I just completed the Greater Waterbury YMCA ab challenge, a 30 day challenge where you increase the number of crunches, leg raises and planks by increments of 5. The last day of the challenge meant I had to do 160 crunches, 64 leg raises and a 2 minute, 35 second plank! As you can imagine, it was not easy.
So was it worth it? Definitely! My abs feel a lot tighter, despite having a pouch of loose skin. I can see some muscle there, so I know my abs are strong. I never imagined being able to do this many crunches, but that's the purpose of these challenges, to accomplish goals and increase your fitness level.

