What are some effective ab workouts for someone who has none?

Planks: Doing core exercises is the best way to build up almost else and stabilize the abdomen while building abdominal muscles planes are good where are you arrest on your elbows and feet with your frame perfectly straight hold this for 30 seconds and do this 10 times resting in between also military push-ups are very good sit ups are okay but side planks are you better inverted planks are good to where the belly is toward the ceiling and you lift up on your hands and feet with your head off the ground and frame straight.

Ab exercises: Eat healthy & get physically active. Calories burned > calories consumed. To tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge & “bicycling” exercise on back. Engage in regular aerobic exercise (i.e. running, swimming, Nordic track, bicycling, kickboxing, walking, cross country skiing, hiking, etc.)