It is always a pleasure to work with Sif: rigor, challenge and surpassing oneself all in a good mood! I met Sifedine as part of my professional activity. Thanks to him, we had set up boxing coaching for our runners, in order to make them work on their muscle strengthening. Every Saturday morning we left as a group for a boxing session, strengthening, physical preparation fun and super nice! Everyone was delighted. Personally, Sifedine helped me prepare for the GR 20 in Corsica in Trail version in five days. His help was invaluable in being able to succeed in this performance in good conditions.