Recently I've skimmed through a book written by a pretty famous local coach. He is coaching I. Kalentieva and many more less successful but still strong racers. He uses running all year round for XC training. He substantiates his position asserting that an XC racer has to have an ability to run well when it's not possible to ride and a rider has to be accustomed to running stress. Running (jogging) might also be used as relaxation after an intensive cycling session.