scholarly journals Identifying differences in gait adaptability across various speeds using movement synergy analysis

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0244582
Author(s):  
David Ó’Reilly ◽  
Peter Federolf
Keyword(s):  
Principal Component ◽  
Neuromuscular Control ◽  
Whole Body ◽  
Supporting Evidence ◽  
Normal Walking ◽  
Optimal Model ◽  
Double Support ◽  
Leg Dominance ◽  
Perturbed Walking

Introduction The aim of this study was to identify movement synergies during normal-walking that can differentiate healthy adults in terms of gait adaptability at various speeds. To this end, the association between movement synergies and lower-limb coordination variability or Deviation Phase (DP) was investigated. This study also investigated the moderating effect of movement synergies on the relationship between DP and the smoothness of arm-swing motion (NJI). Method A principal component analysis of whole-body marker trajectories from normal-walking treadmill trials at 0.8m/s, 1.2m/s and 1.6m/s was undertaken. Both DP and NJI were derived from approx. 8 minutes of perturbed-walking treadmill trials. Principal movement components, PMk, were derived and the RMS of the 2nd-order differentiation of these PMk (PAkRMS) were included as independent variables representing the magnitude of neuromuscular control in each PMk. Each PAkRMS were input into maximal linear mixed-effects models against DP and (DP x NJI) respectively. A stepwise elimination of terms and comparison of models using Anova identified optimal models for both aims. Results The principal movement related to the push-off mechanism of gait (PA4RMS) was identified as an optimal model and demonstrated a significant negative effect on DP however this effect may differ considerably across walking-speeds. An optimal model for describing the variance in (DP x NJI) included a fixed-effect of PA6RMS representing Right—Left side weight transfer was identified. Interpretation The hypotheses that individuals who exhibited greater control on specific kinematic synergies would exhibit variations during perturbed walking was substantiated. Supporting evidence for the role of movement synergies during the double-support phase of gait in proactively correcting balance was presented as well as the potential for this approach in targeted rehabilitation. The potential influence of leg dominance on gait adaptability was also discussed. Future studies should investigate further the role of walking-speed and leg dominance on movement synergies and look to generalize these findings to patient populations.

scholarly journals Identifying differences in gait adaptability across various speeds using movement synergy analysis

2020 ◽  
Author(s):  
David Ó’Reilly ◽  
Peter Federolf
Keyword(s):  
Lower Limb ◽  
Optimal Model ◽  
Double Support ◽  
Limb Coordination ◽  
Leg Dominance ◽  
Weight Transfer ◽  
Perturbed Walking ◽  
Support Phase ◽  
Double Support Phase

AbstractIntroductionThe aim of this study was to identify movement synergies during normal-walking that can differentiate healthy adults in terms of gait adaptability at various speeds. To this end, the association between movement synergies and lower-limb coordination variability or Deviation Phase (DP) was investigated. A secondary aim of this study included an investigation into the moderating effect of these movement synergies on the relationship between DP and the smoothness of arm-swing motion quantified as the normalised jerk index (NJI).MethodA principal component analysis of whole-body marker trajectories from normal-walking treadmill trials at 0.8m/s, 1.2m/s and 1.6m/s was undertaken. Both DP and NJI were derived from approx. 8 minutes of perturbed-walking treadmill trials. Principal movement components, PMk, were derived and the RMS of the 2nd-order differentiation of these PMk (PAkRMS) were included as independent variables representing the magnitude of neuromuscular control in each PMk. The PAkRMS were input into separate maximal linear mixed-effects regression models to explain the variance in DP and (DP × NJI). A stepwise elimination of terms and comparison of models using Anova identified optimal models for both aims.ResultsAmong the first 7 validated PMk, PA4RMS (double-support phase) was identified as an optimal model and demonstrated a significant negative effect on DP however this effect may differ considerably across walking-speeds. An optimal model for describing the variance in (DP × NJI) included a fixed-effect of PA6RMS (Left – Right side weight transfer). Within-participant clustering was prevalent within both optimal models.InterpretationThe hypotheses that individuals who exhibited greater control on specific kinematic synergies would exhibit variations during perturbed walking was substantiated. Supporting evidence for the role of movement synergies during the double-support phase of gait in proactively correcting balance was presented. The potential influence of leg dominance on gait adaptability was also discussed. Future studies should investigate further the role of walking-speed and leg dominance on movement synergies and look to generalize these findings to patient populations.HighlightsBaseline movement synergies representing terminal-swing and double-support phases of gait were found to have significant negative effects on lower-limb coordination variability during perturbed-walking trials at various speeds.Movement synergies related to the double-support phase and weight transfer events of gait were determined to have a negative moderating effect on the translation of lower-limb coordination variability into upper-limb postural corrections.Evidence was presented for the important role of the double-stance phase of gait in gait adaptability while leg dominance was shown to play a potential role in differentiating healthy adults in this study.

scholarly journals Slow walking synergies reveal a functional role for arm swing asymmetry in healthy adults: a principal component analysis with relation to mechanical work

2020 ◽  
Author(s):  
David Ó’ Reilly
Keyword(s):  
Lower Limb ◽  
Principal Component ◽  
Neuromuscular Control ◽  
Mechanical Work ◽  
Arm Swing ◽  
Double Support ◽  
Slow Walking ◽  
Negative Effect ◽  
The Difference ◽  
Support Phase

AbstractIntroductionThe purpose of this study was to reveal a functional role for arm-swing asymmetry during gait in healthy adults. The primary aim was to identify differences in propulsive and collision work between sides at either end of the double-support phase of slow-walking (WDS). The secondary aim was to identify differences between sides in propulsive and collision work done at either end of the single-support phase (WSS) and the effect of arm-swing asymmetry on this difference. It was hypothesized that differences between sides would be evident during the double-support phase and that these differences would be coherent with differences in single-support control symmetry. It was also hypothesized that left-side dominant arm-swing would reduce the collision work done on the dominant lower-limb side.MethodsA secondary analysis of slow-walking trials of 25 healthy, uninjured adults was undertaken where a principal component analysis of kinematic data was carried out to generate the movement synergies (PMk). Independent variables included the tightness of neuromuscular control (Nk) which was formulated from the first PMk and arm-swing asymmetry which was quantified using the directional Arm-swing asymmetry index (dASI). Dependent variables included the difference between double-support collision and propulsive work (WDS) and a ratio consisting of the difference between single-support collision and propulsive work of both sides (WSS). A linear mixed-effects model was utilized for aim 1 while a multiple linear regression analysis was undertaken for aim 2.ResultsHealthy adult gait was accompanied by a left-side dominant arm-swing on average as seen elsewhere. For aim 1, Nk demonstrated a significant negative effect on WDS while sidedness had a direct negative effect and indirect positive effect through Nk on WDS. The most notable finding was the effect of a crossover interaction between dASI and Nk which demonstrated a highly significant positive effect on Wss. All main-effects in aim 2 were in the hypothesized direction but were insignificant.InterpretationThe aim 1 hypothesis was supported while the aim 2 hypothesis was not supported. Nk exhibited opposing signs between ipsilateral and contralateral WBAM regulation, revealing a differential control strategy while the effect of sidedness on WDS was evident. The findings from aim 2 describe a relationship between arm-swing asymmetry and the magnitude of lower-limb mechanical work asymmetry that is cohesive with the sidedness effect found in aim 1. Individuals with left-side dominant arm-swing had an increased collision work indicative of a lateralised preference for WBAM regulation. Evidence was therefore put forward that arm-swing asymmetry during gait is related to footedness. Future studies should look to formally confirm this finding. Implications for further research into dynamic balance control mechanisms are also discussed.HighlightsLeft-side dominant arm-swing was found to be related to the degree of lower-limb mechanical work asymmetry.The relationship between arm-swing asymmetry and lower-limb mechanical work symmetry was explained by a moderating effect of neuromuscular control.A differential control on single-and double-support phases was demonstrated by the neuromuscular system, supporting previous studies and this control may be heavily influenced by sidedness.

scholarly journals Leg Dominance Effects on Postural Control When Performing Challenging Balance Exercises

2020 ◽  
Vol 10 (3) ◽  
pp. 128 ◽  
Author(s):  
Arunee Promsri ◽  
Thomas Haid ◽  
Inge Werner ◽  
Peter Federolf
Keyword(s):  
Motion Tracking ◽  
Motor Behavior ◽  
Time Derivative ◽  
Principal Component ◽  
Neuromuscular Control ◽  
Movement Component ◽  
Balance Exercises ◽  
Coordinative Structure ◽  
Diagonal Plane ◽  
Leg Dominance

Leg dominance reflects the preferential use of one leg over another and is typically attributed to asymmetries in the neural circuitry. Detecting leg dominance effects on motor behavior, particularly during balancing exercises, has proven difficult. The current study applied a principal component analysis (PCA) on kinematic data, to assess bilateral asymmetry on the coordinative structure (hypothesis H1) or on the control characteristics of specific movement components (hypothesis H2). Marker-based motion tracking was performed on 26 healthy adults (aged 25.3 ± 4.1 years), who stood unipedally on a multiaxial unstable board, in a randomized order, on their dominant and non-dominant leg. Leg dominance was defined as the kicking leg. PCA was performed to determine patterns of correlated segment movements (“principal movements” PMks). The control of each PMk was characterized by assessing its acceleration (second-time derivative). Results were inconclusive regarding a leg-dominance effect on the coordinative structure of balancing movements (H1 inconclusive); however, different control (p = 0.005) was observed in PM3, representing a diagonal plane movement component (H2 was supported). These findings supported that leg dominance effects should be considered when assessing or training lower-limb neuromuscular control and suggest that specific attention should be given to diagonal plane movements.

Changes in the VI-VCO2 relationship during exercise in goats: role of carotid bodies

1984 ◽  
Vol 57 (6) ◽  
pp. 1894-1900 ◽  
Author(s):  
G. S. Mitchell ◽  
C. A. Smith ◽  
J. A. Dempsey
Keyword(s):  
Principal Component ◽  
Blood Gases ◽  
Whole Body ◽  
Co2 Production ◽  
Similar Degree ◽  
Experimental Conditions ◽  
Serotonin Depletion ◽  
Arterial Blood ◽  
Carotid Bodies

To assess the role of carotid bodies in modulating the ventilation-CO2 production relationship, steady-state responses to mild exercise were determined in goats following several experimental manipulations that led to chronic changes in resting ventilation and arterial blood gases. The experimental conditions were 1) control, 2) whole body serotonin depletion (induced by p-chlorophenylalanine, 100 mg/kg), 3) carotid body denervation (CBX), and 4) serotonin depletion with CBX. Resting values of arterial CO2 pressure (Pco2) ranged from 32 to 48 Torr. In each condition, arterial Pco2 was regulated to a similar degree in exercise due to changes in the slope of the ventilation-CO2 production relationship (delta Vi/delta Vco2) in accordance with the requirements of gas exchange. delta Vi/delta Vco2 increased with serotonin depletion both before and after CBX. The principal component of ventilation contributing to changes in delta Vi/delta Vco2 was tidal volume. These results suggest a basic property of the ventilatory control system whereby enhanced ventilatory activity at rest is associated with an increased ventilatory response to exercise via a mechanism that does not require peripheral chemoreceptors.

280-LB: Role of A1 and A3 Adenosine Receptors in Whole Body Glucose Metabolism

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 280-LB ◽  
Author(s):  
SHANU JAIN ◽  
DILIP K. TOSH ◽  
MARC REITMAN ◽  
KENNETH A. JACOBSON
Keyword(s):  
Glucose Metabolism ◽  
Adenosine Receptors ◽  
Whole Body

Practical consensus recommendations - Current role of immune response evaluation criteria in solid tumors criteria in the management of cancer patients receiving immunotherapy

2019 ◽  
Vol 4 ◽  
pp. 21-23
Author(s):  
Purvish M. Parikh ◽  
T. P. Sahoo ◽  
Randeep Singh ◽  
Bahl Ankur ◽  
Talvar Vineet ◽  
...  
Keyword(s):  
Immune Response ◽  
Solid Tumors ◽  
Evaluation Criteria ◽  
Supporting Evidence ◽  
Response Evaluation ◽  
Consensus Recommendation ◽  
Current Role ◽  
New Class ◽  
Response Evaluation Criteria

Response evaluation criteria in solid tumors (RECIST) are a method used to evaluate and document the response to cancer treatment in solid tumors. The availability of a new class of immuneoncology drugs has resulted in the need to modify RECIST criteria methodology. The first leadership immuno-oncology network (LION) master course brought together experts in oncology and immuno-oncology. Six questions were put to the experts and their opinion, supporting evidence, and experience were discussed to arrive at a practical consensus recommendation. n this nascent field, the availability of a practical consensus recommendation developed by experts in the field is of immense value to the community oncologist and other health-care consultants.

Determinants of maximal whole-body fat oxidation in elite cross-country skiers: Role of skeletal muscle mitochondria

2018 ◽  
Vol 28 (12) ◽  
pp. 2494-2504 ◽  
Author(s):  
Sune Dandanell ◽  
Anne-Kristine Meinild-Lundby ◽  
Andreas B. Andersen ◽  
Paul F. Lang ◽  
Laura Oberholzer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Fat ◽  
Fat Oxidation ◽  
Whole Body ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Cross Country

scholarly journals Distribution and Severity of Placental Lesions Caused by the Chlamydia abortus 1B Vaccine Strain in Vaccinated Ewes

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 543
Author(s):  
Sergio Gastón Caspe ◽  
Javier Palarea-Albaladejo ◽  
Clare Underwood ◽  
Morag Livingstone ◽  
Sean Ranjan Wattegedera ◽  
...  
Keyword(s):  
Disease Outbreaks ◽  
Principal Component ◽  
Placental Pathology ◽  
Wild Type ◽  
Cell Infiltrate ◽  
Chlamydia Abortus ◽  
Vaccine Type ◽  
The Difference ◽  
Enzootic Abortion Of Ewes

Chlamydia abortus infects livestock species worldwide and is the cause of enzootic abortion of ewes (EAE). In Europe, control of the disease is achieved using a live vaccine based on C. abortus 1B strain. Although the vaccine has been useful for controlling disease outbreaks, abortion events due to the vaccine have been reported. Recently, placental pathology resulting from a vaccine type strain (vt) infection has been reported and shown to be similar to that resulting from a natural wild-type (wt) infection. The aim of this study was to extend these observations by comparing the distribution and severity of the lesions, the composition of the predominating cell infiltrate, the amount of bacteria present and the role of the blood supply in infection. A novel system for grading the histological and pathological features present was developed and the resulting multi-parameter data were statistically transformed for exploration and visualisation through a tailored principal component analysis (PCA) to evaluate the difference between them. The analysis provided no evidence of meaningful differences between vt and wt strains in terms of the measured pathological parameters. The study also contributes a novel methodology for analysing the progression of infection in the placenta for other abortifacient pathogens.

The Role of the Representative: Some Empirical Observations on the Theory of Edmund Burke

1959 ◽  
Vol 53 (3) ◽  
pp. 742-756 ◽  
Author(s):  
Heinz Eulau ◽  
John C. Wahlke ◽  
William Buchanan ◽  
Leroy C. Ferguson
Keyword(s):  
Decision Making ◽  
Political Theory ◽  
Empirical Research ◽  
Body Politic ◽  
Whole Body ◽  
Edmund Burke ◽  
Political Systems ◽  
General Consensus ◽  
History Of

The problem of representation is central to all discussions of the functions of legislatures or the behavior of legislators. For it is commonly taken for granted that, in democratic political systems, legislatures are both legitimate and authoritative decision-making institutions, and that it is their representative character which makes them authoritative and legitimate. Through the process of representation, presumably, legislatures are empowered to act for the whole body politic and are legitimized. And because, by virtue of representation, they participate in legislation, the represented accept legislative decisions as authoritative. But agreement about the meaning of the term “representation” hardly goes beyond a general consensus regarding the context within which it is appropriately used. The history of political theory is studded with definitions of representation, usually embedded in ideological assumptions and postulates which cannot serve the uses of empirical research without conceptual clarification.

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