Effects of two types of fatigue on the VO(2) slow component.

The aim of the study was to test the hypothesis of the involvement of type II fibres in the V.O (2) slow component phenomenon by using two prior fatiguing protocols on the knee extensor muscles. Nine subjects performed three constant-load cycling exercises at a work rate corresponding to 80 % of their V.O (2) max: (i) preceded by a 20-min fatiguing protocol using electromyostimulation (EMS), (ii) preceded by a 20-min fatiguing protocol using voluntary contractions (VOL), and (iii) without fatiguing protocol (NFP). Voluntary and evoked neuromuscular properties of the knee extensor muscles were tested before (PRE) and after (POST) the two fatiguing protocols. Results show a significant reduction in voluntary force after both fatiguing protocols (-19.9 % and -11.8 %, in EMS and VOL, respectively p<0.01). After EMS, this decrease was greater than after VOL (p<0.05) and was combined with a slackening of muscle contractile properties which was absent after VOL (p<0.05). Regarding the effects on oxygen uptake kinetics, the appearance of the slow component was delayed after EMS and its amplitude was lower than those obtained in VOL and NFP conditions (0.48+/-0.07 vs. 0.75+/-0.09 and 0.69+/-0.08 L . min (-1), respectively; p<0.05). It can thus be concluded that exercises dedicated to preferentially fatiguing type II fibres may alter V.O (2) kinetics.

(.)VO(2) and EMG activity kinetics during moderate and severe constant work rate exercise in trained cyclists.

The purpose of this study was to compare O(2) uptake ((.)VO(2)) and muscle electromyography activity kinetics during moderate and severe exercise to test the hypothesis of progressive recruitment of fast-twitch fibers in the explanation of the VO(2) slow component. After an incremental test to exhaustion, 7 trained cyclists (mean +/- SD, 61.4 +/- 4.2 ml x min(-1) x kg(- 1)) performed several square-wave transitions for 6 min at moderate and severe intensities on a bicycle ergometer. The (.)VO(2) response and the electrical activity (i.e., median power frequency, MDF) of the quadriceps vastus lateralis and vastus medialis of both lower limbs were measured continuously during exercise. After 2 to 3 min of exercise onset, MDF values increased similarly during moderate and severe exercise for almost all muscles whereas a (.)VO(2) slow component occurred during severe exercise. There was no relationship between the increase of MDF values and the magnitude of the (.)VO(2) slow component during the severe exercise. These results suggest that the origin of the slow component may not be due to the progressive recruitment of fast-twitch fibers.

Les événements de la vie et le bien-être dans la grande vieillesse

Après 80 ans, les événements qui jalonnent la vie signifient la plupart du temps des pertes de quelque chose ou de quelqu'un. Sur la base de certains résultats obtenus dans le cadre de la recherche SWILSO-0, les auteurs nt quelques résultats concernant les effets à court et à moyen terme des événements sur le bien-être des aînés. Ils mettent l'accent sur les conséquences des événements sur le bien-être et l'identité psychosociale, ainsi que les processus qui permettent le cas échéant de réguler ces conséquences.

La liberté d'expression du whistleblower: Cour européenne des droits de l'homme (Grande Chambre), Guja c. Moldova, 12 février 2008

Pour la première fois, le 12 février 2008, la Cour européenne des droits de l'homme a consacré une forme de protection pour les "whistleblowers". La Cour a ainsi condamné la Moldavie pour atteinte à la liberté d’expression d’un fonctionnaire licencié pour avoir communiqué à la presse un document confidentiel : une dénonciation aux médias peut exceptionnellement intervenir lorsque la dénonciation au supérieur hiérarchique ou à une autorité publique compétente semble impossible ou vouée à l'échec. L'arrêt Guja c. Moldova énonce plusieurs critères destinés à encadrer la démarche du whistleblower. Plusieurs questions importantes demeurent cependant ouvertes.