The WTA Tour is introducing a new statistic index to measure the power with which a player hits the ball.
Six-time Grand Slam champion Venus Williams ranked No. 1 in the new "power index" during last week's Acura Classic, averaging 152 kph (94.5 mph) on her hardest shots.
The index takes into account a player's fastest groundstroke (forehand or backhand), first serve, second serve, first-serve return, second-serve return and smash or volley.
It uses ball-tracking technology from Hawk-Eye Innovations, the company involved in instant replay in tennis, and measures players in center-court matches.
"Other leading professional sports have introduced new methods to measure and compare the performance of their players to provide another level of insight for fans," tour president Stacy Allaster said Monday. "The power index affords that same opportunity for women's tennis."
The statistic made its debut at the Acura Classic, with Maria Kirilenko finishing second to Williams at 149.1 kph (92.7 mph). Victoria Azarenka was third at 148.5 kph (92.3 mph), followed by tournament champion Maria Sharapova at 145.6 kph (90.5 mph ).