Watching some of the coverage of Wimbledon you can't fail to have noticed Andy Murray's training. One of his exercises in particular seems to have caught wider attention; the 'Donkey Press-Up'.
It is good to see such novel bodyweight exercises getting wider exposure but I think that Murray might well get bigger bang for his buck with two other variations on this movement.
The first is the plyometric push up. This is best done with blocks/platforms for the hands onto which you can bounce on and off. As this relies on the fundamental press-up movement, you can focus on the shoulders and simple core alignment throughout.
My second recommendation would be the planche. There are many variations of the planche all of which will, if performed properly, reach deep in to your reserves in a matter of seconds, or, if trained, longer (depending on what you want from the session).
Both of these variations require control - and it is easier to execute this control than the donkey push up with the 'wild' precursor to the movement proper. One of the main drawbacks of the DPU is the difficulty in kicking the legs upwards whilst maintaining form.
Variety is what it is about. Donkey push ups are just another tool to do the job. But the static demands of planching and the dynamic demands of the plyometric push up may well be a source of greater gains due to their inherent focus on those muscles intended as the target of the exercise.
Still, it looks like DPUs have got Murray this far so who am I to criticise? Let's hope he can continue his storming form!