Every day at the U.S. Open, Serena and Venus Williams will walk out to either a practice court or a match with six racquets in their respective bags. They might use two of them.
After every use, they will send all their racquets – including the ones still wrapped in plastic – back to be restrung. This is the point where the engineering that's added so much power to the modern game becomes mystic.
Stringing is one of tennis's dark arts – a combination of precision work and an unquantifiable feel.
Many of the top pros – Milos Raonic among them – pay a dedicated service such as Priority One Tennis to handle all their racquets. Priority One has a three-man team in New York, working out of a Manhattan hotel.
Most players – which is to say, the ones not making big money – use an on-site service. Here at Flushing Meadows, the work is done by a travelling team of master technicians provided by Wilson.
The staff has been scouted from across the world, put through a boot camp, tested and retested. One bad tournament and you're out.
They work out of an airy office alongside the garden where players hang out between matches. It's a lovely contrast – the stars at rest, while one part of the machine that makes their jobs possible hums behind them.
At 44, Joe Heydt is one of the veterans on the team. He runs a tennis pro shop in Omaha, Neb. He's been stringing since he was 17. Two or three times a year, he packs up to work a big tournament. Other guys in the shop will spend as many as 300 days a year on the road, stringing for the team or individual players.
For Heydt, it's a lark rather than a living.
"Would I work here if they paid me five bucks a day? Probably."
But it's not quite a vacation.
"I string a lot at my shop. We do maybe 2,800 or 2,900 racquets a year. Here, we'll do over 4,000 in three weeks. It's insane. When I get home, my fingertips are like M&Ms."
Racquets are dropped off with the specifics – type of string, tension, pattern, stencilling instructions. Some are a little odd – the lettering on the butt end must face a certain way, or small lead weights must be taped to the racquet frame at odd intervals. Each stringer is responsible for a stable of 30 or 40 players. The cost is $30 (U.S.) per racquet – a decent price, but it adds up.
"A lot of players don't string their racquets as often as they should, because of the expense," Heydt says sadly.
While he talks, Heydt works, expertly weaving about 20 feet of roughly measured string. He's able to maintain eye contact throughout the process. If he makes a mistake, he can feel it during the next pull.
It's around noon – a slow time. Most of those working are wearing headphones. The only sound is the intermittent clacking as a framing machine is turned to attack a different angle.
Several stringers are lounged around on the floor, stretching. One guy is giving another a very deep massage. Whether at work or not, all have the thousand-yard stare of men who do detail work they've practised over many hundreds of hours.
As play picks up through the day, the pace will get more frantic. Players are superstitious. If they break a string during a match, they often want to use the same racquet despite having others in their bag. This necessitates what's called an 'on court.'
A runner sprints the racquet back to the shop. Typically, it takes 20 minutes or so to finish a racquet, including painting the branded stencil on the face. During an on court, the Wilson team is expected to turn the racquet around in less than 15 minutes.
This is where the war stories come from. The best of them involves Jared Magee, an Australian, who, as I speak to Heydt, is crashed out on a folding chair.
At an Australian Open, Magee handled Rafael Nadal's racquets. During a night match, Nadal sent back a racquet. There were only two people staffing the shop. Then he sent back another.
"How fast did you manage the second one?" Heydt asks teasingly as Magee walks over.
"Eleven minutes," Magee drawls.
"Of course, Rafa has a pretty simple pattern," Heydt says teasingly.
Magee smirks and wanders off. Everywhere you turn at an event like this, someone is making a name in his or her particular professional world, big or small.
Since they have no on-site facility, players who use a dedicated service don't get the benefit of on courts.
"We're consistent. We're the same guys they see every tournament," says Ron Yu, one-third of the Priority One team. "That way, they get on the court, they don't have to check their racquets when they pull them out of the bag."
This eliminates the "favourite racquet" problem.
"They all feel exactly the same," Yu says.
Regardless of who does the work, "the same" is a constantly changing metric. The way a racquet feels out of the shop is not how it will feel a day later, regardless of whether it's been used.
Heydt has just pulled through all of the vertical strings (or mains) on the racquet he's working on. He ties off the end and points at it.
"Right now, this racquet is already losing tension. You can't stop it," Heydt says. "Whether or not a player can tell the difference, who am I say? If they say to me, 'When my stencil points the right way, I play better,' well, you can't argue with that."