Complex sentence: As a four-year-old in 1932, Equipoise returned to win ten of his fourteen stsrts including the Metropolitan Handicap, the Stars and Stripes Handicap, and Whitney Stakes and set a world record of 1:34⅖ for the mile at Arlington Park.
Split into simpler sentences: As a four-year-old in 1932, Equipoise returned to win ten of his fourteen stsrts. He won the Metropolitan Handicap, the Stars and Stripes Handicap, and Whitney Stakes and set a world record of 1:34⅖ for the mile at Arlington Park.