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Howard CK, Van Gemmert AWA, Kuznetsov NA. Attentional focus effects on joint covariation in a reaching task. Hum Mov Sci 2023; 89:103089. [PMID: 37150111 DOI: 10.1016/j.humov.2023.103089] [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: 12/19/2022] [Revised: 03/19/2023] [Accepted: 04/09/2023] [Indexed: 05/09/2023]
Abstract
Adopting an external focus of attention (EF) has been found beneficial over internal focus (IF) for performing motor skills. Previous studies primarily examined focus of attention (FOA) effects on performance outcomes (such as error and accuracy), with relatively less emphasis on movement coordination. Given that human movements are kinematically and kinetically abundant (Gefland & Latash, 1998), FOA instructions may change how motor abundance is utilized by the CNS. This study applied the uncontrolled manifold analysis (UCM) to address this question in a reaching task. Healthy young adults (N = 38; 22 ± 1 yr; 7 men, 31 women) performed planar reaching movements to a target using either the dominant or nondominant arm under two different FOA instructions: EF and IF. Reaching was performed without online visual feedback and at a preferred pace. Joint angles of the clavicle-scapula, shoulder, elbow, and wrist were recorded, and their covariation for controlling dowel endpoint position was analyzed via UCM. As expected, IF led to a higher mean radial error than EF, driven by increases in aiming bias and variability. Consistent with this result, the UCM analysis showed that IF led to higher goal-relevant variance among the joints (VORT) compared to EF starting from the first 20% of the reach to the end. However, the goal-irrelevant variance (VUCM)-index of joint variance that does not affect the end-effector position-did not show FOA effects. The index of stability of joint coordination with respect to endpoint position (ΔV) was also not different between the EF and IF. Consistent with the constrained action hypothesis, these results provide evidence that IF disrupted goal-relevant joint covariation starting in the early phases of the reach without affecting goal-irrelevant coordination.
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Affiliation(s)
- Charlend K Howard
- School of Kinesiology, Louisiana State University, Baton Rouge, LA, USA.
| | | | - Nikita A Kuznetsov
- Department of Rehabilitation, Exercise and Nutrition Sciences, College of Allied Health Sciences, University of Cincinnati, Cincinnati, Ohio, USA.
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Singh H, Shih HT, Kal E, Bennett T, Wulf G. A distal external focus of attention facilitates compensatory coordination of body parts. J Sports Sci 2022; 40:2282-2291. [PMID: 36418176 DOI: 10.1080/02640414.2022.2150419] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Many studies have shown that focusing on an intended movement effect that is farther away from the body (distal external focus) results in performance benefits relative to focusing on an effect that is closer to the body (proximal external focus) or focusing on the body itself (internal focus) (see, Chua, Jimenez-Diaz, Lewthwaite, Kim & Wulf, 2021). Furthermore, the advantages of a distal external focus seem to be particularly pronounced in skilled performers (Singh & Wulf, 2020). The present study examined whether such benefits of more distal attentional focus may be associated with enhanced functional variability. Volleyball players (n = 20) performed 60 overhand volleyball serves to a target. Using a within-participants design, the effects of a distal external focus (bullseye), proximal external focus (ball) and an internal focus (hand) were compared. The distal focus condition resulted in significantly higher accuracy scores than did the proximal and internal focus conditions. In addition, uncontrolled manifold analysis showed that functional variability (as measured by the index of synergy) was greatest in the distal focus condition. These findings suggest that a distal external focus on the task goal may enhance movement outcomes by optimising compensatory coordination of body parts.
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Affiliation(s)
- Harjiv Singh
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA.,Orlando Magic Basketball Club, Orlando, FL, USA
| | - Hui-Ting Shih
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA
| | - Elmar Kal
- Centre for Cognitive Neuroscience, Brunel University London, London, UK
| | - Tim Bennett
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - Gabriele Wulf
- Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV, USA
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Andrade V, Mazoni A, Vasconcelos C, Mattos D, Mitra S, Ocarino J, Vaz D. Effects of Age and Attentional Focus on the Performance and Coordination of the Sit-to-Stand Task. J Mot Behav 2022; 55:78-91. [PMID: 36120733 DOI: 10.1080/00222895.2022.2122921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study investigated whether age and attentional focus affect synergy organization of sit-to-stand (STS). Young and older adults performed STS while holding a cup under internal (IF) and external focus (EF) instructions. Uncontrolled manifold analysis was used to decompose trial-to-trial variability in joint kinematics into variability that preserves (VUCM) and interferes (VORT) with the horizontal and vertical positions of the center of mass (CoM) and cup. VUCM was significantly higher than VORT for all variables in both age groups and focus conditions. Older adults demonstrated higher VUCM for all variables and higher VORT for all variables except the vertical position of the cup. IF instructions benefited older adults, leading to decreased VORT of the vertical position of CoM and horizontal and vertical positions of the cup.
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Affiliation(s)
- Valéria Andrade
- Center for Cognition, Action, & Perception, Department of Psychology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Alysson Mazoni
- InSySPo, System Innovation Institute of Geosciences, UniversidadeEstadualde Campinas, Campinas, São Paulo, Brazil
| | - Camila Vasconcelos
- Department of Physical Therapy, School of Physical Education, Physical Therapy, and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Daniela Mattos
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Suvobrata Mitra
- Department of Psychology, Nottingham Trent University, Nottingham, UK
| | - Juliana Ocarino
- Department of Physical Therapy, School of Physical Education, Physical Therapy, and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Daniela Vaz
- Department of Physical Therapy, School of Physical Education, Physical Therapy, and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Werner I, Peer-Kratzer M, Mohr M, van-Andel S, Federolf P. Intervention for Better Knee Alignment during Jump Landing: Is There an Effect of Internally vs. Externally Focused Instructions? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:10763. [PMID: 36078475 PMCID: PMC9518031 DOI: 10.3390/ijerph191710763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
Externally focused attention is known to induce superior results in the movement outcome, whereas focusing attention on the moving body (internal focus) causes conscious control and constrains action. The study investigated effects on knee trajectory and whole-body movement complexity when addressing knee alignment using externally (EF) vs. internally (IF) focused instructions. Young ski racers, n = 24 (12 male), performed landings with subsequent jumps to submaximal height. Movements were tracked and analyzed during the ground contact phase. Sets of jumps were executed without instruction (CON), followed by EF and IF instructions on knee alignment in a random order. Medial-lateral displacement of the knee in landing quantified task achievement, and whole-body principal component analysis was used to compute movement complexity. Knee alignment instructions led to a significantly lower medial knee displacement compared to CON (p = 0.001, ηp2 = 0.35). EF vs. IF did not reach significance. EF, as well as IF instructions increased the prominence of the first movement pattern (p = 0.01, ηp2 = 0.22) with a reduction of higher-order patterns (p = 0.002, W = 0.11), suggesting a strategy of freezing degrees of freedom. Both instructions addressing the movement form positively influenced knee displacement during landing, and both led to a freezing strategy, simplifying whole-body coordination.
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Affiliation(s)
- Inge Werner
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Maurice Mohr
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria
| | - Steven van-Andel
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria
| | - Peter Federolf
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria
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Yamagata M, Tateuchi H, Shimizu I, Ichihashi N. Changes in kinematic synergy in older adults during walking: A two-year follow-up study. Gait Posture 2022; 96:244-250. [PMID: 35700642 DOI: 10.1016/j.gaitpost.2022.05.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 05/19/2022] [Accepted: 05/24/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND A well-controlled center of mass (CoM) in a coordinated segmental manner is required during gait. A synergy index that quantifies the strength of the synergistic control of the body segments that control the CoM can be evaluated using uncontrolled manifold (UCM) analysis. Several studies have compared the synergy index between older and younger adults; however, contradictory results have been found regarding age-related changes in the synergy index. Moreover, no study has investigated these changes longitudinally. RESEARCH QUESTION To evaluate age-related changes in the synergy index to control the CoM during gait in a longitudinal study. METHODS Twenty-five older adults participated at a baseline visit. The gait task at the two-year follow-up was completed by 16 older adults. Participants walked on a 6-m walkway at baseline and the two-year follow-up, and kinematic data were collected. Using UCM analysis, the synergy indices controlling CoM in the mediolateral and vertical directions were evaluated at baseline and follow-up. We also evaluated the Timed Up and Go (TUG) test and the strength of the knee extensor at both periods. RESULTS We found that TUG was significantly slower at follow-up; however, no difference was found in muscle strength. The synergy index in the mediolateral direction increased significantly after two years; such increases were found in individuals with decreased gait speed. SIGNIFICANCE This study showed that changes in gait patterns, including decreasing gait speed and increasing segmental coordination, may be important for gait with appropriate postural control relative to the environment and dynamic stability of the body in individuals with low functional mobility.
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Affiliation(s)
- Momoko Yamagata
- Faculty of Rehabilitation, Kansai Medical University, 18-89 Uyama Higashimachi, Hirakata, Osaka 573-1136, Japan; Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Hiroshige Tateuchi
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Itsuroh Shimizu
- Fukui General Clinic, 1-42-1 Nittazuka, Fukui-shi,Fukui 910-0067, Japan
| | - Noriaki Ichihashi
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
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Lafe CW, Newell KM. Instructions on Task Constraints Mediate Perceptual-Motor Search and How Movement Variability Relates to Performance Outcome. J Mot Behav 2022; 54:669-685. [PMID: 35440288 DOI: 10.1080/00222895.2022.2063787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Movement variability has been postulated to afford perception of the perceptual motor workspace and to be directly linked to improved performance. Here, we investigated how instructions mediate the search process and the relation between performance outcome and movement variability. We used a novel bimanual force tracking task where zero error was achieved via proportional output between the hands. Participants were either instructed or not as to how to coordinate their force output to achieve this goal, but the goal to minimize error was explained to all participants. The provision of instructions restricted the overall area of the task space that was searched. Moreover, the time dependent properties of the search were influenced; where instructions increased the likelihood that participants would produce a higher force level over practice. Multiple regression revealed that variability was positively correlated with performance outcome, but the strength of this relation was dependent on instructions and individual search strategies. The findings are consistent with the view that information through instructions shapes individual emergent perceptual-motor search strategies that in turn mediate how movement variability relates to performance outcome.
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Affiliation(s)
- Charley W Lafe
- Department of Kinesiology, University of Georgia, Athens, GA, USA
| | - Karl M Newell
- Department of Kinesiology, University of Georgia, Athens, GA, USA
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The patterning of local variability during the acquisition of a novel whole-body continuous motor skill in young adults. Exp Brain Res 2020; 238:1797-1812. [PMID: 32494848 DOI: 10.1007/s00221-020-05840-9] [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] [Received: 11/12/2019] [Accepted: 05/25/2020] [Indexed: 10/24/2022]
Abstract
There is increasing evidence that movement variability during motor skill acquisition plays a functional role. Specifically, initial variability might represent exploration of the possible motor space for solutions and error identification. Following practice, individuals might exploit a reduced amount of motor solutions to execute the task. While this variability pattern has been supported during discrete upper limb and multi-finger force tasks, there is a paucity of evidence for continuous whole-body motor tasks. Therefore, the purpose of this study was to characterize the role of variability during the acquisition of a whole-body continuous motor task across practice sessions in young adults. Twelve young adults aged 18-35-years participated in this study. Subjects practiced a novel, sagittal plane task, the kettlebell swing, using an online training video. We conducted an uncontrolled manifold analysis to partition local variability of the configuration of the kettlebell and body segments based on their impact on the position of the center-of-mass (COM) in the sagittal plane. Our results demonstrated that following initial practice, variability that did not affect the COM position remained elevated, suggesting sustained exploration of motor solutions. Following multiple practice sessions, variability related to motor solutions decreased, potentially indicating exploitation. The results from this study support the proposal that young adults initially utilize a range of motor solutions when acquiring a whole-body motor skill, followed by exploitation of stereotypic movement.
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Liew BXW, Abichandani D, De Nunzio AM. Individuals with patellofemoral pain syndrome have altered inter-leg force coordination. Gait Posture 2020; 79:65-70. [PMID: 32361127 DOI: 10.1016/j.gaitpost.2020.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/13/2020] [Accepted: 04/06/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Patellofemoral pain syndrome (PFPS) is one of the most common musculoskeletal disorders. Pain may be further exacerbated by atypical motor coordination strategies. It has been thought that low coordination variability may concentrate loads onto painful knee tissues. RESEARCH QUESTION To investigate if inter-limb force coordination is altered between individuals with and without PFPS. METHODS 31 individuals (control = 17, PFPS = 14) performed bilateral vertical hopping, on two force plates at three frequencies (2.2, 2.6, 3.0 Hz). Uncontrolled manifold analysis (UCM) was used to provide an index of motor abundance (IMA) in the coordination of inter-limb forces to stabilize the two-limb's total force. UCM was applied to the study of forces in each plane (medial-lateral (ML), anterior-posterior (AP), vertical). Bayesian Functional Data Analysis was used for statistical inference. We calculated the mean (u) with 95 % credible interval (CrI) of the difference ΔIMAcon>PFPS between the two groups. We also calculated the probability PΔIMAcon>PFPS>0data). RESULTS Individuals with PFPS had the greatest significant decrement from controls at 6% of stance hopping at 2.6 Hz by a mean difference of -0.23 for ML GRF; at 19 % of stance hopping at 2.2 Hz by a mean difference of -0.14 for AP GRF; and 52 % of stance hopping at 2.6 Hz by a mean difference of -0.14 for vertical GRF. For vertical GRF, there was a > 0.95 probability that controls had greater IMA than individuals with PFPS hopping between 12-13% of stance at 2.2 Hz, and between 48-55% at 2.6 Hz. SIGNIFICANCE Individuals with PFPS have reduced inter-leg force coordination for impact force attenuation and body support, compared to asymptomatic controls. The present study provides insights into a plausible mechanism underpinning persistent knee pain which could be used in the development of novel rehabilitative approaches for individuals with PFPS.
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Affiliation(s)
- Bernard X W Liew
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, Essex, CO4 3SQ, United Kingdom; Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, B152TT, United Kingdom.
| | - Deepa Abichandani
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, B152TT, United Kingdom
| | - Alessandro Marco De Nunzio
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, B152TT, United Kingdom; LUNEX International University of Health, Exercise and Sports, 50, avenue du Parc des Sports, L-4671, Differdange, Luxembourg
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Myoelectric Responses of Lower-Body Muscles Performing Squat and Lunge Exercise Variations Adopting Visual Feedback With a Laser Sensor. J Sport Rehabil 2020; 29:1159-1165. [PMID: 31945738 DOI: 10.1123/jsr.2019-0194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/30/2019] [Accepted: 11/25/2019] [Indexed: 11/18/2022]
Abstract
STUDY DESIGN Cross-over study. CONTEXT The squat, single-leg squat, forward lunge, and reverse lunge are fundamental movements often performed in activities of daily living, sports competitions, and sport-specific training. OBJECTIVE The purpose of this study was to investigate the effect of visual feedback with a laser sensor (VFLS) versus a control condition on the myoelectric activity (surface electromyography [sEMG]) of the vastus medialis oblique (VMO), vastus lateralis, gluteus medius (Gmed), and erector spinae muscles during the performance of several squat variations with bodyweight. METHODS Nineteen female college students (20 [2.5] y, 165.3 [10.2] cm, 66.4 [4.1] kg, 2 [1.2] y of resistance training experience) with a background in strength or sports training volunteered to participate in this study. Over 4 separate visits, subjects performed 2 sets of 10 repetitions of a squat variation exercise in random order (ie, squat, single-leg squat, forward lunge, and reverse lunge). The first set of a given squat variation condition was considered a control set, and then after 3-minute rest, a second set was performed with VFLS. RESULTS Significant decreases in VMO and Gmed myoelectric activity were observed during the VFLS set versus the control set for the forward lunge exercise (P = .03). No differences were observed between the control set and VFLS set in the sEMG normalized signal for all muscles analyzed for the squat and single-leg squat, respectively. However, the sample entropy of the sEMG signal for the erector spinae became more irregular during the VFLS set versus the control set for the squat exercise (P = .01), whereas the Gmed presented a more irregular sEMG signal during the VFLS set versus the control set for the single-leg squat (P = .08). CONCLUSION Laser sensor biofeedback may induce significant decreases in VMO and Gmed activation performing forward lunge exercise. Therefore, laser sensor biofeedback may induce a reduction in muscle activity of neutralizers muscles during a few squat bodyweight variations (bilateral, single-leg, forward, and reverse lunge).
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Apolinário-Souza T, Ugrinowitsch H, Campos CE, Lacerda LTD, Tourino FD, Figueiredo LS, Lage GM. Focus of attention and online demonstration effects on temporal error and muscle activation. REVISTA BRASILEIRA DE CINEANTROPOMETRIA E DESEMPENHO HUMANO 2020. [DOI: 10.1590/1980-0037.2020v22e62893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Abstract The purpose of the present study was to examine whether there would be performance differences between external and internal focus of attention conditions and an online demonstration condition, and if these differences would be observed at a neuromuscular level through EMG analysis, in addition to traditional outcome measures. We hypothesized that under the demonstration condition participants would perform better than under external and internal focus conditions. We also hypothesized that demonstration condition would show smaller EMG activity than external and internal focus conditions. Furthermore, we hope to replicate the benefits of external focus in relation to internal focus, both in outcome and product measures. Six male participants performed a bilateral leg extension under internal focus of attention, external focus of attention and online demonstration conditions. Muscular contractions goal times were set for concentric muscle action (4 seconds) and eccentric muscle action (2 seconds). An electrogoniometer was used to record muscular activation (production measures), and temporal error was used to observe performance (outcome measures). Results showed that online demonstration condition obtained better performance than external focus condition and a reduced muscular activation. However, differences between internal focus and the other experimental conditions were not found. These findings advance in the understanding mechanisms underpining the focus of attention, such as proposed by Constrained Action Hypothesis.
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Affiliation(s)
| | | | | | - Lucas Túlio de Lacerda
- Universidade Federal de Minas Gerais, Brazil; Universidade do Estado de Minas Gerais, Brazil; Pontifícia Universidade Católica de Minas Gerais, Brazil; Centro Federal de Educação Tecnológica de Minas Gerais, Brazil
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Differentiating Successful and Unsuccessful Single-Leg Drop Landing Performance Using Uncontrolled Manifold Analysis. Motor Control 2020; 24:75-90. [PMID: 31323641 PMCID: PMC9899352 DOI: 10.1123/mc.2017-0076] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 04/10/2019] [Accepted: 05/05/2019] [Indexed: 02/07/2023]
Abstract
Biomechanical analysis can effectively identify factors associated with task performance and injury risk, but often does not account for the interaction among the components that underlie task execution. Uncontrolled manifold (UCM) analyses were applied to data from 38 female, adolescent athletes performing single-leg drop landings and were used to differentiate successful and unsuccessful task performance by examining the frontal plane joint variance within the UCM (VUCM) that stabilized the horizontal center of mass position (VUCM) and within the orthogonal subspace (VORT). The UCM revealed stronger coordination, indicated by the VUCM/VORT ratio, in the successful condition. This may inform future research examining reduced motor coordination in failed movement tasks and its relation to injury risk and allow for targeted interventions that consider coordination processes rather than joint-specific outcomes.
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