Complex sentence: By the end of the year, he had compiled 1,432 rushing yards and 1,442 passing yards; his 18 touchdowns set a professional football record that was not surpassed until the 1960s.
Split into simpler sentences: By the end of the year, he had compiled 1,432 rushing yards and 1,442 passing yards. His 18 touchdowns during the season set a professional football record that was not surpassed until the 1960s.