Science of the Winter Olympics – Cross-Country Skiing, Internal Athlete

♪music♪ LESTER HOLT, anchor: The United States hasn’t won an Olympic medal in cross-country skiing since 1976, but in 2010, several skiers hope to change that. If they’re successful, you can be certain it’s due to their incredible endurance. As Olympic athletes, trainers, and a sports scientist and chemist funded by the National Science Foundation…