Interactive Forum May 2010: More New High Speed Footage! Nadal Point Sequence

[johnyandell]

Nadal Point Sequence

This month we are escalating the wow factor on our new high speed footage with a point sequence of Rafael Nadal, filmed at 500 frames/second at Indian Wells. A second serve, an inside forehand, a backhand and a wide forehand.

You can see just how that reverse finish Robert Lansdorp discovered works, and you can count the spin for yourself--just the way we do it in our research.

In fact I want you to. Watch the ball markings and count the frames it takes for the ball to make one revolution. Now let's see who can do some simple algebra. At 500 frames per second what are the rpms on the four shots?

I have a set of new backhand DVDs for the first person to answer all 4 correctly!

Nadal Point Sequence

[johnyandell]

Quicktime version

Nadal Point Sequence

[gsheiner]

I'll take a crack even though I can see that there is an certain element of subjectivity.

I'll go with:

Serve 4285
1st FH --3333
Backhand 1000
2nd Forehand 3750

If these numbers are correct, then his forehand rpm's exceed that of Bruguera but his backhand is surprisingly flat.

GS

[stumphges]

I'm pretty much with gsheiner, but:

Serve: 4285 rpm
1st forehand: 3333 rpm
Backhand: 833 rpm
2nd forehand: 4000 rpm (incoming ball spin is noticeably less on this shot, so outgoing spin is, not surprisingly, higher)

Roger's 2nd serve shot from a month or two ago: 5000 rpm

[johnyandell]

Excellent! I'll double check my own numbers all later but you guys may be called upon to count a few hundred more examples.

Note on Roger's serve--did you figure that at 500 or 250 frames? We shot mainly at 250 last year in Cincy, and that is the case with that serve. Our new lens configuration was so much better (more light) in IW that we bumped most of it to 500 frames.

[stumphges]

Hey John,

I figured the Fed 2nd serve assuming 500fps. The ball is only on the strings for 2 frames in that clip, and knowing that contact usually lasts about 4-5 milliseconds I figured it must be 500. But, I miscounted that one - I missed that the ball has two markings on it. It looks more like 2700 on second look.

I would be open to doing some counting for you if it would mean getting some sneak peaks at your footage.

[johnyandell]

you know what I had a mental breakdown there for a minute! (Hopefully only a minute...) You were right in the first place--that last match was the one where we did film at 500 frames. The ball on the strings for 2 frames is the giveaway as the contact is 4-5 milliseconds--1 frame at 250 and 2 frames at 500.

[uspta146749877]

Number of rptations per sec

Stumphges,
there was a number quoted some time ago by Patrick McEnroe
that a forehand by Nadal has around 25%-50% more rotations per sec
than forehands of other players.
It would put us in a 2700-3000 range.
Please note that I am referring to NADAL,not Federer ( as you did ABOVE)
julian

[johnyandell]

BTW I gave Pat those numbers. They are on the site in the various articles.

[vaculik]

Having trouble using this so my reply is attached as a pdf file.

[vaculik]

Further to my earlier post, I see the steps in the video clip are actually at 10 steps per second in my iMovie program, twice that of regular speed video clips from the archive. Then I get figures that should be divided by 50! Serve = 375 rpm FH-172, BH-188, WFH-200, so that can't be right either.

Perhaps somewhere in all this, it is the displayed slo-mo speed that should used. Using the frames I obtained we need to apply the correct rate at which they are occurring. I need to sleep on this one.

On another calculation method, I don't know how the duration of contact on the strings is obtained. We could have a circular calculation going on here: using an assumption to verify that assumption.

[johnyandell]

I looked at the pdf and having a hard time figuring that out, but think you have made this more complicated than it is.

The frame rate is set by the software that controls the camera so that is fixed and not a variable. How many frames the ball is on the strings is not an assumption based on frame rate, but an observation.

The balls are marked on both sides.

With these simple facts you can actually do it simply with the QT files in the Forum. Not sure what is happening for you with i movie--it should work, but it's not really necessary.

Try the first Rafa forehand because it's clearer. You'll see 9 frames equals 1 rev
At 500 frames sec that equals 55 revs X 60 equals about 3300rpm. This is consistent with the previous studies that showed this was about his average.

[bababooey76]

Reverse forehand...

I'll probably be blasted for this but I would hardly say that Lansdorp "discovered" the reverse forehand. He has in the past told anyone who cared to listen that he thought the reverse forehand was a "lazy" shot. His players (most notably Sampras, Davenport, and Sharapova) came about this shot possibly because their forehands were so flat and erratic. If you look at Sampras specifically, he only began to purposely use the reverse forehand once he began working with Gully (RIP). Agassi had a similar awakening to the reverse forehand when he began working with Cahill.
Lansdorp has been instrumental to tennis and has coached some of the best backhands pro tennis has ever seen but lets call a spade a spade and not say he's to be credited for the reverse forehand. Keep up the good work everyone!

[johnyandell]

Interesting and no need for blasting. Robert told me the same thing--that he used to mercilessly criticize Pete when he hit that finish.

By the time Sharapova came around though he was training it. I know because one of the first times I ever did an article with Robert he said something like "hey you should film this little Russian kid who's out her from Bollettieri's--she's pretty good."

I still have the tape box and wrote on it "Lansdorp with Russian Kid."

That kid of course turned out to be Maria age 12 or whatever. He would have her drive 5 or 10 balls, then hold it out front or a ball or two, then have her reverse 5 or 10 and then repeat the whole thing until Maria was begging for mercy.

So I can tell you were there a while before I showed up, and that you heard the truth, but I think one thing about Robert he will change his mind. Just like he did on the wiper or what he calls the downward finish...

He himself always said players invented the reverse as a shot (turns out Fred Perry hit it too...) But I do think the term was original to him, and maybe he was one of the first if not the first to consciously develop it with a lot of juniors.