Complex sentence: Marta Domínguez Azpeleta (born 3 November 1975 in Palencia) is a Spanish runner who currently competes mainly in 3000 m steeplechase, a distance in which she is the current world champion.
Split into simpler sentences: Marta Domínguez Azpeleta (born 3 November 1975 in Palencia) is a Spanish runner. She currently competes mainly in 3000 m steeplechase, a distance in which she is the current world champion.