Step-to-step reproducibility and asymmetry to study gait auto-optimization in healthy and cerebral palsied subjects

AbstractObjectiveThe purpose of our study was to compare plantar pressure asymmetry and step-to-step reproducibility in both able-bodied persons and two groups of hemiplegics. The relevance of the research was to determine the efficiency of asymmetry and reproducibility as indexes for diagnosis and rehabilitation processes.Material and methodThis study comprised 31 healthy young subjects and 20 young subjects suffering from cerebral palsy hemiplegia assigned to two groups of 10 subjects according to the severity of their musculoskeletal disorders. The peaks of plantar pressure and the time to peak pressure were recorded with an in-shoe measurement system. The intra-individual coefficient of variability was calculated to indicate the consistency of plantar pressure during walking and to define gait stability. The effect size was computed to quantify the asymmetry and measurements were conducted at eight footprint locations.ResultsResults indicated few differences in step-to-step reproducibility between the healthy group and the less spastic group while the most affected group showed a more asymmetrical and unstable gait.ConclusionFrom the concept of self-optimisation and depending on the neuromotor disorders the organism could make priorities based on pain, mobility, stability or energy expenditure to develop the best gait auto-optimisation

How can video feedback be used in physical education to support novice learning in gymnastics? Effects on motor learning, self-assessment and motivation

Background: Much of the existing research concerning the use of video feedback (VFB) to enhance motor learning has been undertaken under strictly controlled experimental conditions. Few studies have sought to explore the impact of VFB on the skill learning experience of the students in a structured, school-based physical education (PE) setting. Most of those studies have only used qualitative approaches to implicate the potential value of VFB to enhance skill acquisition, students ’ engagement or self- assessment ability. Using a quantitative approach, the aim of this study was to investigate effects of using VFB on motor skill acquisition, self- assessment ability and motivation in a school-based learning environment (structured PE programme) with novice children learning a gymnastic skill. Method: Two French classes of beginners took part in a typical five-week learning programme in gymnastics. During each of the five, weekly lessons participants carried out the same warm-up routine and exercises. The experimental group (10 girls – 8 boys, 12.4 ± 0.5 years) received VFB intermittently when learning a front handstand to flat back landing. VFB was given after every five attempts, combined with self-assessment and verbal instructions from the teacher. The control group (12 girls – 13 boys, 12.6 ± 0.4 years) received exactly the same training but was not given VFB. In order to assess progress in motor skills, the arm-trunk angle (hand- shoulder-hip) was measured in the sagittal plane just as the hips formed a vertical line with the shoulders. Motivation was assessed using the Situational Motivation Scale questionnaire (Guay, F., R. J. Vallerand, and C. Blanchard. 2000. “ On the Assessment of Situational Intrinsic and Extrinsic Motivation: The Situational Motivation Scale (SIMS). ” Motivation and Emotion 24 (3): 175 – 213), and self-assessment ability was measured by self-perception task scores. Results: Statistical analysis of arm-trunk angle values showed significant differences only for the VFB group between the fifth lesson and all other lessons. Between lessons 4 and 5, the arm-trunk angle value increased significantly from 146.6 ± 16.9 degrees to 161.2 ± 14.2 degrees ( p < .001; ES = 0.94). Self-assessment scores improved significantly for the VFB group between lesson 1 and lesson 2 ( p < 0.01, ES = 1.79) and between lesson 4 to lesson 5 ( p < .01, ES = 0.94). Amotivation decreased significantly for the VFB group between lesson 1 and lesson 5 (3.06 ± 1.42 vs. 2.12 ± 0.62, p < .001, ES = − 0.89). Discussion/conclusion: Our quantitative data, identifying key movement changes as a function of experience in a structured PE programme, were congruent with outcomes of previous qualitative research supporting the role of VFB. This study highlights the potential relevance of using VFB in fostering motor learning, motivation and self-assessment during a PE programme with young children. Future pedagogical research is needed to examine the ways students could use VFB technology for greater self- regulation, with the potential to deliver appropriate movement feedback, based on different levels of experience in students

Nanocrystalline lanthanide-doped Lu3Ga5O12 garnets: interesting materials for light-emitting devices

Nanocrystalline Lu3Ga5O12, with average particle sizes of 40 nm, doped with a wide variety of luminescent trivalent lanthanide ions have been prepared using a sol\u2013gel technique. The structural and morphological properties of the powders have been investigated by x-ray powder diffraction, high resolution transmission electron microscopy and Raman spectroscopy. Structural data have been refined and are presented for Pr3+, Eu3+, Gd3+, Ho3+, Er3+ and Tm3+ dopants, while room temperature excited luminescence spectra and emission decay curves of Eu3+-, Tm3+- and Ho3+-doped Lu3Ga5O12 nanocrystals have been measured and are discussed. The Eu3+ emission spectrum shows typical bands due to 5D0 \u21927FJ (J = 0, 1, 2, 3, 4) transitions and the broadening of these emission bands with the non-exponential behaviour of the decay curves indicates the presence of structural disorder around the lanthanide ions. Lanthanide-doped nanocrystalline Lu3Ga5O12 materials show better luminescence intensities compared to Y2O3, Gd3Ga5O12 and Y3Al5O12 nanocrystalline hosts. Moreover, the upconversion emission intensity in the blue-green region for the Tm3+- and Ho3+-doped samples shows a significant increase upon 647.5 nm excitation with respect to other common oxide hosts doped with the same lanthanide ions

Quantitative wave-optical numerical analysis of the dark-field signal in grating-based X-ray interferometry

Here we report a full wave-optical numerical simulation framework that quantitatively predicts the outcome of grating-based X-ray dark-field imaging experiments on an ensemble of sub-pixel spherical scatterers. We particularly show how the behavior of the dark-field imaging signal differs from and complements the conventional X-ray transmission imaging signal when certain sample parameters, such as the size, number, and total volume of sub-pixel spherical substructures are changed and compare our findings to previous experiments and theoretical work. We believe that this work represents an important step in further understanding and applying the dark-field signal for future advanced X-ray imaging applications in medicine, materials science, and non-destructive industrial testing

Synthesis and characterization of chromium-doped Yttrium Aluminum Garnet crystals by Pechini and co-precipitation.

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Modèle de compaction élastoplastique et viscoplastique pour simulateur de bassins sédimentaires

Cette étude complète un travail antérieur (Schneider, 1993) qui a permis d'interpréter et de formaliser le modèle de compaction classiquement utilisé dans des simulateurs comme Temispack (Doligez et al, 1986; Ungerer et al. , 1990). Le nouveau modèle présenté ici se distingue du précédent par l'introduction d'une composante viscoplastique dans l'équation qui décrit la compaction. L'ajout de cette composante permet de prendre en compte de façon macroscopique les phénomènes visqueux de la compaction comme la pression-dissolution. En utilisant des valeurs de coefficients de viscosité extrapolées à partir d'expériences de laboratoire, une étude de sensibilité montre que la déformation visqueuse est significative pour des bassins vieux de plus de 1 Ma. Certains tests montrent que le coefficient de viscosité peut être calibré simplement à partir de données de puits et d'expériences simples de laboratoire. À partir de données extraites de la littérature, il a été possible de calibrer un coefficient de viscosité de 2,5 GPa. Ma (= 8 x 10 puissance (22) Pa. s) pour la craie

Lead-free manganese based perovskite inspired metal halides: from synthesis to (micro)-LED application.

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Elaboration of multiscale nanostructured luminescent coatings by combining ZnO nanowires and Y3Al5O12:Ce3+ luminescent coatings.

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