Sodium (Na) inside your cells has a water retention effect. So what you want to do is to "trick" your body into shuttling out excess sodium. To understand how this works, I'll quote Layne Norton who is majoring in biochemistry:
"Ok a little lesson in cellular biology to explain sodium loading. In the body sodium is present in large quantities compared to potassium and other ions. As a result the body's cells are always trying to pump sodium out and take postasium in. To do this task there are what is called sodium potassium pumps (I will refer to them as Na & K pumps to make it shorter in this reply) So what happens is Na (sodium) is constantly pumped out and K (potassium) is constantly pumped in. For every 3 molecules of K that come in 2 Na molecules are pumped out. Since this reaction is occurring against equilibrium ATP is used to power the reaction. Now what happens when you Na load? Well your sodium pumps have to work harder to pump out all the sodium that comes into the cell. Then when you cut out your Na intake the day before the show your body will continue to pump out Na at that fast rate. Since Na inside the cell makes you retain more water, all this water will be flushed out giving you the skin tight look. I believe sodium loading almost eliminates the need for water depletion."
Also adding potassium (K), it will help you stay hydrating as well as assist in pulling out sodium. When you are sodium loading, you will be holding more water than usual. Don't be afraid though, because if done correctly, this technique will get rid of the excess water you are holding.
When I did this, I was adding salt to my meals throughout the day. Three days before the contest, I stopped adding salt. Then the day of the contest, I ate foods that were very low in sodium.
The idea here is to drop creatine (if you are taking it) about four to six weeks before your contest. Then 3-5 days before the comp do a quick loading phase. This is supposed to draw water into your muscles and away from under the skin. This will make you appear fuller.
I used this technique for my contest and did not have a problem with holding any extra water. I'm not sure exactly what effect doing this had though. So, you'll just have to try it and see how it works for you. I would suggest loading it 3 days before the comp instead of 5 though to be on the safe side.
The point of carbing up before a contest is to replenish your muscles glycogen levels. This will make your muscles look full and hard. It is important to do it right though. For my competition, I carbed up the day of the contest only because I had a 7 PM show. I believe I needed to start the day before with about 200 carbs, then eat 300 carbs on the day of the contest like I did. It is very important to note that the amount of time needed to carb-up correctly varies from person to person. Some people need one day, some two, some three, and so on. You also do not want to consume too many carbs because you will appear flat and smooth. In order to know how much carbs to consume, you have to know your body.
I know you're thinking, "I don't have hemorrhoids, so why would Prep. H be useful for a bodybuilding contest?" Prep. H is great for pulling water out from under your skin. When a bodybuilder is holding too much water, they look smooth and undefined. But when they have shed the excess water they are holding, they look hard and ripped. Applying Prep. H, to areas prone to hold water, abs, love handles, hamstrings, you can pull out the excess water. I used Prep H on my love handles before my comp. I noticed a BIG difference in the size of my love handles before and after applying the Prep H. So if you're holding too much water in a certain area, and your contest is getting close, try applying Prep H to the area.
Something To Avoid
The top two placers at the competition I entered both used a product called "Hot Stuff" because they went on stage. Before they put it on, they looked flat and smooth. Then suddenly, BAM! They both looked ripped and had veins popping out all over. So, after the comp, I decided to order a bottle and see how it would work on me. All I can say is the products name fits. All it did for me was burn my skin. Not very fun at all. I immediately washed the crap off and applied some ointment to help my skin. I recommend staying away from this product.
Well, those are the contest tricks I have experience with. Try them, they could work wonders for you. The most important thing to remember is, if you did not diet and train hard while preparing for your competition all the tricks in the world won't save. NOTHING BEATS PROPER PREPARATION! These will just help perfect what you have created.
Don't forget to check out my huge contest preparation section!