If you don't work with Bodyweight on a regular basis for strength training, then chances are you barely know this exercise exists. I've never seen it in a muscle rag (magazines) at all. I've barely heard of any coach mentioning it, much less using it for training purposes (Which is yet another reason why Zach Even-Esh rocks so much: he loves this one!). If you mention this exercise to the average person they'll probably think you're some kind of lunatic for attempting it.
Which makes me love this exercise even more.
It's the handstand push-up (HSPU), and it's probably second only to horizontal one-arm push-up training as the ultimate bad-ass subspecies of push-ups. It's most obvious benefit is some much-needed overhead pushing strength. It's no secret that a lot of strength trainers are pathetically weak on overhead pressing/pushing strength. That's borderline criminal in my mind (and a lot of legit strength coaches too, I might add). What's less obvious about the HSPU is it's sick glute and ab strengthening capabilities. All of these muscles have to contract to hold the spine in place and keep the body stable while pushing up and down. This is also one of the few push-ups where you're working against virtually every pound of your bodyweight (except for your forearms and hands. big deal). So, you can train with even the plain-vanilla HSPU for quite a while and get a lot of the more-enviable max strength benefits before it becomes a strength-endurance exercise.
First, however, you have to get to the point of being able to do a HSPU. I fully understand that most weren't like me when I starting doing them. I was able to do them, with my back against the wall, the very first time that I tried. The answer for the rest of the world is the Pike push-up.
This overhead push-up works well for a progression because you don't engage the core or the glutes like a full-blown HSPU and you're not forced to move the weight of your legs. As this exercise gets easier, you simply raise your legs higher off the ground. The easy way to do this is by standing on an object, such as a milk crate or a chair (just make sure that they're not going to kick out on you when you're on them). Another, more challenging option is to press your feet against the wall. With both options, the higher up your feet go, the harder it gets. Adjust accordingly.
Once you're getting past those without an issue, try doing HSPU with your back against the wall. Like I said, this is where I got my start with handstand push-ups. I worked them like this for about 2-3 years. Once I got to 20, I moved away from the wall, using only my feet to keep balance.
Am I doing them free-standing yet? Um, no. I'd like to get to that point sometime soon. That way, this exercise would truly become a do-anywhere deal. All I'd need is the ground and my BW. No wall necessary. One goal at a time, like Sally says...
That doesn't mean that there aren't other ways to progress other than just free-standing. I've done HSPU's on fists, blocks and push-up handles. All of these extend the range that you have to lower yourself. Inches count here and it doesn't take much more than two, measly little inches to make this push-up much harder. I also love doing them with the Perfect Push-up handles. That's a good way to slice off about half of your reps.
Yes, I did these on the T's. I don't recommend you doing that though. That definetly crosses the line between exercise and stunt. Exercise is for everyone. Stunts are for particularly-powerful, trained pro's... or idiots who think they are. I'd like to think that at the very least, I fall somewhere between the two. As far as I'm concerned, there are other, safer ways to develop this kind of grip strength that don't carry the same amount of risk that there is with HSPU's on T's.
That aside, this is probably my very favorite push-up out there. It's a great exercise for the upper back, shoulders, triceps, abs, and glutes. It's the queen of the push-up world beyond a shadow of a doubt. It's one of those exercises that you rub in the face of any ironhead who says that BW isn't as good as weights for getting strong. It takes a ruggedly powerful person to fully master all of the benefits that this exercise has to offer.
More bragging rights...