You can literally do this with your eyes closed, though it is not recommended. Thumbnail jokes are funny.
For real though. We can get stabilized with a wall or if you have too much art hanging on your walls simply close a door and use it work our chest, hips and buns.
Use what you got! Get in motion and make it a beautiful day.
personal trainer, recovering comedian chatting about muscle from the mean streets of the cul-de-sac