It's been an interesting experience. On the first day, I struggled to get the 100 pushups done, 14 here, 10 there, then 5, then 5, then 5, and finally they were done and my arms and chest hurt!!!
A week into it, and I've gotten stronger and a bit more creative. Here I am stopped on my bike ride yesterday doing some push-ups.
And on Friday, I did a few after my swim in the ocean:
Even after a week, I feel stronger. Today as I got out of the pool in the deep end, I was able to do a full "deck-up", whereby I use both hands on the pool ledge to pull myself straight out of the pool. No leaning on a forearm, no ladder, no lurching my belly onto the pool deck. I pushed myself straight out of the pool.
By the end of the month, I will have done 3,000 push-ups.