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 Dysfunctional muscle activities and co-contraction in the lower-limb of lumbar disc herniation patients during walking

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wei Wang ◽  
Hui Wei ◽  
Runxiu Shi ◽  
Leitong Lin ◽  
Lechi Zhang ◽  
...  
Keyword(s):  
Lumbar Disc Herniation ◽  
Disc Herniation ◽  
Lower Limb ◽  
Gait Cycle ◽  
Lumbar Disc ◽  
Lower Limbs ◽  
Heel Strike ◽  
Control Group ◽  
Double Support ◽  
Support Phase

AbstractThis study aimed to investigate lower-limb muscle activities in gait phases and co-contraction of one gait cycle in patients with lumbar disc herniation (LDH). This study enrolled 17 LDH patients and 17 sex- and age-matched healthy individuals. Bilateral muscle activities of the rectus femoris (RF), biceps femoris long head (BL), tibialis anterior (TA), and lateral gastrocnemius (LG) during walking were recorded. The gait cycle was divided into four phases by the heel strike and top off according to the kinematics tracks. Root mean square (RMS), mean frequency (MF), and co-contraction of surface electromyography signals were calculated. The LDH patients showed enhanced BL RMS during the single support phase (SS), second double support phase, and swing phase (SW) as well as decreased MF of RF during SS and of TA and LG during SW (p < 0.05). The co-contraction of the TA-LG was increased in LDH patients than in the control group (p < 0.05). Positive correlations were observed between TA-LG co-contraction (affected side, r = 0.557, p = 0.020; contralateral side, r = 0.627, p = 0.007) and the Oswestry disability index scores in LDH patients. LDH patients have increased BL firing rate and insufficient motor unit recruitment in specific phases in the lower limbs during walking. Dysfunction in LDH patients was associated with immoderate intermuscular co-contraction of the TA-LG during walking.

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.

Effect of moderate physical exercise on the immune system modulation in patients with breast cancer during preoperative chemotherapy: The NEO-RUNNER study.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 581-581
Author(s):  
Ornella Garrone ◽  
Andrea Abbona ◽  
Antonella Falletta ◽  
Matteo Paccagnella ◽  
Nicoletta Croce ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Immune System ◽  
Principal Component ◽  
Tnf Α ◽  
Negative Effect ◽  
Potential Negative Effect ◽  
Ifn Γ ◽  
The Difference ◽  
Immune System Modulation ◽  
Inflammatory Effect

581 Background: The link between physical activity (PA) and the immune system (IS) is known. However, it is not yet fully understood the immune mechanisms activated by PA. We investigated the immune effect of moderate PA (MPA), nordic or fit walking, during neoadjuvant chemotherapy (NACT) in patients (pts) with breast cancer. Methods: Pts received sequential epirubicin and cyclophosphamide for 4 cycles followed by paclitaxel for 12 weeks. Blood samples from pts underwent MPA (TR) were collected before starting chemotherapy (CT) at baseline (T0), at day 1 of week 6 of paclitaxel (before starting MPA) (T1), before surgery (S) (T2) and after S (T3). Samples were also collected in a group of pts who declined MPA (UN) at the same time points and in 15 healthy volunteers (HV). MPA consisted of 3 workouts per week, 1 hour each, in the 9 weeks before S. At each time point the level of 17 cytokines (IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-15, CCL-2, CCL-4, CXCL-10, CCL-22, IFN-γ, TGF-β, TNF-α, VEGF) was measured. The difference among the median value of cytokines was analyzed using non parametric Mann Whitney U test. Principal component analysis (PCA) was computed to compare the best discriminating cytokine, identified by ROC analysis, of pts at T1, T2, T3 and in HV. Each patient was distributed in the PCA. Pts having similar cytokine values were plotted in the near position. Normalized values of 8 cytokines (IL-2, IL-4, IL-5, IL-6, IL-13, IL-15, CCL-2, VEGF) were used in PCA. Results: Data from 27 pts are available: 10 TR and 17 UN. A significant increase of IFN-γ, IL-5, IL-8, CCL-2 and CXCL-10 between T0 and T1 (P = 0.004, P = 0.013, P = 0.032, P = 0.046, P = 0.046, respectively) was found in the whole population. CXCL-10 significantly increased also between T1 and T2 in UN pts (P = 0.033). TR pts showed a significant lower level of IL-6, IL-13, CCL-2 at T2 (P = 0.012, P = 0.038, P = 0.023) and higher IL-15 level at T3 (P = 0.047) compared to UN pts. Moreover, a significant decrease of IL-5 was observed between T2 and T3 (P = 0.031). PCA showed that TR and UN pts were mixed at T1. HV were clustered all together and distinct from pts. At T2 TR pts moved toward HV and mixed with them while UN remained separated. TR pts tended to separate from HV at T3, while UN pts still remained distinct. Conclusions: NACT upregulated median values of IFN-γ, IL-5, IL-8, CCL-2 and CXCL-10; CXCL-10 value continues to increase during CT only in UN pts supporting the inflammatory effect of CT. On the contrary, during MPA the level of IL-6, IL-13, CCL-2 decreases in TR compared to UN pts. All together these data suggest that MPA damps the inflammatory response to NACT. Our results show that the majority of TR pts reach an immune profile similar to that of HV in PCA. However, at T3 the effect of MPA is dampened, suggesting a potential negative effect of S.

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 A Study of Movement Classification of the Lower Limb Based on up to 4-EMG Channels

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 259 ◽  
Author(s):  
Diana Toledo-Pérez ◽  
Miguel Martínez-Prado ◽  
Roberto Gómez-Loenzo ◽  
Wilfrido Paredes-García ◽  
Juvenal Rodríguez-Reséndiz
Keyword(s):  
Lower Limb ◽  
Classification Accuracy ◽  
Research Work ◽  
Principal Component ◽  
Support Vector ◽  
Semg Signal ◽  
Zero Crossings ◽  
The Difference ◽  
The Right

The number and position of sEMG electrodes have been studied extensively due to the need to improve the accuracy of the classification they carry out of the intention of movement. Nevertheless, increasing the number of channels used for this classification often increases their processing time as well. This research work contributes with a comparison of the classification accuracy based on the different number of sEMG signal channels (one to four) placed in the right lower limb of healthy subjects. The analysis is performed using Mean Absolute Values, Zero Crossings, Waveform Length, and Slope Sign Changes; these characteristics comprise the feature vector. The algorithm used for the classification is the Support Vector Machine after applying a Principal Component Analysis to the features. The results show that it is possible to reach more than 90% of classification accuracy by using 4 or 3 channels. Moreover, the difference obtained with 500 and 1000 samples, with 2, 3 and 4 channels, is not higher than 5%, which means that increasing the number of channels does not guarantee 100% precision in the classification.

scholarly journals Effects of Ankle Joint Motion on Pelvis-Hip Biomechanics and Muscle Activity Patterns of Healthy Individuals in Knee Immobilization Gait

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Xinyu Guan ◽  
Shengzheng Kuai ◽  
Liang Song ◽  
Weifeng Liu ◽  
Yali Liu ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscle Activity ◽  
Activity Patterns ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Double Support ◽  
Hip Biomechanics ◽  
Single Support Phase ◽  
Support Phase ◽  
Double Support Phase

The purpose of the study was to investigate the pelvis-hip biomechanics and trunk and lower limb muscle activity patterns between healthy people walking in two gaits and evaluate the effects of ankle joint motion on these two gaits. The two gaits included walking with combined knee and ankle immobilization and with individual knee immobilization. Ten healthy participants were recruited and asked to walk along a 10 m walk away at their comfortable speeds in the two gaits. Kinematic data, ground reaction force, and electromyography waveforms of trunk and lower limb muscles on the right side were collected synchronously. Compared to individual knee immobilization gait, people walking in the combined knee and ankle immobilization gait increased the range and average angle of the anterior pelvic tilt during the first double support and the single support phase, respectively. The combined knee and ankle immobilization gait also increased the range of hip abduction during the second double support phase. These kinematic alternations caused changes in trunk and lower limb muscle activity patterns. The ankle immobilization increased the range of gluteus maximus activation in the first double support phase, the range of rectus abdominis activation, the average amplitude of rectus femoris activation in the single support phase, and the range of rectus femoris activation in swing phase and decreased the range of and tibialis anterior activation in the first double support phase. The ankle immobilization also increased the average values of proximodistal component in AKI gait during the single support phase. This study revealed significant differences in pelvis-hip biomechanics and trunk and lower limb muscle activity patterns between the two gaits.

Multivariate micropollutants analysis in marine waters

1995 ◽  
Vol 32 (9-10) ◽  
pp. 341-348
Author(s):  
V. Librando ◽  
G. Magazzù ◽  
A. Puglisi
Keyword(s):  
Multivariate Data Analysis ◽  
Partial Least Squares Regression ◽  
Environmental Chemistry ◽  
Sampling Site ◽  
Principal Component ◽  
Least Squares Regression ◽  
Organic Micropollutants ◽  
Suspended Material ◽  
The Difference

The monitoring of water quality today provides a great quantity of data consisting of the values of the parameters measured as a function of time. In the marine environment, and especially in the suspended material, increasing importance is being given to the presence of organic micropollutants, particularly since some are known to be carcinogenic. As the number of measured parameters increases examining the data and their consequent interpretation becomes more difficult. To overcome such difficulties, numerous chemometric techniques have been introduced in environmental chemistry, such as Multivariate Data Analysis (MVDA), Principal Component Analysis (PCA) and Partial Least Squares Regression (PLSR). The use of the first technique in this work has been applied to the interpretation of the quality of Augusta bay, by measuring the concentration of numerous organic micropollutants, together with the classical water pollution parameters, in different sites and at different times. The MVDA has highlighted the difference between various sampling sites whose data were initially thought to be similar. Furthermore, it has allowed a choice of more significant parameters for future monitoring and more suitable sampling site locations.

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.

scholarly journals Possibility of Human Gender Recognition Using Raman Spectra of Teeth

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3983
Author(s):  
Ozren Gamulin ◽  
Marko Škrabić ◽  
Kristina Serec ◽  
Matej Par ◽  
Marija Baković ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Principal Component ◽  
Support Vector ◽  
Gender Recognition ◽  
Proof Of Concept ◽  
Male And Female ◽  
Tooth Type ◽  
Tooth Apex ◽  
The Difference

Gender determination of the human remains can be very challenging, especially in the case of incomplete ones. Herein, we report a proof-of-concept experiment where the possibility of gender recognition using Raman spectroscopy of teeth is investigated. Raman spectra were recorded from male and female molars and premolars on two distinct sites, tooth apex and anatomical neck. Recorded spectra were sorted into suitable datasets and initially analyzed with principal component analysis, which showed a distinction between spectra of male and female teeth. Then, reduced datasets with scores of the first 20 principal components were formed and two classification algorithms, support vector machine and artificial neural networks, were applied to form classification models for gender recognition. The obtained results showed that gender recognition with Raman spectra of teeth is possible but strongly depends both on the tooth type and spectrum recording site. The difference in classification accuracy between different tooth types and recording sites are discussed in terms of the molecular structure difference caused by the influence of masticatory loading or gender-dependent life events.

Sign in / Sign up

Export Citation Format

Share Document