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Gurchiek RD, Teplin Z, Falisse A, Hicks JL, Delp SL. Hamstrings are stretched more and faster during accelerative running compared to speed-matched constant speed running. bioRxiv 2024:2024.03.25.586659. [PMID: 38585841 PMCID: PMC10996654 DOI: 10.1101/2024.03.25.586659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Background Hamstring strain injuries are associated with significant time away from sport and high reinjury rates. Recent evidence suggests that hamstring injuries often occur during accelerative running, but investigations of hamstring mechanics have primarily examined constant speed running on a treadmill. To help fill this gap in knowledge, this study compares hamstring lengths and lengthening velocities between accelerative running and constant speed overground running. Methods We recorded 2 synchronized videos of 10 participants (5 female, 5 male) during 6 accelerative running trials and 6 constant speed running trials. We used OpenCap (a markerless motion capture system) to estimate body segment kinematics for each trial and a 3-dimensional musculoskeletal model to compute peak length and step-average lengthening velocity of the biceps femoris (long head) muscle-tendon unit. To compare running conditions, we used linear mixed regression models with running speed (normalized by the subject-specific maximum) as the independent variable. Results At running speeds below 75% of top speed accelerative running resulted in greater peak lengths than constant speed running. For example, the peak hamstring muscle-tendon length when a person accelerated from running at only 50% of top speed was equivalent to running at a constant 88% of top speed. Lengthening velocities were greater during accelerative running at all running speeds. Differences in hip flexion kinematics primarily drove the greater peak muscle-tendon lengths and lengthening velocities observed in accelerative running. Conclusion Hamstrings are subjected to longer muscle-tendon lengths and faster lengthening velocities in accelerative running compared to constant speed running. This provides a biomechanical explanation for the observation that hamstring strain injuries often occur during acceleration. Our results suggest coaches who monitor exposure to high-risk circumstances (long lengths, fast lengthening velocities) should consider the accelerative nature of running in addition to running speed.
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Affiliation(s)
- Reed D. Gurchiek
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Zachary Teplin
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Antoine Falisse
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Jennifer L. Hicks
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Scott L. Delp
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
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2
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Uhlrich SD, Falisse A, Kidziński Ł, Muccini J, Ko M, Chaudhari AS, Hicks JL, Delp SL. OpenCap: Human movement dynamics from smartphone videos. PLoS Comput Biol 2023; 19:e1011462. [PMID: 37856442 PMCID: PMC10586693 DOI: 10.1371/journal.pcbi.1011462] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 08/24/2023] [Indexed: 10/21/2023] Open
Abstract
Measures of human movement dynamics can predict outcomes like injury risk or musculoskeletal disease progression. However, these measures are rarely quantified in large-scale research studies or clinical practice due to the prohibitive cost, time, and expertise required. Here we present and validate OpenCap, an open-source platform for computing both the kinematics (i.e., motion) and dynamics (i.e., forces) of human movement using videos captured from two or more smartphones. OpenCap leverages pose estimation algorithms to identify body landmarks from videos; deep learning and biomechanical models to estimate three-dimensional kinematics; and physics-based simulations to estimate muscle activations and musculoskeletal dynamics. OpenCap's web application enables users to collect synchronous videos and visualize movement data that is automatically processed in the cloud, thereby eliminating the need for specialized hardware, software, and expertise. We show that OpenCap accurately predicts dynamic measures, like muscle activations, joint loads, and joint moments, which can be used to screen for disease risk, evaluate intervention efficacy, assess between-group movement differences, and inform rehabilitation decisions. Additionally, we demonstrate OpenCap's practical utility through a 100-subject field study, where a clinician using OpenCap estimated musculoskeletal dynamics 25 times faster than a laboratory-based approach at less than 1% of the cost. By democratizing access to human movement analysis, OpenCap can accelerate the incorporation of biomechanical metrics into large-scale research studies, clinical trials, and clinical practice.
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Affiliation(s)
- Scott D. Uhlrich
- Departments of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Antoine Falisse
- Departments of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Łukasz Kidziński
- Departments of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Julie Muccini
- Radiology, Stanford University, Stanford, California, United States of America
| | - Michael Ko
- Radiology, Stanford University, Stanford, California, United States of America
| | - Akshay S. Chaudhari
- Radiology, Stanford University, Stanford, California, United States of America
- Biomedical Data Science, Stanford University, Stanford, California, United States of America
| | - Jennifer L. Hicks
- Departments of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Scott L. Delp
- Departments of Bioengineering, Stanford University, Stanford, California, United States of America
- Mechanical Engineering, Stanford University, Stanford, California, United States of America
- Orthopaedic Surgery, Stanford University, Stanford, California, United States of America
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3
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Falisse A, Afschrift M, De Groote F. Modeling toes contributes to realistic stance knee mechanics in three-dimensional predictive simulations of walking. PLoS One 2022; 17:e0256311. [PMID: 35077455 PMCID: PMC8789163 DOI: 10.1371/journal.pone.0256311] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/10/2022] [Indexed: 11/18/2022] Open
Abstract
Physics-based predictive simulations have been shown to capture many salient features of human walking. Yet they often fail to produce realistic stance knee and ankle mechanics. While the influence of the performance criterion on the predicted walking pattern has been previously studied, the influence of musculoskeletal mechanics has been less explored. Here, we investigated the influence of two mechanical assumptions on the predicted walking pattern: the complexity of the foot model and the stiffness of the Achilles tendon. We found, through three-dimensional muscle-driven predictive simulations of walking, that modeling the toes, and thus using two-segment instead of single-segment foot models, contributed to robustly eliciting physiological stance knee flexion angles, knee extension torques, and knee extensor activity. Modeling toes also slightly decreased the first vertical ground reaction force peak, increasing its agreement with experimental data, and improved stance ankle kinetics. It nevertheless slightly worsened predictions of ankle kinematics. Decreasing Achilles tendon stiffness improved the realism of ankle kinematics, but there remain large discrepancies with experimental data. Overall, this simulation study shows that not only the performance criterion but also mechanical assumptions affect predictive simulations of walking. Improving the realism of predictive simulations is required for their application in clinical contexts. Here, we suggest that using more complex foot models might contribute to such realism.
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Affiliation(s)
- Antoine Falisse
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
- * E-mail:
| | - Maarten Afschrift
- Department of Mechanical Engineering, Robotics Core Lab of Flanders Make, KU Leuven, Leuven, Belgium
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Bishop PJ, Falisse A, De Groote F, Hutchinson JR. Predictive simulations of running gait reveal a critical dynamic role for the tail in bipedal dinosaur locomotion. Sci Adv 2021; 7:eabi7348. [PMID: 34550734 PMCID: PMC8457660 DOI: 10.1126/sciadv.abi7348] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Locomotion has influenced the ecology, evolution, and extinction of species throughout history, yet studying locomotion in the fossil record is challenging. Computational biomechanics can provide novel insight by mechanistically relating observed anatomy to whole-animal function and behavior. Here, we leverage optimal control methods to generate the first fully predictive, three-dimensional, muscle-driven simulations of locomotion in an extinct terrestrial vertebrate, the bipedal non-avian theropod dinosaur Coelophysis. Unexpectedly, our simulations involved pronounced lateroflexion movements of the tail. Rather than just being a static counterbalance, simulations indicate that the tail played a crucial dynamic role, with lateroflexion acting as a passive, physics-based mechanism for regulating angular momentum and improving locomotor economy, analogous to the swinging arms of humans. We infer this mechanism to have existed in many other bipedal non-avian dinosaurs as well, and our methodology provides new avenues for exploring the functional diversity of dinosaur tails in the future.
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Affiliation(s)
- Peter J. Bishop
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
- Geosciences Program, Queensland Museum, Brisbane, Queensland 4011, Australia
- Corresponding author. (P.J.B.); (J.R.H.)
| | - Antoine Falisse
- Department of Movement Sciences, KU Leuven, Leuven 3000, Belgium
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Friedl De Groote
- Department of Movement Sciences, KU Leuven, Leuven 3000, Belgium
| | - John R. Hutchinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield AL9 7TA, UK
- Corresponding author. (P.J.B.); (J.R.H.)
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Wang W, Wang D, Falisse A, Severijns P, Overbergh T, Moke L, Scheys L, De Groote F, Jonkers I. Correction to: A Dynamic Optimization Approach for Solving Spine Kinematics While Calibrating Subject-Specific Mechanical Properties. Ann Biomed Eng 2021; 49:1784. [PMID: 34014422 DOI: 10.1007/s10439-021-02791-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wei Wang
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China.,Department of Movement Sciences, KU Leuven, Leuven, Belgium.,The CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences, Shenzhen, China
| | - Dongmei Wang
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | | | - Pieter Severijns
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, KU Leuven, Leuven, Belgium
| | - Thomas Overbergh
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, KU Leuven, Leuven, Belgium
| | - Lieven Moke
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, KU Leuven, Leuven, Belgium
| | - Lennart Scheys
- Department of Development and Regeneration, Institute for Orthopaedic Research and Training, KU Leuven, Leuven, Belgium
| | | | - Ilse Jonkers
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
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Bishop PJ, Falisse A, De Groote F, Hutchinson JR. Predictive Simulations of Musculoskeletal Function and Jumping Performance in a Generalized Bird. ACTA ACUST UNITED AC 2021; 3:obab006. [PMID: 34377939 PMCID: PMC8341896 DOI: 10.1093/iob/obab006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Jumping is a common, but demanding, behavior that many animals employ during everyday activity. In contrast to jump-specialists such as anurans and some primates, jumping biomechanics and the factors that influence performance remains little studied for generalized species that lack marked adaptations for jumping. Computational biomechanical modeling approaches offer a way of addressing this in a rigorous, mechanistic fashion. Here, optimal control theory and musculoskeletal modeling are integrated to generate predictive simulations of maximal height jumping in a small ground-dwelling bird, a tinamou. A three-dimensional musculoskeletal model with 36 actuators per leg is used, and direct collocation is employed to formulate a rapidly solvable optimal control problem involving both liftoff and landing phases. The resulting simulation raises the whole-body center of mass to over double its standing height, and key aspects of the simulated behavior qualitatively replicate empirical observations for other jumping birds. However, quantitative performance is lower, with reduced ground forces, jump heights, and muscle–tendon power. A pronounced countermovement maneuver is used during launch. The use of a countermovement is demonstrated to be critical to the achievement of greater jump heights, and this phenomenon may only need to exploit physical principles alone to be successful; amplification of muscle performance may not necessarily be a proximate reason for the use of this maneuver. Increasing muscle strength or contractile velocity above nominal values greatly improves jump performance, and interestingly has the greatest effect on more distal limb extensor muscles (i.e., those of the ankle), suggesting that the distal limb may be a critical link for jumping behavior. These results warrant a re-evaluation of previous inferences of jumping ability in some extinct species with foreshortened distal limb segments, such as dromaeosaurid dinosaurs. Simulations prédictives de la fonction musculo-squelettique et des performances de saut chez un oiseau généralisé Sauter est un comportement commun, mais exigeant, que de nombreux animaux utilisent au cours de leurs activités quotidiennes. Contrairement aux spécialistes du saut tels que les anoures et certains primates, la biomécanique du saut et les facteurs qui influencent la performance restent peu étudiés pour les espèces généralisées qui n’ont pas d’adaptations marquées pour le saut. Les approches de modélisation biomécanique computationnelle offrent un moyen d’aborder cette question de manière rigoureuse et mécaniste. Ici, la théorie du contrôle optimal et la modélisation musculo-squelettique sont intégrées pour générer des simulations prédictives du saut en hauteur maximal chez un petit oiseau terrestre, le tinamou. Un modèle musculo-squelettique tridimensionnel avec 36 actionneurs par patte est utilisé, et une méthode numérique nommée “direct collocation” est employée pour formuler un problème de contrôle optimal rapidement résoluble impliquant les phases de décollage et d’atterrissage. La simulation qui en résulte élève le centre de masse du corps entier à plus du double de sa hauteur debout, et les aspects clés du comportement simulé reproduisent qualitativement les observations empiriques d’autres oiseaux sauteurs. Cependant, les performances quantitatives sont moindres, avec une réduction des forces au sol, des hauteurs de saut et de la puissance musculo-tendineuse. Une manœuvre de contre-mouvement prononcée est utilisée pendant le lancement. Il a été démontré que l’utilisation d’un contre-mouvement est essentielle à l’obtention de hauteurs de saut plus importantes, et il se peut que ce phénomène doive exploiter uniquement des principes physiques pour réussir; l’amplification de la performance musculaire n’est pas nécessairement une raison immédiate de l’utilisation de cette manœuvre. L’augmentation de la force musculaire ou de la vitesse de contraction au-dessus des valeurs nominales améliore grandement la performance de saut et, fait intéressant, a le plus grand effet sur les muscles extenseurs des membres plus distaux (c'est-à-dire ceux de la cheville), ce qui suggère que le membre distal peut être un lien critique pour le comportement de saut. Ces résultats justifient une réévaluation des déductions précédentes de la capacité de sauter chez certaines espèces éteintes avec des segments de membres distaux raccourcis, comme les dinosaures droméosauridés. Voorspellende simulaties van musculoskeletale functie en springprestaties bij een gegeneraliseerde vogel Springen is een veel voorkomend, maar veeleisend, gedrag dat veel dieren toepassen tijdens hun dagelijkse bezigheden. In tegenstelling tot de springspecialisten zoals de anura en sommige primaten, is de biomechanica van het springen en de factoren die de prestaties beïnvloeden nog weinig bestudeerd voor algemene soorten die geen uitgesproken adaptaties voor het springen hebben. Computationele biomechanische modelbenaderingen bieden een manier om dit op een rigoureuze, mechanistische manier aan te pakken. Hier worden optimale controle theorie en musculoskeletale modellering geïntegreerd om voorspellende simulaties te genereren van maximale hoogtesprong bij een kleine grondbewonende vogel, een tinamou. Een driedimensionaal musculoskeletaal model met 36 actuatoren per poot wordt gebruikt, en directe collocatie wordt toegepast om een snel oplosbaar optimaal controleprobleem te formuleren dat zowel de opstijg-als de landingsfase omvat. De resulterende simulatie verhoogt het lichaamszwaartepunt tot meer dan het dubbele van de stahoogte, en belangrijke aspecten van het gesimuleerde gedrag komen kwalitatief overeen met empirische waarnemingen voor andere springende vogels. De kwantitatieve prestaties zijn echter minder, met verminderde grondkrachten, spronghoogtes en spierpeeskracht. Tijdens de lancering wordt een uitgesproken tegenbewegingsmanoeuvre gebruikt. Aangetoond is dat het gebruik van een tegenbeweging van cruciaal belang is voor het bereiken van grotere spronghoogten, en dit fenomeen hoeft alleen op fysische principes te berusten om succesvol te zijn; versterking van de spierprestaties hoeft niet noodzakelijk een proximate reden te zijn voor het gebruik van deze manoeuvre. Het verhogen van de spierkracht of van de contractiesnelheid boven de nominale waarden verbetert de sprongprestatie aanzienlijk, en heeft interessant genoeg het grootste effect op de meer distale extensoren van de ledematen (d.w.z. die van de enkel), wat suggereert dat de distale ledematen een kritieke schakel kunnen zijn voor het springgedrag. Deze resultaten rechtvaardigen een herevaluatie van eerdere conclusies over springvermogen bij sommige uitgestorven soorten met voorgekorte distale ledematen, zoals dromaeosauride dinosauriërs. Prädiktive Simulationen der muskuloskelettalen Funktion und Sprungleistung bei einem generalisierten Vogel Springen ist ein übliches jedoch anstrengendes Verhalten, das viele Tiere bei ihren täglichen Aktivitäten einsetzen. Im Gegensatz zu Springspezialisten, wie Fröschen und einigen Primaten, sind bei allgemeinen Arten, welche keine ausgeprägten Anpassung für Sprungverhalten aufweisen, die Biomechanik beim Springen und die Faktoren, welche die Leistungsfähigkeit beeinflussen, noch wenig untersucht. Computergestützte biomechanische Modellierungsverfahren bieten hier eine Möglichkeit, dies in einer gründlichen, mechanistischen Weise anzugehen. In dieser Arbeit werden die optimale Steuerungstheorie und Muskel-Skelett-Modellierung zusammen eingesetzt, um die maximale Sprunghöhe eines kleinen bodenlebenden Vogels, eines Perlsteisshuhns, zu simulieren und zu prognostizieren. Es wird ein dreidimensionales Muskel-Skelett-Modell mit 36 Aktuatoren pro Bein verwendet, und durch direkte Kollokation wird ein schnell lösbares optimales Steuerungsproblem formuliert, das sowohl die Abstoss- als auch die Landephase umfasst. Die daraus folgende Simulation bringt den Ganzkörperschwerpunkt auf mehr als das Doppelte seiner Standhöhe und entscheidende Aspekte des simulierten Verhaltens entsprechen qualitativ empirischen Beobachtungen für andere springende Vögel. Allerdings ist die quantitative Leistungsfähigkeit geringer, mit reduzierten Bodenkräften, Sprunghöhen und Muskel-Sehnen-Kräften. Beim Abstossen wird ein ausgeprägtes Gegenbewegungsmanöver durchgeführt. Die Durchführung einer Gegenbewegung ist nachweislich entscheidend für das Erreichen grösserer Sprunghöhen, wobei dieses Phänomen möglicherweise nur physikalische Prinzipien auszuschöpfen braucht, um erfolgreich zu sein. Die Verstärkung der Muskelleistung ist daher möglicherweise nicht zwingend ein unmittelbarer Grund für die Verwendung dieses Manövers. Eine Erhöhung der Muskelkraft oder der Kontraktionsgeschwindigkeit über die Nominalwerte hinaus führt zu einer erheblichen Zunahme der Sprungleistung und hat interessanterweise den grössten Effekt bei den weiter distal gelegenen Streckmuskeln der Beine (d.h. bei denjenigen des Sprunggelenks), was darauf hindeutet, dass die distale Gliedmasse ein entscheidendes Element für das Sprungverhalten sein könnte. Diese Ergebnisse geben Anlass zur Überprüfung früherer Schlussfolgerungen hinsichtlich der Sprungfähigkeit einiger ausgestorbener Arten mit verkürzten distalen Gliedmassen, wie beispielsweise bei dromaeosauriden Dinosauriern.
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Affiliation(s)
- P J Bishop
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.,Geosciences Program, Queensland Museum, Brisbane, Australia.,Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - A Falisse
- Department of Movement Sciences, KU Leuven, Leuven, Belgium.,Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - F De Groote
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - J R Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK
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Bishop PJ, Michel KB, Falisse A, Cuff AR, Allen VR, De Groote F, Hutchinson JR. Computational modelling of muscle fibre operating ranges in the hindlimb of a small ground bird (Eudromia elegans), with implications for modelling locomotion in extinct species. PLoS Comput Biol 2021; 17:e1008843. [PMID: 33793558 PMCID: PMC8016346 DOI: 10.1371/journal.pcbi.1008843] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 03/01/2021] [Indexed: 01/01/2023] Open
Abstract
The arrangement and physiology of muscle fibres can strongly influence musculoskeletal function and whole-organismal performance. However, experimental investigation of muscle function during in vivo activity is typically limited to relatively few muscles in a given system. Computational models and simulations of the musculoskeletal system can partly overcome these limitations, by exploring the dynamics of muscles, tendons and other tissues in a robust and quantitative fashion. Here, a high-fidelity, 26-degree-of-freedom musculoskeletal model was developed of the hindlimb of a small ground bird, the elegant-crested tinamou (Eudromia elegans, ~550 g), including all the major muscles of the limb (36 actuators per leg). The model was integrated with biplanar fluoroscopy (XROMM) and forceplate data for walking and running, where dynamic optimization was used to estimate muscle excitations and fibre length changes throughout both gaits. Following this, a series of static simulations over the total range of physiological limb postures were performed, to circumscribe the bounds of possible variation in fibre length. During gait, fibre lengths for all muscles remained between 0.5 to 1.21 times optimal fibre length, but operated mostly on the ascending limb and plateau of the active force-length curve, a result that parallels previous experimental findings for birds, humans and other species. However, the ranges of fibre length varied considerably among individual muscles, especially when considered across the total possible range of joint excursion. Net length change of muscle-tendon units was mostly less than optimal fibre length, sometimes markedly so, suggesting that approaches that use muscle-tendon length change to estimate optimal fibre length in extinct species are likely underestimating this important parameter for many muscles. The results of this study clarify and broaden understanding of muscle function in extant animals, and can help refine approaches used to study extinct species.
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Affiliation(s)
- Peter J. Bishop
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom
- Geosciences Program, Queensland Museum, Brisbane, Australia
| | - Krijn B. Michel
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | - Antoine Falisse
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Andrew R. Cuff
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom
- Hull York Medical School, University of York, York, United Kingdom
| | - Vivian R. Allen
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom
| | | | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom
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De Groote F, Falisse A. Perspective on musculoskeletal modelling and predictive simulations of human movement to assess the neuromechanics of gait. Proc Biol Sci 2021; 288:20202432. [PMID: 33653141 PMCID: PMC7935082 DOI: 10.1098/rspb.2020.2432] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/02/2021] [Indexed: 01/10/2023] Open
Abstract
Locomotion results from complex interactions between the central nervous system and the musculoskeletal system with its many degrees of freedom and muscles. Gaining insight into how the properties of each subsystem shape human gait is challenging as experimental methods to manipulate and assess isolated subsystems are limited. Simulations that predict movement patterns based on a mathematical model of the neuro-musculoskeletal system without relying on experimental data can reveal principles of locomotion by elucidating cause-effect relationships. New computational approaches have enabled the use of such predictive simulations with complex neuro-musculoskeletal models. Here, we review recent advances in predictive simulations of human movement and how those simulations have been used to deepen our knowledge about the neuromechanics of gait. In addition, we give a perspective on challenges towards using predictive simulations to gain new fundamental insight into motor control of gait, and to help design personalized treatments in patients with neurological disorders and assistive devices that improve gait performance. Such applications will require more detailed neuro-musculoskeletal models and simulation approaches that take uncertainty into account, tools to efficiently personalize those models, and validation studies to demonstrate the ability of simulations to predict gait in novel circumstances.
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Affiliation(s)
- Friedl De Groote
- Department of Movement Sciences, KU Leuven, Leuven, Flanders, Belgium
| | - Antoine Falisse
- Department of Movement Sciences, KU Leuven, Leuven, Flanders, Belgium
- Department of Bioengineering, Stanford University, Stanford, CA, USA
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9
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Dembia CL, Bianco NA, Falisse A, Hicks JL, Delp SL. OpenSim Moco: Musculoskeletal optimal control. PLoS Comput Biol 2020; 16:e1008493. [PMID: 33370252 PMCID: PMC7793308 DOI: 10.1371/journal.pcbi.1008493] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 01/08/2021] [Accepted: 11/05/2020] [Indexed: 11/18/2022] Open
Abstract
Musculoskeletal simulations are used in many different applications, ranging from the design of wearable robots that interact with humans to the analysis of patients with impaired movement. Here, we introduce OpenSim Moco, a software toolkit for optimizing the motion and control of musculoskeletal models built in the OpenSim modeling and simulation package. OpenSim Moco uses the direct collocation method, which is often faster and can handle more diverse problems than other methods for musculoskeletal simulation. Moco frees researchers from implementing direct collocation themselves-which typically requires extensive technical expertise-and allows them to focus on their scientific questions. The software can handle a wide range of problems that interest biomechanists, including motion tracking, motion prediction, parameter optimization, model fitting, electromyography-driven simulation, and device design. Moco is the first musculoskeletal direct collocation tool to handle kinematic constraints, which enable modeling of kinematic loops (e.g., cycling models) and complex anatomy (e.g., patellar motion). To show the abilities of Moco, we first solved for muscle activity that produced an observed walking motion while minimizing squared muscle excitations and knee joint loading. Next, we predicted how muscle weakness may cause deviations from a normal walking motion. Lastly, we predicted a squat-to-stand motion and optimized the stiffness of an assistive device placed at the knee. We designed Moco to be easy to use, customizable, and extensible, thereby accelerating the use of simulations to understand the movement of humans and other animals.
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Affiliation(s)
- Christopher L. Dembia
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America
| | - Nicholas A. Bianco
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America
| | - Antoine Falisse
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Jennifer L. Hicks
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
| | - Scott L. Delp
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America
- Department of Bioengineering, Stanford University, Stanford, California, United States of America
- Department of Orthopaedic Surgery, Stanford University, Stanford, California, United States of America
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Falisse A, Pitto L, Kainz H, Hoang H, Wesseling M, Van Rossom S, Papageorgiou E, Bar-On L, Hallemans A, Desloovere K, Molenaers G, Van Campenhout A, De Groote F, Jonkers I. Physics-Based Simulations to Predict the Differential Effects of Motor Control and Musculoskeletal Deficits on Gait Dysfunction in Cerebral Palsy: A Retrospective Case Study. Front Hum Neurosci 2020; 14:40. [PMID: 32132911 PMCID: PMC7040166 DOI: 10.3389/fnhum.2020.00040] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/27/2020] [Indexed: 12/05/2022] Open
Abstract
Physics-based simulations of walking have the theoretical potential to support clinical decision-making by predicting the functional outcome of treatments in terms of walking performance. Yet before using such simulations in clinical practice, their ability to identify the main treatment targets in specific patients needs to be demonstrated. In this study, we generated predictive simulations of walking with a medical imaging based neuro-musculoskeletal model of a child with cerebral palsy presenting crouch gait. We explored the influence of altered muscle-tendon properties, reduced neuromuscular control complexity, and spasticity on gait dysfunction in terms of joint kinematics, kinetics, muscle activity, and metabolic cost of transport. We modeled altered muscle-tendon properties by personalizing Hill-type muscle-tendon parameters based on data collected during functional movements, simpler neuromuscular control by reducing the number of independent muscle synergies, and spasticity through delayed muscle activity feedback from muscle force and force rate. Our simulations revealed that, in the presence of aberrant musculoskeletal geometries, altered muscle-tendon properties rather than reduced neuromuscular control complexity and spasticity were the primary cause of the crouch gait pattern observed for this child, which is in agreement with the clinical examination. These results suggest that muscle-tendon properties should be the primary target of interventions aiming to restore an upright gait pattern for this child. This suggestion is in line with the gait analysis following muscle-tendon property and bone deformity corrections. Future work should extend this single case analysis to more patients in order to validate the ability of our physics-based simulations to capture the gait patterns of individual patients pre- and post-treatment. Such validation would open the door for identifying targeted treatment strategies with the aim of designing optimized interventions for neuro-musculoskeletal disorders.
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Affiliation(s)
| | - Lorenzo Pitto
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Hans Kainz
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Hoa Hoang
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | | | - Sam Van Rossom
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | | | - Lynn Bar-On
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.,Department of Rehabilitation Medicine, Amsterdam Movement Sciences, Amsterdam UMC, VU University Medical Center, Amsterdam, Netherlands
| | - Ann Hallemans
- Department of Rehabilitation Sciences and Physiotherapy, University of Antwerp, Antwerp, Belgium
| | - Kaat Desloovere
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Guy Molenaers
- Department of Orthopaedic Surgery, UZ Leuven, Leuven, Belgium.,Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Anja Van Campenhout
- Department of Orthopaedic Surgery, UZ Leuven, Leuven, Belgium.,Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | | | - Ilse Jonkers
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
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11
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Falisse A, Serrancolí G, Dembia CL, Gillis J, De Groote F. Algorithmic differentiation improves the computational efficiency of OpenSim-based trajectory optimization of human movement. PLoS One 2019; 14:e0217730. [PMID: 31622352 PMCID: PMC6797126 DOI: 10.1371/journal.pone.0217730] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/19/2019] [Indexed: 11/26/2022] Open
Abstract
Algorithmic differentiation (AD) is an alternative to finite differences (FD) for evaluating function derivatives. The primary aim of this study was to demonstrate the computational benefits of using AD instead of FD in OpenSim-based trajectory optimization of human movement. The secondary aim was to evaluate computational choices including different AD tools, different linear solvers, and the use of first- or second-order derivatives. First, we enabled the use of AD in OpenSim through a custom source code transformation tool and through the operator overloading tool ADOL-C. Second, we developed an interface between OpenSim and CasADi to solve trajectory optimization problems. Third, we evaluated computational choices through simulations of perturbed balance, two-dimensional predictive simulations of walking, and three-dimensional tracking simulations of walking. We performed all simulations using direct collocation and implicit differential equations. Using AD through our custom tool was between 1.8 ± 0.1 and 17.8 ± 4.9 times faster than using FD, and between 3.6 ± 0.3 and 12.3 ± 1.3 times faster than using AD through ADOL-C. The linear solver efficiency was problem-dependent and no solver was consistently more efficient. Using second-order derivatives was more efficient for balance simulations but less efficient for walking simulations. The walking simulations were physiologically realistic. These results highlight how the use of AD drastically decreases computational time of trajectory optimization problems as compared to more common FD. Overall, combining AD with direct collocation and implicit differential equations decreases the computational burden of trajectory optimization of human movement, which will facilitate their use for biomechanical applications requiring the use of detailed models of the musculoskeletal system.
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Affiliation(s)
- Antoine Falisse
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
- * E-mail:
| | - Gil Serrancolí
- Department of Mechanical Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalunya, Spain
| | - Christopher L. Dembia
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America
| | - Joris Gillis
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
- DMMS Lab, Flanders Make, Leuven, Belgium
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12
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Falisse A, Serrancolí G, Dembia CL, Gillis J, Jonkers I, De Groote F. Rapid predictive simulations with complex musculoskeletal models suggest that diverse healthy and pathological human gaits can emerge from similar control strategies. J R Soc Interface 2019; 16:20190402. [PMID: 31431186 PMCID: PMC6731507 DOI: 10.1098/rsif.2019.0402] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Physics-based predictive simulations of human movement have the potential to support personalized medicine, but large computational costs and difficulties to model control strategies have limited their use. We have developed a computationally efficient optimal control framework to predict human gaits based on optimization of a performance criterion without relying on experimental data. The framework generates three-dimensional muscle-driven simulations in 36 min on average—more than 20 times faster than existing simulations—by using direct collocation, implicit differential equations and algorithmic differentiation. Using this framework, we identified a multi-objective performance criterion combining energy and effort considerations that produces physiologically realistic walking gaits. The same criterion also predicted the walk-to-run transition and clinical gait deficiencies caused by muscle weakness and prosthesis use, suggesting that diverse healthy and pathological gaits can emerge from the same control strategy. The ability to predict the mechanics and energetics of a broad range of gaits with complex three-dimensional musculoskeletal models will allow testing novel hypotheses about gait control and hasten the development of optimal treatments for neuro-musculoskeletal disorders.
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Affiliation(s)
| | - Gil Serrancolí
- Department of Mechanical Engineering, Universitat Politècnica de Catalunya, Barcelona, Catalunya, Spain
| | | | - Joris Gillis
- Department of Mechanical Engineering, KU Leuven, Leuven, Belgium.,DMMS Lab, Flanders Make, Leuven, Belgium
| | - Ilse Jonkers
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
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Serrancoli G, Falisse A, Dembia C, Vantilt J, Tanghe K, Lefeber D, Jonkers I, De Schutter J, De Groote F. Subject-Exoskeleton Contact Model Calibration Leads to Accurate Interaction Force Predictions. IEEE Trans Neural Syst Rehabil Eng 2019; 27:1597-1605. [DOI: 10.1109/tnsre.2019.2924536] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Pitto L, Kainz H, Falisse A, Wesseling M, Van Rossom S, Hoang H, Papageorgiou E, Hallemans A, Desloovere K, Molenaers G, Van Campenhout A, De Groote F, Jonkers I. SimCP: A Simulation Platform to Predict Gait Performance Following Orthopedic Intervention in Children With Cerebral Palsy. Front Neurorobot 2019; 13:54. [PMID: 31379550 PMCID: PMC6650580 DOI: 10.3389/fnbot.2019.00054] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 07/03/2019] [Indexed: 12/19/2022] Open
Abstract
Gait deficits in cerebral palsy (CP) are often treated with a single-event multi-level surgery (SEMLS). Selecting the treatment options (combination of bony and soft tissue corrections) for a specific patient is a complex endeavor and very often treatment outcome is not satisfying. A deterioration in 22.8% of the parameters describing gait performance has been reported and there is need for additional surgery in 11% of the patients. Computational simulations based on musculoskeletal models that allow clinicians to test the effects of different treatment options before surgery have the potential to drastically improve treatment outcome. However, to date, no such simulation and modeling method is available. Two important challenges are the development of methods to include patient-specific neuromechanical impairments into the models and to simulate the effect of different surgical procedures on post-operative gait performance. Therefore, we developed the SimCP framework that allows the evaluation of the effect of different simulated surgeries on gait performance of a specific patient and includes a graphical user interface (GUI) that enables performing virtual surgery on the models. We demonstrated the potential of our framework for two case studies. Models reflecting the patient-specific musculoskeletal geometry and muscle properties are generated based solely on data collected before the treatment. The patient's motor control is described based on muscle synergies derived from pre-operative EMG. The GUI is then used to modify the musculoskeletal properties according to the surgical plan. Since SEMLS does not affect motor control, the same motor control model is used to define gait performance pre- and post-operative. We use the capability gap (CG), i.e., the difference between the joint moments needed to perform healthy walking and the joint moments the personalized model can generate, to quantify gait performance. In both cases, the CG was smaller post- then pre-operative and this was in accordance with the measured change in gait kinematics after treatment.
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Affiliation(s)
- Lorenzo Pitto
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Hans Kainz
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | | | | | - Sam Van Rossom
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Hoa Hoang
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Eirini Papageorgiou
- Department of Rehabilitation Sciences, Doctoral School of Biomedical Sciences, KU Leuven, Leuven, Belgium.,Clinical Motion Analysis Laboratory, University Hospitals Leuven, Leuven, Belgium
| | - Ann Hallemans
- Department of Rehabilitation Sciences and Physiotherapy, University of Antwerp, Antwerp, Belgium
| | - Kaat Desloovere
- Department of Rehabilitation Sciences, Doctoral School of Biomedical Sciences, KU Leuven, Leuven, Belgium.,Clinical Motion Analysis Laboratory, University Hospitals Leuven, Leuven, Belgium
| | - Guy Molenaers
- Department of Orthopedics, University Hospitals Leuven, Leuven, Belgium.,Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | - Anja Van Campenhout
- Department of Orthopedics, University Hospitals Leuven, Leuven, Belgium.,Department of Development and Regeneration, KU Leuven, Leuven, Belgium
| | | | - Ilse Jonkers
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
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Falisse A, Bar-On L, Desloovere K, Jonkers I, De Groote F. A spasticity model based on feedback from muscle force explains muscle activity during passive stretches and gait in children with cerebral palsy. PLoS One 2018; 13:e0208811. [PMID: 30532154 PMCID: PMC6286045 DOI: 10.1371/journal.pone.0208811] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 11/24/2018] [Indexed: 11/19/2022] Open
Abstract
Muscle spasticity is characterized by exaggerated stretch reflexes and affects about 85% of the children with cerebral palsy. However, the mechanisms underlying spasticity and its influence on gait are not well understood. Here, we first aimed to model the response of spastic hamstrings and gastrocnemii in children with cerebral palsy to fast passive stretches. Then, we evaluated how the model applied to gait. We developed three models based on exaggerated proprioceptive feedback. The first model relied on feedback from muscle fiber length and velocity (velocity-related model), the second model relied on feedback from muscle fiber length, velocity, and acceleration (acceleration-related model), and the third model relied on feedback from muscle force and its first time derivative (force-related model). The force-related model better reproduced measured hamstrings and gastrocnemii activity during fast passive stretches (coefficients of determination (R2): 0.73 ± 0.10 and 0.60 ± 0.13, respectively, and root mean square errors (RMSE): 0.034 ± 0.031 and 0.009 ± 0.007, respectively) than the velocity-related model (R2: 0.46 ± 0.15 and 0.07 ± 0.13, and RMSE: 0.053 ± 0.051 and 0.015 ± 0.009), and the acceleration-related model (R2: 0.47 ± 0.15 and 0.09 ± 0.14, and RMSE: 0.052 ± 0.050 and 0.015 ± 0.008). Additionally, the force-related model predicted hamstrings and gastrocnemii activity that better correlated with measured activity during gait (cross correlations: 0.82 ± 0.09 and 0.85 ± 0.06, respectively) than the activity predicted by the velocity-related model (cross correlations: 0.49 ± 0.17 and 0.71 ± 0.22) and the acceleration-related model (cross correlations: 0.51 ± 0.16 and 0.67 ± 0.20). Our results therefore suggest that force encoding in muscle spindles in combination with altered feedback gains and thresholds underlie activity of spastic muscles during passive stretches and gait. Our model of spasticity opens new perspectives for studying movement impairments due to spasticity through simulation.
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Affiliation(s)
- Antoine Falisse
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
- * E-mail:
| | - Lynn Bar-On
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Rehabilitation Medicine, Amsterdam Movement Sciences, Amsterdam, Netherlands
| | - Kaat Desloovere
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | - Ilse Jonkers
- Department of Movement Sciences, KU Leuven, Leuven, Belgium
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Falisse A, Van Rossom S, Gijsbers J, Steenbrink F, van Basten BJH, Jonkers I, van den Bogert AJ, De Groote F. OpenSim Versus Human Body Model: A Comparison Study for the Lower Limbs During Gait. J Appl Biomech 2018; 34:496-502. [PMID: 29809082 DOI: 10.1123/jab.2017-0156] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 04/16/2018] [Accepted: 05/04/2018] [Indexed: 11/18/2022]
Abstract
Musculoskeletal modeling and simulations have become popular tools for analyzing human movements. However, end users are often not aware of underlying modeling and computational assumptions. This study investigates how these assumptions affect biomechanical gait analysis outcomes performed with Human Body Model and the OpenSim gait2392 model. The authors compared joint kinematics, kinetics, and muscle forces resulting from processing data from 7 healthy adults with both models. Although outcome variables had similar patterns, there were statistically significant differences in joint kinematics (maximal difference: 9.8° [1.5°] in sagittal plane hip rotation), kinetics (maximal difference: 0.36 [0.10] N·m/kg in sagittal plane hip moment), and muscle forces (maximal difference: 8.51 [1.80] N/kg for psoas). These differences might be explained by differences in hip and knee joint center locations up to 2.4 (0.5) and 1.9 (0.2) cm in the posteroanterior and inferosuperior directions, respectively, and by the offset in pelvic reference frames of about 10° around the mediolateral axis. The choice of model may not influence the conclusions in clinical settings, where the focus is on interpreting deviations from the reference data, but it will affect the conclusions of mechanical analyses in which the goal is to obtain accurate estimates of kinematics and loading.
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Kainz H, Goudriaan M, Falisse A, Huenaerts C, Desloovere K, De Groote F, Jonkers I. The influence of maximum isometric muscle force scaling on estimated muscle forces from musculoskeletal models of children with cerebral palsy. Gait Posture 2018; 65:213-220. [PMID: 30558934 DOI: 10.1016/j.gaitpost.2018.07.172] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/02/2018] [Accepted: 07/21/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND Musculoskeletal models do not include patient-specific muscle forces but rely on a scaled generic model, with muscle forces left unscaled in most cases. However, to use musculoskeletal simulations to inform clinical decision-making in children with cerebral palsy (CP), inclusion of subject-specific muscle forces is of utmost importance in order to represent each child's compensation mechanisms introduced through muscle weakness. RESEARCH AIM The aims of this study were to (i) evaluate if maximum isometric muscle forces (MIMF) in musculoskeletal models of children with CP can be scaled based on strength measurements obtained with a hand-held-dynamometer (HHD), (ii) evaluate the impact of the HHD based scaling approach and previously published MIMF scaling methods on computed muscle forces during gait, and (iii) compare maximum muscle forces during gait between CP and typically developing (TD) children. METHODS Strength and motion capture data of six CP and motion capture data of six TD children were collected. The HHD measurements to obtain hip, knee and ankle muscle strength were simulated in OpenSim and used to modify MIMF of the 2392-OpenSim model. These muscle forces were compared to the MIMF scaled on the child's body mass and a scaling approach, which included the body mass and muscle-tendon lengths. OpenSim was used to calculate peak muscle forces during gait. RESULTS Ankle muscle strength was insufficient to reproduce joint moments during walking when MIMF were scaled based on HHD. During gait, peak hip and knee extensor muscle forces were higher and peak ankle dorsi-flexor forces were lower in CP compared to TD participants. SIGNIFICANCE HHD measurements can be used to scale MIMF for the hip and knee muscle groups but underestimate the force capacity of the ankle muscle groups during walking. Muscle-tendon-length and mass based scaling methods affected muscle activations but had little influence on peak muscle forces during gait.
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Affiliation(s)
- Hans Kainz
- Department of Kinesiology, KU Leuven, Leuven, Belgium.
| | - Marije Goudriaan
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium
| | | | - Catherine Huenaerts
- Clinical Motion Analysis Laboratory, University Hospital Leuven, Pellenberg, Belgium
| | - Kaat Desloovere
- Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium; Clinical Motion Analysis Laboratory, University Hospital Leuven, Pellenberg, Belgium
| | | | - Ilse Jonkers
- Department of Kinesiology, KU Leuven, Leuven, Belgium
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Arba M, Falisse A, Choukr-Allah R, Sindic M. Effect of irrigation at critical stages on the phenology of flowering and fruiting of the cactus Opuntia spp. BRAZ J BIOL 2018; 78:653-660. [PMID: 29412245 DOI: 10.1590/1519-6984.170086] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 05/10/2017] [Indexed: 11/22/2022] Open
Abstract
This paper briefly reports some effects of irrigations at two critical periods on the phenology of three varieties of cactus pear cultivated in Agadir area: the spineless varieties 'Aissa' and 'Moussa' and the thorny one 'Achefri'. In the first year experiments (2010-2011) treatments of irrigation used were: (T1) 0 mm, (T2) 30 mm during flowering and 30 mm during fruit enlargement and (T3) 30 mm only during fruit enlargement. In the 2nd year experiments, irrigation treatments were: (T1) 0 mm, (T2) 60 mm during flowering and 60 mm during fruit enlargement and (T3) 60 mm only during fruit enlargement. Treatments of irrigation were applied between mid-April and mid-June in the 1st year experiments and in February and May in the 2nd year experiments. Results of the first year experiments showed that the emission of buds was higher in the thorny variety than in the spineless ones (more than 6 emitted buds/cladode vs less than 4.5 in the spineless varieties). In the second year, irrigation increased the emission of buds in the three varieties (more than 7 emitted buds/cladode for each T2 and T3 of all varieties vs not more than 5 for T1) and the duration of the flowering phase of these varieties. However, irrigation did not modify the proportions of fruits reaching commercial maturity during the early or the late period of maturation.
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Affiliation(s)
- M Arba
- Plant ecophysiology unit, Department of Horticulture, Hassan II Institute of Agronomy and Veterinary Medicine, Horticultural Complex of Agadir, Morocco
| | - A Falisse
- Crop Production Unit, Gembloux Agro-Bio Tech, University of Liège, Liège, Belgium.,Faculty of Agriculture, University of Agricultural Sciences and Veterinary Medicine, Cluj, Romania
| | - R Choukr-Allah
- Plant ecophysiology unit, Department of Horticulture, Hassan II Institute of Agronomy and Veterinary Medicine, Horticultural Complex of Agadir, Morocco
| | - M Sindic
- Laboratory of Food Quality and Safety, Gembloux Agro Bio Tech, University of Liège, Liège, Belgium
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Falisse A, Van Rossom S, Jonkers I, De Groote F. EMG-Driven Optimal Estimation of Subject-SPECIFIC Hill Model Muscle-Tendon Parameters of the Knee Joint Actuators. IEEE Trans Biomed Eng 2016; 64:2253-2262. [PMID: 27875132 DOI: 10.1109/tbme.2016.2630009] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE the purpose of this paper is to propose an optimal control problem formulation to estimate subject-specific Hill model muscle-tendon (MT-) parameters of the knee joint actuators by optimizing the fit between experimental and model-based knee moments. Additionally, this paper aims at determining which sets of functional motions contain the necessary information to identify the MT-parameters. METHODS the optimal control and parameter estimation problem underlying the MT-parameter estimation is solved for subject-specific MT-parameters via direct collocation using an electromyography-driven musculoskeletal model. The sets of motions containing sufficient information to identify the MT-parameters are determined by evaluating knee moments simulated based on subject-specific MT-parameters against experimental moments. RESULTS the MT-parameter estimation problem was solved in about 30 CPU minutes. MT-parameters could be identified from only seven of the 62 investigated sets of motions, underlining the importance of the experimental protocol. Using subject-specific MT-parameters instead of more common linearly scaled MT-parameters improved the fit between inverse dynamics moments and simulated moments by about 30% in terms of the coefficient of determination (from [Formula: see text] to [Formula: see text]) and by about 26% in terms of the root mean square error (from [Formula: see text] to [Formula: see text] ). In particular, subject-specific MT-parameters of the knee flexors were very different from linearly scaled MT-parameters. CONCLUSION we introduced a computationally efficient optimal control problem formulation and provided guidelines for designing an experimental protocol to estimate subject-specific MT-parameters improving the accuracy of motion simulations. SIGNIFICANCE the proposed formulation opens new perspectives for subject-specific musculoskeletal modeling, which might be beneficial for simulating and understanding pathological motions.
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