The IV International Congress of Trail Running, organized by the Servei d'Esports of the Universitat Jaume I and the 5th International Congress of Medicine & Science in ultraendurance sports organized by the Ultra Sports Science Foundation in collaboration with the Club de Carreres de Muntanya Desert Amunt and Penyagolosa Trails, will be held on 9 and 10 May 2018 at the Universitat Jaume I of Castellón de la Plana, Spain. This event will be the scientific precursor of the World Trail Championship, which will take place in the province of Castellón. This event has the institutional support of the Diputación Provincial de Castellón (Castellón Council) and the city of Castellón, as well as the sponsorship of the Cátedra Endavant Villarreal CF de l’Esport.
In 2012, the Servei d'Esports of the Universitat Jaume I and the Club de Carreres de Muntanya Desert Amunt organized the first edition of this event, pioneer in Spain, and 6 years later the organizers intend to give continuity and to consolidate the training and research in this area with the fourth edition of a scientific meeting that has already become a reference.
It is, therefore, a project that has been set as a horizon to unite the work of the world of scientific research and the sporting world, so that they can enrich one another. This has meant joining efforts to find common objectives; those related to scientific development in the different areas that converge in this Congress, and those looking for the creation of innovative lines of work in the different professional areas that will coexist within the framework of this IV International Congress of Trail Running.
Joining forces with our Spanish friends we are happy to be holding the congress jointly with our 5th International Congress of Medicine & Science in ultraendurance sports. The concept for an annual conference devoted to the science and clinical aspects of ultra-endurance sports participation dates back many years to Dr. Marty Hoffman who in 2014, organized the  1st Medicine & Science in Ultra-Endurance Sports Conference in Squaw Valley, California. From the beginning, the conference has focused on blending the science and the clinical aspects of ultra-endurance sports by bringing together the leaders in these disciplines. This explains our three-ringed logo – the overlap of science, medicine and ultra-endurance sports. While the programs have been primarily geared towards scientists and clinicians, many educated athletes and coaches have also enjoyed our conferences. Net proceeds from the conference have always been directed back to support the enhancement and distribution of scientific and medical knowledge related to participation in ultra-endurance activities. In 2016, with the development of the Ultra Sports Science Foundation, the organization of the conference was placed under the umbrella of the Foundation. In 2016 the congress was held in Chamonix and in 2017 in Denver.
Experts in diverse scientific areas of recognized world prestige are incorporated into the start up of this joint Congress, which will be a qualitative leap in its development and confirms the ascending line carried out by the series of Congresses in the past.
The Congress has been raised with the double scientific and sporting aspect, having a set of sessions in which the congressman will be able to orient his interests and select the conference to attend, because parallel sessions will be held with different orientation.
The main themes will be based on the presentation of scientific works based on mountain and ultraendurance races addressing different aspects of medicine and physiology in this area. In the same way, sports and health aspects will be treated in the development of trainings and their progression so that resources can be provided to optimize the level of physical condition of the runners.
As in previous editions and given the interest generated, the feeding, the distribution of workloads and their periodization, the biomedical parameters to be taken into account, as well as the most frequent injuries or disorders that occur in this type of sports tests will be addressed in the development of the congress