Tightening your stomach muscles while sitting won't help you get a six pack, but it can improve your muscle tone and strengthen your core. ... Repeatedly tightening your abdominal muscles can improve your balance, stability and coordination.

Does flexing your abs do anything?

Although keeping your stomach muscles flexed throughout the day won't guarantee washboard abs, the engagement of your belly button moving toward your spine provides additional exercise and could help improve your posture.

Does tensing abs burn fat?

Evidence shows that you can't lose belly fat by exercising your abs alone. For total-body fat loss, use a combination of aerobic exercise and resistance training, such as lifting weights. In addition, eat a healthy diet with plenty of protein, fiber and portion control — all of which are proven to help reduce body fat.