“The No-Depletion Carbo-Loading Method

1. Perform a long workout (but not an exhaustive workout) one week before race day.
2. Eat normally (55-60% carbohydrate) until three days before a longer race.
3. Eat a high-carb diet (70%) the final three days before racing while training very lightly.

Note that you should increase your carbohydrate intake not by increasing your total caloric intake, but rather by reducing fat and protein intake in an amount that equals or slightly exceeds the amount of carbohydrate you add. Combining less training with more total calories could result in last-minute weight gain that will only slow you down.

Be aware, too, that for every gram of carbohydrate the body stores, it also stores 3 to 5 grams of water, which leads many athletes to feel bloated by the end of a three-day loading period. The water weight will be long gone by the time you finish your race, however

The Western Australia Carbo-Loading Method

1. During the pre-race week, eat normally while training lightly until the day before a longer race.
2. On the morning of the day before the race, perform a very brief, very high-intensity workout.

The creators of this innovative protocol recognized that a single, short workout performed at extremely high intensity creates a powerful demand for glycogen storage in both the slow-twitch and fast-twitch fibers of the muscles. They hypothesized that following such a workout with heavy carbohydrate intake could result in a high level of glycogen supercompensation without a lot of fuss.

In an experiment, the researchers asked athletes to perform a short-duration, high-intensity workout consisting of two and a half minutes at 130 percent of VO2max (about one-mile race pace) followed by a 30-second sprint. During the next 24 hours, the athletes consumed 12 grams of carbohydrate per kilogram of lean muscle mass. This resulted in a 90-percent increase in muscle glycogen storage.

The Western Australia carbo-loading strategy works best if preceded by a proper taper–that is, by several days of reduced training whose purpose is to render your body rested, regenerated, and race-ready. In fact, several days of reduced training combined with your normal diet will substantially increase your glycogen storage level even before the final day’s workout and carbohydrate binge.

Having said all of this, [.] note finally that carbo-loading in general has been shown to enhance race performance only when athletes consume little or no carbohydrate during the race itself. If you do use a sports drink or sports gels to fuel your race effort–as you should–prior carbo-loading probably will have no effect. But it doesn’t hurt to do it anyway, as insurance.”

Excerpted from Active.com.
(There was another plan, that really wasn’t of any use for long-distance swimmers. All three did have a focus on runners. I don’t think any of this considers anything longer than marathon running event.)