Determination of Neuromuscular Control of the Upper Limbs in Children - Case Study

The objective of this case study is to observe the existence of an anticipation mechanism at the muscle groups level of the upper limbs. We tried to highlighted this anticipation process by measuring the potential of surface electric for some muscle groups representing the kinematic chain on the right side, involved in the motor action of catching a basketball and a 3kg medicine ball with two hands to the chest. We conducted a case study of a 13-year-old child, female gender. As a measurement method, we used surface electromyography signals of the EMG Trigno Delsys wireless system with 16 electrodes. We determined the moment when the muscles come into action by increasing the potential of surface electric and the moment when the action of catching the ball takes place, using the information provided by the accelerometers incorporated in the sensors of the Delsys equipment used. Therefore, we obtained information about how different muscle groups come into action which helped us to get an idea of how the child's movement is structured. Based on results of accelerations and EMG signals acquired we have formulated conclusions regarding the neuromuscular control of the tested subject. We also planned for the future to test a larger group of participants in the study research of anticipation mechanism in children who do not practice any performance sports.</strong

Physical activity, screen time and the COVID-19 school closures in Europe – an observational study in 10 countries

To date, few data on how the COVID-19 pandemic and restrictions affected children’s physical activity in Europe have been published. This study examined the prevalence and correlates of physical activity and screen time from a large sample of European children during the COVID-19 pandemic to inform strategies and provide adequate mitigation measures. An online survey was conducted using convenience sampling from 15 May to 22 June, 2020. Parents were eligible if they resided in one of the survey countries and their children aged 6–18 years. 8395 children were included (median age [IQR], 13 [10–15] years; 47% boys; 57.6% urban residents; 15.5% in self-isolation). Approximately two-thirds followed structured routines (66.4% [95%CI, 65.4–67.4]), and more than half were active during online P.E. (56.6% [95%CI, 55.5–57.6]). 19.0% (95%CI, 18.2–19.9) met the WHO Global physical activity recommendation. Total screen time in excess of 2 h/day was highly prevalent (weekdays: 69.5% [95%CI, 68.5–70.5]; weekend: 63.8% [95%CI, 62.7–64.8]). Playing outdoors more than 2 h/day, following a daily routine and being active in online P.E. increased the odds of healthy levels of physical activity and screen time, particularly in mildly affected countries. In severely affected countries, online P.E. contributed most to meet screen time recommendation, whereas outdoor play was most important for adequate physical activity. Promoting safe and responsible outdoor activities, safeguarding P.E. lessons during distance learning and setting pre-planned, consistent daily routines are important in helping children maintain healthy active lifestyle in pandemic situation. These factors should be prioritised by policymakers, schools and parents. Highlights • To our knowledge, our data provide the first multi-national estimates on physical activity and total screen time in European children roughly two months after COVID-19 was declared a global pandemic. • Only 1 in 5 children met the WHO Global physical activity recommendations. • Under pandemic conditions, parents should set pre-planned, consistent daily routines and integrate at least 2-hours outdoor activities into the daily schedule, preferable on each day. Schools should make P.E. lessons a priority. Decision makers should mandate online P.E. be delivered by schools during distance learning. Closing outdoor facilities for PA should be considered only as the last resort during lockdowns

Comparaison des deux systèmes de capture du mouvement Vicon et Moven

International audienceL'objectif de cette étude biomécanique est d'une part la comparaison des deux systèmes capture du mouvement Vicon et Moven et d'autre part d'analyse de l'influence de la masse du poids (6,26 vs 7,26 kg) sur les paramètres cinématiques du mouvement du lancer du poids. La comparaison de la cinématique du poids a montré l'absence d'altération significative du geste de lancer lors de l'utilisation d'un poids léger chez les lanceurs experts : l'évolution de la norme de la vitesse du disque au cours des 5 phases, n'est pas significativement modifiée par la masse de l'engin. En conséquence, ces résultats suggèrent qu'un poids plus léger pourrait être employé pour l'entraînement des athlètes de haut niveau sans dégradation cinématique du lancer. La comparaison des données pour un même jet réalisé simultanément avec les deux systèmes Vicon-Moven montre:-un même profil pour le début et la fin du mouvement mais pas les mêmes valeurs de vitesse.-l'opposition de phase observé aux étapes intermédiaires du mouvement pour la vitesse n'est' elle pas, en fait, un décalage computationnel? Causes probables:-l'algorithme utilisé pour le calcul logiciel;-traitement spécifique du signal (lissage, filtrage);-interférences magnétiques avec d’autres appareils présentes sur le lieu de l’expérimentatio