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Tennis · Interesting Facts

Chapter 5: Equipment & Technology

10 parts · 10 tests · 100 facts · updated 15 October 2026 · markdown

The kit behind the game and the people who invented it: Wimbledon's balls, the first gut strings, a blue clay court, a ball machine, a banned racket and a line-calling machine that beeped.

5.51Balls, Strings and Clay

Wimbledon's ball supplier and how many balls it uses, the first gut strings and the Madrid Open's blue clay.

Test 1Balls, strings and court colourTake a test

  1. Slazenger calls itself the oldest partner of any Grand Slam event; for decades its balls were supplied with no branding on court.

    Source: Slazenger Heritage, 'Curiosities of Wimbledon tennis balls' (slazengerheritage.com); Insider Sport (2025) · recall

  2. Estimates run from about 52,000 to 55,000; the balls are changed often during each match.

    Source: Yahoo Sports, 'How many tennis balls does Wimbledon use?'; Wimbledon Debenture Holders · recall

  3. The first change comes after seven games, to allow for the warm-up, and then every nine games.

    Source: Yahoo Sports, 'How many tennis balls does Wimbledon use?'; Wimbledon Debenture Holders · recall

  4. Pierre Babolat's firm in Lyon made the strings a year after Wingfield's game appeared.

    Source: Babolat, 'Natural gut string, a living legend made in France' and '150 years' (babolat.com) · recall

  5. The firm was a specialist in processing gut for sausages, surgical thread, musical instruments and archery.

    Source: Babolat, 'Natural gut string, a living legend made in France' and '150 years' (babolat.com) · recall

  6. Tiriac pushed for blue courts; the ATP allowed a one-year trial.

    Source: CNN, 'Smurf jokes and a billionaire's dream: where did Madrid go wrong?' (2012); Tennis365 · recall

  7. Players such as Rafael Nadal and Victoria Azarenka complained the courts were slippery, and the one-year trial was not continued.

    Source: CNN, 'Smurf jokes and a billionaire's dream: where did Madrid go wrong?' (2012); Tennis365 · recall

  8. 1875, 1902, 2012 and 2013.

    Source: Babolat; Slazenger Heritage; CNN; Tennis365 · recall

  9. The first set of balls covers the warm-up and seven games; each new set then covers nine.

    Source: Yahoo Sports, 'How many tennis balls does Wimbledon use?'; Wimbledon Debenture Holders · recall

  10. Tiriac said a yellow ball shows up better against blue; players found the courts too slippery.

    Source: CNN, 'Smurf jokes and a billionaire's dream: where did Madrid go wrong?' (2012); Tennis365 · recall

5.52Inventors and Gadgets

Lacoste the inventor, the banned spaghetti racket, the Cyclops line machine and Fred Perry's laurel.

Test 1Machines, rackets and logosTake a test

  1. He registered his hand-cranked ball thrower in 1927.

    Source: International Tennis Hall of Fame, Rene Lacoste (tennisfame.com); Lacoste, 'Rene Lacoste, Renaissance man' (lacoste.com) · recall

  2. He told his captain he would win a crocodile-skin case he had seen; the logo went on his shirts in 1933.

    Source: International Tennis Hall of Fame, Rene Lacoste (tennisfame.com); Lacoste, 'Rene Lacoste, Renaissance man' (lacoste.com) · recall

  3. Wilson licensed Lacoste's patented steel racket and launched it in 1967.

    Source: International Tennis Hall of Fame, Rene Lacoste (tennisfame.com); Lacoste, 'Rene Lacoste, Renaissance man' (lacoste.com) · recall

  4. Fischer's racket had two layers of strings that gave huge topspin; it was banned after a few months of upsets in 1977.

    Source: Wimbledon Lawn Tennis Museum blog / Tennis Museum, 'History: spaghetti stringing (1971)'; Tennis Majors · recall

  5. The ball left the strings with extreme, unpredictable spin.

    Source: Wimbledon Lawn Tennis Museum blog / Tennis Museum, 'History: spaghetti stringing (1971)'; Tennis Majors · recall

  6. It sent infrared beams along the service line and beeped when a serve landed long.

    Source: Perfect Tennis, 'Cyclops in tennis: assisted line judging before Hawk-Eye'; That 1980s Sports Blog (The Telegraph, 1980) · recall

  7. The wreath was the club's emblem, and the club agreed to let him use it on his shirts in 1952.

    Source: Harrods, Fred Perry laurel wreath (harrods.com); Logos-World, Fred Perry logo history · recall

  8. 1927, 1967, 1977 and 1980.

    Source: Hall of Fame; Tennis Museum; Perfect Tennis · recall

  9. It had to be switched on before each serve; a beam broken beyond the line set off the signal.

    Source: Perfect Tennis, 'Cyclops in tennis: assisted line judging before Hawk-Eye'; That 1980s Sports Blog (The Telegraph, 1980) · recall

  10. Cyclops stayed on Centre Court and No. 1 Court until Hawk-Eye replaced it in 2007.

    Source: Perfect Tennis, 'Cyclops in tennis: assisted line judging before Hawk-Eye'; That 1980s Sports Blog (The Telegraph, 1980) · recall

5.53Making the Ball

How a ball is put together, where Wimbledon's come from, how they are kept and which brands serve the majors.

Test 1Inside the tennis ballTake a test

  1. The halves are pressed together with gas inside, which gives the ball its bounce.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), 'How a tennis ball is made' · recall

  2. Wool gives the felt its fluff; nylon makes it last longer.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), 'How a tennis ball is made' · recall

  3. Production moved from Yorkshire to a factory in Bataan; the materials come from many countries.

    Source: Slazenger, Wimbledon ball (slazenger.com); Wimbledon.com, 'Behind the scenes' · recall

  4. Keeping every ball at the same temperature makes them all bounce alike.

    Source: Wimbledon.com, 'Behind the scenes' · recall

  5. The deal is one of the longest in sport.

    Source: US Open official site (usopen.org) · recall

  6. It replaced Wilson, which had supplied the event for years.

    Source: Australian Open official site (ausopen.com) · recall

  7. Used balls go on sale during the Championships.

    Source: Wimbledon.com, 'Behind the scenes'; Wimbledon Foundation · recall

  8. Core, cover, then a can that keeps the pressure in.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), 'How a tennis ball is made' · recall

  9. 1902, 1979 and 2019.

    Source: Wimbledon.com, 'Behind the scenes'; US Open official site (usopen.org); Australian Open official site (ausopen.com) · recall

  10. The two curved pieces lock together round the core and leave the familiar seam.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), 'How a tennis ball is made' · recall

5.54Strings and Stringing

Borg's tight rackets, Federer's mix, the Belgian polyester and the strings that wear, snap or stiffen.

Test 1What the ball meetsTake a test

  1. His rackets were said to pop at night as the strings tightened.

    Source: International Tennis Hall of Fame (tennisfame.com), Bjorn Borg · recall

  2. The soft gut gave feel, the polyester control and spin.

    Source: ATP Tour (atptour.com), Roger Federer · recall

  3. Its strings became the choice of most of the top men from the late 1990s.

    Source: Luxilon (luxilon.com) · recall

  4. Despite its name, it contains no gut at all.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  5. They suit players who break strings often, at the cost of comfort.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  6. Some gut strings carry a coating to keep water out.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  7. They sit where the strings cross and slow the wear that leads to breaks.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  8. Mains first, then the crosses woven through them.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  9. Gut is the softest; Kevlar is the stiffest of all.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  10. Many professionals mix strings to blend feel and control.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

5.55Electronic Line Calling

From a cricket broadcast to the end of line judges: who made Hawk-Eye, who owns it and when the majors switched.

Test 1Calls without line judgesTake a test

  1. He was a British engineer with a doctorate in artificial intelligence.

    Source: Hawk-Eye Innovations, history (hawkeyeinnovations.com) · recall

  2. It tracked bowling on British TV in 2001, years before tennis players could challenge with it.

    Source: Hawk-Eye Innovations, history (hawkeyeinnovations.com) · recall

  3. The system is now used in more than 20 sports.

    Source: Hawk-Eye Innovations, history (hawkeyeinnovations.com) · recall

  4. Only the two main stadiums kept human line judges that year.

    Source: US Open official site (usopen.org) · recall

  5. It was the first major played with no line judges at all.

    Source: Australian Open official site (ausopen.com) · recall

  6. Clay events were included, so line judges left the men's tour.

    Source: ATP Tour (atptour.com) news (2024) · recall

  7. It is built on high-speed cameras around the court.

    Source: FoxTenn (foxtenn.com) · recall

  8. 2001, 2006, 2020 and 2025.

    Source: Hawk-Eye Innovations, history (hawkeyeinnovations.com); US Open official site (usopen.org); ATP Tour (atptour.com) · recall

  9. The whole process takes a fraction of a second.

    Source: Hawk-Eye Innovations, history (hawkeyeinnovations.com) · recall

  10. The calls 'out' and 'fault' were recorded in advance.

    Source: Hawk-Eye Innovations, history (hawkeyeinnovations.com) · recall

5.56Court Surfaces

What lies under the lines: blue hard courts, green clay, a sticky surface and the sand that sets the pace.

Test 1From clay to acrylicTake a test

  1. It replaced DecoTurf, which had been used since 1978.

    Source: US Open official site (usopen.org) · recall

  2. The blue makes the yellow ball easier to follow on television.

    Source: US Open official site (usopen.org) · recall

  3. The change came with a new surface that year.

    Source: Australian Open official site (ausopen.com) · recall

  4. Crushed metabasalt, a hard green rock, makes it play faster than European red clay.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), court surfaces · recall

  5. Damp clay binds together; dry clay turns loose and dusty.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), court surfaces · recall

  6. Players blamed it for ankle injuries; it was replaced in 2008.

    Source: Australian Open official site (ausopen.com) · recall

  7. Sand roughens the surface and grips the ball.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), court surfaces · recall

  8. 1978, 2005, 2008 and 2020.

    Source: US Open official site (usopen.org); Australian Open official site (ausopen.com) · recall

  9. The playing surface is only a few millimetres of acrylic on a solid slab.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), court surfaces · recall

  10. It is the biggest event played on green clay.

    Source: Credit One Charleston Open (charlestontennisllc.com) · recall

5.57Rackets of the Greats

The rackets behind famous careers: Borg's Donnay, McEnroe's and Graf's Max 200G, Sampras's Pro Staff and the modern makers.

Test 1Champions' racketsTake a test

  1. The small-headed racket suited their serve-and-volley game.

    Source: International Tennis Hall of Fame (tennisfame.com); ATP Tour (atptour.com) · recall

  2. It was one of the first moulded graphite rackets.

    Source: International Tennis Hall of Fame (tennisfame.com); ATP Tour (atptour.com) · recall

  3. The Belgian firm made his signature racket.

    Source: International Tennis Hall of Fame (tennisfame.com), Bjorn Borg · recall

  4. The larger head gave him more margin on his backhand.

    Source: ATP Tour (atptour.com), Roger Federer · recall

  5. His heavy topspin came from a light, open-strung frame.

    Source: ATP Tour (atptour.com), Rafael Nadal · recall

  6. He has played with its rackets through most of his major wins.

    Source: ATP Tour (atptour.com), Novak Djokovic · recall

  7. It became one of the best-selling rackets ever.

    Source: ATP Tour (atptour.com), Andy Roddick · recall

  8. The 1970s, 1980s, 2000s and 2010s.

    Source: International Tennis Hall of Fame (tennisfame.com); ATP Tour (atptour.com) · recall

  9. About 65, 85, 97 and 110 square inches.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), rackets · recall

  10. Damp or heat could bend a wooden frame out of shape.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), rackets · recall

5.58Data and Partners

The companies and gadgets behind the screens: IBM, Rolex, Infosys, a sensor racket and the serve clock.

Test 1Data at the courtTake a test

  1. It runs the scoring data and the official website and app.

    Source: Wimbledon.com, 'Behind the scenes', IBM · recall

  2. Its clocks stand at the ends of the show courts.

    Source: Wimbledon.com, 'Behind the scenes', Rolex · recall

  3. The AI voiced commentary on clips in the official app and website.

    Source: Wimbledon.com, 'Behind the scenes', IBM (2023) · recall

  4. The clock counts down the time between points, in view of players and fans.

    Source: US Open official site (usopen.org) · recall

  5. It powers the tour's statistics and match centre.

    Source: ATP Tour (atptour.com), Infosys · recall

  6. It recorded strokes, spin and impact spots for the player to study afterwards.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com); Babolat · recall

  7. The ball is fastest as it leaves the strings and slows through the air and the bounce.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), ball testing · recall

  8. 1978, 1990 and 2015.

    Source: Wimbledon.com, 'Behind the scenes'; ATP Tour (atptour.com) · recall

  9. 1980, 1990, 2018 and 2023.

    Source: Wimbledon.com, 'Behind the scenes'; US Open official site (usopen.org) · recall

  10. The clock starts when the umpire announces the score.

    Source: US Open official site (usopen.org) · recall

5.59Shirts and Shoes

Tennis kit that became fashion: the piqué polo, the laurel-wreath shirt, the Green Flash, all-leather shoes and a famous face on a tongue.

Test 1Kit off the courtTake a test

  1. The breathable knit replaced the long-sleeved woven shirts of the time.

    Source: Lacoste, history (lacoste.com) · recall

  2. It was first worn at Wimbledon and carries a laurel wreath.

    Source: Fred Perry, history (fredperry.com) · recall

  3. Its green stripes became a classic of British sportswear.

    Source: Dunlop, Green Flash history · recall

  4. The firm was founded in California by two Swiss brothers.

    Source: K-Swiss, history (k-swiss.com) · recall

  5. His name and face went on the shoe in the 1970s.

    Source: adidas, Stan Smith (adidas.com) · recall

  6. He beat Ilie Nastase in a five-set final.

    Source: Wimbledon.com, champions; International Tennis Hall of Fame (tennisfame.com) · recall

  7. His headband and striped shirt became one of the best-known looks in sport.

    Source: International Tennis Hall of Fame (tennisfame.com), Bjorn Borg · recall

  8. 1881, 1911, 1933 and 1952.

    Source: Brand histories · recall

  9. 1929, 1933, 1952 and 1966.

    Source: Brand histories · recall

  10. The longer 'tennis tail' still marks a classic polo shirt.

    Source: Lacoste, history (lacoste.com) · recall

5.60Altitude and Weather

How heat, cold, damp and mountain air change the ball, and the events played high above the sea.

Test 1Conditions and the ballTake a test

  1. Thinner air means less drag, so the ball flies faster and bounces higher.

    Source: Mutua Madrid Open (mutuamadridopen.com); ITF Technical Centre, equipment and court testing (itftennis.com) · recall

  2. The town lies about 760 m above sea level.

    Source: ATP Tour (atptour.com), Generali Open Kitzbuhel · recall

  3. Warm gas inside the ball raises its pressure.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), ball testing · recall

  4. A wet, fluffy ball meets more drag and comes off the court slower.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), ball testing · recall

  5. Players often say cold balls feel dead off the strings.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), ball testing · recall

  6. Conditions stay even, which often helps big servers.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), court testing · recall

  7. Tighter strings give a little less power and more control.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), strings · recall

  8. Near sea level, about 650 m, about 760 m and about 1,050 m.

    Source: Tournament venues · recall

  9. Cold and damp slow the ball; heat and thin air speed it up.

    Source: ITF Technical Centre, equipment and court testing (itftennis.com), ball testing · recall

  10. The Swiss Open has been played there since 1915.

    Source: ATP Tour (atptour.com), Swiss Open Gstaad · recall

Sources

Primary/official sources only, no Wikipedia citations: Slazenger, Babolat, Lacoste, the International Tennis Hall of Fame, CNN, Yahoo Sports, Tennis365, the Tennis Museum, Perfect Tennis, Harrods. The T2000's debut, the oversized racket, polyester and gut strings as materials, yellow balls and Hawk-Eye are asked in Knowledge Testing and left out on purpose.

  • ITF Technical Centre, equipment and court testing (itftennis.com), strings8
  • US Open official site (usopen.org)6
  • Hawk-Eye Innovations, history (hawkeyeinnovations.com)5
  • ITF Technical Centre, equipment and court testing (itftennis.com), ball testing5
  • ITF Technical Centre, equipment and court testing (itftennis.com), 'How a tennis ball is made'4
  • Australian Open official site (ausopen.com)4
  • ITF Technical Centre, equipment and court testing (itftennis.com), court surfaces4
  • Yahoo Sports, 'How many tennis balls does Wimbledon use?'; Wimbledon Debenture Holders3
  • CNN, 'Smurf jokes and a billionaire's dream: where did Madrid go wrong?' (2012); Tennis3653
  • International Tennis Hall of Fame, Rene Lacoste (tennisfame.com); Lacoste, 'Rene Lacoste, Renaissance man' (lacoste.com)3
  • Perfect Tennis, 'Cyclops in tennis: assisted line judging before Hawk-Eye'; That 1980s Sports Blog (The Telegraph, 1980)3
  • International Tennis Hall of Fame (tennisfame.com), Bjorn Borg3
  • International Tennis Hall of Fame (tennisfame.com); ATP Tour (atptour.com)3
  • Babolat, 'Natural gut string, a living legend made in France' and '150 years' (babolat.com)2
  • Wimbledon Lawn Tennis Museum blog / Tennis Museum, 'History: spaghetti stringing (1971)'; Tennis Majors2
  • ATP Tour (atptour.com), Roger Federer2
  • ITF Technical Centre, equipment and court testing (itftennis.com), rackets2
  • Lacoste, history (lacoste.com)2
  • Brand histories2
  • Slazenger Heritage, 'Curiosities of Wimbledon tennis balls' (slazengerheritage.com); Insider Sport (2025)1
  • Babolat; Slazenger Heritage; CNN; Tennis3651
  • Harrods, Fred Perry laurel wreath (harrods.com); Logos-World, Fred Perry logo history1
  • Hall of Fame; Tennis Museum; Perfect Tennis1
  • Slazenger, Wimbledon ball (slazenger.com); Wimbledon.com, 'Behind the scenes'1
  • Wimbledon.com, 'Behind the scenes'1
  • Wimbledon.com, 'Behind the scenes'; Wimbledon Foundation1
  • Wimbledon.com, 'Behind the scenes'; US Open official site (usopen.org); Australian Open official site (ausopen.com)1
  • Luxilon (luxilon.com)1
  • ATP Tour (atptour.com) news (2024)1
  • FoxTenn (foxtenn.com)1
  • Hawk-Eye Innovations, history (hawkeyeinnovations.com); US Open official site (usopen.org); ATP Tour (atptour.com)1
  • US Open official site (usopen.org); Australian Open official site (ausopen.com)1
  • Credit One Charleston Open (charlestontennisllc.com)1
  • ATP Tour (atptour.com), Rafael Nadal1
  • ATP Tour (atptour.com), Novak Djokovic1
  • ATP Tour (atptour.com), Andy Roddick1
  • Wimbledon.com, 'Behind the scenes', IBM1
  • Wimbledon.com, 'Behind the scenes', Rolex1
  • Wimbledon.com, 'Behind the scenes', IBM (2023)1
  • ATP Tour (atptour.com), Infosys1
  • ITF Technical Centre, equipment and court testing (itftennis.com); Babolat1
  • Wimbledon.com, 'Behind the scenes'; ATP Tour (atptour.com)1
  • Wimbledon.com, 'Behind the scenes'; US Open official site (usopen.org)1
  • Fred Perry, history (fredperry.com)1
  • Dunlop, Green Flash history1
  • K-Swiss, history (k-swiss.com)1
  • adidas, Stan Smith (adidas.com)1
  • Wimbledon.com, champions; International Tennis Hall of Fame (tennisfame.com)1
  • Mutua Madrid Open (mutuamadridopen.com); ITF Technical Centre, equipment and court testing (itftennis.com)1
  • ATP Tour (atptour.com), Generali Open Kitzbuhel1
  • ITF Technical Centre, equipment and court testing (itftennis.com), court testing1
  • Tournament venues1
  • ATP Tour (atptour.com), Swiss Open Gstaad1