This study presents and applies a quantitative metric, based on entire time series of measured surface electromyography (sEMG) from selected lower limb muscles to validate multibody dynamics (MBD) estimated action of ...
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ISBN:
(纸本)9788001061749
This study presents and applies a quantitative metric, based on entire time series of measured surface electromyography (sEMG) from selected lower limb muscles to validate multibody dynamics (MBD) estimated action of the same subject muscles during modified gait, stiff knee gait (SKG) and slow running (SR) in relation to normal gait (NG). MBD is being increasingly applied for estimation of internal actions according to difficulty of its direct measurements under natural conditions of movement and the importance of this estimation for prevention, diagnosis and treatment planning of specific subject skeletal and neuromuscular diseases. Inverse kinematics and inverse dynamics from position and force data have been used to estimate internal joint force moments, with muscle grouping and optimization techniques applied along with musculoskeletal model for estimation of muscle action. Nevertheless kinematic and kinetic input data of human movement must be accurate and employed model for simulation must be personalized to subject, task and moment of application. Also the results provided by the simulation with the musculoskeletal model must be compared with measured results for validation. Comparative analysis of kinematic and kinetic input data of human lower limbs is performed during modified gait modes and a personalized musculoskeletal model employed for MBD estimation of muscle actions and compare estimated muscle actions with measured sEMG of selected muscles on different gait modes, SKG and SR in relation to those registered at NG. The results from quantitative metrics followed qualitative agreement from visual inspection with better agreement between processed sEMG and MBD muscle estimated activity on phase metric than at magnitude, and combined metric presenting overall better agreement at NG and SKG than at SR, pointing to higher ability of the model to predict muscle force patterns in agreement with measured sEMG activity at NG and SKG than at SR and the need to
This study presents and applies generalized angular phase space analysis to lower limb joint angles of specific subject during normal and modified gait for discrimination of gait and joint angular movements. Case stud...
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This study presents and applies generalized angular phase space analysis to lower limb joint angles of specific subject during normal and modified gait for discrimination of gait and joint angular movements. Case study of an adult healthy male in-vivo and noninvasive kinematic assessment of skin surface adhesive markers at lower limb was performed at human movement lab during normal gait, stiff knee gait and slow running. Musculoskeletal modeling was performed using Any Gait v.0.92 morphing Twente Lower Extremity Model (TLEM) to match the size and joint morphology of the stick-figure model. Inverse kinematics was performed obtaining hip, knee and ankle joint flexion-extension angular displacements, velocities and accelerations. Generalized phase space analysis was applied to lower limb joint angular displacements, velocities and accelerations. Directional statistics was applied to generalized phase planes with mean direction, resultant length and circular standard deviation assessment. Rayleigh test was employed for directional concentration and coordination assessment, and Watson's U~2 goodness of fit test applied to the von Mises distribution. Results point for the importance of subject specific study, generalized joint angular phase space analysis, comparing results with other normalization methods and validation of applied methods with qualitative clinical analysis.
Given the difficulty of invasive methods to assess muscle action during natural human movement, surface electromyography (sEMG) has been increasingly used to capture muscle activity in relation to kinesiological analy...
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ISBN:
(纸本)9781509028092
Given the difficulty of invasive methods to assess muscle action during natural human movement, surface electromyography (sEMG) has been increasingly used to capture muscle activity in relation to kinesiological analysis of specific tasks. Isolated isometric, concentric and eccentric forms of muscle action have been receiving the most attention for research purposes. Nevertheless natural muscle action frequently involves the use of a preceding eccentric muscle action as a form of potentiation of immediate muscle concentric action, in what is designated as muscle stretch-shortening cycle (SSC). The most frequently applied protocols for the evaluation of SSC on vertical jumps are by virtue of their reproducibility and control of experimental conditions, squat jump (SJ) without countermovement (CM), countermovement jump (CMJ) with long CM and drop jump (DJ) with short CM. The methods used to extract information and relationship of the captured signals also present a high diversity, with the question about the consistency of the methods and obtained results. The objective of this study is to evaluate the consistency of the analysis and results by applying different EMGs signal analysis techniques related to strategic muscle groups of the lower limbs at different countermovement evaluated in vertical jumps. Raw sEMG signals of 5 lower limb muscles of 6 subjects during SJ, CMJ and DJ were rectified, filtered and obtained their envelope, and then correlated (CR) for detection of synergistic, agonist and antagonist activity, applied principal component analysis (PCA) for the detection of uncorrelated components explaining maximum variability and normalized cross-correlation (CCRN) for detection of maximum correlations and time lag. CR of EMG envelopes presented higher coactivities (CoA) in DJ relative to SJ and these CoA superior to CMJ with greater synergy in DJ relative to SJ and CMJ that present several loop cycles corresponding to time lag of activity. CCRN of the EMG e
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