Application of Principal Component Analysis to Forward Reactive Stepping: Whole-body Movement Strategy Differs as a Function of Age and Sex

Author(s):  
Daniel P. Armstrong ◽  
Steven P. Pretty ◽  
Tyler B. Weaver ◽  
Steven L. Fischer ◽  
Andrew C. Laing
2021 ◽  
Vol 11 ◽  
Author(s):  
Inge Werner ◽  
Nicolai Szelenczy ◽  
Felix Wachholz ◽  
Peter Federolf

This study compared whole body kinematics of the clean movement when lifting three different loads, implementing two data analysis approaches based on principal component analysis (PCA). Nine weightlifters were equipped with 39 markers and their motion captured with 8 Vicon cameras at 100 Hz. Lifts of 60, 85, and 95% of the one repetition maximum were analyzed. The first PCA (PCAtrial) analyzed variance among time-normed waveforms compiled from subjects and trials; the second PCA (PCAposture) analyzed postural positions compiled over time, subjects and trials. Load effects were identified through repeated measures ANOVAs with Bonferroni-corrected post-hocs and through Cousineau-Morey confidence intervals. PCAtrial scores differed in the first (p < 0.016, ηp2 = 0.694) and fifth (p < 0.006, ηp2 = 0.768) principal component, suggesting that increased barbell load produced higher initial elevation, lower squat position, wider feet position after squatting, and less inclined arms. PCAposture revealed significant timing differences in all components. We conclude, first, barbell load affects specific aspects of the movement pattern of the clean; second, the PCAtrial approach is better suited for detecting deviations from a mean motion trajectory and its results are easier to interpret; the PCAposture approach reveals coordination patterns and facilitates comparisons of postural speeds and accelerations.


2021 ◽  
Author(s):  
Onoruoyiza Asuku Ibrahim ◽  
Kayode Anthony Olutunmogun ◽  
Mallam Iliya ◽  
Chima Martin Umego ◽  
Opeyemi Rachel Alao ◽  
...  

Abstract An experiment was conducted to determine the principal component analysis of body morphometric traits as affected by age and sex in donkeys reared on a research station in the National Animal Production Research Institute, Shika-Zaria, Nigeria. This was based on the objective of classifying age and sex using the multivariant method of principal component analysis (PCA) on morphometric traits of donkeys. Data were collected from a total of 101 donkeys based on age and sex on body wright, heart girth, body length, height at withers, tail length, shoulder width, head width, ear length, head length, neck circumference and neck length. The data obtained were subjected to multivariate factor analysis with varimax rotation using IBM® SPSS® Version 21. The results obtained revealed that the age group ≤ 1 year had one PCA, 2–3 years age group had four PCA, 4–5 years group had three PCA while those ≥ 6 years had two PCA. Most of the variables in combination with age largely formed the block of PC1 while other PCA had one or two variables correlating with them. Most of the variables formed PC1 for the Jacks while head width (HW) and ear length (EL) formed PC2. The Jennies had its entire variable in one PCA. Therefore, PC1 had the highest loading for the variables both by age and by sex as the animals are relatively well adapted to their environment. It can be concluded that donkeys between 2-3years have more PC correlation proportions.


PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0259464
Author(s):  
Félix Bigand ◽  
Elise Prigent ◽  
Bastien Berret ◽  
Annelies Braffort

Sign Language (SL) is a continuous and complex stream of multiple body movement features. That raises the challenging issue of providing efficient computational models for the description and analysis of these movements. In the present paper, we used Principal Component Analysis (PCA) to decompose SL motion into elementary movements called principal movements (PMs). PCA was applied to the upper-body motion capture data of six different signers freely producing discourses in French Sign Language. Common PMs were extracted from the whole dataset containing all signers, while individual PMs were extracted separately from the data of individual signers. This study provides three main findings: (1) although the data were not synchronized in time across signers and discourses, the first eight common PMs contained 94.6% of the variance of the movements; (2) the number of PMs that represented 94.6% of the variance was nearly the same for individual as for common PMs; (3) the PM subspaces were highly similar across signers. These results suggest that upper-body motion in unconstrained continuous SL discourses can be described through the dynamic combination of a reduced number of elementary movements. This opens up promising perspectives toward providing efficient automatic SL processing tools based on heavy mocap datasets, in particular for automatic recognition and generation.


2010 ◽  
Vol 49 (02) ◽  
pp. 161-167
Author(s):  
R. Simoliuniene ◽  
M. Tamosiunas ◽  
V. Saferis ◽  
A. Vainoras ◽  
L. Gargasas ◽  
...  

Summary Background: Cardiac output is controlled by the autonomic nervous system by changing the heart rate and/or the contractions of the heart muscle in response to the hemodynamic needs of the whole body. Malfunction of these mechanisms causes the postural orthostatic tachycardia syndrome and/or the chronic fatigue syndrome. Evaluation of functionality and efficiency of the control mechanisms could give valuable diagnostic information in the early stages of dysfunction of the heart control systems and help to monitor the healing process in rehabilitation period after interventions. Objectives: In this study we demonstrate how P-wave changes evoked by an ortho-static test could be quantitatively evaluated by using the method based on the principal component analysis. Methods: ECG signals were recorded during an orthostatic test performed according to the typical protocol in three groups of volunteer subjects representing healthy young and older persons, part of which had transient periods of supraventricular arrhythmias. Quantitative evaluation of P-wave morphology changes was performed by means of principal component analysis-based method. Results: Principal component-based estimates showed certain variety of P-wave shape during orthostatic test, what revealed a possibility to evaluate the properties of para-sympathetic heart control. Conclusions: Quantitative evaluation of ECG P-wave changes evoked by an orthostatic test by using a newly developed method provides a quantitative estimate for functionality and efficiency of the heart rate control mechanisms. The method could be used in eHealth systems.


2020 ◽  
Author(s):  
Carlyn Patterson Gentile ◽  
Nabin R Joshi ◽  
Kenneth Ciuffreda ◽  
Kristy Arbogast ◽  
Christina Master ◽  
...  

Purpose: Peak amplitude and latency in the pattern reversal visual evoked potential (prVEP) vary with maturation. We considered that principal component analysis (PCA) may be used to describe age-related variation over the entire prVEP time course and provide a means of modeling and removing variation due to developmental age. Methods: prVEP was recorded from 155 healthy subjects ages 11-19 years during two sessions (spaced 0.7 to 17 months apart). We created a model of the prVEP by identifying principal components (PCs) that explained >95% of the variance in a training dataset of 40 subjects. We examined the ability of the PCs to explain variance in an age- and sex-matched test subject group (n=40) and calculated the intra-subject reliability of the PC coefficients between the two sessions. We then explored the effect of subject age and sex upon the PC coefficients. Results: Seven PCs accounted for 96.0% of the variability. The model was generalizable (training vs. test coefficient distributions p>0.36 for all PCs) with good within-subject reliability (R>0.7 for all PCs). The PCA model did not show a significant difference between males and females (F(7,147)=1.69, p=0.12), but showed a significant effect of subject age (F(7,147)=4.37, p=0.0002). Conclusions: PCA is a generalizable, reliable, and unbiased method of analyzing prVEP that can quantify and remove developmental variability present in the global temporal VEP signal. Translational relevance: We describe a novel application of PCA to characterize developmental changes of prVEP in youth that can be used to compare healthy and pathologic pediatric cohorts.


2017 ◽  
Vol 48 (3) ◽  
pp. 261-304 ◽  
Author(s):  
Ryan Bennett ◽  
Máire Ní Chiosáin ◽  
Jaye Padgett ◽  
Grant McGuire

We present the first ultrasound analysis of the secondary palatalization contrast in Irish, analyzing data from five speakers from the Connemara dialect group. Word-initial /pʲ(bʲ)pˠ(bˠ)tʲtˠkʲkˠfʲfˠsʲsˠxʲxˠ/ are analyzed in the context of /iːuː/. We find, first, that tongue body position robustly distinguishes palatalized from velarized consonants, across place of articulation, manner, and vowel place contexts, with palatalized consonants having fronter and/or higher tongue body realizations than their velarized counterparts. This conclusion holds equally for labial consonants, contrary to some previous descriptive claims. Second, the nature and degree of palatalization and velarization depend in systematic ways on consonant place and manner. In coronal consonants, for example, velarization is weaker or absent. Third, the Irish consonants examined resist coarticulation in backness with a following vowel. In all of these respects Irish palatalization is remarkably similar to that of Russian. Our results also support an independent role for pharyngeal cavity expansion/retraction in the production of the palatalization contrast. Finally, we discuss preliminary findings on the dynamics of the secondary articulation gestures. Our use of principal component analysis (PCA) in reaching these findings is also of interest, since PCA has not been employed a great deal in analyses of tongue body movement.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Linpei Jia ◽  
Weiguang Zhang ◽  
Rufu Jia ◽  
Hongliang Zhang ◽  
Xiangmei Chen

The biological age (BA) equation is a prediction model that utilizes an algorithm to combine various biological markers of ageing. Different from traditional concepts, the BA equation does not emphasize the importance of a golden index but focuses on using indices of vital organs to represent the senescence of whole body. This model has been used to assess the ageing process in a more precise way and may predict possible diseases better as compared with the chronological age (CA). The principal component analysis (PCA) is applied as one of the common and frequently used methods in the construction of the BA formula. Compared with other methods, PCA has its own study procedures and features. Herein we summarize the up-to-date knowledge about the BA formula construction and discuss the influential factors, so as to give an overview of BA estimate by PCA, including composition of samples, choices of test items, and selection of ageing biomarkers. We also discussed the advantages and disadvantages of PCA with reference to the construction mechanism, accuracy, and practicability of several common methods in the construction of the BA formula.


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