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Variability of segment coordination using a vector coding technique: Reliability analysis for treadmill walking and running

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GAIT & POSTURE 2017年 51卷 222-227页

作者： Hafer, Jocelyn F. Boyer, Katherine A. Univ Massachusetts Dept Kinesiol Musculoskeletal & Orthoped Biomech Lab Amherst MA 01003 USA 110 Totman Bldg 30 Eastman Lane Amherst MA 01003 USA

Coordination variability (CV) quantifies the variety of movement patterns an individual uses during a task and may provide a measure of the flexibility of that individual's motor system. While there is growing popularity of segment CV as a marker of motor system health or adaptability, it is not known how many strides of data are needed to reliably calculate CV. This study aimed to determine the number of strides needed to reliably calculate CV in treadmill walking and running, and to compare CV between walking and running in a healthy population. Ten healthy young adults walked and ran at preferred speeds on a treadmill and a modified vector coding technique was used to calculate CV for the following segment couples: pelvis frontal plane vs. thigh frontal plane, thigh sagittal plane vs. shank sagittal plane, thigh sagittal plane vs. shank transverse plane, and shank transverse plane vs. rearfoot frontal plane. CV for each coupling of interest was calculated for 2-15 strides for each participant and gait type. Mean CV was calculated across the entire gait cycle and, separately, for 4 phases of the gait cycle. For running and walking 8 and 10 strides, respectively, were sufficient to obtain a reliable CV estimate. CV was significantly different between walking and running for the thigh vs. shank couple comparisons. These results suggest that 10 strides of treadmill data are needed to reliably calculate CV for walking and running. Additionally, the differences in CV between walking and running suggest that the role of knee (i.e., inter-thigh-shank) control may differ between these forms of locomotion. (C) 2016 Elsevier B.V. All rights reserved.

关键词： vector coding Coordination variability Reliability Gait Walking Running

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Scalable motion vector coding

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ELECTRONICS LETTERS 2004年第15期40卷 932-934页

作者： Barbarien, J Munteanu, A Verdicchio, E Andreopoulos, Y Cornelis, J Schelkens, P Free Univ Brussels Dept Elect & Informat Proc B-1050 Brussels Belgium

Scalable wavelet-based video codecs using spatial-domain motion compensated temporal filtering require a quality-scalable motion vector codec to support a large range of bit rates with optimal compression efficiency. Introduced is a new prediction-based architecture for quality-scalable motion vector coding that outperforms the state-of-the-art wavelet-based techniques previously proposed in the literature.

关键词： .bit rates motion information temporal ltering vector coding Scalable motion macro-block quantised motion vectors predicted frame MVCs

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Is coordination variability using vector coding different in overground and treadmill walking and running?

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GAIT & POSTURE 2022年第0期92卷 413-420页

作者： Toro, Isabella Santana Weir, Gillian Amado, Avelino van Emmerik, Richard Ervilha, Ulysses Hamill, Joseph Univ Massachusetts Biomech Lab 30 Eastman Lane Amherst MA 01003 USA Univ Sao Paulo Sch Arts Sci & Humanities Sao Paulo Brazil Univ Massachusetts Motor Control Lab Amherst MA 01003 USA

Background: Coordination variability has been linked to overuse running injuries and has been studied both on a treadmill and over-ground. It is not clear, however, if the coordination variability data from over-ground locomotion can be compared with treadmill locomotion data.& nbsp;Research question: Therefore, the purpose of this study was to compare coordination variability of selected lower extremity couplings at different locomotor speeds during over-ground and treadmill walking and running.& nbsp;Methods: Nineteen (10 female, 9 male) healthy, recreational collegiate runners participated in this study. Each participant performed in two different conditions: over-ground and on a treadmill at three walking speeds (1.2, 1.6, and 2.0 m?& nbsp;s(-1)) and three running speeds (2.8, 3.2, and 3.6 m?& nbsp;s(-1)). A modified vector coding technique was used to calculate coordination variability for five selected coupled segment and joint angles. Each of the segmental couples was analyzed separately using a two-way repeated measures ANOVA (Condition X Speed) implemented with one-dimensional statistical parametric ***: While no interaction effects were observed for condition X speed, we saw increased coordination vari-ability in the sagittal couples during overground compared with treadmill locomotion, which predominantly occurred during the stance phase. There were mixed results for changes in coordination variability as a function of gait speed. However, for the sagital plane couplings, coordination variability decreased with speed, particu-larly during the stance phase.& nbsp;Significance: These results suggest that the controlled belt speed of the treadmill affects the intrinsic dynamics of human movement and this should be considered when making comparisons between treadmill and over-ground studies and in future study designs.

关键词： Coordination variability vector coding Coupling Statistical parametric mapping

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Gait Coordination Quantification of Thigh-Leg Segments in Sedentary and Active Youngs at Different Speeds Using the Modified vector coding Technique 27th

Gait Coordination Quantification of Thigh-Leg Segments in Se...

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27th Brazilian Congress on Biomedical Engineering (CBEB)

作者： De Villa, G. A. G. Rodrigues, F. B. Abbasi, A. Andrade, A. O. Vieira, M. F. Univ Fed Goias Bioengn & Biomech Lab Ave Esperanea BR-74690900 Goiania Go Brazil State Univ Goias Goiania Go Brazil Kharazmi Univ Fac Phys Educ & Sports Sci Dept Biomech & Sports Injuries Tehran Iran Univ Fed Uberlandia Ctr Innovat & Technol Assessment Hlth Uberlandia MG Brazil

ISBN: (纸本)9783030706012;9783030706005

The aim of the present study was to quantify the variability coordination of Thigh-Leg segments, during gait, of young sedentary and active at different speeds (preferred walk- ing speed (PWS), 120% of PWS and 80% of PWS) using the previously reported modified vector coding technique, to record the segmental angles. Thirty young people participated in this study, of which 15 practiced physical activities at least an hour a day and three times a week, and 15 were sedentary. For data collection they executed a protocol of one-minute walking on a treadmill at each speed, in a randomized order. For the Thigh-Leg segments, the angles were computed during four phases of the gait (first double support, single support, second double support, and swing), in the sagittal plane (flexion/extension angles). The data were analyzed using a customized Matlab code. There were statistical differences for the Thigh-Leg segment pair, with great differences observed in 120 and 80% of PWS for both groups.

关键词： Variability Coordination vector coding

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Roundhouse Kick's TEAKWONDO Variability in Kinematic Coupling Assessed by Continuous Relative Phase and vector coding 22

Roundhouse Kick's TEAKWONDO Variability in Kinematic Couplin...

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22nd Iranian Conference on Biomedical Engineering (ICBME)

作者： Barnamei, H. R. Kharazi, M. R. Islamic Azad Univ Sci & Res Branch Tehran Iran Noorafshar Hosp Rehabil & Sports Med Tehran Iran

ISBN: (纸本)9781467393515

This study aimed to investigate the kicking limb coordinative patterns adopted by Taekwondo practitioners (Taekwondoka) during a roundhouse kick (Ap Dollio Chagi). Six Taekwondoka performed five repetitions of both kicks while kicking limb kinematics were recorded using a motion analysis system. Lower-limb coordination was quantified for hip and knee flexionextension from toe-off to kick completion, using the Continuous relative phase (CRP). For all trials, across all participants, CRP curve peaks and maximum and minimum were determined. The CRP analysis highlighted, during the central portion of both kicks, a delayed flexion of the hip with respect to the knee. Our findings suggested that there was a slight difference in the pattern and variability of inter-joint coordination presented by CRP. This difference may be caused by the velocity (temporal evolution) and the normalization procedure involved in calculating CRP.

关键词： Taekwondo VICON vector coding Motion Analysis

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Quantification of Gait Coordination Variability of Pelvis-Thigh Segments in Young Sedentary and Practitioners People Walking in Different Slopes Using the vector coding Technique 27th

Quantification of Gait Coordination Variability of Pelvis-Th...

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27th Brazilian Congress on Biomedical Engineering (CBEB)

作者： De Villa, G. A. G. Mochizuki, L. Abbasi, A. Andrade, A. O. Vieira, M. F. Univ Fed Goias Bioengn & Biomech Lab Goiania Go Brazil Univ Sao Paulo Biomech Lab Sao Paulo Brazil Kharazmi Univ Fac Phys Educ & Sports Sci Dept Biomech & Sports Injuries Tehran Iran Univ Fed Uberlandia Ctr Innovat & Technol Assessment Hlth Uberlandia MG Brazil

ISBN: (纸本)9783030706012;9783030706005

The present study aimed quantify the variability of segmental coordination, during the gait of young practitioners and sedentary people on different slopes (Horizontal, 8% and 10% Upward (Up) and Downward (Down) conditions) maintaining the self-selected speed (VAS), using the vector coding technique. Thirty young people participated in this study, of which 15 were sedentary and 15 practiced physical exercises at least one hour a day, three times a week. They per- formed a protocol of walking 1 min on a treadmill on each inclination for data collection, in randomized order. For the Pelvis-Thigh segment, the angles were computed during the four phases of the gait (first double support, single support, second double support, and swing), in the sagittal Flat. The data were analyzed using a customized Matlab code, how had a normal distribution, an ANOVA was used to classify. There were significant statistical differences for the Simple Support and Swing phases, with greater variability for the slope situation.

关键词： Variability Coordination vector coding Slope

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Wireless Packet Communications Protected by Secret Sharing and vector coding

Wireless Packet Communications Protected by Secret Sharing a...

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39th Symposium on Information Theory and Its Applications (SITA)

作者： Yamasaki, Shoichiro Matsushima, Tomoko K. Miyazaki, Shinichiro Omura, Kotoku Tanaka, Hirokazu Polytech Univ Japan Kodaira Tokyo 1870035 Japan Hiroshima City Univ Hiroshima 7313194 Japan

Secret sharing is a method to protect information for security. The information is divided into n shares, and the information is reconstructed from any k shares but no knowledge of it is revealed from k 1 shares. Physical layer security is a method to yield a favorable receive condition to an authorized destination terminal in wireless communications based on multi-antenna transmission. In this study, we propose wireless packet communications protected by the secret sharing based on Reed Solomon coding and the physical layer security based on vector coding, which implements a single-antenna system and a multi-antenna system. Evaluation results show the validity of the proposed scheme.

关键词： secret sharing physical layer security multi-antenna transmission vector coding packet communications

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Secure Wireless Communications Using Secret Sharing and vector coding

Secure Wireless Communications Using Secret Sharing and Vect...

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IEEE Asia Pacific Conference on Circuits and Systems (APCCAS)

作者： Yamasaki, Shoichiro Matsushima, Tomoko K. Miyazaki, Shinichiro Polytech Univ Tokyo Japan

ISBN: (纸本)9781479952304

A secret sharing is a method to protect the information for security. The information is divided into n shares, and the information is reconstructed from any k shares but no knowledge of it is revealed from k - 1 shares. A physical layer security is a method to yield a favorable receive condition to the destination terminal in wireless communications. In this study, we propose a security scheme using the secret sharing based on systematic Reed Solomon (RS) codes and the physical layer security based on vector coding. The vector coding realizes the physical layer security in one-antenna system over multi-path channels and the secret sharing with systematic RS codes enhances the security.

关键词： Reed-Solomon codes antennas channel coding data privacy multipath channels radio networks telecommunication security vectors RS code information protection multipath channel one-antenna system physical layer security secret sharing method secure wireless communication systematic Reed Solomon code vector coding Cryptography Encoding Physical layer Systematics vectors Wireless communication

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Modified vector coding analysis of trunk and lower extremity kinematics during maximum and sub-maximum back squats

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JOURNAL OF BIOMECHANICS 2020年 106卷 109830-109830页

作者： Maddox, Eva U. Sievert, Zachary A. Bennett, Hunter J. Old Dominion Univ Dept Human Movement Sci 2016 Student Recreat Ctr Norfolk VA 23529 USA

The back squat is a complex movement with significant demands on the lower extremities and trunk to raise an external load. The back squat is simultaneously an open and closed kinetic chain movement that requires coordination of the entire body for successful completion of the lift. Therefore, this study aimed to examine coordination of the thigh and shank, trunk and thigh, and the hip and knee during the concentric phase of maximum, supra-maximum (at 105% max), and sub-maximum (at 80% max) back squats. Fourteen resistance trained adults participated in this study. Maximum back squat loads were determined using a previously determined progressive load protocol. Motion capture of the trunk and lower extremities and ground reaction force data were recorded during all squats. Angle-angle plots and modified vector coding were performed to analyze segment and joint coupling angles and knee-hip moments. Overall, the concentric phase of back squats depict a transition from early knee dominance to hip dominance as the system ascends. Interestingly, all squats presented with coupling of thigh-rising and trunk-falling. Based on the angle-angle plots and the modified vector coding results, the prolonged coupling of trunk falling and thigh rising likely resulted in too large of a moment arm for the external load for the participants to overcome during Supramax conditions. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： vector coding Joint coupling Back squats Squat mechanics One repetition maximum

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Using continuous relative phase and modified vector coding analyses to quantify spinal coordination and coordinative variability for healthy and chronic low back pain patients: An exploratory comparative analysis

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JOURNAL OF BIOMECHANICS 2024年 172卷 112207-112207页

作者： Ippersiel, Patrick Larson, Dennis Robbins, Shawn M. McGill Univ Sch Phys & Occupat Therapy 3654 Promenade Sir William Osler Quebec City PQ H3G 1Y5 Canada Lethbridge Layton Mackay Rehabil Ctr Ctr Interdisciplinary Res Rehabil Montreal PQ Canada Univ Montreal Fac Med Sch Kinesiol & Phys Act Sci Montreal PQ Canada Univ Waterloo Dept Kinesiol Waterloo ON Canada

Differences in coordination and coordinative variability are common in people with low back pain. While differences may relate to the different analyses used to quantify these metrics, the preferred approach remains unclear. We aimed to compare coordination and coordinative variability, in people with and without low back pain performing a lifting/lowering task, using continuous relative phase and vector coding procedures, and to identify which technique better detects group differences. Upper lumbar (T12-L3), lower lumbar (L3-S1), and hip angular kinematics were measured using electromagnetic motion capture during 10 crate lifting/lowering repetitions from adults with (n = 47) and without (n = 17) low back pain. Coordination and coordinative variability for the Hip-Lower Lumbar and Lower Lumbar-Upper Lumbar joint pairs were quantified using mean absolute relative phase and deviation phase (continuous relative phase), and coupling angle and coupling angle variability (vector coding), respectively. T-tests examined group differences in coordination and variability. Cohen's d bootstrapping analyses identified the more sensitive technique for detecting group differences. Less in-phase and more variable behavior was observed in the low back pain group, mostly independent of joint pair and analytical technique (P < 0.05, Cohen's d range = 0.61 to 1.33). Qualitatively, the low back group limited motion at the lower lumbar spine during lifting/lowering. Continuous relative phase was more sensitive in detecting group differences in coordinative variability, while vector coding was more sensitive towards differences in coordination. These procedures convey distinct information and have their respective merits. Researchers should consider the choice of analytical techniques based on their study objectives.

关键词： Coordination Coordinative variability Continuous relative phase vector coding Low back pain

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