Variabilité de la fréquence cardiaque en fonction de l'intensité de la pratique physique chez la femme ménopausée

Aim. – Study was to asses the heart rate variability related to the physical practice intensity in post menopausal women.Method. – Time domain measurement of heart rate variability has been realised from the electrocardiogram at rest and during exercice in 3 groups of 6 women : untrained, active and trained. At rest, no significant difference betwen groups appears. But, in the standing position, RR interval and the dispersion around RR interval decrease in trained group only. During submaximal exercise, this dispersion is more elevated in active and trained groups.Conclusion. – Physical practice induces a higher response of sinus node to vagal modulation during standing position and submaximal exercise.     

La résistance cutanée comme indice objectif de la concentration au lancer de poids

Aims – Rules of track and fields events allow subjects to prepare themselves before throwing. As time allocated to preparation was two minutes, it has been reduced to one minute. The aim of this study was to test whether preparation duration decrease had an effect on subjects activation and on performance in shot put.Materiels and methods – Subjects were divided into two groups: beginners and experts. Each subject had to perform seven throws in i) throwing with preparation within the minute allowed ii) without preparation iii) mental representation. Skin resistance tonic level was continuously recorded during the experiment. This autonomic variable is well-known to be a reliable index in predicting activation variations.Results – No difference in performance between the preparation and no-preparation modalities is showed. All the subjects did not reach the same activation during the mental imagery. Activation was shown to be higher in novice than in expert population. However, differences in activation between throwing with and without preparation did not reach the significant threshold. These results suggested that decrease in preparation duration did not affect performance. Subjects were shown to increase their activation themselves rapidly. Performance seems to be mainly dependent upon execution quality rather than reaching an optimal activation level. Motor program of throwing is thought to be rapidly intialised by subjects whatever their practice level.Conclusion – Differences have been evidenced between real trials and mental imagery, both, in movement sequences duration and in activation. If the subjects are not training in the mental imagery, the imagery ability improve with the expertise level.     

Effet de l’intensité de course sur la force de poussée en rugby

Introduction. – The rugby is a discipline requiring, in the same time, strength qualities and a high aerobic capacity for repeating intense exercises over 2 × 40 min.Synthesis of the facts. – Fourteen rugby players performed a maximal progressive test of journey (running) then two sequences of 40 min, respectively, to 60% and 80% of HR_max, interrupted with pushes on a yoke with constraint gauges. At 80% HR_max, the mean scrummaging force (1466 ± 244 N) was lower (P < 0.05) than at 60% HR_max (1523 ± 266 N).Conclusion. – The qualities of specific force are directly affected by the intensity of running. Therefore, there is a need to optimize the aerobic potential notably for the players of the first line directly concerned by the fight.     

Effet de la course d’endurance et/ou des isoflavones sur la masse osseuse de la rate castrée

Aim – To study the effects of endurance running (15 m/min during 20 min/day to 28 m/min during 1 h/d, 6 days/week during 12 weeks, corresponding to 62% of the VO₂ max of the animals) or of a treatment by isoflavones (Soylife 100 : 400 μg j^–1 g^–1 of body weight during 12 weeks), either only or cumulated with running, on the osteopenia induced by castration in adult female rat.Results and discussion – Each one of these two treatment has a protective effect of the bone mineral density at the femoral total, diaphysaire and metaphysaire level. But contrary to what had been reported on the cumulated effects of long term endurance running and of a 17β-estradiol treatment 〚3〛, we did not note any additive effect of these two treatments.     

Etude Comparée de certains aspects de la conservation des tomates de la variété “Pantano” suivant des irradiations gamma effectuées à des stades successifs de maturation

The paper discusses some—so far neglected—aspects of the radio-conservation of tomatoes. It deals with the results of a recent irradiation experiment made with tomatoes of the Pantano variety,— a variety foreseen for consumption in fresh state. Several parameters have been analysed: evolution of fruit decay, loss of weight, progressive ripening, vitamin C content, variation of pH, acidity, per cent of sugars and resistance to penetration. The results show that the irradiations hardly modify the technological characteristics and the nutritional constituents—in particular the vitamins—of the tomatoes, whereas they have a negative effect on resistance to penetration and on decay.