Adrian Mannarino strings his racket at about 10 kilograms, or roughly 22 pounds. That’s less than half of what most of the tour uses.
He’s the extreme, but the overall trend in recent years has been toward lower string tensions. Alexander Zverev, who won his first US Open title last month, now strings around 21 kg, well below where he sat a few years ago. That setup has now carried him to two majors this season. Before New York, he won his first Grand Slam title at Roland Garros in June.
How Low Tension Creates Power
Looser strings stretch more on contact, so the ball flattens less and retains more energy. Researchers Rob Bower and Rod Cross found lower tensions produce faster rebound speeds.
However, an ITF-funded study found that string tension doesn’t change rebound speed or spin. Instead, tighter strings shorten the ball’s contact time on the string bed, with a racket strung at 40 pounds making 20% longer contact than one strung at 70 pounds.
The bigger payoff is trajectory. Tennis Lab testing found ball speed changes only 1% to 2% between high and low tensions, while launch angle rises. In one test, balls struck at 44 pounds traveled about half a meter farther than at 54, with nearly identical speed and spin.
Pros can also tame a livelier setup with racket-head speed and heavy spin in ways most club players can’t. Patrick Cai, who has strung rackets for three decades, says tensions have come down because players now hit with more spin.
Polyester Changed the Math
Polyester’s spin potential has made it the tour’s dominant string. At this year’s Australian Open, 75% of players used full monofilament setups, and none used full natural gut.
Poly is also stiff, so stringing it looser makes it more forgiving. Jim Downes, head of the Yonex stringing team, has said that players are increasingly requesting lower tensions to ease the impact on their arms.
Zverev, Tiafoe, and the Low-Tension Club
Zverev uses Head Hawk Touch mains at 20.8 kg with gut crosses at 21.8 kg, and his stringer says he can feel differences most players never would. Asked about that oddly specific number at a HEAD event during the US Open, Zverev explained that he’s very particular about his equipment.
Frances Tiafoe goes lower still. He strung his Poly Tour Pro at 44 pounds in Halle this June, then won the biggest title of his career there. Mannarino himself has gone as low as 8 kilos (17.6 pounds). “The looser the strings, the more trampoline effect you get,” he says.
Not Every Star Is Going Low
Although the trend is toward looser strings, some top pros still prefer higher tensions. Jannik Sinner strings at 28 to 29 kg, a tight setup that suits the pinpoint precision behind his serve.
Novak Djokovic, who is aiming to play the ATP Finals, sits around 28 kg with his gut-and-poly hybrid. Carlos Alcaraz lands in the middle, generally around 25 kg in the mains and 23 kg in the crosses.
String Tension by the Numbers
The ATP top 50 averages about 23.5 kg, or 52 pounds. Pete Sampras strung between 32 and 35 kg. At the Australian Open, players raise tension by about 2 kg in the heat, and strings lose roughly 1 kg overnight.
From Mannarino’s 10 kg to Sinner’s 29, there’s no magic number. The right tension is whatever lets a player swing freely and still find the court.
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