Excellent App!
I have been using this app for 3 months now and the results are really good. Variety of exercises, recognition of your fitness level with recommendations to change the sequence, connection to social media if you like, frequent exercise updates and more. All you need is a chair and little space. With 15 min duration - you can take longer sequences - it is hard to make an excuse to yourself not to do it every day. Enjoy.
Sandro Bernardes about
J&J Official 7 Minute Workout, v1.5