Close Friends Can Now Track Your Fitness Successes (And Failures) On Path, With A Daily Sparkline From Nike+ Fuelband

Nike has been quietly transforming itself from an apparel company to an apparel company that builds sensors into everything… blending man and machine so that we’ll all be able to track our every move and figure out what we’re doing right or wrong on our journey to greater personal fitness.

Path to greater fitness, I suppose (har). Because the private social network has a new update out today, that pairs its mobile-only app with the Nike+ Fuelband so that the device on your wrist can use the device in your pocket to tell your close friends just how active you are each day.

Once you’ve synced Path and the Fuelband iPhone app, you’ll start generating a slick sparkline-style graphic of Fuelband data once a day, that shows when you were active and when you weren’t. Red is for resting and green is for high-energy activity. The X axis is time (as illustrated by little top icons for sun, moon, etc.) and the Y axis the amount of “Nike Fuel” you burn (its basic unit of activity). It’s also interactive — you and your friends can click around on the white dots in each graph to see specific highlights, like when somebody walks to work then checks in.

Yes, not everybody wants to share their exercise patterns, or lack thereof, but Path founder Dave Morin tells me that in testing, the company has found that the more you’re measuring and sharing your habits, the more you’re trying to improve them. It’s small things, like walking to a meeting instead of driving or taking a cab, that can boost your overall activity and help you meet your personal goal at the end of the day.

Also, for those of you who like to post status updates about your runs on Facebook, this sort of feature will blow your mind.

The concept has actually been on the roadmap since Path’s early days, Morin says, when the company was inspired by a Mary Meeker presentation from a couple years back. It described a mobile-first world — which helped inspire the company’s first iteration as a mobile photo-sharing site — but it also talked about a new world of Internet-connected sensors telling us about everything happening around us.

Path’s big transition last fall to a private social network has made it an especially good fit for this type of integration. Nike may be the only third-party developer building on Path for now, but Morin adds that he’s looking hard at other companies working on sensor-driven products, and says to stay tuned.