Question: What sport do both Jim Grabb and Michael Chang play?
Related documents: [0]  [DOC] Jim Grabb (born April 14, 1964) is an American former professional tennis player. He was ranked the World No. 1 doubles player in 1989 and in 1993. Grabb's best singles ranking was World No. 24, a ranking he achieved in February 1990. [END] 
[1]  [DOC] Michael Te-Pei Chang (born February 22, 1972) is a retired American professional tennis player. He won 34 top-level professional singles titles, including the 1989 French Open when he was 17. He also was a three-time runner-up at the majors and reached a career best ranking of world No. 2 in 1996. Since he was shorter than virtually all of his opponents, he played a dogged defensive style utilizing his quickness and speed. In 2008, he was inducted into the International Tennis Hall of Fame, and he has coached Kei Nishikori since 2014. [END] 
Answer: 
tennis
tennis