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.     

Peut-on encore améliorer la méthodologie des épreuves d’effort maximales pour un suivi longitudinal plus informatif de la filière énergétique aérobie ?

Introduction  – The aim of this work was in a first time to propose the validation of the concept of fractional uses of reserves (Fu r) and especially, in a second time to test the pertinence of this concept in the appreciation of the possible effects of training on aerobic endurance.Synthesis of facts – The first set regrouped 89 athletic males (49 endurance sportsmen and 40 team sportsmen) with aerobic endurance clearly different. The second set reassembled 27 sportsmen of all disciplines in the course of a period of endurance training.Conclusion – The Fu r of the three magnitudes (HR–W–VO₂) selected provides effectively submaximal indices of aerobic endurance. Fu r to VT₁ and to R = 1,00 appear as excellent indicators of aerobic endurance, particularly for VT₁, the Fu r follow the long-term evolution of aerobic endurance on several years. Fu r to R = 1,00 (HR–W–VO₂) and to VT₂ (HR and W but not for VO₂) appear, for a sportsman’s longitudinal follow up, as indicators of variation of the aerobic endurance in response to training during the course of a sports season.     

Cinétique du cortisol et de l'hormone de croissance plasmatiques lors de deux épreuves sous-maximales avec et sans récupération

Introduction – The purpose of this study is to evaluate cortisol and growth hormone kinetics in plasma during a sub-maximal exercise with and without recovery.Results – There is a significant difference of cortisol and growth hormone kinetics between the two tests. The cortisol concentration increased significantly during exercise without recovery period, the changes of plasmatic cortisol were not significant during exercise with recovery. Plasmatic growth hormone increases after exercise without recovery.Conclusion – The absence of recovery period contributes to increase considerably the level of cortisol and growth hormone in plasma and decreases probably anabolic process in post exercise period.     

Estimation de la contribution énergétique d'origine aérobie et anaérobie et de sa répartition au cours d'un 800 m couru sur le mode compétition

Aim – Determine the part of each energetic system at different times of 800m competition. Oxygen uptake and speed were recorded continuously.Materials and methods – Five athletes performed on an outdoor track a test to determine the maximal oxygen uptake and the maximal aerobic speed and a supramaximal exercise of 800m.Results – The overall energetic expenditure as well as the oxygen deficit assessed at 31.9% were almost identical at those obtained during an 800m race running on a treadmill. Only the repartition of the oxygen deficit notably differed during the race. This suggered that the kinetic of the speed had a determining incidence on the anaerobic contribution as well as aerobic contribution when there were changes in running velocity.     

Approche électromyographique de la fatigue musculaire

Aims – The aim of this study was to examine the effect of an external apport of protein after a tiring exercise. Surface electromyography was used to evaluated muscular activity.Methods and results – The subjects were lied on the back and performed 3 sets (2 of 10 repetitions and 1 of 5) isometric contraction of the leg during 20 s. Bipolar surface electromyography (EMG) was used to assess the level of electrical activity for vastus lateralis (VL) at 1000 Hz. Integrated electromyography (EMGi) and mean power frequency (MPF) were calculated using the raw signal collected throughout the entire phases. The linear increase of the EMGi was very significant (p<0.001), is associated with an increase in fiber recruitment and/or motor neurone firing rates.Conclusion – The study show the interest for electromyography to approximate the muscular activity and particularly muscular fatigue.     

L'enfant diabétique à l'exercice : étude multiparamétrique

Methods and results – A multiparametric study was realised on insulinodependant diabetic children (n=11) and on control children (n=24) during linear incremental test on ergocycle, normalised with respect to their own maximal aerobic power. It consist in quantifying electromyographic signal of quadriceps muscle (total energy and mean power frequency of the signal), and cardiorespiratory variables (maximal oxygen consumption, heart rate) and metabolic variables (glycemia, lactatemia). Results showed no significant difference of cardiorespiratory changes and significant difference with metabolic changes between diabetic or control children. Changes in electromyographic variables exhibit different profiles between children but not between groups. A discriminant analysis realised on the set of mean power frequency profiles showed difference between diabetic or control children.Conclusion – Thus, electromyographic changes allowed to characterise exercise aptitude for diabetic children.     

Imagerie de la trachée de l'adulte

Imaging of normal and pathologic trachea at the thoracic and cervical levels is described extensively. Beside congenital abnormalities discovered in adulthood, acquired tracheal abnormalities are artificially divided in two subgroups. One group consists of diffuse abnormalities, with all but one diseases associated with a diffuse narrowing of the tracheal lumen. The other group comprises focal abnormalities that lead to tracheal stenoses of various lengths, with a postintubation stenosis as probably the most frequent cause, followed by tumours. The main modality for tracheal imaging is now multidetector-row spiral CT. This technique allows for faster volume coverage and higher spatial and temporal resolution. The improved spatial resolution impacts on both axial images and all reconstructions techniques that have become indispensable for interpretation of a vertical structure such as the trachea. Chest X-ray is no longer the frontline imaging technique. MRI has not yet reached all its potential as compared to CT.