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).     

Évolution de la puissance maximale anaérobie au cours de la croissance chez le footballeur

Purpose – The aim of the study was to assess the improvement in Maximal Anaerobic Power (PMAna) from two tests in soccer players during growth.Methods – The experiment was carried out in 328 players, 11–18 years old, during their stay at the Clairefontaine National Soccer Center. PMAna was measured from the last 10 meters of the a 40 m-sprint test (ST) and a jump test (JT). The skeletal age (AO) is used as reference, and not the chronological one.Results – The results of the two tests are highly correlated (r= 0.8–0.9), PMAna values being always higher in the ST than in the JT.The most significant increase in PMAna occurs between 13 and 14 years AO (+47% for the ST, +27% for the JT), remains still significant up to 16 AO (respectively +38% and +24% between 14 and 16 AO), but the maximum value is reached at 17 AO. Between 12 and 16 AO, the PMAna value is multiplied by 2.29 for the ST and 1.81 for the JT.Conclusions – Sprint and jump tests seem well adapted to estimate PMAna in soccer players. The measure of the skeletal age during growth is needed for a better interpretation of the results. In addition, results obtained during growth allow a reliable estimation of PMAna in adulthood.     

Effet d'un interval-training supra-maximal sur l'apparition d'une hypoxémie d'exercice chez des sportifs non-spécialistes de l'endurance

Highly trained sportsmen and sportswomen in endurance may present exercise-induced hypoxemia (EIH). The aim of this investigation was to determine whether a 8 week interval training period may induced EIH in low trained athletes.Results – After training, in a population of 24 subjects, 7 presented a mild or moderate EIH, 7 presented a light EIH and 10 did not present EIH during a progressive and maximal running test.Conclusion – It seems that after a relative short period of training, EIH may appear in athletes in spite of moderate maximal O₂ consumption.     

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.     

Estimation de la dépense énergétique lors d'une régate en dériveur

Introduction. – Assess the energetic cost during small craft competition.Methods. – Height healthy sailors have been tested during three regattas. Heart rate, vertical jump, glycemia, cortisol and testosterone have been recorded.Results and discussion. – Regattas did not show significant difference for hormones. However, a significant 10% decrease of glycemia was presented. Heart rate increased during competition, but it was different according to the wind velocity and wind direction. The oxygen cost of sailing is relatively light. However, this cost could be increase with bad conditions of sailing. It seems that aerobic capacity is important regarding performance.