How Data Can Improve Your Game?
By: Matt Groh
Tags: Sports, Tennis, Data Visualization, Smartwatch, Apps

How Data Can Improve Your Game?

A premier look at Tennis Sense — a smartwatch technology.

If you want to take your tennis game to the next level, you have four options: play more often, get a coach, read Winning Ugly and The Inner Game of Tennis, and track data on your performance with a smartwatch app like Tennis Sense [Full disclosure: I’m a co-founder of the company, Proprio Labs, that built Tennis Sense.] Here’s a primer on how your data can help you better understand your strengths and weaknesses.

Do you know how often you’re hitting a second serve? How about double faulting? Do your rallies usually last a single groundstroke or do they go on and on? Does the length of your rallies change as you get tired? How often are you hitting forehands? Backhands? Do you usually win points on forehands or backhands? Does this change over the course of a match? And what about how you play under pressure? Relative to other points, do you stumble or dominate at game points, set points, and match points?

Professional tennis players know the answers to all these questions. And with Tennis Sense, you could too! Here are some examples of the insights you can get from collecting data on what tennis strokes you hit, when you hit, how hard you hit, and which points you won and lost. Tennis Sense does this all for you by applying machine learning to the data generated by the motion sensors and microphone on a smartwatch! The following visualizations are currently part of the app or will be added in soon.

How often do my serves go in?

That’s a visualization from a single match. If you knew how often your serves land in and what percent of points you win on your first serve and your second, you could optimize for your personal first-serve, second-serve combo. In this example, the player is hitting her first serve in 80% of the time and winning those points 60% of the time. Her second serve is more accurate (going in 86% of the time), but it’s less effective. She is only winning second serve points 40% of the time. The insight for this particular player may be to serve her second serve just like her first to win more points.

How long are my rallies?

Do you ever lose focus while playing tennis? Maybe this happens to you at the start of the match before you get warmed up. Or, maybe this happens near the end as you’re getting tired. If you know this about yourself, you can force yourself to focus more during those moments when you know you tend to be weak. A short rally, more often than not, is indicative of an unforced error. The key is to figure out when you’re losing short rallies and make sure not to make unforced errors the next time around.

How does my shot selection affect the game’s outcome?

Which side is your dominant shot? You likely know the answer, but it’s hard to know just how much stronger one side is than another. By looking at this graph, you may realize an unknown weakness in your game. You can take action on these insights by practicing a particular stroke or directing your game to hit more shots on your dominant side. The bottom line is that it is possible to quantify how much better your forehand is than your backhand and vice versa. And, this can help improve your game.

How do I perform under pressure?

Game Tree reproduced with permission from Damien Saunder at GameSetMap.com

Some matches are lopsided like the one above, and others are in a dead heat until the end. In tennis, it’s possible to win more points than your opponent and still lose the match. Each game is a mini-match, and certain points (game points, set points, match points) simply matter more than others. The game tree helps you identify how you’re playing at different “score moments.” Do you tend to lose points at 40–15 because you think you have room to breathe? Or do you often come back from 0–40? If so, there are a variety of ways to improve your game. In theory, you should always be playing the same. But, in practice, some players choke when they are up. Other players get motivated when they are down. The more you know about yourself, the more effective a tennis player you can be.

What does your heart rate look like when you play?

Here is an example of what one of our original beta testers’ heart rate looked like when he was practicing his serves after a match. As you see, his heart rate picked up to 150 beats per minute while he practiced his serve. It dropped back down to 100 when he stopped serving and started picking up the balls. This data was collected using Tennis Sense on a Moto 360 Sport. Although it is not as accurate as an EKG, the smartwatch heart rate monitor gives you a good idea of when you’re truly exerting yourself. Understanding this level of effort matters because one singles match can be very different than another let alone a doubles match. Now, you can know how hard you’re working from one match to the next.

Smartwatch technology will not replace hard work, coaches, or great tennis wisdom, but it will serve as another tool to take your tennis game to the next level. The more you know about your own game, the greater you can become.

For more information, watch this video:

Follow Matt Groh for more updates on Tennis Sense. Finally, make sure to check out Tennis Sense on Google Play or visit Proprio Labs!