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Frayne DH, Norman-Gerum VT, Howarth SJ, Brown SHM. Experience influences kinematic motor synergies: an Uncontrolled manifold approach to simulated Nordic skiing. J Sports Sci 2023:1-12. [PMID: 37742214 DOI: 10.1080/02640414.2023.2260237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 09/11/2023] [Indexed: 09/26/2023]
Abstract
Motor synergies are defined as central nervous system mechanisms which adjust participating degrees of freedom to ensure dynamic stability (control) of certain performance variables and have been identified during many motor tasks. The potential for synergistic control of individual segments during full-body tasks is often overlooked. Thus, this study compared individual differences in the potential stabilization of multiple performance variables on the basis of experience during a full-body sport activity. Normalized time series of synergy indices from Uncontrolled Manifold analyses on experienced (n = 9) and inexperienced (n = 19) participants were analysed using statistical parametric mapping during simulated Nordic skiing. Regardless of experience, hand, upper arm, and whole-body centre of mass (COM) kinematics were found to be stabilized by kinematic motor synergies. Only experienced Nordic skiers stabilized trunk COM position at all, while trunk COM velocity was stabilized for a longer duration than inexperienced participants. However, inexperienced participants stabilized hand velocity for a greater duration overall and to a greater magnitude during early pull phase than the experienced skiers. That motor synergies for hand and trunk COM velocity differed between experience groups suggests potential utility for these performance variables as indicators of motor skill development for full-body tasks such as Nordic skiing.
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Affiliation(s)
- Devon H Frayne
- Department of Human Health and Nutritional Sciences, University of Guelph, Guleph, Canada
| | - Valerie T Norman-Gerum
- Department of Human Health and Nutritional Sciences, University of Guelph, Guleph, Canada
| | - Samuel J Howarth
- Division of Research and Innovation, Canadian Memorial Chiropractic College, Toronto, ON, Canada
| | - Stephen H M Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guleph, Canada
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2
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Azimi R, Abdoli B, Sanjari MA, Khosrowabadi R. Variability of Postural Coordination in Dual-Task Paradigm. J Mot Behav 2023; 56:22-29. [PMID: 37429586 DOI: 10.1080/00222895.2023.2226630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 07/12/2023]
Abstract
Postural control is influenced by cognition. In most studies, variability of motor output has been considered regardless of variability in patterns of joint coordination. Uncontrolled manifold framework has been applied to decompose the joint's variance in two components. The first component leaves position of the center of mass in anterior-posterior direction (CoMAP) unchanged (VUCM) while the second component is in charge of variations of CoM (VORT). In this study, 30 healthy young volunteers were recruited. The experimental protocol consisted of three random conditions: quiet standing on a narrow wooden block without a cognitive task (NB), quiet standing on a narrow wooden block with an easy cognitive task (NBE), and quiet standing on a narrow wooden block with a difficult cognitive task (NBD). Results showed that CoMAP sway in NB condition was higher than both NBE and NBD conditions (p = .001). VORT in NB condition was higher than NBE and NBD conditions (p = .003). VORT in NB condition was higher than NBE and NBD conditions (p = .003). VUCM was unchanged in all conditions (p = 1.00) and synergy index in NB condition was smaller than NBE and NBD conditions (p = .006). These results showed that postural synergies increased under dual-task conditions.
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Affiliation(s)
- Rezvan Azimi
- Department of Cognitive and Behavioral Science and Technology in Sport, Faculty of Sport Sciences and Health, Shahid Beheshti University, Tehran, Iran
| | - Behrouz Abdoli
- Department of Cognitive and Behavioral Science and Technology in Sport, Faculty of Sport Sciences and Health, Shahid Beheshti University, Tehran, Iran
| | - Mohammad Ali Sanjari
- Department of Basic Rehabilitation Sciences, School of Rehabilitation Sciences and Biomechanics Lab, Rehabilitation Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Reza Khosrowabadi
- Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran
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3
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Bonnet CT, Barela J, Singh T. Behavioral synergic relations between eye and postural movements in young adults searching to locate objects in room inside houses. Exp Brain Res 2021; 240:549-559. [PMID: 34845500 DOI: 10.1007/s00221-021-06276-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/14/2021] [Indexed: 11/29/2022]
Abstract
During precise gaze shifts, eye, head, and body movements exhibit synergic relations. In the present study, we tested the existence of behavioural synergic relations between eye and postural movements in a goal-directed, precise, visual search task (locate target objects in large images). More precisely, we tested if postural control could be adjusted specifically to facilitate precise gaze shifts. Participants also performed a free-viewing task (gaze images with no goal) and a fixation task. In both search and free-viewing tasks, young participants (n = 20; mean age = 22 years) were free to move their eyes, head, and body segments as they pleased to self-explore the images with no external perturbation. We measured eye and postural kinematic movements. The results showed significant negative correlations between eye and postural (head and upper back) movements in the precise task, but not in the free-viewing task. The negative correlations were considered to be stabilizing and synergic. Indeed, the further the eyes moved, the more postural variables were adjusted to reduce postural sway. These results suggest that postural control was adjusted to succeed in subtle and active self-induced precise gaze shifts. Furthermore, partial correlations showed significant relations between (1) task performance to find target objects and (2) synergic relations between eye and postural movements. These later results tend to show that synergic eye-postural relations were performed to improve the task performance in the precise visual task.
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Affiliation(s)
- Cédrick T Bonnet
- Univ. Lille, CNRS, UMR 9193, SCALab-Sciences Cognitives et Sciences Affectives, F-59000, Lille, France.
| | - Jose Barela
- Institute of Biosciences, São Paulo State University, Rio Claro, São Paulo, 13506-900, Brazil
| | - Tarkeshwar Singh
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, 16802, USA
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4
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Morelli N, Hoch M. A Proposed Postural Control Theory Synthesizing Optimal Feedback Control Theory, Postural Motor Learning, and Cerebellar Supervision Learning. Percept Mot Skills 2020; 127:1118-1133. [PMID: 32580643 DOI: 10.1177/0031512520930868] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Multiple theories regarding motor learning and postural control development aim to explain how the central nervous system (CNS) acquires, adjusts, and learns postural behaviors. However, few theories of postural motor development and learning propose possible neurophysiologic correlates to support their assumptions. Evidence from behavioral and computational models support the cerebellum's role in supervising motor learning through the production of forward internal models, corrected by sensory prediction errors. Optimal Feedback Control Theory (OFCT) states that the CNS learns new behaviors by minimizing the cost of multi-joint movements that attain a task goal. By synthesizing principles of the OFCT, postural sway characteristics, and cerebellar anatomy and its internal models, we propose an integrated learning model in which cerebellar supervision of postural control is governed by movement cost functions.
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Affiliation(s)
- Nathan Morelli
- Sports Medicine Research Institute, College of Health Sciences, 4530University of Kentucky
| | - Matthew Hoch
- Sports Medicine Research Institute, College of Health Sciences, 4530University of Kentucky
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5
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Hagio K, Obata H, Nakazawa K. Effects on Postural Kinematics of Performing a Cognitive Task During Upright Standing. Percept Mot Skills 2020; 127:639-650. [PMID: 32340552 DOI: 10.1177/0031512520919543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The execution of cognitive tasks is known to alter postural sway during standing, but the underlying mechanisms are still debated. This study investigated how performing a mental task modified balance control during standing. We required 15 healthy adult males to maintain an upright stance under conditions of simply relaxing and maintaining normal quiet standing (control condition) or while performing a secondary cognitive task (mental arithmetic). Under each condition, we measured the participants' center of pressure and used kinematic measurements for a quantitative evaluation of postural control modulation. We calculated the standard deviation of the joint angles (ankle, knee, and hip) and the estimated joint stiffness to measure joint mobility changes in postural control. To estimate the kinematic pattern of covariation among these joints, we used uncontrolled manifold analysis, an assessment of the strength of multijoint coordination. Compared to normal standing, executing the cognitive task while standing led to reduced movements of the ankle and hip joints. There were no significant differences in ankle stiffness or uncontrolled manifold ratios between the conditions. Our results suggest that when performing a secondary cognitive task during standing, neither changes in the modification of stiffness nor the strength of multijoint coordination (both of which preserve the center of mass position) explains changes in postural sway.
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Affiliation(s)
- Kohtaroh Hagio
- Sports Science Laboratory, Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
| | - Hiroki Obata
- Department of Humanities and Social Sciences, Institute of Liberal Arts, Kyushu Institute of Technology
| | - Kimitaka Nakazawa
- Sports Science Laboratory, Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo
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6
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Clavel L, Attali V, Rivals I, Niérat MC, Laveneziana P, Rouch P, Similowski T, Sandoz B. Decreased respiratory-related postural perturbations at the cervical level under cognitive load. Eur J Appl Physiol 2020; 120:1063-1074. [PMID: 32185476 DOI: 10.1007/s00421-020-04345-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 03/10/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE In healthy humans, postural and respiratory dynamics are intimately linked and a breathing-related postural perturbation is evident in joint kinematics. A cognitive dual-task paradigm that is known to induce both postural and ventilatory disturbances can be used to modulate this multijoint posturo-ventilatory (PV) interaction, particularly in the cervical spine, which supports the head. The objective of this study was to assess this modulation. METHODS With the use of optoelectronic sensors, the breathing profile, articular joint motions of the cervical spine, hip, knees and ankles, and centre of pressure (CoP) displacement were measured in 20 healthy subjects (37 years old [29; 49], 10 females) during natural breathing (NB), a cognitive dual task (COG), and eyes-closed and increased-tidal-volume conditions. The PV interaction in the CoP and joint motions were evaluated by calculating the respiratory emergence (REm). RESULTS Only the COG condition induced a decrease in the cervical REm (NB: 17.2% [7.8; 37.2]; COG: 4.2% [1.8; 10.0] p = 0.0020) concurrent with no changes in the cervical motion. The CoP REm (NB: 6.2% [3.8; 10.3]; COG: 12.9% [5.8; 20.7] p = 0.0696) and breathing frequency (NB: 16.6 min-1 [13.3; 18.7]; COG: 18.6 min-1 [16.3; 19.4] p = 0.0731) tended to increase, while the CoP (p = 0.0072) and lower joint motion displacements (p < 0.05) increased. CONCLUSION This study shows stable cervical spine motion during a cognitive dual task, as well as increased postural perturbations globally and in other joints. The concurrent reduction in the PV interaction at the cervical spine suggests that this "stabilization strategy" is centrally controlled and is achieved by a reduction in the breathing-related postural perturbations at this level. Whether this strategy is a goal for maintaining balance remains to be studied.
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Affiliation(s)
- Louis Clavel
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, INSERM, 75005, Paris, France. .,Arts et Metiers Institute of Technology, IBHGC, 151 bd de l'Hopital, 75013, Paris, France.
| | - Valérie Attali
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, INSERM, 75005, Paris, France.,Arts et Metiers Institute of Technology, IBHGC, 151 bd de l'Hopital, 75013, Paris, France.,Service des Pathologies du Sommeil (Département R3S), AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Site Pitié-Salpêtrière, 75013, Paris, France
| | - Isabelle Rivals
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, INSERM, 75005, Paris, France.,Equipe de Statistique Appliquée, ESPCI Paris, PSL Research University, 75005, Paris, France
| | - Marie-Cécile Niérat
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, INSERM, 75005, Paris, France
| | - Pierantonio Laveneziana
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, INSERM, 75005, Paris, France.,Service des Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée, Département "R3S", Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, 75013, Paris, France
| | - Philippe Rouch
- Arts et Metiers Institute of Technology, IBHGC, 151 bd de l'Hopital, 75013, Paris, France
| | - Thomas Similowski
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, INSERM, 75005, Paris, France.,Service de Pneumologie, Médecine Intensive et Réanimation (Département R3S), AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Site Pitié-Salpêtrière, 75013, Paris, France
| | - Baptiste Sandoz
- Arts et Metiers Institute of Technology, IBHGC, 151 bd de l'Hopital, 75013, Paris, France
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Tsai YY, Chang GC, Hwang IS. Adaptation of kinematic synergy and postural control to mechanical ankle constraint on an unsteady stance surface. Hum Mov Sci 2018; 60:10-17. [PMID: 29753125 DOI: 10.1016/j.humov.2018.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 11/17/2022]
Abstract
Joint constraint interferes with the coordinative structure in joint movements used to optimize postural stability. This study aimed to investigate changes in postural synergy when the ankle joints were bilaterally braced during a stabilometer stance. Twenty-four young adults stood on a stabilometer plate while wearing a pair of ankle-foot orthoses, which were either unlocked or locked to restrict ankle motion (the ankle constraint (AC) and non-constraint (NC) conditions). Although ankle constraint did not significantly affect the dynamics of the stabilometer movements, the size and regularity of the first principal component (PC1), which explained more than 80% of the variance of joint movements in the lower limb, were increased. In addition, PC1 exhibited higher communalities with angular movements of the knee and hip joints in the AC condition than in the NC condition. Those subjects who exhibited a constraint-induced increase in postural sway (the I group) showed greater increases in the size and regularity of PC1 than did those who exhibited reduced postural sway during ankle constraint (the D group). Constraint-induced changes in postural synergy were group-dependent. Only the I group exhibited an increase of communality of PC1 with the hip angular movement following bilateral ankle constraint. In summary, bilateral ankle constraint altered the coordination solution, with increasing reliance on compensatory knee movement to maintain a balanced posture on the stabilometer. However, accessory hip movement due to ankle constraint was not economical and was disadvantageous to stance stability.
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Affiliation(s)
- Yi-Ying Tsai
- Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan
| | - Gwo-Ching Chang
- Department of Information Engineering, I-Shou Univeristy, Kaohsiung City 84001, Taiwan
| | - Ing-Shiou Hwang
- Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan; Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan City 701, Taiwan.
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8
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dos Anjos F, Lemos T, Imbiriba LA. Does the type of visual feedback information change the control of standing balance? Eur J Appl Physiol 2016; 116:1771-9. [DOI: 10.1007/s00421-016-3434-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/12/2016] [Indexed: 11/25/2022]
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9
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Park E, Reimann H, Schöner G. Coordination of muscle torques stabilizes upright standing posture: an UCM analysis. Exp Brain Res 2016; 234:1757-67. [PMID: 26879770 DOI: 10.1007/s00221-016-4576-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 01/28/2016] [Indexed: 10/22/2022]
Abstract
The control of upright stance is commonly explained on the basis of the single inverted pendulum model (ankle strategy) or the double inverted pendulum model (combination of ankle and hip strategy). Kinematic analysis using the uncontrolled manifold (UCM) approach suggests, however, that stability in upright standing results from coordinated movement of multiple joints. This is based on evidence that postural sway induces more variance in joint configurations that leave the body position in space invariant than in joint configurations that move the body in space. But does this UCM structure of kinematic variance truly reflect coordination at the level of the neural control strategy or could it result from passive biomechanical factors? To address this question, we applied the UCM approach at the level of muscle torques rather than joint angles. Participants stood on the floor or on a narrow base of support. We estimated torques at the ankle, knee, and hip joints using a model of the body dynamics. We then partitioned the joint torques into contributions from net, motion-dependent, gravitational, and generalized muscle torques. A UCM analysis of the structure of variance of the muscle torque revealed that postural sway induced substantially more variance in directions in muscle torque space that leave the Center of Mass (COM) force invariant than in directions that affect the force acting on the COM. This difference decreased when we decorrelated the muscle torque data by randomizing across time. Our findings show that the UCM structure of variance exists at the level of muscle torques and is thus not merely a by-product of biomechanical coupling. Because muscle torques reflect neural control signals more directly than joint angles do, our results suggest that the control strategy for upright stance involves the task-specific coordination of multiple degrees of freedom.
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Affiliation(s)
- Eunse Park
- Biomechanics and Movement Science, Univeristy of Delaware, Newark, DE, USA. .,School of Applied Physiology, Georgia Institution of Technology, 555 14th St NW, Atlanta, GA, 30332, USA.
| | - Hendrik Reimann
- Department of Kinesiology, Temple University, Philadelphia, PA, USA
| | - Gregor Schöner
- Institut für Neuroinformatik, Ruhr-Universität, Bochum, Germany
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10
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Frame-difference analysis of video-recorded laser-beam projections. ACTA ACUST UNITED AC 2015; 20:879-83. [PMID: 26143505 DOI: 10.1016/j.math.2015.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 06/09/2015] [Accepted: 06/12/2015] [Indexed: 11/22/2022]
Abstract
Laser beams have been applied in many human motion research contexts to project movements in specific motor tasks. Currently, there are no objective analysis methods for laser projection recordings. The principal aim of this study was to investigate the feasibility of quantifying motion by applying frame differencing and image analysis methods to video streams of laser beam projections. The laser projection was controlled by a mechanical device that produced pseudo random rotations. The 2D motion recorded by the video was compared with recordings obtained with an electromagnetic system where a sensor was fixed to the same device as the laser. High correlations in the time and frequency domains were found between the methods. We conclude that the proposed method can accurately quantify complex motion patterns from laser beam projections.
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Kilby MC, Molenaar PCM, Newell KM. Models of Postural Control: Shared Variance in Joint and COM Motions. PLoS One 2015; 10:e0126379. [PMID: 25973896 PMCID: PMC4431684 DOI: 10.1371/journal.pone.0126379] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 04/01/2015] [Indexed: 11/18/2022] Open
Abstract
This paper investigated the organization of the postural control system in human upright stance. To this aim the shared variance between joint and 3D total body center of mass (COM) motions was analyzed using multivariate canonical correlation analysis (CCA). The CCA was performed as a function of established models of postural control that varied in their joint degrees of freedom (DOF), namely, an inverted pendulum ankle model (2DOF), ankle-hip model (4DOF), ankle-knee-hip model (5DOF), and ankle-knee-hip-neck model (7DOF). Healthy young adults performed various postural tasks (two-leg and one-leg quiet stances, voluntary AP and ML sway) on a foam and rigid surface of support. Based on CCA model selection procedures, the amount of shared variance between joint and 3D COM motions and the cross-loading patterns we provide direct evidence of the contribution of multi-DOF postural control mechanisms to human balance. The direct model fitting of CCA showed that incrementing the DOFs in the model through to 7DOF was associated with progressively enhanced shared variance with COM motion. In the 7DOF model, the first canonical function revealed more active involvement of all joints during more challenging one leg stances and dynamic posture tasks. Furthermore, the shared variance was enhanced during the dynamic posture conditions, consistent with a reduction of dimension. This set of outcomes shows directly the degeneracy of multivariate joint regulation in postural control that is influenced by stance and surface of support conditions.
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Affiliation(s)
- Melissa C. Kilby
- Department of Kinesiology, The Pennsylvania State University, 23 Recreation Building, University Park, Pennsylvania, 16802, United States of America
- Department of Kinesiology, The University of Georgia, Athens, Georgia, 30602, United States of America
- * E-mail:
| | - Peter C. M. Molenaar
- Department of Human Development and Family Studies, The Pennsylvania State University, 315 Health and Human Development - East, University Park, Pennsylvania, 16802, United States of America
| | - Karl M. Newell
- Department of Kinesiology, The Pennsylvania State University, 23 Recreation Building, University Park, Pennsylvania, 16802, United States of America
- Department of Kinesiology, The University of Georgia, Athens, Georgia, 30602, United States of America
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12
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Hsu WL. Adaptive postural control for joint immobilization during multitask performance. PLoS One 2014; 9:e108667. [PMID: 25329477 PMCID: PMC4201483 DOI: 10.1371/journal.pone.0108667] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 09/02/2014] [Indexed: 11/22/2022] Open
Abstract
Motor abundance is an essential feature of adaptive control. The range of joint combinations enabled by motor abundance provides the body with the necessary freedom to adopt different positions, configurations, and movements that allow for exploratory postural behavior. This study investigated the adaptation of postural control to joint immobilization during multi-task performance. Twelve healthy volunteers (6 males and 6 females; 21–29 yr) without any known neurological deficits, musculoskeletal conditions, or balance disorders participated in this study. The participants executed a targeting task, alone or combined with a ball-balancing task, while standing with free or restricted joint motions. The effects of joint configuration variability on center of mass (COM) stability were examined using uncontrolled manifold (UCM) analysis. The UCM method separates joint variability into two components: the first is consistent with the use of motor abundance, which does not affect COM position (VUCM); the second leads to COM position variability (VORT). The analysis showed that joints were coordinated such that their variability had a minimal effect on COM position. However, the component of joint variability that reflects the use of motor abundance to stabilize COM (VUCM) was significant decreased when the participants performed the combined task with immobilized joints. The component of joint variability that leads to COM variability (VORT) tended to increase with a reduction in joint degrees of freedom. The results suggested that joint immobilization increases the difficulty of stabilizing COM when multiple tasks are performed simultaneously. These findings are important for developing rehabilitation approaches for patients with limited joint movements.
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Affiliation(s)
- Wei-Li Hsu
- School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan
- Physical Therapy Center, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail:
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13
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Use of motor abundance in old adults in the regulation of a narrow-based stance. Eur J Appl Physiol 2013; 114:261-71. [DOI: 10.1007/s00421-013-2768-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 10/30/2013] [Indexed: 10/26/2022]
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14
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Federolf P, Roos L, Nigg BM. Analysis of the multi-segmental postural movement strategies utilized in bipedal, tandem and one-leg stance as quantified by a principal component decomposition of marker coordinates. J Biomech 2013; 46:2626-33. [PMID: 24021753 DOI: 10.1016/j.jbiomech.2013.08.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 08/08/2013] [Accepted: 08/11/2013] [Indexed: 11/25/2022]
Abstract
Postural control research describes ankle-, hip-, or multi-joint strategies as mechanisms to control upright posture. The objectives of this study were, first, development of an analysis technique facilitating a direct comparison of the structure of such multi-segment postural movement patterns between subjects; second, comparison of the complexity of postural movements between three stances of different difficulty levels; and third, investigation of between-subject differences in the structure of postural movements and of factors that may contribute to these differences. Twenty-nine subjects completed 100-s trials in bipedal (BP), tandem (TA) and one-leg stance (OL). Their postural movements were recorded using 28 reflective markers distributed over all body segments. These marker coordinates were interpreted as 84-dimensional posture vectors, normalized, concatenated from all subjects, and submitted to a principal component analysis (PCA) to extract principal movement components (PMs). The PMs were characterized by determining their relative contribution to the subject's entire postural movements and the smoothness of their time series. Four, eight, and nine PM were needed to represent 90% of the total variance in BP, TA, and OL, respectively, suggesting that increased task difficulty is associated with increased complexity of the movement structure. Different subjects utilized different combinations of PMs to control their posture. In several PMs, the relative contribution of a PM to a subject's overall postural movements correlated with the smoothness of the PM's time series, suggesting that utilization of specific postural PMs may depend on the subject's ability to control the PM's temporal evolution.
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Affiliation(s)
- Peter Federolf
- Norwegian School of Sport Sciences, P.O. Box 4014, Ulleval Stadion, 0806 Oslo, Norway; Human Performance Lab, Faculty of Kinesiology, University of Calgary, Canada.
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