Match Facts

http://www.atptennis.com/en/players/matchfacts/

这是ATP官网上关于球员发球跟接发球的数据，每周更新一次

Power Index

http://www.sonyericssonwtatour.com/2/rankings/powerindex/default.asp

这是WTA官网上的“力量指数”统计，更新得相当慢，目前更新到迈阿密站，而且只有在中心球场亮相的球员才会被统计

The Power Index is the average maximum hitting speed of any player judged by maximum: a) 1st Serve Speed; b) 2nd Serve Speed; c) Forehand; d) Backhand; e) 1st Serve Return;
f) 2nd Serve Return; and g) Smash.
*Only calculates players appearing on center court.