I don't know why but I find it embarrassing to exercise in front of my parents. This is one of the downsides of living with your parents. I could easily lock my bedroom door and proceeding to exercise in my bedroom but the problem with this is that my parents often want to go into my bedroom, e.g. to give me clean underwear or to remind me that dinner is ready. If I have locked my doors, they won't be able to get in and they will wonder if I am doing anything illegitimate in my room.
I could always go to a gym or move out of my parents home, but both these options are expensive. Thrift is a virtue!
After some thinking, I have realized that the answer to this problem is to do wall push-ups in the toilet. When I am in the toilet I can lock the door and do wall push-ups. If my parents try to get into the toilet, the door will be locked, and locking the toilet door is understandable because my parents would just assume that I am expelling feces, which is a normal and legitimate thing.