Welcome to the second post of the Sinner Series! Jannik Sinner completed the 2024 season with an outrageous 73-6 record. Of those 6 losses, half were to Carlos Alcaraz. Can you guess who else, out of the following options, was able to defeat him in 3 sets?
Of the options below, who was able to defeat Sinner in 3 sets in 2024?
Alexander Zverev
Novak Djokovic
Andrey Rublev
Casper Ruud
Answer can be found at the bottom of this post, after the citations.
In September, we went over how a key part of Sinner’s game is his crisp forehand, which is enabled by his ability to distance himself from the ball. Doing so allows him to bend his elbow at just over a 90-degree angle, generating maximum flexion force to transfer to the ball upon extension. However, many other players are quite good at this skill too, namely Carlos Alcaraz and Casper Ruud. This begs the question, what else makes Sinner’s forehand – and backhand – so special?
Let’s start with his forehand! When Sinner prepares to hit a forehand, he split-steps, turns, pulls his racket head back, etc. This is all pretty standard. However, what does he do right before he makes contact with the ball?
Answer: He makes a last-second adjustment to his grip, turning it slightly western to optimize for spin.
Sinner technically uses a semi-western grip for his forehand – a common choice, given that it enables players to maximize a balance of power and topspin, both of which are paramount in the modern game. However, there are multiple different types of the semi-western grip. What comes after a semi-western grip but before a western grip? And what comes before a semi-western grip but after a continental grip? Sinner is the master of making precise, last-second, grip adjustments to optimize for either power or spin.
To further break this down, in picture 1, he begins to take his racket head back, with the help of his left hand. At this point, he’s holding something in between a continental and semi-western grip. In picture 2, you can start to see him using his left hand to turn the racket clockwise in his right hand. Finally, in picture 3, you can see that he has completed the upshift to a semi-western. If you take a look at any of his footage, you will see that sometimes he goes towards more of a western grip, which prioritizes spin over power for more defensive balls. If you’ve ever wondered how his shots dip in when you think they’re going long, this subtle tactic is one of the key reasons (3,049 rpm vs. 2,708 tour average in 2024; in other words, when he hits a topspin forehand, it spins in a circle almost 6 times per second more than the average player).
To think about this incredible stat another way, let’s calculate the centripetal force he’s applying to the ball. Centripetal force is the force that makes an object follow a curved / circular path. This force is directed from the outside, in. One good example is hammer throw in track & field. As the thrower spins the hammer around, centripetal force is generated in the direction of the hammer toward the axis of rotation, which is towards the thrower. In tennis, when the ball is hit with spin, the racket transfers force going from the outside of the ball to the core. This is the formula we can use to calculate the magnitude of the force Sinner generates:
Centripetal force = mass of the ball (angular velocity) ^ 2 radius of the ball
= mass (2π RPM / 60 sec per min) ^ 2 * radius
= 0.0577 kg (2pi 3,049 rev per min / 60 sec per min) ^ 2 * 0.0135m
= 79 Newtons
In our September blog post, we calculated that Sinner’s fastest forehand generated 532 Newtons, which is roughly equal to 120 pounds. Imagine brushing up on the ball and creating a 20-lb-dumbbell’s worth of force directed toward the ball’s core – that’s just what the carrot-loving Italian is doing!
The second interesting aspect of Sinner’s forehand is that he hits it from the slot position (see picture 6 for how far back he takes the racket head). He actually does the exact same thing with his backhand, which he hits with a normal eastern grip.
Jannik Sinner’s backhand using an eastern grip
Why is this important? Think about it this way - would a boxer be able to punch their opponent harder if their hand was in front of their own body or if they pulled it back behind their head and then unleashed? Same thing here – the answer is almost always F = ma! For a given mass (of the ball), force is maximized with acceleration, which is equal to the change in velocity divided by the change in time.
For a relatively fixed change in time, it is intuitively easier to reach top speed with more space, as in scenario 2 vs. 1 below:
However, many players prefer something closer to scenario 1, including Alcaraz, given that it requires simpler preparation! Ultimately, what you use is up to your style of play and what feels comfortable. The only thing certain is that Sinner made the best players in the world feel very uncomfortable this season by utilizing these skills. Is there an even better forehand / backhand technique that no one has thought of yet? Time will tell…
Comment down below what other pro tennis players you’ve seen use a slot backhand and give it a try yourself! It may feel unnatural at first but it can help if you have trouble hitting deep balls..
Stay tuned next month for a deep dive into Electronic Line Calling (ELC) – which the ATP has mandated will be used across all tournaments in 2025!
Happy holidays and happy new year from all of us here at Court Dry!
Works Cited
12kgp-Tennis. (2024, March 13). Jannik Sinner - 2024 IW Practice Sessions. YouTube. https://www.youtube.com/watch?v=3m80hWeNLqg
Bhuyan, S. (2023, August 1). Centripetal force: Definition, examples, & equation. Science Facts. https://www.sciencefacts.net/centripetal-force.html
Jannik Sinner’s 1-2 baseline punch underpins his standout season: ATP tour: Tennis. ATP Tour. (2024, September 11). https://www.atptour.com/en/news/sinner-2024-insights
Trivia Answer: Andrey Rublev
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