Seven-time Tour de France champ Lance Armstrong will be back on the bike competing in the XTERRA USA Championship at Snowbasin Ski Resort in Utah. Armstrong has confirmed he will compete Sept. 24 in the XTERRA course that covers a 1-mile swim, 20-mile mountain bike ride and 6-mile trail run. He scouted the course for three hours last week with the past president of the foundation that sponsors the…