Demonstration of the shaolin push up / muy thai push up. This is currently my personal record, 19 reps in 19 seconds.
I think this is one of the hardest pushups, also much because of its extreme core involvement. It is often called and considered as the hardest push up in the world.
"Top 10 Extreme Push Ups" for more effective and great Push Ups and Bodyweight Exercises:
"Hardest push ups in the world": An extreme workout with many of the hardest push ups in the world, some freestyle and improvisation with combos and variations.