Spin Rates and Spin Axis in Elite Serving

[johnyandell]

Would love to get your thoughts on "Spin Rates and Spin Axis in Elite Serving"

[dipperhitter]

Well I guess it was a little different than I visualized it. And maybe that doesn't matter? It's weird that this kind of research is like so epoch making.
Why isn't the USTA or the tour or someone funding this?

[brent]

Need more data

I'm glad your referenced the ATRP work done earlier. I remembered the high spin rates measured, but assumed those were mostly flat serves (because of the average speed) and totally missed the sidespin indicated in that article. While this newer research shows spin axes similar to the earlier work, I'm still surprised by the apparent similarity between the flat and spin axes in this article. It always appeared to me that flat serve spin and racquet travel are more vertical vs. a spin serve than this data shows.

I say apparent above because I wish we had a three dimensional view of the spin and axes. Did the researchers measure those from a side view? It would be interesting to see how much the rotational axes lean out from the page vs. vertical. By the shape of the partial ellipse your drawings suggest that the axes looking at each type of the serve from the side have similar backward lean, but I suspect that's not correct - particularly for the flat and slice serves vs. the kicker.

Maybe it's a dumb question, but is it reasonable to assume that the direction of racquet travel at impact aligns with the direction of ball spin? I think so, because I can't visualize racquet orientation having significant effect.

It's also interesting that the Sampras and Rusedski serves ("flat"?) in the older work had essentially the same average velocity (117-118 mph) as those in this study (116 mph). Yet the average spin measured in this study (1200 rpm) is only about half of that in the older work (2492-2549 rpm). Certainly technology has changed in 25 years, but I would have expected more spin today than then.

This is good stuff, but I sure would like to see it explained in the context of racquet swing path/orientation and serve technique and in contrast to your ATRP work.

[jimlosaltos]

Good stuff

Would love to get your thoughts on "Spin Rates and Spin Axis in Elite Serving"

Great article. I remember your Sampras-Rusedski comparison and got a lot out of that as well.

I know the measurement issues are tough, but I'd like to see a piece on Nadal's serve. My suspicion is growing that he has a great deal of variation in his spin. I can't see any other reason that top pros can have such difficulty timing returns on a 106 mph serve -- they're beyond simply being befuddled by his "leftyness".

While we're waiting for wonderful new camera tech that lets you quantify this, John, do you have any thoughts on Nadal's slice serve spin?

Thanks again. / jim

[johnyandell]

Brent,

Great post. But no I am not surprised by the higher spin values. The ability to hit with speed plus rotation is what characterized the serves of arguably two of the greatest servers in the game--Greg and Pete.

In our 1997 spin studies we saw examples of servers in the same speed/spin range as the guys in the Elliot study. And remember you are comparing "elite" servers with grand slam champions.

The study by the way was fully three dimensional. The key point I take away from the two in conjunction is how much a relatively small amount of spin affects trajectory and the precision required to generate the differences.

Jim,

Again an interesting question. Impossible to say about the spin type of Nadal though without these types of measurements described in the articles.