We cover a lot of activities here, most are related to wrist worn fitness trackers. But sometimes the wrist worn device is not entirely enough. That is the case for Tennis, and pretty much any sport with technique coaching, where the addition of a camera can make a huge difference.
Can Apple Watch Measure Tennis Serve Speed?
The apple watch does have a native workout tracker for Tennis but the data is limited mostly to just time and a guess at the calories burned. The series 7 Apple Watch claims to be able to measure tennis serve speed, but it must be worn on the dominant wrist and even then has issue. Tracking tennis on the watch is not made for tracking serve speed, but rather as a general tennis workout summary. The summary of the playing can be imported as a workout and contributes to closing the watch exercise rings. But what if you want output for an Apple watch tennis serve speed? To get that you are going to need more than just the watch.
It is possible to get advanced stats and analytics on a wide variety of sports by using cameras that measure all sorts of data. Tennis is one of those and the market leader is SwingVision which measures serve speed and shot placement and enables professional level highlights even for amateurs. If you want to get the most out of playing sessions you will need to a non-native app like SwingVision or one of it’s competitors.
There is one app that claims to measure serve speed using just the Apple Watch, called Tennis Keeper. The major downside for Tennis Keeper is that in order to get a measurement it has to be worn on the swinging hand. Even when worn on the proper hand that speed of the serve is calculated based on movement from the gyroscope and does not account for any errant hits, winds, etc.
In general it appears to be more erratic than a camera based system. Still, if you want to find your serving speed using your watch it does an okay job. The speed accuracy is has at least gives some sense of how hard you are swinging if comparing to another player (or yourself) using the same app. Comparing Tennis keeper serve speed to a tennis radar gun serve speed though is not super accurate in our experience.
Using SwingVision with Apple Watch for Tennis
SwingVision is design to provide automated scoring, stats, and line calling. By capturing all of this data on video it also becomes a unique opportunity to enable coaching. This can be done either directly, by recording a live coaching session, or by sharing your data with a coach to get feedback on technique.
Compared to the output provided in the workout analysis, the video is beyond valuable. A simple Apple workout summary even using Swing Vision just has time and calories. To get more you need to use the SwingVision app to dove into stats.
The app for SwingVision is designed for iOS. There is a desktop version of the app, so android users can record sessions and upload them, but the easiest way to setup the tool is to have it on an iPhone. After properly placing the camera it is best to have an Apple Watch as well. This lets you start and stop sessions without having to mess with the phone placement.
Using the Apple Watch all you have to do is navigate to the app, and tell it what type of session to start. They have options for serve sessions, singles/doubles rallies, and even the option to hit against a ball machine.
Is SwingVision Speed Accurate?
The biggest question for any of these AI tools is if they are accurate. To asses this there are their claims, and there are anecdotes.
The claim: SwingVision claims to be accurate to within 10% for things like ball speed. And they claim 5% accurate for ball placement. All of this is assuming proper camera setup and 60FPS analysis. It is unclear what their claims mean, is there 10% variability around the actual value (meaning a 100MPH served ball may appear 90-110MPH). Or does it mean that 10% of your shots will be wilding inaccurate, while 90% are within an acceptable bound? SwingVision has not produced verified studies against their accuracy so it is hard to tell. We’ve yet to take an actual speed gun out to the courts to compare, but anecdotes will serve well.
The Anecdotes: The benefit of having video attached to all of the shots is that you can gut check what the analysis says. In this since, SwingVision is very accurate. Enough so that we trust the aggregate metrics that it puts together.
There are times where the accuracy is blatantly wrong. For example, after hitting a bad tossed serve well short of the net in the near court, SwingVision showed it as a good serve in the far court’s service box.
In terms of hitting speed, even without calibrating against a radar gun, the speed’s analyzed feel right. It is nice that within the first few hits of opening the app we were able to get the feel that this analysis was trustworthy. This continued and was strengthened when additional players and sessions started. Relative to other recorded hits the speeds always seem to be accurately higher or lower than others. Nicely too there has rarely been an outlier that seems completely wild (ie. a 140MPH ball out of one of a beginner, or a hard hit ball tracking at 18MPH).
What is the Cost of SwingVision?
The best part of SwingVision is that their free tier is useful by itself. Without paying for anything additional you can have up to two hours of hitting analyzed per month. As a supplement to a real coach this is an amazing value. Because the videos get auto clipped, eliminating time in between sets and serves, even just rewatching an hour long session as a 25 minute highlight real is an amazing value. This is especially true if you are working on form, as a 20 minute serve session will be auto-edited down to around 10 minutes within which you can really analyze movements from serve to serve.
The point where you will want to start paying for SwingVision is if you are using it for match and competition analysis. The advanced features, which are available for $12.50/month or $150/year, will be needed if you plan to analyze a full match. What’s more the trend trackers, where you can see the performance of each type of hit is only available at these levels.
Overall SwingVision is an amazing tool to make you a better tennis player. The ability to have feedback on your game so quickly, and have it analyzed in a way to objectively measure if you are improving is amazing. At the cost of only a few lessons, or about the monthly price of a single court fee in some areas, there are few better options.
If you want to look at other Tennis tracking, there are competitors to SwingVision. The primary ones are again Apple Watch type tools that claim to generate ball speed analysis and swing analysis using the accelerometer of your watch. This includes Tennis Keeper, and the default Apple Workout type “Tennis”. While both of these are viable options, their accuracy is no where near what the camera based system of SwingVision is. What’s more they also require that you have your watch on, and on your dominant hand. In some competitions this might not even be allowed, and for many players having a watch on their dominant hand would just feel out of place. Still, each of these tools offers significantly more insights than we all used to get from wooden rackets and grainy videos.