L’activité physique et sportive régulière : un déterminant des résultats scolaires au collège

ObjectiveTo measure the long-term effects of an extracurricular sports practice on the academic performances in college, according to whether this practice is regular, irregular, or absent.MethodsWe conducted a prospective cohort study, which has included all of the pupils entering the first year of secondary school (sixth grade) in the Vosges department (East France) during the school year 2001–2002 and followed during four years. Data were collected every six months by self-reported questionnaires.ResultsOne thousand four hundred and eleven pupils were present at each of the data collection sessions and completed all the questionnaires, representing 54.4% girls, initially aged 12.7 ± 0.6 years (average ± S.D.). On the whole, 13.8% never practised sport except physical education, 44.7% always practised an extracurricular sport and 41.5% did some from time to time. The reported school results are higher among regular athletes (P < 0.001). It is the regularity more than the number of hours per week, which explains this difference.ConclusionPractice of a physical activity by adolescents would deserve being largely encouraged, taking into account its beneficial effects not only on health, but also on academic performances. Parents and teachers, as well as health professionals, should be strongly informed.     

Électromyostimulation et récupération fonctionnelle d’un muscle dénervé

Aim. – The purpose of this revue is to focus on research concerning the effect of chronic muscle electrical stimulation after denervation and reinnervation.Actuality. – The therapeutic use of electricity date back to ancient times, when the greeks used electric eels to treat physical ailment. Today electrotherapy is very commonly applied by certified athletic trainers. Alpha motor neurons conduct impulses from the spinal cord to the muscle. When the conduction of impulses to muscle is disrupted, the individual loses control of the affected muscle. When the nerve to the muscle is not functioning, the muscle is denervated, or without innervation. Unlike nerve fibers in the central nervous system, peripheral nerve fibers can regenerate and active control of the muscle can be restored.Perspectives and projects. – The efficacy of electrical stimulation of denervated muscle has not been established in human. Electrical stimulation does not bring about reinnervation; however a regularly stimulated muscle may recover force-generating capacity sooner if reinnervation occurs. In mammals, it has been show since several years that the regular stimulation of a denervated and reinnervated muscle promoted the motor function return. Recently, it has also been observed in animals, that muscle stimulation with a biphasic current was responsible to a more rapid return of the muscle sensibility. However, these preliminary works realized in the young mammals need to be improved.