World Serve Value: A New, Digital Gazette Way To Measure FEBRUARY 2020 Vol 12 No 9 A Tennis Stroke

directs a team of scien- BY JOHN MARTIN tists working in artificial MELBOURNE, Aus- intelligence for Tennis tralia — As Jim Courier Australia. They form a leaned forward, he tilted team called Game Insight his microphone toward Group, or GIG. Novak Djokovic, who had Standing over his lap- just defeated Yoshihito top on the seventh floor Nishioka of Japan in the of the nearby Tennis third round of the 2020 Australia headquarters, . They Reid chatted with a stood on the Rod Laver young colleague as a Arena court. photographer snapped “Novak,” Courier said, shots of the maze of “your coaching team is computers and desks. said to be looking for Reid is an author and ways to improve your sports scientist deeply serve. Tell me, how can invested in both the theo- you improve your serve?” retical and the practical. “Hit more aces?” “What Serve Value Djokovic replied with a does is it combines the smile in his voice. The speed of someone’s audience roared with serve, the placement of laughter. their serve, and the spin The Serb had just hit of their serve with a view 17 aces and only two to giving you one number double faults over three on a scale of 0 to 100, sets, holding his serve 13 where you’re able to rate consecutive times. the effectiveness of your Courier and Djokovic serve, each and every stood less than 100 yards serve that’s hit. So, it’s from where a digital study the likelihood of my serve World Tennis Gazette/John Martin of the serve had been un- winning the point.” SERVE: Djokovic asked ‘Hit more aces?’ derway for some time. Its In 2015, Reid co- goal: create a new way to wrote Tennis Science: How Player and evaluate and improve the serve. Something Racket Work Together, a look at many fac- called Serve Value is the first digital step. ets of the sport, including an effort to de- The leader of the study, Dr. Machar Reid, Page 2 World Tennis Gazette FEBRUARY 2020 Data Science Confronts Conventional Wisdom About Serving

World Tennis Gazette/John Martin SEARCH: Dr. Reid works on 7th floor of Tennis Australia headquarters in Melbourne Park. scribe “the main technological developments combination of his serve directly winning those and software programs that can be used to as- points, which happens quite a bit for Novak rela- sist in performance and notational analysis in tive to a lot of other players, and then also his tennis.“ rally ability relative to a lot of other players.” At times, data science is thick One result, Reid said, is “this with complex technical terms aimed gives you probably the sport’s first at capturing insights. Reid simplified: attempt at trying to put first serves “You’re essentially looking at the and second serves, treat them the relationship between ball speeds, same way, consider them on the spin and placement, and the point same scale, and say, okay, how outcome,” Reid said. “So, did the effective is someone’s second combination of those factors allow serve, really?” any particular player to win the One question is whether a Serve point?” Value rating is of more use to the Reid said his team uses a data- server or the opponent. base of Hawk-Eye video stretching Dr Machar Reid “I think it’s far more actionable back more than four years, a vast for the player, not so much the op- compendium of a hundred thousand or more ponent,” Reid said. “So, a lot of stats in tennis first and second serves and the points they focus on me preparing to meet a certain oppo- won or lost. nent. Here, this is about, as much as anything, One striking discovery, he said, is that monitoring my own improvement, my own serve Djokovic, for example, ranks well below the top performance over time. So, if my serve value first servers, but records a remarkable high drops from tournament to tournament or year to second serve rating. year, that’s something that I can control.” “Novak wins approximately, 50, 55 percent A partner in the study, Victoria University of second server’s points,” Reid said. “That’s a Professor of Sports Analytics Sam Robertson Page 3 World Tennis Gazette FEBRUARY 2020 Question: Did Champion Djokovic Know His Serve Value Score?

was quoted by the Tennis Austral- who were rated using Serve Val- ia website: ue, the first serve of Sam Querry “Using science to measure of the United States ranked speed is easy, using science to highest at 96. At 87, Serena Wil- measure the value of a shot not liams’s first serve ranked highest so much. Serve Value brings ten- among women.. nis in line with many other major By Friday of the first week of sports who are developing new play, Querry had slipped to third and informative ways to quantify and Williams had dropped off the skill of its players.” what Tennis Australia called the For players (and magazine leaderboard (see chart). writers) unfamiliar with data sci- Djokovic’s first serve was not ence, the terrain can be especially among the top five men. His daunting. Dr Reid’s online bio second serve was reported at sketch lists some projects in the BOOK: ‘Tennis Science’ 28.86. field of research. Three examples Dr. Reid was asked what this make the case that there is a SERVE VALUE meant. bright but sometimes baffling fu- FIRST WEEK What “28 indicates, in this ture for data science in sport: Source: Tennis Australia context,” he said, “is 28 percent “A qualitative exploration of FIRST SERVE MEN of Novak Djokovic’s second mentally tough behaviour in Aus- MILOS RAONIC 61.23 serves are likely to result in him tralian football.” JOHN ISNER 57.01 directly winning the point, so “Chronic Adherence to a Keto- SAM QUERRY 54.68 forcing his opponent to make a genic Diet Modifies Iron Metabo- ANDREY RUBLEV 54.61 mistake off the return or even lism in Elite Athlete(s).” MARIO BERRETTINI 53.28 potentially hitting a second

“Different visual stimuli affect serve ace.” muscle activation at the knee dur- SECOND SERVE MEN In the five-set final, Djokovic ing sidestepping.” IVO KARLOVIC 39.82 hit only 9 aces, but won 66 of 87 JOHN ISNER 38.29 Some equally sophisticated points (76%) on his first serve MILOS RAONIC 33.88 measures are in various stages of and 24 of 47 second serves NOVAK DJOKOVIC 28.86 development elsewhere. (51%).(As Reid forecast.) ALEXEI POPYRIN 24.19 Cyclists, for example, can use Final Score: Djokovic won 6-

a particularly rigorous scale called 4, 4-6, 2-6, 6-3, 6-4 FIRST SERVE WOMEN “Suffer Score.” An ATP analyst observed 51.77 “Suffer Score is one index “Djokovic won 24 of his 29 JULIA GOERGES 51.53 made up of a few combined data points at the net and hit 46 win- KAROLINA PLISKOVA 47.82 areas,” said Robert Kitchingman, ners, including nine aces. Thiem 47.16 an avid competitive cyclist (and won 29 of 134 points on return PETRA KVITOVA 44.36 friend of the writer) who lives in of serve and committed 57 un-

Melbourne. He listed heart rate forced errors, the same number and power output as measures. SECOND SERVE WOMEN as Djokovic. Each player also hit 20.79 “VO2 Max is another measure five double faults.” based on the body’s ability to pro- PETRA KVITOVA 20.10 Was champion Djokovic duce oxygen,” he said. CORI GAUFF 16.64 aware of the Serve Value fore- After opening day of this CAMILA GIORGI 16.39 cast that his second serve year’s Australian Open, Dr. Reid JULIA GOERGES 14.89 would be vital? WTG will get said that among all competitors back to you on that.