Fréquence cardiaque chez des adolescents âgés de 11 à 16 ans lors de séances d'éducation physique intensifiées

Introduction – Exercise physiologists notice sometimes that Physical Education (PE) sessions are lacking of intensity. This lack of intensity would not allow obtaining desired physiological responses. Thus, we measured heart rate (HR) in adolescents (boys and girls) aged 11–16 years old during intensified EP lessons.Method and results – Sessions consisted in short intermittent running (G1) and jumping exercises (G2). Heart rate was averaged over 30 min. There was no significant difference between mean HR for G1 and G2 (154±12 vs 155±12 bpm, p<0.001). Nevertheless, for both G1 and G2, mean HR was significantly higher for girls than for boys (153±12 vs 156±12 bpm, p<0.001).Conclusion – This type of intensified lessons request at a high level adolescents HR (75.4±5.4% of maximal HR) to reach health objectives.     

Infections ORL,immunodépression et stress liés à la pratique des activités physiques et sportives

Objectives – Understand the pathophysiology of upper respiratory tract infections (URTI), the most common ailment of elite athletes.Actualities – URTI likely develop as a consequence of local or systemic immunosuppression. Such a lowered protection may result both from training and from the stress associated to competitive sports. This literature review summarises the physiology of the immune system associated to the upper respiratory tract, then presents evidence supporting the impact of stress and training respectively on the immune system.Perspective – Better knowledge of the impact of high-level sport on the immune system may allow to adapt training and competition in order to avoid or limit the immunosuppression leading to an increased susceptibility to infections.     

Influence de la pratique sportive intensive et précoce sur l'âge à la ménarche dans une population de femmes Congolaises

Aim – Evaluation of intensive and early sports (before puberty) influence on the first menstruation's (menarche) upcoming in African subjects.Methods – The age of menarche (AMC) is obtained by a standard recall method on a population of 399 young women from Congo-Brazzaville. They are 20 to 30 years old and are divided in three groups: (1) 111 handball players having started training before menarche, 50 of them being of high national and international sport levels players (AH-pre), and 61 of them competing in local and academic leagues (AS-pre); (2) 74 handball players as a control group having started training after menarche, including 24 players of high sport levels (AH-post) and 50 others competing in academic leagues (AS-post); and (3) 214 sedentary young women (SYW). The averages are compared with the help of a one way variance analysis test (ANOVA) followed by a Fisher PLSD post-hoc multi-comparison test. The level of significance is set at p < 0.05.Results – The average AMC is not significantly different when looking at AH-post (13.88 ± 1.33 years) and AS-post (13.94 ± 1.3 years), and when considering each of them with SYW (13.92 ± 1.3 years). However these three groups show an average AMC significantly lower (p < 0.0001) than the ones of AH-pre (15.36 ± 1.57 years) on one hand and of AS-pre (14.74 ± 1.06 years) on the other hand. Furthermore there is a significant difference between these two latter groups (p < 0.05).Conclusions – AMC is delayed in the group of women having started sports before puberty, and the higher the level of competition is reached, the more AMC is delayed. This result can be explained by a possible sampling factor that would make these women a menarche's group subjects of late nature, but this theory is excluded. The hypothesis of a menarche's selection in elite sport subjects is also excluded. These results therefore confirm the effect of sports on puberty in a population of African women.     

Réentraı̂nement des bronchiteux chroniques obstructifs supplémentés en acides aminés ramifiés

Introduction – The aim of this work was to establish if it is possible to improve the efficacy of retraining on rehabilitation of patients suffering from chronic obstructive bronchitis, by oral supply in branched-chain aminoacids.Synthesis of facts – Thirty retrained patients with chronic obstructive bronchitis were supplied in branched-chain aminoacids and matched with 30 retrained witnesses (identical patients) without additional supply in branched-chain aminoacids. The two groups improved their reached maximal power and their VO₂SL. Only the supplied patients improved their PaO₂ at rest highly significantly, and developed hypocapnia expressing a gaseous alkalosis. The discussion of the responsible mechanism leads to favour the hypothesis of a direct action of branched-chain aminoacids on the respiratory centres. This observation could have practical outcomes.Conclusion – it should be useful to systematically supplement the patients with branched-chain aminoacids during their retraining in order to obtain a more effective improvement of their respiratory function.     

Évaluation des masses musculaires et des densités osseuses régionales chez des kayakistes de haut niveau

Aim. – To determine the body composition and bone densities in elite teenagers kayak paddlers.Materials and methods. – The population consisted of 14 boys (seven kayak paddlers and seven controls). The training frequency of kayak paddlers was 10 h/week when the control group had less than 4 h/week of physical activity. The body composition and bone density were measured by DXA.Conclusion. – The intensive kayak training seems to improve lean body mass and bone density at the specific sites involved in this activity (arms, trunk).     

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.