Altitude Adjustment

Last month, 20 years after winning her only Wimbledon singles crown, Martina Hingis partnered with Jamie Murray of Britain — the brother of Andy Murray — to take the mixed-doubles title at the All England Lawn Tennis and Croquet Club. It was the eighth Grand Slam doubles title that Hingis, now 36, has won since coming out of retirement in 2013 — yet another demonstration of the racket skills and tactical brilliance that make her one of the craftiest players tennis has ever known. But this year’s Wimbledon also highlighted, with particular clarity, the change in the sport that helped sink her singles career.

When Hingis won Wimbledon in 1997, she was 16 and in the midst of an incredible season in which she would claim three of the four Grand Slam singles titles. If not for her loss in the final of the French Open, she would have become the sixth player ever to complete a calendar-year Grand Slam. Given her age, her court smarts (like “a young Bobby Fischer playing chess,” one coach said) and her ruthless drive — underscored by the slightly diabolical grin that she wore as she crushed one opponent after another — it stood to reason that Hingis would dominate women’s tennis for years to come. As she told me over lunch a few weeks ago in Florida: “I felt invincible.”

But Hingis’s ascendancy coincided with the emergence of a trio of players, all Californians, who were, by the standards of the time, unusually tall and strong. Lindsay Davenport and the sisters Venus and Serena Williams were at the vanguard of what the sports commentator Mary Carillo soon named “Big Babe Tennis”: Davenport was 6-foot-2 1/2, Venus Williams an inch and a half shorter, Serena Williams 5-foot-9. All three hit with concussive power. Hingis wasn’t small, exactly, but she was certainly not big: At a waifish 5-foot-7, she had a game that was based on touch and guile, and she struggled to handle the pace of her larger foes. After that historic ’97 season, she won only two more singles majors. In 2003, at age 22, she retired. She had been troubled by injuries, but it was also clear that the game was outgrowing her — quite literally.

The success that she has had on the doubles circuit over the last four years is a great story of perseverance and reinvention. But before finding a path back to the top of the sport, Hingis was a casualty of an evolutionary lurch in tennis. There have always been tall athletes among the pros, and average heights had increased incrementally for years. But over the last two decades, players — women and men alike — have become significantly bigger, a point that was underscored last month at Wimbledon. When Hingis won in 1997, the tallest woman to reach the quarterfinals was 5-foot-9. This year, there were only two women in the quarterfinals under that height.

On the men’s side, the numbers were even more arresting. Five of the eight quarterfinalists this year were 6-foot-4 or above, and not one was under six feet. It was Big Dude Tennis, you might say, and it continued in the lead-up to the U.S. Open. The veteran American John Isner, who is 6-foot-10, won the BB&T Atlanta Open. In early August, Alexander Zverev, a 6-foot-6 German who goes by Sascha, captured the Citi Open in Washington by beating Kevin Anderson of South Africa, who is 6-foot-8. A week later, Zverev won the Rogers Cup in Montreal, beating Roger Federer in the final. It was Zverev’s fifth title of the year, and there’s an excellent chance that the U.S. Open will be the sixth — and the first major title of his career. At 20, Zverev is rapidly emerging as the game’s next superstar, and if he lives up to his vast potential, he could redefine what we think of as the optimal height for a male tennis player.

Already, when you walk through the players’ lounge of a tournament these days, you can easily think that you have stepped into a misplaced N.B.A. locker room. The game’s newest goliath is Reilly Opelka, a 6-foot-11 Floridian. He is only 19, which presumably means he might still be growing, and could yet become the first pro player to breach the seven-foot mark. In the meantime, short players are becoming harder to find. Japan’s Kei Nishikori is the only player in the men’s Top 10 who is under six feet, and no man under six feet tall has won a major since 2004. In a 2015 interview, the Spaniard David Ferrer, who is 5-foot-9 and was ranked as high as No. 3 in the world, suggested there was no hope for players his size. “I would guess that you will have to be at least between 5-foot-11 or 6-foot-3 to play tennis,” he said. “I think players like me, around my height, are going to be extinct.”

In many professional sports, the athletes are a lot bigger now than they were a generation or two ago. Since the late 1940s, the average height of N.B.A. players has gone from 6-foot-2 to about 6-foot-7. But basketball was always a big person’s sport. Tennis was not. Tennis used to be like soccer: a sport in which height was considered largely inconsequential. Many of the game’s greatest champions were on the compact side. Rod Laver was 5-foot-8, Jimmy Connors 5-foot-10. John McEnroe and Bjorn Borg were under six feet. Martina Navratilova was 5-foot-8 and Chris Evert 5-foot-6. Billie Jean King was only 5-foot-4 1/2.

Now, however, height seems to matter a great deal. The ramifications of this are being felt not just at the professional level but at the junior level too. Young players — and their parents and coaches — have always had to wonder whether they had the athletic ability and emotional resilience to make it in tennis. Now there is a more fundamental question: Will they grow big enough to be competitive?

One weekday morning in mid-July, with the heat and humidity already brutal, Kevin Anderson was wrapping up a practice session at the Delray Beach Tennis Center in Florida. I’d come to see the boys’ 18-and-under National Clay Court Championships; as one of the junior “majors,” it always attracts talent-scouting college coaches, and it seemed like a good place to gather impressions about the role of size in tennis. On the morning I arrived, I noticed Anderson, who lives in the area, working out on the stadium court . (At 6-foot-8, he was kind of hard to miss.) A former Top 10 player, Anderson reached the fourth round at Wimbledon the week before, losing in five sets to the 6-foot-6 American Sam Querrey. Up close, his height was startling in that holy-crap-you’re-tall kind of way, but his speed and agility were even more impressive. He was doing short, sharp sprints along the baseline, simulating the bursts of movement required in a typical rally. As he lunged from the center of the court, stutter-stepping to the doubles alley and then back to the middle, the squeaking of his sneakers echoing across the empty stadium, I couldn’t believe how quick and light he was on his feet.

While he suffered in the sun, I struck up a conversation with his sparring partner from that morning, a starting player for Florida State University named Jose Gracia. When I told Gracia what I was writing about, he nodded knowingly. Even at the collegiate level, he said, the guys were now huge; in fact, he could think of only one of his F.S.U. teammates who was under six feet. Gracia was on the ground stretching, and I couldn’t make out how tall he was, so I asked. “Six-foot-7,” he replied, matter-of-factly.

Players this size used to be outliers, and they didn’t enjoy much success. They usually had thunderous serves, with their long limbs generating enormous force and their height letting them pound the ball down toward the court at severe angles. But booming serves were often all they had. They tended to be lumbering giants who couldn’t keep rallies going and struggled with balls hit below their waists. Being of modest height, or even a little on the short side, was considered preferable to being supersize. Things are different now. The sport’s so-called Big 4 — Federer, Rafael Nadal, Novak Djokovic and Andy Murray — are all between 6-foot-1 and 6-foot-3. For a while now, this height has been considered the sweet spot for male players, even as taller competitors enter the scene. In 2009, Juan Martín del Potro, a 6-foot-6 Argentine, overpowered Federer to win the U.S. Open, becoming the tallest man ever to win a grand slam title. Three years ago, Marin Cilic of Croatia, who is also 6-foot-6, won the Open. The 6-foot-5 Canadian Milos Raonic was a Wimbledon finalist last year and a quarterfinalist this year. And then there’s Sascha Zverev, 6-foot-6, who seems likeliest to recalibrate the “sweet spot” entirely.

Zverev’s parents, who have both played professionally, immigrated to Germany from Russia in 1991, the year the Soviet Union fell. His older brother, Mischa, who is 6-foot-3, is also a pro. Zverev broke into the Top 10 earlier this spring, and he looks like a sure bet to eventually reach No. 1 and win a clutch of majors. Like other big men, he has a huge serve, but there is much more to his game than blistering serves and groundstrokes. He’s also exceptionally nimble and supple — he has what his fitness trainer, Jez Green, calls “elasticity.” It is a word that has been used to describe the N.B.A. star Kevin Durant, whose speed and ball handling have redefined what’s possible for an N.B.A. big man. Zverev, whose lanky frame is not unlike the seven-foot Durant’s, could have a similarly revolutionary impact on tennis.

When I spoke with Zverev earlier this month in Washington, he wasn’t thinking in quite such lofty terms. He had just finished a practice session with the French player Gaël Monfils (who is 6-foot-4), and with his shaggy blond hair flowing loosely, he looked more like a surfer than a pro tennis player. As he took a seat in the players’ cafeteria, he scooped up his toy poodle, Lovik, and held him as we talked. His mother, at an adjoining table, was texting while his father, who doubles as his coach, was playing a video game on a tablet. Neither of them, Zverev said, had ever expressed concern about him being too tall for tennis.

“We always knew I wasn’t going to be like Isner or Karlovic,” Zverev said, the latter referring to the 6-foot-11 Croatian player. “Anything up to 6-foot-7, 6-foot-8 is a great height for tennis these days. You look at Cilic, at del Potro, at me — we all move really well, which is a big change from how it was 20 or 30 years ago.” He credited his agility to having played soccer and field hockey as a kid. “They are low-gravity sports,” he explained. “They taught me how to be low all the time, how to change direction quickly.” He thought smaller players could still hold their own in today’s game, and figured anything over 6-foot-11 was probably too tall to reach the top of the rankings. Even this caveat underscored just how much things have changed: Not so long ago, the mere idea of a seven-footer competing successfully would have seemed ridiculous. “I just want a 6-foot-6 German guy to be the dominant player,” he said with a laugh.

Green is confident that this will be the case. When I spoke with him by phone from Montreal a few weeks ago, he recalled the first time he watched Zverev play, when the German was 16. “The thing I saw immediately was his ability to move,” he said. “I thought: My God, this guy moves incredibly smoothly for someone his height. This could change the idea of how tall guys move.” Green, who previously trained Andy Murray, also brought up the soccer and field hockey. “I don’t know if it was deliberate or not, but having him play soccer and field hockey was a masterstroke,” he said. “For someone that tall to get used to playing low — it helped his movement hugely.” He saw Zverev as part of a group of strapping young players — including the 6-foot-6 Russian Karen Khachanov and the 6-foot-5 Australian Thanasi Kokkinakis — who move with the speed and fluidity of much shorter men and who could raise the bar for what is considered the ideal height. “I think 6-foot-4 to 6-foot-6 will become the new norm,” Green told me.

This was the day after Zverev won the tournament in Washington. The same afternoon, the final of the Stanford Classic, in Northern California, was a showcase for the new norm in women’s tennis. On the women’s side, players aren’t necessarily getting taller; 6-foot-3 still seems to be the ceiling. But they are becoming even more powerful. You hear the word “convergence” in tennis circles these days. It refers to the way the women’s game is coming to resemble the men’s game — specifically, the narrowing of the gender gap on serves and groundstrokes. The finalists in Stanford were two Americans at the forefront of this trend, Madison Keys and Coco Vandeweghe. Keys was hitting first serves at 114 to 118 miles per hour, which would be very competitive on the men’s tour; her fastest was 121 miles per hour. Both women routinely hit forehands as fast or faster than the hardest forehands on the men’s side. They are not alone. En route to winning the French Open this year, Jelena Ostapenko, a 20-year-old Latvian, averaged 76 miles per hour on her forehand, three miles per hour faster than Murray, then the No. 1 male player.

Ostapenko and Keys are 5-foot-10. Vandeweghe, whose grandfather and uncle played in the N.B.A., is 6-foot-1. But Lindsay Davenport, who now coaches Keys, doesn’t believe that height is the sole or even primary explanation for why the women are hitting so much harder these days. When we spoke recently, she said much of it had to do with lighter, more flexible rackets. “Everyone can crack the ball now, even the shorter players,” she says. She also points to a change in attitude, on the women’s tour, about the role of the serve. “For so long, the serve was just seen as a means of starting the rally,” she told me. “When I was playing, we’d practice groundstrokes and volleys for 45 minutes, then do just a few minutes of serves and returns.” Now, there’s much more emphasis on developing and refining the serve. “Players like Madison and Coco are looking to get free points on their first serves,” Davenport says, which she describes as “a men’s-tennis mentality that has now shifted to the women’s side.” Height is definitely an advantage on the serve, she says. But more important is the increased athleticism, across the board. Even in her era, players didn’t pour their time into the gym, and big ones weren’t spending hours a day trying to develop the footwork and balance of players six inches shorter than them. “They are such great athletes now,” she says. “You could take them and put them into another sport, and they’d succeed. I was a great tennis player, but I wasn’t a great athlete. If you’d stuck me in another sport, I probably would have drowned or something.”

Around 8:30 on a warm night in Washington, Dudi Sela, a 32-year-old Israeli player, came off the court after losing his first-round match to the young American Jared Donaldson. Sela knew I wanted to discuss the role of size in pro tennis, and as he plopped down on a couch in the players’ lounge, he exclaimed, “That was exactly what you are talking about!” Sela is one of the smaller players on the men’s tour; he’s listed as 5-foot-9 but told me that he’s actually a little under 5-foot-8. At 6-foot-2, Donaldson is not one of the game’s giants, but he’s big enough to have a first serve in the 120-to-130 miles per hour range. Against Donaldson, Sela’s first serve was barely above 100 miles per hour, and his second serves hovered around 80. Those numbers told the story of the match. Sela did what he could to parry Donaldson’s power — he frequently sliced on the backhand, sending off-speed balls across the net to try to lure his opponent into errors — but Donaldson used his serve to bail himself out repeatedly, and took merciless advantage of Sela’s weaker delivery. On the last point, Donaldson floated a gentle lob that landed just inside the baseline. Had Sela been a few inches taller, he probably could have reached the ball and put it away. Instead, he helplessly watched it sail over his head. Game, set, match.

Sela was surprisingly chipper for a guy who had just lost a tough three-setter. But then, he had long ago resigned himself to being a Lilliputian in a sport increasingly dominated by Brobdingnagians. A few years ago, after losing a match in Colombia to Ivo Karlovic, the 6-foot-11 Croatian, he grabbed a plastic chair, brought it to the net and stood on it to give Karlovic a hug. A few weeks before the Washington tournament, he struck a mighty blow for the small fry, beating John Isner in five sets at Wimbledon. But when I mentioned the Isner match and suggested that maybe the outlook wasn’t entirely bleak, he was dismissive. “It was on grass — the ball skids, it stays low,” he said. It would never have happened, he added, on the hard courts in Washington.

The match with Donaldson struck him as more illustrative of the direction in which tennis was heading. “No disrespect for him — he’s a good player, he hits the ball clean — but I feel I’m a much better player,” Sela said. If they’d played only baseline points, without serves, he didn’t imagine Donaldson would have had much of a chance. “But all these young guys serve bombs. I’m smaller, so I don’t have the reach.” Sela agreed with David Ferrer that there was no future in pro tennis for players his size. A nearby television was showing the match that had followed his, pitting Opelka, the 6-foot-11 American teenager, against a 6-foot-6 Russian named Daniil Medvedev. In a decade, Sela said, even players the size of Federer and Nadal would be in trouble. His tone was observational, dispassionate, until he brought up his kid. “I have a 4-year-old son,” he said. “My wife is not big. He’s maybe not going to be very tall. If he’s going to play tennis. . . . “ His voice trailed off, and he didn’t finish the thought.

Forty years ago, height was not a big part of the conversation in junior tennis. Now it is central. I know this in part because my 12-year-old daughter plays junior tennis. A few months ago, as she and I came off the court at an indoor facility near our house, the pro who owned the place complimented Ava on her game and said to me, “She looks like she’s going to be tall; that’s good.” (She’s been of average height most of her life, but she had a nice growth spurt this summer, and her long legs give us hope.) John Evert, who used to coach Madison Keys, and who with his sister Chris owns the Evert Tennis Academy in Boca Raton, Fla., where Ava trained this summer, told me that size is now widely seen as a critical benchmark in evaluating a kid’s prospects: “In the coaching community, it is talked about all the time.” Parents talk about it, too, often with a kind of crude Darwinism — “Yeah, she’s good, but she’s such a tiny little thing.”

At Delray Beach, a few days after my conversation with Jose Gracia, I bumped into Ryler DeHeart, the associate head coach of the F.S.U. men’s team. We were watching a quarterfinal match featuring the local kid who would eventually win the tournament, a 6-foot-3 lefty named Axel Nefve. I mentioned what Gracia had told me — that there was just one player on the F.S.U. team under six feet tall. DeHeart said that wasn’t necessarily by design; while there might be some college coaches who refuse to recruit players under six feet, he wasn’t one of them. “There are so many factors that go into it, so many intangibles,” he said. But if forced to choose between two players of comparable ability, one 5-foot-10, the other 6-foot-2, he’d have to take the taller one. “A guy who is tall and strong and has a big serve — that’s obviously an advantage,” DeHeart said. “It’s easier to hit an ace than to grind out a 30-shot rally.” He also made an interesting point: The discussion about height inevitably revolves around the serve, but string technology has now given taller players an edge in rallies, too. Polyester strings can generate enormous topspin, producing forehands and backhands that come down deep in the court and jump up after landing. “The strike zone was a lot lower 20 years ago,” DeHeart said — and higher balls can be a nightmare for undersize players, forcing them to move back from the baseline or play lots of shots above their shoulders, which can be exhausting. For a tall player like Gracia, those topspin shots will end up just above the hips, an ideal contact point.

Twenty-five years ago, John Evert told me, big players had to try to figure out how to be competitive despite their size; now, it was the complete reverse, and it was shorter players who faced that challenge. In addition to running his academy, Evert is a consultant for Nike’s tennis division, helping identify juniors that the company might want to sponsor. “When I talk to Nike,” he said, “I let them know if I’m concerned about how tall a kid is going to be.” Still, he would never discourage a small kid from pursuing a career in tennis, and he said shorter players could be equipped with skills and strategies that would allow them to contend. Smaller kids at the academy sometimes express frustration when they are pushed around on the court by larger, stronger players. “I tell them that they have to work around it,” Evert said. “I tell them what they need to do to be successful. And we hope for a growth spurt.”

A few weeks after her mixed-doubles victory at Wimbledon, Martina Hingis was training at the Saddlebrook Resort and Spa, north of Tampa Bay, Fla. Her practice partner was a 15-year-old local kid named Daniel Labrador, a promising junior. (John Isner, all 6-foot-10 of him, practiced on an adjoining court.) After a leisurely warm-up, Hingis and Labrador played a very competitive and entertaining set, with lots of long, lung-burning rallies. But when they went to a deciding tiebreaker, Labrador fell apart: His serve abandoned him, and he had trouble keeping the ball in play. Hingis went up 5-1 and asked Labrador if he wanted to change sides. When he equivocated, Hingis showed that she had lost none of the sass that had been a hallmark of her teenage years. “Well, you’re down 5-1, so maybe you should try this side,” she said, flashing that sadistic smile. “You know, no excuses.” They switched sides, and Hingis quickly closed out the tiebreaker. “Yay, experience wins,” she said, raising her arms in mock triumph as she walked to the net to shake hands.

A short while later, we met for lunch at a sports bar on the Saddlebrook grounds. Her tennis mind was just as formidable in conversation as it is on court, and she was full of trenchant observations about players, trends and tactics. (She said she had no interest in becoming a tennis commentator, which is television’s loss: She’d be a seriously good one.) Over turkey-and-ham club wraps, we talked about height, the advent of power tennis and the impact they had on her career. Hingis wanted to clarify a few things. She said that it was really just five players — the Williamses, Lindsay Davenport, Monica Seles and Jennifer Capriati — whose power caused her trouble, and the problem was not so much when she had to play one or another individually. “I never felt like I couldn’t hang in there with them,” she said, “but it was hard to beat two or three of them in a row.” At the 1999 U.S. Open she beat Venus Williams in a grueling three-set semifinal, then had to come back the next day to face Serena Williams in the final. She didn’t have enough energy left to handle the onslaught, and lost in straight sets. It was the first of the 23 Grand Slam singles titles that Serena would win.

If Hingis had any lingering frustration or bitterness over the way things turned out, it wasn’t apparent. She had no temptation to give singles another try: “I don’t want to practice for four hours a day like I used to do,” she said. “I feel like I could hang for a set or a set and a half with the top players, but I know physically I wouldn’t last.” But she disputed the idea that there was no longer a place in the pro game for players her size. “Yeah, it helps if you are taller and stronger, but that’s not everything,” she said. One reason we’re seeing fewer women on the short side, she suggested, is that many of them are quitting the game as juniors — they become frustrated at losing to bigger opponents, their coaches give up on them and they walk away from tennis. If only they would stick it out, Hingis said, they would get stronger and develop better defensive skills, and some of them could definitely make it as pros.

While she was lavish in her praise of the Williams sisters and also spoke admiringly of a couple of other current stars, Hingis said a lot of women these days — even some who have cracked the Top 20 — were very limited in their abilities. “They are one-dimensional,” she said. “It’s boom, boom, boom, and when they don’t hit a winner after three or four shots, they panic. Once you get them on the run, they are in trouble. The big players are not as agile. Shorter players just have to learn to defend the first and second shot. Once the ball passes over the net three times, we have the advantage.” Still, she had to acknowledge the value in being a little closer in height to today’s giants. “I wish I was five centimeters taller,” she said. “I wouldn’t say no to that.”