You don’t need giant exercise machines to get a good workout indoors these days. Take the Space Saver Gym by Dunn Concepts: it is a resistance based training system that you can attach to your wall. It has 8 height levels for you to choose from to work your muscles all over.
Thanks to this fitness trainer, you can exercise upper body and lower body. You can adjust the height by sliding the rail car in 2 inch increments.