Effets d'un réentraı̂nement à l'effort réalisé au seuil ventilatoire chez l'insuffisant cardiaque

Objectives – Study was to assess the effects of exercise training at the ventilatory threshold on exercise tolerance and quality of life in subjects with chronic heart failure.Methods and results – Nine subjects with moderate chronic heart failureperformed: a maximal exercise test and a six-minute walk test and responded to a quality of life questionnaire, both before and after the training program. The exercise training consisted of 46 minutes of cycling, three times per week, for eight weeks, and the exercise intensity was the heart rate at the ventilatory threshold ±5 beats/min. The results showed that exercise training at the ventilatory threshold improves exercise tolerance (maximal and submaximal) and quality of life in subjects with chronic heart failure. These training benefits were very satisfactory compared with other results in the literature.Conclusion – An individualized exercise intensity set at the ventilatory threshold ensures optimal benefits of exercise training in subjects with chronic heart failure.     

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.     

Le surentraînement : à la recherche d’un outil d’évaluation standardisé utilisable en routine

Aim. – To develop and to validate a simple system of evaluation of the syndrome of overtraining.Synthesis of facts. – The French questionnaire of the “Société Française de Médecine du Sport” for detection of early signs of overtraining has undergone intensive methodological investigations, demonstrating its reproducibility and sensitivity. A multicentric study has been performed. It is easy to employ and the risk of misunderstanding is low. It can be used in follow-up studies and is correlated with biological markers. Actually its score is increased by both training and overtraining, so that the cut-off value between physiology and pathology remains elusive. However, values higher than 20–25 may reflect overreaching or overtraining or a situation at risk for them. Differential diagnosis with depression, eating disorders, of lack of sincerity due to external influences are not likely to induce misinterpretations if the clinician is aware of these possibilities.Conclusion. – This questionnaire remains a subject of research but appears to be suitable for clinical practice.     

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.     

Réponses du réseau capillaire du muscle squelettique à l’entraînement

Objectives – There are now experimental evidences about the growth of capillary bed in response to increased functional load in skeletal muscle such as physical exercise. The objective of this review is to discuss the present state of our knowledge on the adaptive responses of the capillary bed to physical training.Topics – The skeletal muscle is known to respond to physical training and the adaptive response of the microcirculation in mammals is the high capillarity observed in trained skeletal muscles. The increase in the capillary bed after endurance training results mainly from angiogenesis, and only for a short part from changes in the capillary tortuosity. Capillary growth involves several molecular factors ; some are expressed and induced by alterations in local oxygen pressure. The specific role played by mechanical factors and shear stress for capillary growth stimulation remains the matter of debate.Future prospects – A better knowledge of molecular mechanisms involved in capillary growth is an important stage to examine the general responses to physical training. Researches on exercise-induced capillary growth have many important practical consequences, especially on therapeutic domain.