Complex sentence: Brown became the all-time rushing leader at BYU during his senior year, with his accumulated 3,218 career yards between 2002 and 2006, which eclipsed the previous mark set by Jamal Willis.
Split into simpler sentences: Brown became the all-time rushing leader at BYU during his senior year. From 2002 to 2006, he accumulated 3,218 career yards, which eclipsed the previous mark set by Jamal Willis.