This app was mentioned in 6 comments, with an average of 2.00 upvotes
Just 6 Weeks. It's not bad. I've had it for probably a couple years. The plank part of the app is newer and slowly builds you into longer and longer planks in sets of 3 or 5 per workout.
Quick Review --> Good: It's straight forward, easy to use, and continuously pushes your limits. Bad: I always plateau around week 4 and question the graded increases; there is no way I'll ever hit the stated goals in "just 6 weeks." I paid for the full app and have definitely gotten my money's worth.
Check out the Just 6 Weeks app- very helpful routines for doing push-ups, sit-ups, pull-ups, squats and increasing your level of fitness over time. Very helpful system.
Yeah, you make it out to be far more complicated than it needs to be. I've had great success so far with this:
https://play.google.com/store/apps/details?id=alexcrusher.just6weeks.full&hl=en
I love Just 6 Weeks. Bought the pro version very quickly. No regrets. Lost about 15 lbs and look a lot fitter.
https://play.google.com/store/apps/details?id=alexcrusher.just6weeks.full