According to new data from Tennis Australia’s Game Insight Group, world No. 1s Andy Murray and Angelique Kerber have the highest average top speeds (kph) in tennis.

Novak Djokovic and Simona Halep have the highest top speed (kph) in the sport.

The Game Insight Group (GIG) measured players when running across a distance of three meters or more during play, using match statistics collected at three Australian Opens. According to the data released, Murray has a higher average top speed (15.89 kph) than Djokovic (14.89 kph), though the Serb has the highest top speed (36.02 kph). A complete ranking of average top speed was not released, but Roger Federer was second (15.55 kph) and Rafael Nadal third (15.38 kph) among players provided. The Swiss and the Spaniard were 17th and 12th, respectively, in top speed. Among the most surprising findings was that Milos Raonic is fourth in average top speed (15.36).

Murray has the second-highest top speed (34.86 kph), and Lleyton Hewitt, who retired earlier this year, has the third-highest (31.24 kph. Gilles Simon, Grigor Dimitrov and David Ferrer followed them. Also surprising is the relatively low placement of Kei Nishikori (27.17 kph), who was 10th behind Raonic (ninth) and Tomas Berdych (eighth).

Among the women who were researched, Kerber had the highest average top speed (14.27 kph). Julia Goerges (13.85 kph) was second, followed by Agnieszka Radwanska (13.79 kph) and Halep (13.69 kph).

Halep had the highest top speed (23.04 kph), with Carla Suarez Navarro (22.48 kph) coming in second. Dominika Cibulkova is third, followed by Radwanska. Among the surprises were Alja Tomljanovic—who has the sixth-highest top speed (21.69 kph)—and Ana Ivanovic, who top speed is ninth (20.9 kph).

Maria Sharapova has a higher top speed (20.61 kph) and average (13.6) kph than world No. 2 Serena Williams, whose top speed is 20.52 kph and average top speed is 13.5 kph. Victoria Azarenka lagged in both categories, with a top speed of 19.45 kph and an average of 13.34 kph.

A more detailed description of the measurement used was not given.

Below is the full list (Top speed/Average Top Speed):

WTA

1. Simona Halep: 23.04/13.69

2. Carla Suarez Navarro: 22.48/13.56

3. Dominika Cibulkova: 21.98/13.43

4. Agnieszka Radwanska: 21.82/13.79

5. Eugenie Bouchard: 21.82/12.95

6. Ajla Tomljanovic: 21.69/13.33

7. Angelique Kerber: 21.46/14.27

8. Garbine Muguruza: 21.32/13.21

9. Ana Ivanovic: 20.9/13.64

10. Julia Goerges: 20.75/13.85

11. Maria Sharapova: 20.61/13.6

13. Serena Williams: 20.52/13.5

ATP

1. Novak Djokovic: 36.02/14.89

2. Andy Murray: 34.87/15.89

3. Lleyton Hewitt: 31.24/15.24

4. Gilles Simon: 30.76/14.93

5. Grigor Dimitrov: 28.91/15.05

6. David Ferrer: 27.82/14.71

7. Stan Wawrinka: 27.66/15.17

8. Tomas Berdych: 27.28/14.49

9. Milos Raonic: 27.28/15.36

10. Kei Nishikori: 27.17/14.52

12. Rafael Nadal: 26.84/15.38

17. Roger Federer: 26.03/15.55