JOIN Running is a training tool for cyclists who want to incorporate (some) running into their training regime. You just need to let JOIN know how many times you would like to run and what your threshold pace is, and JOIN shows you when and what kind of running workouts you can do best. It takes into account your running experience and your training history.
The more and longer you run, the more challenging workouts you get. Also, the other way around, if you are unable to run for a longer period of time, JOIN will start with some shorter base runs to not avoid injuries and let the body slowly adapt.