“If you’re a scientist, and you have to have an answer, even in the absence of data, you’re not going to be a good scientist.” – Neil deGrasse Tyson, Astrophysicist

In part 1 of this article – DIGITAL TECHNOLOGY, DATA AND PLAYER DEVELOPMENT IN TENNIS – PART 1, I talked about living in a stream of data so powerful that we are completely unable to process more than just a tiny little bit of it. Or as Peter Diamandis, Founder of the X-Prize puts it – “Every second of every day, our senses bring in way too much data than we can possibly process in our brains.”

It is interesting that most of us reject even a thought to sift through a vast amount of data on a daily basis. It’s a love-hate relationship that we have. Although we rely on and use data consciously or subconsciously every second of the day, if nothing else for our daily chores, we dig in like a mule when something requires from us in-depth analysis based on data. It’s understandable if we don’t possess skills or patience to do it. But more and more activities in our life will soon call for better understanding of what is going on based on data or data based information. It’s one of the simple rules of survival – if new, better methods are introduced, one has to adapt. With new data based technologies the bar is being raised, and you need to learn how to jump higher or stay out of the competition.


Let’s take a hypothetical case of buying a car. The best, the newest. A beast. I can’t live without it and can afford it. So I pay a visit to a dealership, and I like what I see. I see a powerful car that will take me anywhere in no time. It looks gorgeous from the outside and seems better and faster than anything I have ever seen. A car salesman approaches me, with a big grin on his face. I like what I see from the outside, so I don’t want to spend any time on pleasantries. ”Can you show me the inside of the car, please?” “Sure, sir.”

The inside is impeccable. The dashboard is a surprise though, built from a single block of aluminum. Beautiful but with no instruments at all.

“So this car has only a head-up display?” “No, sir, it doesn’t have a head-up display either.” “So where are the instruments?” “It doesn’t have any.” “What do you mean it doesn’t have any?” “Well, you look like an experienced driver, you don’t need any. The instruments are just a disturbance.” “So no speedometer?” “No.” “How do I know how fast I drive?” “As I said before, sir, you look very experienced. I’m sure that you can estimate the speed very accurately based on how fast the trees or the houses are passing by.” “What about a fuel gauge? How will I know how much gas I have in the tank?” “This car has a big gas tank. Just stop regularly.” “But what if I run out of gas anyway? My wife and my son will be driving this car too, and I don’t know what they will be doing with the car.” “Sir, not only that you look experienced, but very strong as well. Our car is among the lightest on the market. If that happens, get out of the car and push it to the nearest gas station.” “You think I’m strong?” “Yes, sir. Very strong.” “You are right; I am strong, I guess I can do a little pushing if necessary. OK, I guess I don’t need a tachometer either, but what about an odometer?” “You don’t need one, sir. Use landmarks to determine the distance.” “What about the oil? How will I know when the car is due for an oil change without an oil gauge and an odometer?” Now car salesman face brightens, and his grin gets even bigger – “This car has an oil gauge, sir. It has a very accurate dipstick. All you have to do is to unscrew a few screws under the hood and pull it out to see what is going on. Just don’t forget to screw the screws back when you are done.” “ A dipstick?” “Trust me; it’s more accurate than any oil gauge that you can find on the dashboard. On top of that, you look very wealthy, sir. I’m sure you can afford a couple of minor repairs if you forget to change the oil and something goes wrong.”

So I’ve bought the car without any instruments because I liked it and because the salesman was hitting all the right notes. I’ve run out of gas a couple of times and the longest distance I pushed the car was somewhere around… well, I can’t tell without an odometer. I’ve got stopped for speeding more than once, and the traffic cop couldn’t have cared less about me being an experienced driver. Two to three times a year I must take it to a repair shop –it is much easier to damage the engine without oil gauge and tachometer.

So why exactly am I driving a car without any instruments? I don’t know. But I know that I am not experienced enough to estimate speed by the objects passing by; that I’m not strong enough to push the car to the nearest gas station when I’m out of gas, and that I’m not rich enough to pay for the constant repairs. I’m pretty sure that the car salesman took advantage of me.

This article is about the performance and development in tennis, and I hope that you can see the analogies between these two and my fictitious car buying and driving experience. Too often we are conducting tennis practices without actually knowing what is going on. In reality, being strong doesn’t mean much if you use your strength for the wrong purposes. Being experienced will get you somewhere, but it will get you further with more and better data-based information. And spending money on repairs (read injuries)? Most of them should never happen in the first place as they are easy to prevent with the right set of data.

As Neil deGrasse Tyson said, it’s hard to be a good scientist in the absence of data. It’s also hard to be a good driver. It’s even harder to be a good tennis coach or a tennis player.


“We’ve got to use every piece of data and piece of information, and hopefully that will help us be accurate with our player evaluation. For us, that’s our lifeblood.” – Billy Beane, General Manager Oakland As

Use of modern technology has slowly become more important in sport in general. Billy Beane’s words say enough about the importance of data in sport, especially when we talk about high-stakes competition. Tech in sport has gradually progressed in the last 50 years from bulky and expensive to less bulky but still costly.

Nowadays, latest achievements in miniaturization of the tech have brought the price from several thousand dollars to a few hundred or less. Devices have become portable, most of them fit in a pocket. This way the use of analytics in the sport, in general, has become more widespread and less elitist. No longer you have to be a wealthy athletic club to be able to afford necessary analytical tools for video analysis, physiological assessments, speed measurements, etc.

If you understand that data is your lifeblood and that data-based practice is the fastest and the safest way to develop tennis players of all levels, you are in luck. New tech is coming to the market every day and is only getting better and cheaper.


“Data adds concrete information to a teacher’s observations and intuition, but it will never replace experience, personal relationships, and cultural understanding.”- Jose Ferreira, Founder, and CEO of Knewton

As I said in Part 1, Armbeep Tennis Performance Analysis System helps monitor, assess and analyze practice or match data and it is a helpful tool when coaches need to optimize the practice loads and determine the appropriate daily, weekly and monthly amount of repetition during practice, among other things. However, it is not meant to replace them, only to provide additional data based support.

Our intuition tells us that more we have to process, e.g., more data, more work we can expect, but in this case, it’s precisely the opposite. With Armbeep your job as a coach will be less stressful. More data, in this case, mean less work because the Armbeep Performance Analysis Software will do the heavy lifting for you. You will be able to see the big picture and see all the vital information at a glance. And all that player has to do is to wear a monitoring device, that weighs about one-tenth of an ounce on his wrist, and transfer the data from the device to the cloud afterward.

In Part 1I mentioned some of the data Armbeep System collects – the number of shots, active hitting time and the length of rallies. Here are some more:

Tempo –Optimal practice is not determined only by the number of shots but also by the hitting pace. Armbeep System provides the number of shots per hour of on-court activity or the number of shots per minute of active time of on-court activity.

Wrist speed –Armbeep System provides the average wrist speed during on-court activity, and also wrist speed of individual shots.

Wrist acceleration –As with the wrist speed, Armbeep System provides average wrist acceleration during on-court activity or wrist acceleration of each shot.

Heart rate during practice/match –One of the unique features of Armbeep System is that it provides heart rate monitoring during the on-court activity and merges this physiological indicator with the hitting data for more accurate practice or match analysis. Armbeep System provides average heart rate during on-court activity or the heart rate during a specific part of that activity.

Heart Rate Variability –Armbeep System additionally measures HRV (Heart Rate Variability) for more accurate assessment of the physiological state of tennis players. In a nutshell, heart rate variability is one of the indicators of the state of players’ health and fitness, recovery, and readiness. Not the only one, but a good indicator of their physical state that day.

As you can see, Armbeep Tennis Performance Analysis System offers a lot. Once you learn how to use it to your advantage, you’ll see a real difference in every aspect of the development of your players. The risk of injuries will go down, and their performance will go up.

And if you start to share and compare the data with other users, you will learn even more. Your reality will shift, if not change completely. Your knowledge will grow. You and your players will feel more comfortable. And if your work has ever made you feel like a deer on a highway, you know exactly what I have in mind.


See more about Armbeep in action and how Armbeep could help you.