OK all you dads, I know you mowed your lawns yesterday so you wouldn't have to do it today, right? And how many of you have a new Apple Watch? Oh, you got one today as a Father's Day gift? Good for you! Here's some more good news: mow a half-acre suburban lawn and your Apple Watch will track the same level of activity as if you ran a 10K race!
The iOS Activity app on the Apple Watch has mixed results tracking exercise in general (see Macworld contributor Kirk McElhearn's review ) but it's spot on with lawn mowing. Although a brisk half-hour walk may only net six minutes of "Exercise" in the activity tracker, two hours of leisurely lawnmowing earned me about 80 minutes! Running a 10K (6.2 miles) would rack up fewer minutes and about the same number of "Move" calories.
When I first saw the activity display loop around after I finished mowing my lawn yesterday, I considered it a fluke. (The animation is "delightful," a technical term for making data seem more compelling.) I thought it would be funny to write about how the Watch didn't register a half-hour bike ride as exercise but exaggerated my lawn mowing efforts. But it turns out, according to Livestrong.com, "Those weighing 155 pounds burn 167 calories per 30 minutes [of lawnmowing]." So those two hours really did burn almost 700 calories. (Note: I did a bit of other activity yesterday, but the bulk of the display below is from the lawn.)
Is it good that Apple has distilled your activity down to three dimensions, Move, Exercise, and Stand? It's a mixed bag. On the positive side, simple metrics are easier to metabolize. Three numbers (or colored rings) times the days of the month make for an easily comprehensible matrix. As is often the case at Apple, design bends engineering to its will. On the negative side, the algorithms that convert the Apple Watch and iPhone sensor data into these metrics are not quite soup yet. The Exercise tracking has many gaps, in particular. A five-minute workout from a five-minute workout app doesn't count as five minutes of exercise. There is a way around this algorithmic imprecision: the Apple Watch's own Workout app. If you manually start and stop a workout in the app (for instance "Outdoor Cycle" or "Indoor Walk"), the Activity app will count your full time.
This workaround is a stop gap. If you don't have enough data in a machine learning application, one technique is to use a rules-based onramp to increase accuracy until you have an adequate amount of training data. (See my post on Guesswork for more on this approach.) So if I tell the Watch I am biking, it doesn't have to do a lot of computations to guess what I am doing. But since the watch automatically keeps track of some of your activity it is confusing to users that some exercise "counts" and others don't.
McElhearn goes even farther to say that Apple's "One-size-fits-all fitness tracking is misguided." He points out that "most people who really need to exercise are far from the artificial norm that Apple has chosen." His most salient example is the insensitivity of the "Stand" metric for paraplegics. "I wonder how disabled people in wheelchairs feel about seeing the Stand ring all the time. These people could be extremely active," he writes, "even racing marathons, yet they will constantly see the Stand ring at zero. It would be nice if there were an option to disable it." As a ruder aside, it is humorous to get the "Stand" command when in the toilet!
As with everything about the Apple Watch, activity tracking is a work in progress. Even in its current shape it does provide useful nudges to do more. And, in the case of lawn mowing, it reminds you that what you are already doing is pretty great. Thank you, dads!
(Of course, dads are not the only people who mow lawns, and many dads don't mow their own, either. This post is in the spirit of the day designed by marketers for the honoring of traditional patriarchy!)
