The problem is that the facilities in my area are not very adequate so in the end the stairs look difficult to do, is it possible to replace it with regular walking because incidentally I also still do this on the field for a few rounds when doing the push up challenge.
Do you have a hill?
Could be a small hill.
Go up 🔝 turn around go down turn around go up ⬆️
they key is you are actually lifting more weight as you go up the hill.
If you walk on a flat surface you do not get the same benefit.
But if all you can do is walk on a flat surface. Do at least 10 minutes each day in one shot. preferably right after your set of pushups.
As for proof, maybe a picture like this can be good enough evidence because I always use a tracker application when I do sports such as walking/running I use this as a benchmark.