Complex sentence: At UCLA, he majored in sociology and became the first three-time All-American, establishing himself as the premier freshman hitter in the school's history--his accomplishments included compiling a 33-game hitting streak and batting cleanup just as many times.
Split into simpler sentences: At UCLA, Atkins majored in sociology and became the first three-time All-American. He established himself as the premier freshman hitter in the school's history--his accomplishments included compiling a 33-game hitting streak and batting cleanup just as many times.