I would recommend doing a Wall Pushup
How to Do Pushups Against Wall
1 Stand approximately two to three feet from a bare wall. Make certain there is nothing on the ground between you and the wall.
2 Place both hands shoulder width apart against the wall with your palms flat. Your arms should be straight, but avoid locking your elbows when in the starting position.
3 Lean in until your nose is approximately two inches from the wall. Keep your hands flat.
4 Push out with your arms to return to your starting position. Repeat this motion until you feel discomfort or until it becomes difficult to return to the starting position.