“The mountain marathon requires a lot more than the city marathon, and it requires approximately 1.5 times more energy than in the city.” These words from Dr. Chen at the beginning of his lecture were a bit of a blow to the enthusiastic runners.  Then he continued, “Mountain marathon involves going uphill and downhill.  There are many types of surfaces, including highways, street roads, sandy roads, grass roads, graveled roads and so on.  The roads are mostly uneven; some are narrow, some are unpredictable; obstacles, such as grass and tree branches, can pop up any time.  Compared with city marathons, it is much more likely, participating in mountain marathons, that one will meet with injuries such as falls and ankle sprains.”