Pushups. Even just saying that word in polite company often generates horrified gasps, and I won't even mention the responses I often get from my clients, as swearing is frowned upon in our blogs.
We love to hate pushups because they work every muscle in the body and, of course, the more muscle groups you involve, the more challenging an exercise is. Even better, there are a million and one ways to do pushups, making them an exercise almost anyone can do...even the haters.
One of the hardest versions out there are divebombers. This pushup is similar to a yoga series in which you go from downward dog to upward dog. The difference is that you're repeating the movements for more reps than you would in yoga.
The key to this move is, first, being very comfortable with traditional pushups. You'll need a good amount of core strength as well as arm strength to do this move without causing injury. This move will also tax the shoulders in a way you may not be used to, so consider keeping the knees on the floor throughout the movement to take the pressure off and give yourself a chance to practice the exercise.
Do it right: Begin the move in a pike position, with hands about shoulder-width apart and a bit forward of the body, legs straight and hips to the ceiling (as in a downward dog). Bend the elbows as you dive forward, bringing your head towards the floor. Keep moving forward, pushing the chest towards the floor and then through the arms. Keep going until your torso is lifted, hips still off the floor and you're looking forward, shoulders down (as in an upward dog. Reverse the movement and repeat for 1-3 sets of 4-12 reps.