For a FLAT STRONG STOMACH, don't focus on crunches; this will only strengthen the muscles in that area, but not help you lose the belly fat. Instead, do INTERVAL TRAINING exercises, build muscle in your entire body since muscle builds more fat even
when you are not exercising. Also, make sure you eat and drink healthy foods and beverages.
Great fitness programs offered by BeachBody which you can do at homethat incorporate interval training: Turbo Fire and P90X3.