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Rock CG, Kwak ST, Luo A, Yang X, Yun K, Chang YH. Realizing the gravity of the simulation: adaptation to simulated hypogravity leads to altered predictive control. Front Physiol 2024; 15:1397016. [PMID: 38854629 PMCID: PMC11157081 DOI: 10.3389/fphys.2024.1397016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/06/2024] [Indexed: 06/11/2024] Open
Abstract
Accurate predictive abilities are important for a wide variety of animal behaviors. Inherent to many of these predictions is an understanding of the physics that underlie the behavior. Humans are specifically attuned to the physics on Earth but can learn to move in other environments (e.g., the surface of the Moon). However, the adjustments made to their physics-based predictions in the face of altered gravity are not fully understood. The current study aimed to characterize the locomotor adaptation to a novel paradigm for simulated reduced gravity. We hypothesized that exposure to simulated hypogravity would result in updated predictions of gravity-based movement. Twenty participants took part in a protocol that had them perform vertically targeted countermovement jumps before (PRE), during, and after (POST) a physical simulation of hypogravity. Jumping in simulated hypogravity had different neuromechanics from the PRE condition, with reduced ground impulses (p ≤ .009) and muscle activity prior to the time of landing (i.e., preactivation; p ≤ .016). In the 1 g POST condition, muscle preactivation remained reduced (p ≤ .033) and was delayed (p ≤ .008) by up to 33% for most muscles of the triceps surae, reflecting an expectation of hypogravity. The aftereffects in muscle preactivation, along with little-to-no change in muscle dynamics during ground contact, point to a neuromechanical adaptation that affects predictive, feed-forward systems over feedback systems. As such, we conclude that the neural representation, or internal model, of gravity is updated after exposure to simulated hypogravity.
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Affiliation(s)
- Chase G. Rock
- Comparative Neuromechanics Laboratory, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | | | | | | | | | - Young-Hui Chang
- Comparative Neuromechanics Laboratory, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
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Waldvogel J, Freyler K, Ritzmann R, Gollhofer A. Energy transfer in reactive movements as a function of individual stretch load. Front Physiol 2023; 14:1265443. [PMID: 38098807 PMCID: PMC10720888 DOI: 10.3389/fphys.2023.1265443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 11/13/2023] [Indexed: 12/17/2023] Open
Abstract
Background: By directly recording electromyographic activity profiles and muscle-tendon interaction, this study aimed to elucidate the mechanisms why well-trained track and field athletes (experts) are able to outperform untrained individuals without former systematic experience in reactive jump training (novices). In particular, reactive power output and the elastic recoil properties of the muscle-tendon unit (MTU) were of special interest. For this purpose, stiffness regulation on muscle and joint level, energy management in terms of storing or dissipating elastic energy were compared between experts and novices during various stretch loads. Methods: Experts were compared with novices during reactive drop jumps (DJs) from drop heights ranging between 25 and 61 cm. Delta kinetic energy (Ekin) was calculated as the difference between the Ekin at take-off and ground contact (GC) to determine energy management. By recording electromyography of the lower limb muscles, in vivo fascicle dynamics (gastrocnemius medialis) and by combining kinematics and kinetics in a 3D inverse dynamics approach to compute ankle and knee joint kinetics, this study aimed to compare reactive jump performance, the neuromuscular activity and muscle-tendon interaction between experts and novices among the tested stretch loads. Results: Experts demonstrated significantly higher power output during DJs. Among all drop heights experts realized higher delta Ekin compared to novices. Consequently, higher reactive jump performance shown for experts was characterized by shorter GC time (GCT), higher jump heights and higher neuromuscular activity before and during the GC phase compared to novices. Concomitantly, experts were able to realize highest leg stiffness and delta Ekin in the lowest stretch load; however, both groups compensated the highest stretch load by prolonged GCT and greater joint flexion. On muscle level, experts work quasi-isometrically in the highest stretch load, while in novices GM fascicles were forcefully stretched. Conclusion: Group-specific stiffness regulation and elastic recoil properties are primarily influenced by the neuromuscular system. Due to their higher neuromuscular activity prior and during the GC phase, experts demonstrate higher force generating capacity. A functionally stiffer myotendinous system through enhanced neuromuscular input enables the experts loading their elastic recoil system more efficiently, thus realizing higher reactive power output and allowing a higher amount of energy storage and return. This mechanism is regulated in a stretch load dependent manner.
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Affiliation(s)
- Janice Waldvogel
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
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Bunz EK, Haeufle DFB, Remy CD, Schmitt S. Bioinspired preactivation reflex increases robustness of walking on rough terrain. Sci Rep 2023; 13:13219. [PMID: 37580375 PMCID: PMC10425464 DOI: 10.1038/s41598-023-39364-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 07/24/2023] [Indexed: 08/16/2023] Open
Abstract
Walking on unknown and rough terrain is challenging for (bipedal) robots, while humans naturally cope with perturbations. Therefore, human strategies serve as an excellent inspiration to improve the robustness of robotic systems. Neuromusculoskeletal (NMS) models provide the necessary interface for the validation and transfer of human control strategies. Reflexes play a crucial part during normal locomotion and especially in the face of perturbations, and provide a simple, transferable, and bio-inspired control scheme. Current reflex-based NMS models are not robust to unexpected perturbations. Therefore, in this work, we propose a bio-inspired improvement of a widely used NMS walking model. In humans, different muscles show an increase in activation in anticipation of the landing at the end of the swing phase. This preactivation is not integrated in the used reflex-based walking model. We integrate this activation by adding an additional feedback loop and show that the landing is adapted and the robustness to unexpected step-down perturbations is markedly improved (from 3 to 10 cm). Scrutinizing the effect, we find that the stabilizing effect is caused by changed knee kinematics. Preactivation, therefore, acts as an accommodation strategy to cope with unexpected step-down perturbations, not requiring any detection of the perturbation. Our results indicate that such preactivation can potentially enable a bipedal system to react adequately to upcoming unexpected perturbations and is hence an effective adaptation of reflexes to cope with rough terrain. Preactivation can be ported to robots by leveraging the reflex-control scheme and improves the robustness to step-down perturbation without the need to detect the perturbation. Alternatively, the stabilizing mechanism can also be added in an anticipatory fashion by applying an additional knee torque to the contralateral knee.
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Affiliation(s)
- Elsa K Bunz
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany.
- Stuttgart Center for Simulation Science, University of Stuttgart, Stuttgart, Germany.
| | - Daniel F B Haeufle
- Institute of Computer Engineering, Heidelberg University, Heidelberg, Germany
- Hertie Institute for Clinical Brain Research and Center for Integrative Neuroscience, Tuebingen, Germany
- Center for Bionic Intelligence Tuebingen Stuttgart, Tuebingen Stuttgart, Germany
| | - C David Remy
- Stuttgart Center for Simulation Science, University of Stuttgart, Stuttgart, Germany
- Center for Bionic Intelligence Tuebingen Stuttgart, Tuebingen Stuttgart, Germany
- Institute for Nonlinear Mechanics, University of Stuttgart, Stuttgart, Germany
| | - Syn Schmitt
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
- Stuttgart Center for Simulation Science, University of Stuttgart, Stuttgart, Germany
- Center for Bionic Intelligence Tuebingen Stuttgart, Tuebingen Stuttgart, Germany
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4
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Saveko A, Bekreneva M, Ponomarev I, Zelenskaya I, Riabova A, Shigueva T, Kitov V, Abu Sheli N, Nosikova I, Rukavishnikov I, Sayenko D, Tomilovskaya E. Impact of different ground-based microgravity models on human sensorimotor system. Front Physiol 2023; 14:1085545. [PMID: 36875039 PMCID: PMC9974674 DOI: 10.3389/fphys.2023.1085545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/30/2023] [Indexed: 02/17/2023] Open
Abstract
This review includes current and updated information about various ground-based microgravity models and their impact on the human sensorimotor system. All known models of microgravity are imperfect in a simulation of the physiological effects of microgravity but have their advantages and disadvantages. This review points out that understanding the role of gravity in motion control requires consideration of data from different environments and in various contexts. The compiled information can be helpful to researchers to effectively plan experiments using ground-based models of the effects of space flight, depending on the problem posed.
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Affiliation(s)
- Alina Saveko
- Russian Federation State Scientific Center—Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow, Russia
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Waldvogel J, Freyler K, Helm M, Monti E, Stäudle B, Gollhofer A, Narici MV, Ritzmann R, Albracht K. Changes in gravity affect neuromuscular control, biomechanics, and muscle-tendon mechanics in energy storage and dissipation tasks. J Appl Physiol (1985) 2023; 134:190-202. [PMID: 36476161 DOI: 10.1152/japplphysiol.00279.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
This study evaluates neuromechanical control and muscle-tendon interaction during energy storage and dissipation tasks in hypergravity. During parabolic flights, while 17 subjects performed drop jumps (DJs) and drop landings (DLs), electromyography (EMG) of the lower limb muscles was combined with in vivo fascicle dynamics of the gastrocnemius medialis, two-dimensional (2D) kinematics, and kinetics to measure and analyze changes in energy management. Comparisons were made between movement modalities executed in hypergravity (1.8 G) and gravity on ground (1 G). In 1.8 G, ankle dorsiflexion, knee joint flexion, and vertical center of mass (COM) displacement are lower in DJs than in DLs; within each movement modality, joint flexion amplitudes and COM displacement demonstrate higher values in 1.8 G than in 1 G. Concomitantly, negative peak ankle joint power, vertical ground reaction forces, and leg stiffness are similar between both movement modalities (1.8 G). In DJs, EMG activity in 1.8 G is lower during the COM deceleration phase than in 1 G, thus impairing quasi-isometric fascicle behavior. In DLs, EMG activity before and during the COM deceleration phase is higher, and fascicles are stretched less in 1.8 G than in 1 G. Compared with the situation in 1 G, highly task-specific neuromuscular activity is diminished in 1.8 G, resulting in fascicle lengthening in both movement modalities. Specifically, in DJs, a high magnitude of neuromuscular activity is impaired, resulting in altered energy storage. In contrast, in DLs, linear stiffening of the system due to higher neuromuscular activity combined with lower fascicle stretch enhances the buffering function of the tendon, and thus the capacity to safely dissipate energy.NEW & NOTEWORTHY For the first time, the neuromechanics of distinct movement modalities that fundamentally differ in their energy management function have been investigated during overload systematically induced by hypergravity. Parabolic flight provides a unique experimental setting that allows near-natural movement execution without the confounding effects typically associated with load variation. Our findings show that gravity-adjusted muscle activities are inversely affected within jumps and landings. Specifically, in 1.8 G, typical task-specific differences in neuromuscular activity are reduced during the center of mass deceleration phase, resulting in fascicle lengthening, which is associated with energy dissipation.
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Affiliation(s)
- Janice Waldvogel
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Kathrin Freyler
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Michael Helm
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Elena Monti
- Department of Biomedical Sciences, University of Padua, Padua, Italy.,Department of Neurosciences, Imaging and Clinical Science, University of Chieti "G. D'annunzio", Chieti, Italy
| | - Benjamin Stäudle
- Department of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
| | - Albert Gollhofer
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Marco V Narici
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Ramona Ritzmann
- Institute of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Kirsten Albracht
- Department of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany.,Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany
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Movement in low gravity environments (MoLo) programme-The MoLo-L.O.O.P. study protocol. PLoS One 2022; 17:e0278051. [PMID: 36417480 PMCID: PMC9683620 DOI: 10.1371/journal.pone.0278051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/08/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Exposure to prolonged periods in microgravity is associated with deconditioning of the musculoskeletal system due to chronic changes in mechanical stimulation. Given astronauts will operate on the Lunar surface for extended periods of time, it is critical to quantify both external (e.g., ground reaction forces) and internal (e.g., joint reaction forces) loads of relevant movements performed during Lunar missions. Such knowledge is key to predict musculoskeletal deconditioning and determine appropriate exercise countermeasures associated with extended exposure to hypogravity. OBJECTIVES The aim of this paper is to define an experimental protocol and methodology suitable to estimate in high-fidelity hypogravity conditions the lower limb internal joint reaction forces. State-of-the-art movement kinetics, kinematics, muscle activation and muscle-tendon unit behaviour during locomotor and plyometric movements will be collected and used as inputs (Objective 1), with musculoskeletal modelling and an optimisation framework used to estimate lower limb internal joint loading (Objective 2). METHODS Twenty-six healthy participants will be recruited for this cross-sectional study. Participants will walk, skip and run, at speeds ranging between 0.56-3.6 m/s, and perform plyometric movement trials at each gravity level (1, 0.7, 0.5, 0.38, 0.27 and 0.16g) in a randomized order. Through the collection of state-of-the-art kinetics, kinematics, muscle activation and muscle-tendon behaviour, a musculoskeletal modelling framework will be used to estimate lower limb joint reaction forces via tracking simulations. CONCLUSION The results of this study will provide first estimations of internal musculoskeletal loads associated with human movement performed in a range of hypogravity levels. Thus, our unique data will be a key step towards modelling the musculoskeletal deconditioning associated with long term habitation on the Lunar surface, and thereby aiding the design of Lunar exercise countermeasures and mitigation strategies.
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Monti E, Waldvogel J, Ritzmann R, Freyler K, Albracht K, Helm M, De Cesare N, Pavan P, Reggiani C, Gollhofer A, Narici MV. Muscle in Variable Gravity: "I Do Not Know Where I Am, But I Know What to Do". Front Physiol 2021; 12:714655. [PMID: 34421657 PMCID: PMC8371909 DOI: 10.3389/fphys.2021.714655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/13/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose: Fascicle and sarcomere lengths are important predictors of muscle mechanical performance. However, their regulation during stretch-shortening cycle (SSC) activities in usual and challenging conditions is poorly understood. In this study, we aimed to investigate muscle fascicle and sarcomere behavior during drop jumps (a common SSC activity) in conditions of variable gravity. Methods: Fifteen volunteers performed repeated drop jumps in 1 g, hypo-gravity (0 to 1 g), and hyper-gravity (1 to 2 g) during a parabolic flight. Gastrocnemius medialis (GM) electromyographic activity and fascicle length (Lf) were measured at drop-off, ground contact (GC), minimum ankle joint angle (MAJ), and push-off. GM sarcomere number was estimated by dividing Lf, measured by ultrasound at rest, by published data on GM sarcomere length, and measured in vivo at the same joint angle. Changes in sarcomere length were estimated by dividing GM Lf in each jump phase by sarcomere number calculated individually. The sarcomere force-generating capacity in each jump phase was estimated from the sarcomere length-tension relationship previously reported in the literature. Results: The results showed that, regardless of the gravity level, GM sarcomeres operated in the ascending portion of their length-tension relationship in all the jump phases. Interestingly, although in hypo-gravity and hyper-gravity during the braking phase (GC-MAJ) GM fascicles and sarcomeres experienced a stretch (as opposed to the quasi-isometric behavior in 1 g), at MAJ they reached similar lengths as in 1 g, allowing sarcomeres to develop about the 70% of their maximum force. Conclusion: The observed fascicle behavior during drop jumping seems useful for anchoring the tendon, enabling storage of elastic energy and its release in the subsequent push-off phase for effectively re-bouncing in all gravity levels, suggesting that an innate neuromuscular wisdom enables to perform SSC movements also in challenging conditions.
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Affiliation(s)
- Elena Monti
- Department of Biomedical Science, University of Padova, Padova, Italy
| | - Janice Waldvogel
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Ramona Ritzmann
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany.,Department of Biomechanics, Rennbahnklinik, Muttenz, Switzerland
| | - Kathrin Freyler
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Kirsten Albracht
- Institute of Movement and Neurosciences, German Sport University Cologne, Cologne, Germany.,Department of Medical Engineering and Technomathematics, Aachen University of Applied Sciences, Aachen, Germany
| | - Michael Helm
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
| | - Niccolò De Cesare
- Department of Industrial Engineering, University of Padova, Padova, Italy
| | - Piero Pavan
- Department of Industrial Engineering, University of Padova, Padova, Italy
| | - Carlo Reggiani
- Department of Biomedical Science, University of Padova, Padova, Italy
| | - Albert Gollhofer
- Department of Sport and Sport Science, University of Freiburg, Freiburg, Germany
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Peyré-Tartaruga LA, Dewolf AH, di Prampero PE, Fábrica G, Malatesta D, Minetti AE, Monte A, Pavei G, Silva-Pereyra V, Willems PA, Zamparo P. Mechanical work as a (key) determinant of energy cost in human locomotion: recent findings and future directions. Exp Physiol 2021; 106:1897-1908. [PMID: 34197674 DOI: 10.1113/ep089313] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 06/29/2021] [Indexed: 01/09/2023]
Abstract
NEW FINDINGS What is the topic of this review? This narrative review explores past and recent findings on the mechanical determinants of energy cost during human locomotion, obtained by using a mechanical approach based on König's theorem (Fenn's approach). What advances does it highlight? Developments in analytical methods and their applications allow a better understanding of the mechanical-bioenergetic interaction. Recent advances include the determination of 'frictional' internal work; the association between tendon work and apparent efficiency; a better understanding of the role of energy recovery and internal work in pathological gait (amputees, stroke and obesity); and a comprehensive analysis of human locomotion in (simulated) low gravity conditions. ABSTRACT During locomotion, muscles use metabolic energy to produce mechanical work (in a more or less efficient way), and energetics and mechanics can be considered as two sides of the same coin, the latter being investigated to understand the former. A mechanical approach based on König's theorem (Fenn's approach) has proved to be a useful tool to elucidate the determinants of the energy cost of locomotion (e.g., the pendulum-like model of walking and the bouncing model of running) and has resulted in many advances in this field. During the past 60 years, this approach has been refined and applied to explore the determinants of energy cost and efficiency in a variety of conditions (e.g., low gravity, unsteady speed). This narrative review aims to summarize current knowledge of the role that mechanical work has played in our understanding of energy cost to date, and to underline how recent developments in analytical methods and their applications in specific locomotion modalities (on a gradient, at low gravity and in unsteady conditions) and in pathological gaits (asymmetric gait pathologies, obese subjects and in the elderly) could continue to push this understanding further. The recent in vivo quantification of new aspects that should be included in the assessment of mechanical work (e.g., frictional internal work and elastic contribution) deserves future research that would improve our knowledge of the mechanical-bioenergetic interaction during human locomotion, as well as in sport science and space exploration.
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Affiliation(s)
| | - Arthur H Dewolf
- Laboratory of Biomechanics and Physiology of Locomotion, Institute of NeuroScience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.,Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, Rome, Italy
| | | | - Gabriel Fábrica
- Departamento de Biofísica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Davide Malatesta
- Institute of Sport Sciences of the University of Lausanne (ISSUL), University of Lausanne, Lausanne, Switzerland
| | - Alberto E Minetti
- Department of Pathophysiology and Transplantation, Physiology Division, Laboratory of Physiomechanics of Locomotion, University of Milan, Milan, Italy
| | - Andrea Monte
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Gaspare Pavei
- Department of Pathophysiology and Transplantation, Physiology Division, Laboratory of Physiomechanics of Locomotion, University of Milan, Milan, Italy
| | | | - Patrick A Willems
- Laboratory of Biomechanics and Physiology of Locomotion, Institute of NeuroScience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Paola Zamparo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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