G Serratrice Les organisateurs de ce symposium en ont choisi le titre: " Syndrome de fatigue chronique ", titre dont chacun des termes doit etre defini avec precision, ce qui, paradoxalement, n'est pas aise. Syndrome: ensemble de symptomes ou de signes s'observant dans des etats pathologiques differents mais ne determinant pas a eux seuls la cause de la maladie. Fatigue: symptome plus ou moins exprime, moteur, intellectuel, sensoriel, sexuel selon les cas. Mais aussi signe traduit par l'incapacite a maintenir une force initiale pendant un effort continu. Ceci separe la fatigue de la faiblesse, qui est l'incapacite a produire une force. Stricto sensu, l'asthenie et la fai- blesse sont equivalentes. Mais l'usage, tout au moins en France, fait souvent confondre asthenie et fatigue. Chronique enfin. C'est sans doute sur cet adjectif que s'accumulent les plus grandes ambiguites. La simple lecture du programme d'aujour- d'hui indique la difficulte de se situer entre une definition stricte - chronique signi- fiant " permanent ", " qui dure " - et l'usage, surtout dans l'acception anglo-ameri- caine, qui reserve l'appellation de chronique a une forme particuliere de fatigue, parfois dite post-virale. En fait, il convient, pour une claire comprehension, de sepa- rer ce que l'on pourrait nommer les etats de fatigue chronique " determines " dans leur mecanisme et ceux qui restent " indetermines ". A l'evidence, les etats dont le mecanisme est determine sont tres diversifies.

The main themes presented in this volume are exercise intolerance and muscle contracture. These two topics could seem different at first sight but share common clinical features. For instance, symptoms of exercise intolerance are myalgias and cramps but metabolic contractures as well. Likewise exercise intolerance is sometimes due to dystrophinopathy, it self causing contractures. Therefore, it is justified to gather these two syn dromes in one study. Exercise intolerance and muscle contracture could seem well known, even obsolete. It is not right. A reappraisal of these has be come necessary for two reasons. First of all there are many new causes of exercise intolerance; secondly, the pathophysiology remains ob scure in particular for muscle contracture and a clear classification is probably possible. There is no book devoted to exercise intolerance and muscle contrac ture. This volume is divided in two parts related to the above topics. The two sections are introduced by a didactic and general overview, describ ing the main symptoms, classification and classical etiology. The other chapters, written by the best experts, present the recent advances in these syndromes and show many new aspects: new glycogenosis or mitochondriopathies, dystrophinopathies, malignant hyperthermia, my otonic disorders. Pathophysiology and classification of persistent con tractures are described as well as therapy. Each chapter is thoroughly referenced, representing important progress in research in the field."