What would be a cool feature that could be added to the app that makes it different from the others?

Some type of baseline that can "somehow" be calculated based on the level of ones current fitness. For example, if they not flexible at all, or if they are extra obese, tailor the workplan plan accordingly. Or if they live in a climate that prevents outdoor activities due to excessive heat. If they are tied to an oxygen tank, limit the plans accordingly.... After I'm thinking about everything I'm mentioning I'm realizing more and more that those types of people probably aren't your demographic anyway. Perhaps the weather integration could be an all-around feature to allow you to feature a different workout than jogging if it's raining that day.