefore appears pertinent to reducing anterior cruciate ligament injury rates. With this in mind, the current study examined the relationship between peak valgus moment and lower extremity postures at impact during a sidestep cutting task.

Methods. Ten male and ten female NCAA athletes had initial contact three-dimensional hip, knee and ankle angles and subsequent knee valgus moment quantified during the execution of (n=10 trials) …

Letter To The Editor, Scott G. Mclean, Jack T. Andrish, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

No abstract provided.

Evaluation Of A Two Dimensional Analysis Method As A Screening And Evaluation Tool For Anterior Cruciate Ligament Injury, Scott G. Mclean, K. Walker, K. R. Ford, G. D. Myer, T. E. Hewett, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background: Increased knee valgus predicts the risk of anterior cruciate ligament (ACL) injury, particularly in women. Reducing injury rates thus relies on detecting and continually evaluating people with relatively large valgus motions.

Objectives: To examine the potential of a two dimensional (2D) video analysis method for screening for excessive valgus.

Methods: Ten female and 10 male National Collegiate Athletic Association basketball players had three dimensional (3D) knee valgus and two dimensional (2D) frontal plane knee angle quantified during side step, side jump, and shuttle run tasks. 3D valgus was quantified from external marker coordinates using standard techniques, and 2D data …

Biomechanical Measures Of Neuromuscular Control And Valgus Loading Of The Knee Predict Anterior Cruciate Ligament Injury Risk In Female Athletes, Timothy E. Hewett, Gregory D. Myer, Kevin R. Ford, Robert S. Heidt Jr., Angelo J. Colosimo, Scott G. Mclean, Antonie J. Van Den Bogert, Mark V. Paterno, Paul Succop

Mechanical Engineering Faculty Publications

Background: Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes.

Hypothesis: Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading, predicting anterior cruciate ligament injury risk.

Study Design: Cohort study; Level of evidence, 2.

Methods: There were 205 female athletes in the high-risk sports of soccer, basketball, and volleyball prospectively measured for neuromuscular control using 3-dimensional kinematics (joint angles) and joint loads using kinetics (joint moments) during a jump-landing task. Analysis of variance as well as linear …

Pre-Impact Lower Extremity Posture And Brake Pedal Force Predict Foot And Ankle Forces During An Automobile Collision, Elizabeth C. Hardin, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background: The purpose of this study was to determine how a driver’s foot and ankle forces during a frontal vehicle collision depend on initial lower extremity posture and brake pedal force. Method of Approach: A 2D musculoskeletal model with seven segments and six right-side muscle groups was used. A simulation of a three-second braking task found 3647 sets of muscle activation levels that resulted in stable braking postures with realistic pedal force. These activation patterns were then used in impact simulations where vehicle deceleration was applied and driver movements and foot and ankle forces were simulated. Peak rearfoot ground reaction …

Sagittal Plane Biomechanics Cannot Injure The Acl During Sidestep Cutting, Scott G. Mclean, Xuemei Huang, Anne Su, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Background. Knee joint sagittal plane forces are a proposed mechanism of anterior cruciate ligament injury during sport movements such as sidestep cutting. Ligament force magnitudes for these movements however, remain unknown. The need to examine injury-causing events suggests elucidation via model-based investigations is possible. Using this approach, the current study determined whether sagittal plane knee loading during sidestep cutting could in isolation injure the anterior cruciate ligament.

Methods. Experiments were performed on subject-specific forward dynamic musculoskeletal models, generated from data obtained from 10 male and 10 female athletes. Models were optimized to simulate subject-specific cutting movements. Random perturbations …