All American Birkebeiner coverage is brought to you through the generous support of SkiErg. Dr. Ian Duncan’s first phone call to Vegard Ulvang two years ago met a little dead air. It wasn’t that Ulvang, the executive director of the International Ski Federation’s cross-country committee, didn’t want to talk. He couldn’t at the time. The former Norwegian cross-country skiing superstar had the Olympics to tend to. Last summer, Duncan, a world-renowned National Multiple Sclerosis Society researcher...