With the ascent of single limb training, somewhere along the line someone thought, "why not single arm pushups?" Someone did, I know it, but let's face it - they're not popular. But why? We put our heads together here and came up with a few reasons:
1) They're hard as hell
2) They do not correlate to bench strength, we had a 400 lb bencher who couldn't lower himself 1/2 way down, and that was during a modified/incline version, therefore...
3) They're ego shattering
4) The NFL combine probably won't be switching from the 225 rep test to the 1-arm pushup test any time soon
5) They're hard as hell
Ok, so there are probably better reasons why they're not popular, but regardless, I think there are some pretty solid reasons they should become so, quickly.
1) They're limited by torso stability. Random anatomy fact: the external oblique shares myofascial linkage into the lower fibers of the serratus anterior - I'd like to think that shoulder health is directly related to core function and that any chance we get to exclusively coordinate the shoulder and core is a good thing.
2) They can be progressed using iso holds, and adjusting the depth of descent by stacking airex pads, or placing med balls of various sizes underneath the chest.
3) They aren't victim to any theoretical scapular restriction and other shoulder issues associated with supine pressing.
4) They're about as hard as the rotary-stability FMS test, and no one's convincing Gray Cook to eliminate it based on that excuse.
Like any exercise, proper progression and implementation will make the 1-arm pushup a very effective exercise. Death to bench press? Yea right. But if you list all the benefits of push ups versus benching, push ups unquestionably hold their own.