Here's a personal favorite of mine for standing abs workout
FAST FLAT STOMACH WORKOUT standing abs - YouTube
And as others have said, cardio exercise to lose overall body fat will help get your tummy area back in shape. I know many have suggested walking, but I think more vigorous exercise will help you lose the body fat quicker. If impact workouts don't work for you, the elliptical is a great alternative. I can burn the same amount of calories on the elliptical as I can running...according to my heart rate monitor. Whatever you chose to get your sweat on, challenge yourself!
Best of luck!
COMMIT to a plan
PERSIST when the going gets tough
BENEFIT from not giving up!
Recommit weight - 154 lbs. (Sept. 29, 2015)
Current weight - ??? lbs.
1st Goal - 143 lbs. & to be able to wear my wedding rings again!
2nd Goal - 136 .5lbs.
3rd Goal - 128.5 lbs.
4th Goal - 121 lbs.
5th Goal - 110 - 115 lbs. & to look like the 40-something version of my avatar