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.     

Thérapie génique en traumatologie sportive : mythe ou réalité ?

Objectives. – Assessing gene therapy prospects in sport medicine.Topics. – Gene therapy speculations opened the way to many researches in the transfer of gene of interest by means of increasingly powerful vectors. The hopes in the treatment of congenital severe immunizing deficits were stopped by the perverse effects of the establishment of expression gene. Benefitting from the cellular and genetic discoveries, scientists spontaneously directed their work towards the repair of non-regenerative elements: cartilage, meniscus, tendons and ligaments. The tissue-engineering era appeared concomitantly with cellular therapy and research in genic therapy. The use of hybrid biomaterials, true support to cellular culture ex vivo, is the object of researches within many teams.Prospects. – At the moment and within short term, the cellular therapy raises the best hopes of repair of the traumatic lesions of the young and sporting subject.     

Les records de profondeur en plongée libre : réflexions d'un physiologiste

Object – to study the progression of breath-hold depth records, and to find the factors of improvement, with the help of statistical methods.Results – in the “no limits” class, the depth of records as a function of time can be alined about a straigth line, with a regular slope (2.26 m year⁻¹), but close to the “psycological depth” of 100 m. The improving of the “no limits” records fit with an increase of the mean speed from 0.9 m s⁻¹ in 1976 (no previous figure) to more than 1.5 m s⁻¹ in 1999, due to the change of the diving position head up when going down, to the position head first in every case, going down or going up; the improvement results also in a better shaping of the weigh-brake-buoy kit. We subjected these facts to statistical analysis:

• •the study checks that the depth/time relation can be represented by a straight line with an error of 14%; a graph based on a curvilinear regression of exponential form with periodicity meet better (standard deviation: 0.052); the differential ratio from the logarithmic function is then 1.7%;
• •the speed/time diagram shows a good correlation; its slope points out a speed increasing by 2.83 cm year⁻¹;
• •the analysis of variance upon the quantitative variable depth with two factors (nationality, level of number of records) leads to hightly significant results, with a small residual.

A critical study of the factors restricting the depth of breath-hold records suggests the maximal depth is not yet reached; the limits appear to be still remote.     

Une nouvelle méthode de lecture de la réaction précipitante en Médecine Légale

Sans résuméVortrag, gelegentlich der Tagung der Deutschen Gesellschaft für gerichtliche und soziale Medizin in München 1952.     

Corrélats neurophysiologiques des processus mentaux enregistrés en situation réelle par micro-capteurs non invasifs

Aims. – Objective measurement of mental processes such as emotional reactivity or variation in vigilance presents renewed interest due to its importance in sporting activities in which the general arousal level plays an important role in efficiency (shooting, weightlifting, track and fields events...). The aim is to investigate a method based on objective measurements of peripheral vegetative activity in the field.Current knowledge. – The autonomic nervous system (ANS) is strongly involved in arousal level regulation. Vegetative efferences elicit peripheral responses accompanying behavior. These autonomic responses represent non-conscious physiological mechanisms of central mental processes recorded at the peripheral level.Points of view and plans. – ANS activity is measured by non-invasive sensors associated with portable instrumentation. Three families of indicators are investigated: electro-dermal, thermo-vascular and cardio-respiratory activities. Results show high correlation between vegetative activity and mental processes.Conclusion. – This method is thus well adapted to research in sporting situations.     

Réponses du cortisol et de la testostérone salivaires au cours de la récupération post-compétitive en rugby

Aim. – In order to evaluate the biological repercussions of the post-competitive tiredness state, we measured the progress of the salivary cortisol and testosterone levels in the players of a rugby-team during the week following an international match.Results. – The results reveal a fall of the cortisol levels during the first 4 days following the competition, compared to the values measured at the same hour of a resting day. Conversely, the testosterone levels present an increase during the same period. Consequently, 5 days of recovery are needed for these two biological variables chosen as tiredness markers to return to their basic values.     

Dynamique de la locomotion en fauteuil roulant manuel : influences de la masse totale et de sa répartition antéropostérieure sur la résultante des forces de freinage

Purpose. – This study presents a new method for determining the resultant braking force during wheelchair displacement and investigates the respective effects of the level and the distribution of the system’s mass.Method and results. – A three-dimensional accelerometer was fixed directly under the seat of wheelchair and was used to measure the deceleration of the mass-and-wheelchair’s system. Three masses (50, 70 and 90 kg) were laid on a support in 3 positions corresponding to three distributions (10, 40 and 70%) of the system’s total mass upon the front casters. A series of 15 deceleration trials was performed for each of the 9 combinations. Statistical results showed that the system’s deceleration was mainly explained by the mass distribution upon the front casters (92%) and in the least by the system’s total mass (8%).Conclusion. – Considering the fore-and-aft movements of the subject’s centre of mass during wheelchair locomotion, the results of this study let us assume that the resultant braking force does not remain constant along the propulsion cycle. Moreover, the present method could be used to investigate the influence of wheelchair’s adjustments and floor’s characteristics on the resultant braking force.     

Étude des réactions du cortisol salivaire au déplacement en avion pour une équipe de rugby

Objective – The aim of this study was to check the physiological repercussions of a journey by plane for a team of Rugby players considering the variations of salivary cortisol.Subjects and Method – Thirty three players agreed to take part in the study. A group of 22 players of national up to international level (G1 group) carried out a journey of 2h30 by plane to go to a competition. A second group of 11 players (GII group) were to play a match of equivalent level and stake at the same time, but without displacement. The sampling of saliva for cortisol essays were carried after one day of rest at 8 am, 11 am and 17 pm for reference measurements. For the day of the match, the sampling for GI were effected at 7.45 am (before the departure of plane), 11 am (on arrival of plane), 17.30 pm (before warming-up, eg 30 min before the beginning of match), and 20 pm (15 min after the match). For GII, the sampling were carried out exactly at the same hours in order to eliminate the influence of the circadian rhythm.Results – There is an increase in cortisol levels at 8 am and 11 am for GI in comparison to the reference values and those measured for GII at 8 am. This seems to indicate that a journey by plane induces a stress, probably emotional. This reaction appears mainly for players declaring themselves sensitive to this type of displacement. These results allow to suppose that such a travel close to a competition is not favorable, for some subjects, to the realization of a performance. It thus appears desirable to recommend an interval of 24 hours time between displacement and the competition.