Jonathan S. Dufour

article

Development and testing of a moment-based coactivation index to assess complex dynamic tasks for the lumbar spine

Peter Le, Alexander Aurand, Jonathan S. Dufour, Gregory G. Knapik, more

Clinical Biomechanics > 2017 > 46 > C > 23-32

Many methods exist to describe coactivation between muscles. However, most methods have limited capability in the assessment of coactivation during complex dynamic tasks for multi-muscle systems such as the lumbar spine. The ability to assess coactivation is important for the understanding of neuromuscular inefficiency. In the context of this manuscript, inefficiency is defined as the effort or level...

article

Accuracy map of an optical motion capture system with 42 or 21 cameras in a large measurement volume

Alexander M. Aurand, Jonathan S. Dufour, William S. Marras

Journal of Biomechanics > 2017 > 58 > C > 237-240

Optical motion capture is commonly used in biomechanics to measure human kinematics. However, no studies have yet examined the accuracy of optical motion capture in a large capture volume (>100m³), or how accuracy varies from the center to the extreme edges of the capture volume. This study measured the dynamic 3D errors of an optical motion capture system composed of 42 OptiTrack Prime 41 cameras...

article

Validation of a personalized curved muscle model of the lumbar spine during complex dynamic exertions

Jaejin Hwang, Gregory G. Knapik, Jonathan S. Dufour, Thomas M. Best, more

Journal of Electromyography and Kinesiology > 2017 > 33 > C > 1-9

Previous curved muscle models have typically examined their robustness only under simple, single-plane static exertions. In addition, the empirical validation of curved muscle models through an entire lumbar spine has not been fully realized. The objective of this study was to empirically validate a personalized biologically-assisted curved muscle model during complex dynamic exertions. Twelve subjects...

article

Prediction of magnetic resonance imaging-derived trunk muscle geometry with application to spine biomechanical modeling

Jaejin Hwang, Jonathan S. Dufour, Gregory G. Knapik, Thomas M. Best, more

Clinical Biomechanics > 2016 > 37 > C > 60-64

Accurate geometry of the trunk musculature is essential for reliably estimating spinal loads in biomechanical models. Currently, many models employ straight muscle path assumptions that yield far less accurate tissue loads, particularly in extreme postures. Precise muscle moment-arms and physiological cross-sectional areas are important when incorporating curved muscle geometry in biomechanical models...

article

A biologically-assisted curved muscle model of the lumbar spine: Model structure

Jaejin Hwang, Gregory G. Knapik, Jonathan S. Dufour, Alexander Aurand, more

Clinical Biomechanics > 2016 > 37 > C > 53-59

Biomechanical models have been developed to assess the spine tissue loads of individuals. However, most models have assumed trunk muscle lines of action as straight-lines, which might be less reliable during occupational tasks that require complex lumbar motions. The objective of this study was to describe the model structure and underlying logic of a biologically-assisted curved muscle model of the...

article

A biologically-assisted curved muscle model of the lumbar spine: Model validation

Jaejin Hwang, Gregory G. Knapik, Jonathan S. Dufour, Thomas M. Best, more

Clinical Biomechanics > 2016 > 37 > C > 153-159

Biomechanical models have been developed to predict spinal loads in vivo to assess potential risk of injury in workplaces. Most models represent trunk muscles with straight-lines. Even though straight-line muscles behave reasonably well in simple exertions, they could be less reliable during complex dynamic exertions. A curved muscle representation was developed to overcome this issue. However, most...

article

An EMG-assisted model calibration technique that does not require MVCs

Jonathan S. Dufour, William S. Marras, Gregory G. Knapik

Journal of Electromyography and Kinesiology > 2013 > 23 > 3 > 608-613

As personalized biologically-assisted models of the spine have evolved, the normalization of raw electromyographic (EMG) signals has become increasingly important. The traditional method of normalizing myoelectric signals, relative to measured maximum voluntary contractions (MVCs), is susceptible to error and is problematic for evaluating symptomatic low back pain (LBP) patients. Additionally, efforts...

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Search results for: Jonathan S. Dufour

Development and testing of a moment-based coactivation index to assess complex dynamic tasks for the lumbar spine

Accuracy map of an optical motion capture system with 42 or 21 cameras in a large measurement volume

Validation of a personalized curved muscle model of the lumbar spine during complex dynamic exertions

Prediction of magnetic resonance imaging-derived trunk muscle geometry with application to spine biomechanical modeling

A biologically-assisted curved muscle model of the lumbar spine: Model structure

A biologically-assisted curved muscle model of the lumbar spine: Model validation

An EMG-assisted model calibration technique that does not require MVCs

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INFONA - science communication portal

Search results for: Jonathan S. Dufour

Development and testing of a moment-based coactivation index to assess complex dynamic tasks for the lumbar spine

Accuracy map of an optical motion capture system with 42 or 21 cameras in a large measurement volume

Validation of a personalized curved muscle model of the lumbar spine during complex dynamic exertions

Prediction of magnetic resonance imaging-derived trunk muscle geometry with application to spine biomechanical modeling

A biologically-assisted curved muscle model of the lumbar spine: Model structure

A biologically-assisted curved muscle model of the lumbar spine: Model validation

An EMG-assisted model calibration technique that does not require MVCs

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