Complex sentence: Clouthier holds a professional harness horse driver's license and is an avid marathon runner having ran 22 marathons in the last 8 years including the Boston Marathon in 2005 and 2009.
Split into simpler sentences: Clouthier holds a professional harness horse driver's licence. He is an avid marathon runner and has run 22 marathons in the last eight years, including the Boston Marathon in 2005 and 2009.