Anglo Premier specialises in sports translations. More information at www.anglopremier.com/sport.
There are some excellent online resources for vocabulary related to the Olympic Games in English, French, Spanish, Catalan and Portuguese.
For French and English, the France’s National Institute for Sport, Expertise and Performance produced an excellent glossary for the 2012 Olympics and Paralympics.
Termcat produced a large glossary when Barcelona hosted the 1992 Games, and has continued to develop the glossary ever since. Its Diccionari de l’Esport includes terminology in English, French, Spanish and Catalan for all the Olympic disciplines, as well as for many non-Olympic sports.
Finally, for those who work with Portuguese, the Grupo de Pesquisa em Estudos Olímpicos has produced an English-Portuguese glossary for the Games in Rio de Janeiro, available here.