Another video from one of our long time readers, Blackeroni. If you haven't checked out his stuff, please take the time to do so. I'll be posting some of his videos here for the time being for our current posting hiatus.
Isometrics are a great way to build strength in different positions. I would recommend that you also change your body position when practicing these pushing exercises. You can push with arms fully extended, arm bent, with your shoulder, with your back against the wall, or perhaps even between two walls in a hallway (Made of brick, please. Don't smash your drywall). Whatever you have to push against, put your all into it and eventually you'll see great gains.
That's all for today! Until next time, good luck and train hard!