Australian Open

[stroke]

Novak routines Stef 1st set. Odds now show Novak at a 92.5% implied probability of winning this match.

[jimlosaltos]

Forehand Speeds at AO 2017

For perspective, some of you might like this graphic I dug up for you from the NYT giving forehand speeds from the Australian Open in 2017.

Since averages can mislead, I like the way the horizontal lines show the average on the left of each line and the maximum speed for that player on your right. Relevant to our discussion, the fastest speed shown is about 103 MPH by Rafa, with 15 men reaching 100 MPH. Note: This is from the Tennis Australia stat group, and their methodology takes out outliers, i.e. the fastest and slowest shots are removed.

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[jimlosaltos]

I don't doubt those are the posted stats. Just not sure I believe them. As I posted before a USTA insider tells me that on the groundstrokes any data above 100mph is "unreliable" what ever that means...

John, let's see if I can be more concise and clear without the fog of nighttime <g>.

I'd be surprised if any inaccuracies in the HawkEye data were great enough to alter the basic trends they show.

Let's say the high end measurements are off by 4%, which would be a huge error. Then the top groundstroke speeds of 130 MPH, if inaccurate by +/-4% would actually be 124 - 134 MPH.

So, the extremes, the highest speeds for groundstrokes would still be overlapping with service speeds. That's amazing & yet worth questioning.

The second trend the HawkEye data shows is that the highest groundstroke speeds for most of the top players has moved from several players reaching 100 MPH during a tournament 10 years ago, to most everyone in the top 20 not named Diego Schwartzman, hitting 120 mph on one or both sides from time to time. That, to me, is the bigger takeaway. So, again assume it's off by 4%, then that becomes the top 20 regularly reaching 115 - 125 MPH, not in every game, but over the course of a tournament. That's a big leap from peak Fedal years.

In order to change those two conclusions, the HawkEye errors would have to be, say, over 10% -- which would be so egregious, the reliability of the whole system would be called into question.

There's another interpretation to the USTA official's comment about inaccuracy. That would be that the system has trouble with so-called "Edge Cases". That is, the measurements are accurate most of the time, but have trouble with some difficult conditions. For example, when a player is at the back wall fewer cameras have coverage of the racket striking the ball. Going from bright sun to dark shadow with low contrast but cause problems. But even then, measurements of typical groundstrokes struck from the normal playing area should be accurate.

When I pulled data for the earlier TPN article, I removed data on shots that shows "Spin N/A", or unusual flight paths for the balls, to reduce possible issues like that.

I spent some time searching for information on accuracy of HawkEye used in Major League Baseball. Unlike tennis there are independent studies of HawkEyes accuracy there. Academics discuss the errors, but in fractions of a percent, nothing approaching what would fundamentally change what the groundstroke stats show us. One issue is "calibrating for stadiums". I don't know what they believe varies. But the tennis HawkEye data, paltry and erratically shared as it is, is consistent for players across different events. If Caspar Ruud hits 120MPH and often close to 4,000 RPMs, that is shown at different sites, with different sets of equipment.

Well, I failed in my goal of conciseness. Sorry <g>

[stroke]

Well put. Djokovic learned nothing from the disastrous Adria Tour.

I'd add that it is a big leap from making an individual choice to not get vaccinated to openly promoting pseudo-science above modern healthcare, as Djokovic did when he promoted a scam artist's fake alien pyramids and the healing power of their tunnels. People are paying to visit this hoax because of his celebrity.

To me, we are all responsible for our own decisions. If someone decides to go for some pseudo science whatever because Novak promoted it, that is completely on them to me.

[jimlosaltos]

Happy to see Sabalenka win her first major. After her "painful to watch" struggles with her serve, it was nice to see her come up "big" with it in pressure moments. Was it ever determined which biomechanist she was working with?

SeanO

Agreed. Saby's success is an interesting lesson for all of us about dealing with the "yips". There's a line of thought that once one has them, it's too psychological to overcome. Clearly, she did. Going from hitting 50+ double faults in a match to a major title, where she served with as much pressure as you can face in her profession. Kudos.

[jimlosaltos]

Individual rights vs. public good. Always a tough debate. Novak stood up for individual rights. He bided his time and now he is back. Of course, he was willing to take as many COVID tests as needed.

I completely disagree with him. I had childhood Asthma and ended up in the hospital for an overnight stay when I was 3 and a half. I would take ANY jab to avoid feeling like I was losing my breath. It is the most horrible feeling in the world. There is no painfree euphoria when one is unable to breathe.

Novak clearly had a different life experience. As long as he is making sure not to infect others, I am okay with it.

The problem is he was putting others at risk. Having tournaments and infecting lots of people. He felt he was above others and the illness. If he had really known what it was like to be out of breath, I am sure that he would think differently.

As I said, individual rights vs. public good. Always a tough debate.

All I can say is that 5 shots and one COVID infection later, I am glad to be on the other side of this whole thing. I really appreciate seeing others these days.

Hope all of you are healthy and enjoying the company of others!

Well put. Djokovic learned nothing from the disastrous Adria Tour.

I'd add that it is a big leap from making an individual choice to not get vaccinated to openly promoting pseudo-science above modern healthcare, as Djokovic did when he promoted a scam artist's fake alien pyramids and the healing power of their tunnels. People are paying to visit this hoax because of his celebrity.

[arturohernandez]

2023 Australian Open...Novax appears to be the winner according to Scott Adams (not referring to tennis)

Scott Adams makes a rather bizarre video regarding the COVID Vaccines. Novak Djokovic took a stand and refused to take the jab. But it cost him a shot at winning his 10th Australian Open Championship. A rather steep price considering. The forum ganged up on him last year. He had the audacity to think for himself. I read it. I didn't participate...being on sabbatical as I was.

https://www.youtube.com/watch?v=C41GCgyG4mI&t=182s

Individual rights vs. public good. Always a tough debate. Novak stood up for individual rights. He bided his time and now he is back. Of course, he was willing to take as many COVID tests as needed.

I completely disagree with him. I had childhood Asthma and ended up in the hospital for an overnight stay when I was 3 and a half. I would take ANY jab to avoid feeling like I was losing my breath. It is the most horrible feeling in the world. There is no painfree euphoria when one is unable to breathe.

Novak clearly had a different life experience. As long as he is making sure not to infect others, I am okay with it.

The problem is he was putting others at risk. Having tournaments and infecting lots of people. He felt he was above others and the illness. If he had really known what it was like to be out of breath, I am sure that he would think differently.

As I said, individual rights vs. public good. Always a tough debate.

All I can say is that 5 shots and one COVID infection later, I am glad to be on the other side of this whole thing. I really appreciate seeing others these days.

Hope all of you are healthy and enjoying the company of others!

[stroke]

https://open.substack.com/pub/hughclarke/p/ao-semi-finals-recap-and-final-preview?utm_source=share&utm_medium=android

This is a very good article on the mens semis. It gets into some interesting technique stuff on Tsitsipas' backhand, both the topspin and slice. I have often wondered exactly why his slice backhand is clearly not nearly as good as Roger's or Grigor's, or even Gasquet's or Evans. I think the author of this piece is on to something

[stroke]

https://www.tennis.com/news/articles/novak-djokovic-stefanos-tsitsipas-australian-open-final-2023

Good article on the Final

[arturohernandez]

I have always liked Novak. I like Tsitsipas too, but I am thinking Novak will probably be the favorite in the Final.

Novak on a mission. Tstsipas will need help from up above to pull this one off.

[seano]

Happy to see Sabalenka win her first major. After her "painful to watch" struggles with her serve, it was nice to see her come up "big" with it in pressure moments. Was it ever determined which biomechanist she was working with?

SeanO

[don_budge]

“Reports that say that something hasn't happened are always interesting to me, because as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns- the ones we don't know we don't know.”

[jimlosaltos]

Jim, great stuff. No doubt to my eye these young guys like Rune, Tsitsipas, Korda are producing some groundstrokes, speed and spin totality, on a new level. I am sure you have seen this occasional TennisTV stat where they, during a set, will give their "quantitative " measure of each players forehand "heaviness". That spin/speed thing must be the measure of such a result.

Yes, I have mixed feelings about their "synthetic" stats. I wish they told us what went into them. But they probably feel that would alienate the less involved viewers.

[jimlosaltos]

Amazing post....

Seems outrageous that forehands are reaching such high speeds. A while back I read Wawrinka was the biggest hitter on tour off both wings, averaging the low 80s mph on his forehand and backhand. Del Potro was once singled out at Wimbledon for hitting a 104 mph forehand, which was thought to be the fastest ever hit at SW19.

Yeah. From memory, the fastest speeds recorded using old radar technology were 125 MPH for James Blake and shots by both Delpo and Fernando Gonzalez at around 120 mph. There are YouTube videos for whatever it is worth to simply look at them.

I wonder if there is any reason a forehand, striking an incoming ball going, say 50 mph, wouldn't generate more speed than hitting a stationary service toss?

[jimlosaltos]

I don't doubt those are the posted stats. Just not sure I believe them. As I posted before a USTA insider tells me that on the groundstrokes any data above 100mph is "unreliable" what ever that means...

Yup, John, I believe I referred to that USTA off the record comment.

I understand your skepticism. I waiver between that and acceptance because the alternative is so bizarre.

As I said, I don't have a dog in this hunt. But until proven otherwise, this is what the professional tennis industry is reporting.

Sorry to be verbose but ...

If the "old" speeds are both correct and what players are still achieving, then the errors are about 20-30% or more. A 10% error would be astonishingly incompetent.

Can they provide ANY explanation for why HawkEye can measure the speed of a serve with great accuracy, but not only can not measure a slower groundstroke accurately but has extremely large errors?

And, if that is correct, and the USTA knows this, why have the ATP, French Tennis Federation, and Tennis Australia been posting those numbers for a couple of years now? If its groundstroke numbers are inaccurate -- and we're not talking small errors, but very large ones -- how can they claim electronic line calling is as close to infallible as they want people to believe it is? HawkEye doesn't take a picture of the impact, it computes it from speed, direction and spin. If one of those is way off, the calculation is off.

Hand held radar guns at $300 claim accuracy of +/- 1% or 3 mph up to 130 mph on a baseball {although user reviews vary} $3,000-$5,000 units better

But a $60,000 HawkEye system {not incl cost of staff to run it}, calibrated for a given stadium, can't do as well?

Major League Baseball seems to claim an accuracy of fractions of a percent for its HawkEye system {although I haven't found a specific "guarantee"}, but that is more complex with, I believe it is currently 12 cameras per stadium covering a much larger area.

That would seem to imply that HawkEye, as implemented in tennis, is just plain broken. Which would be a story in itself.

Oh, well back to watching matches