This week, for the first time at the Olympics, skiers will scamper uphill wearing carpet-like skins on their skis or just their stiff boots, then barrel back down an ungroomed course. This is ski mountaineering — or skimo — the newest Olympic event. It’s a brutal high-altitude sport. Follow along for live coverage “I think they are the athletes who have the highest pain threshold and can really suffer,” Dr. Volker Schöffl, the physician for the German ski mountaineering team, said in an