Interactive Forum April 2025: Jakub Mensik Serve

[jeffreycounts]

Jakub Mensik Serve

For this month’s issue, we have exciting footage to share!

If you haven't been following him closely, Mensik is just 19 and on March 30th he defeated his childhood idol Novak Djokovic at the Miami Open. His massive serve is a key part of his game—explosive, fluid, and deceptively powerful. And we have it for you in gorgeous hd, slow motion video!

Take a look at the video and let’s dig into the details:

• What stands out to you technically?
• Any comparisons to other big servers—past or present?

Mensik is clearly one to watch—let’s break down what makes his serve so effective,

Looking forward to your thoughts!

[jimlosaltos]

Since I was focused on where Draper made contact with the ball from Giancarlo's video, here's a comparison.
Both are the same height, and somewhat similar builds. Viewed from different angles.

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[neilchok]

Great video. For me it is the hang time. I think I counted 4 to 5 seconds in the air 1:38 to 1:43, and just his physical size.

[jeffreycounts]

Great video. For me it is the hang time. I think I counted 4 to 5 seconds in the air 1:38 to 1:43, and just his physical size.

Wow you're right. He gets some serious elevation.

[stotty]

Strange ISR. It starts very early and doesn't s fully complete. It's a great pinpoint motion. It repeats beautifully with the rear foot planting up in the same place every time.

[neilchok]

the other thing which seems crazy to me is from the point he lets go of toss to the actual moment he hits the ball is 11 seconds. He lets go at 1:28 and makes contact at 1:39 seconds. To me it seems he really maximizes everything he has.

[neilchok]

fyi 11 seconds almost seems impossible? Is the timing wrong on the video somehow? If I toss a ball in the air and let it land I think at max it will be in the air is around 3-5 seconds?

[jimlosaltos]

fyi 11 seconds almost seems impossible? Is the timing wrong on the video somehow? If I toss a ball in the air and let it land I think at max it will be in the air is around 3-5 seconds?

Maybe I'm not understanding this, but the video is slow motion. So, if anyone wants to measure the duration of any aspect of Mensik's serve you need to adjust for the frame rate. Without importing it to a NLE I can only guess the original recording is 120 frames per second, and that probably isn't exact. Play it back at 20 fps and that 6X slower. Then, there's PAL vs NTSC standards ... more than you want to know.

[neilchok]

image.png

I was playing it right from the video in the chat. And this time right here seems to show the value in seconds, but this does not seems to match reality?

[jimlosaltos]

image.png

I was playing it right from the video in the chat. And this time right here seems to show the value in seconds, but this does not seems to match reality?

I believe that time readout on the grey bar is the play time of the video. If the video is playing at fewer frames than what it was recorded at, the time in the grey bar will be longer than reality. aka slow motion. i.e. A one minute recording at 120 fps, played back at 20 fps will be 6 minutes long. Perhaps that is the issue.

[neilchok]

I see makes sense. I guess I would think the metadata from the video would be giving timestamps to the player, and then using that.

[jeffreycounts]

I see makes sense. I guess I would think the metadata from the video would be giving timestamps to the player, and then using that.

Hey everyone. The video was shot at 300fps if that help!

[giancarlo]

It terms of figuring out the speed it might be easier to just count the actual frames vs. trying to calculate the time (of course it can be converted as well). My suggestion: download the clip to your computer, and open it with QuickTime. Then, change the time display to Frame count (View Menu / Time Display / Frame Count) Then, pick your starting point and count the frames (FYI, that’s how John used to do it).

[jimlosaltos]

It terms of figuring out the speed it might be easier to just count the actual frames vs. trying to calculate the time (of course it can be converted as well). My suggestion: download the clip to your computer, and open it with QuickTime. Then, change the time display to Frame count (View Menu / Time Display / Frame Count) Then, pick your starting point and count the frames (FYI, that’s how John used to do it).

Well remembered. Yes, when John was perhaps the first to report RPMs for players serves and forehands from match play, before Hawkeye, he would count logo revolutions in his slow motion video. If you know how many frames it takes for a ball revolution, the frame rate gives you the spin. Very tedious work. I've done it. Please never make me do it again

P.S. Anecdote from when John was the only source for spin info. Andy Murray asked him if he was up with Rafa and Fed. John had to break the bad news to Sir Andy "No, about 200 RPMs lower".

[asmplm]

The Mensik slo-mo was blacked and could not open- any suggestions?