You might not like to hear this, but as you lie on the floor and do stomach crunch after stomach crunch, you’re not actually making your waist smaller. In fact, you’re making it bigger by strengthening and enlarging your rectus abdominus (abs). If you want to actually make your waist smaller, you need to do ab exercises that strengthen your transverse abdominus – the muscle you use to suck/hold your stomach in. When this muscle is strong, your stomach doesn’t sag and, therefore, your waist becomes smaller because it is tighter.
The Stomach Vacuum Exercise
This exercise alone will reduce the size of your waist. It’s one exercise bodybuilders like to rely on for this very purpose. All you have to do is suck your stomach in. Yep, that’s it. Just stand up straight, exhale, take a deep breath and hold your stomach in as tight as you can for as long as you can, then repeat a few times.
Planks
Planks are a great way to strengthen your transverse abdominus, and really, your entire core, for that matter. Gymnasts and dancers have been doing planks for ages to develop their core strength. A plank is an isometric exercise, which means you don’t move while you do the exercise. You just hold a static position. There are two basic types of planks: front and side planks.
Front plank – Get down into a pushup position. You can balance on your hands or on your forearms. Then just simply hold this position, keeping your back as straight as possible, for about 30 to 60 seconds. Side plank – A side plank is performed exactly the same as a front plank but on your side (go figure). Instead of placing both hands or forearms on the ground in a forward, downward facing position, rotate your body to one side and only use one arm to hold yourself up. This places more emphasis on your obliques.
I’ll give you a tip that will really increase the intensity of your planks. When you are doing a front plank on your hands, walk your feet backwards to make the exercise more challenging on your core muscles. The further you walk your feet back away from your hands, the harder it gets. See if you can walk your feet back to the point that your arms are almost fully extended in front of your head, like you are superman flying through the air. If you can do that without letting your stomach touch the ground, you have some serious core strength.
Sources:
http://www.acefitness.org/exerciselibrary/100/side-plank-with-bent-knee
http://www.acefitness.org/exerciselibrary/32/front-plank
http://www.getbodysmart.com/ap/muscularsystem/abdominalmuscles/transabdominis/tutorial.html
http://www.bodybuilding.com/exercises/detail/view/name/stomach-vacuum