I’ve found that the best way to avoid ad-infested apps for exercising is to use official apps from popular brands. They’re better because they bother you again and again about non-exercise-related matters (ads, social sharing, etc)
For example the following apps are great alternatives to popular ad-filled apps:
- Nike Run Club – Much better than C25k (Couch-to-5k).
- J&J 7 Minute Workout – Alternative to 7 Minute Workout.