• Aaptiv

It's a pocket-sized personal trainer that's all audio-based, so you won't need to pull out your phone to see what comes next -- just focus on the spoken instructions and your body. If you don't know where to start, don't sweat it-- the app picks out which exercises will work best for you. 

• Peloton

If video-guided workouts are more your speed, Peloton offers a whole lot more than cycling. Watch the pros lead strength training classes, yoga, boot camps, and cooldowns. It's free for 30 days, too. 

• Runkeeper

The app tracks your runs and measures your progress -- and if you keep it up, you can earn rewards toward real-life training gear, too!