From what I can gather from the pictures and the poor translation, it looks like Jokerit actually held a team practice outdoors in the woods and in a swamp

League team headed to practice nearby swamp Kirkkonummi last Friday. Coach and Doctor Harri Hakkarainen took players to a new environment that brought break a sweat as well as new physical and mental element. Players were given heart rates up in muddy marks.
Check out the photos and video right here