You need a dedicated cycling computer, or use an app on your phone that pairs with your power meter. The Wahoo Fitness app is actually quite good for this, at least it was when I last used it. I think recently I tried to use it while skiing and it didn't pair with my HR monitor anymore. So now I use my cycling computer while skiing, too. Funnily enough, I have a new pair of pants for that that just happens to have a single little inside pocket where my Wahoo just fits. But yea, try Wahoo app, the Strava app is known to be utter *****.