It used to be so simple. You completed an exhaustive workout and then ate minimal amounts of carbohydrate for three or four days to wipe out your muscle-glycogen stores. Then came the good part: you trained lightly and consumed biscuits, pies, pasta. and potatoes in lavish quantities for three days to supersaturate your leg muscles with carbohydrate.

This was the classic ‘carbo-loading’ strategy developed by top-level Swedish scientists in the late 1960s and early 1970s, a plan which was used by countless endurance cyclists, cross-country skiers, and runners prior to their long-distance races. But then Dave Costill made things simpler still, in his lab at Ball State University, Costill showed that the initial, three- to four-day, low-carbohydrate, ‘depletion’ stage was impractical and unnecessary.

The famed Indiana scientist suggested that endurance athletes could stay on top of the carbohydrate game simply by reducing their training and eating increased amounts of carbohydrate during the three days before an important,long-distance competition.

The two-hour window

It would have been nice if things stayed that uncomplicated. but scientists gradually discovered that many endurance athletes were not storing enough glycogen in their muscles during periods of vigorous training and were consequently having trouble maintaining their desired training loads. In the late 1980s, one reason for this lack of glycogen storage became apparent: research showed that muscle cells are quite temperamental about when they like to sock away glycogen.

For example, muscle fibres usually have little inclination to store glycogen before a meal or during sleep. but they are most willing to pull carbohydrate out of the blood and stockpile it during a fairly brief period: the two hours immediately after a strenuous workout. It seemed that many glycogen-deficient athletes were failing to give their muscles what they needed during this critical two-hour time span. As a result of that discovery, wise athletes began to ‘fuel up’ with copious quantities of sports beverages and high carbohydrate foods, taken in shortly after their workouts had ended. The next step was to figure out exactly how much carbohydrate was actually needed during this muscle primetime (the two hours after a workout), so that glycogen would be replaced as quickly as possible.

Fortunately, in about 1987 John Ivy, Ph.D. and his colleagues at the University of Texas discovered that eating about two thirds of a gram of carbohydrate per pound of body weight, once right after a hard workout and a second time two hours later, helped athletes achieve super-high muscle glycogen levels in a short period of time. If you weighed 150 pounds. all you had to do to ensure that the interiors of your muscle cells were ‘carbohydrate pantries’ was to consume 100 grams of carbohydrate (150 X 2/3) right after your workout and 100 grams two hours later. If your regular meals were also biased toward carbohydrate, you could be fairly certain that your muscle cells would contain enough glycogen to keep you going.

Tips for maximum glycogen storage

If you usually run, cycle, swim, or work out on a stair machine at a moderate intensity for less than about 50 minutes at a time. don’t worry too much about the new carbo-loading scheme unless you train more than once a day or tend to eat too little carbohydrate. However, interval and repetition workouts can dramatically deplete glycogen. even when they last less than 50 minutes, so do consider using the strategy after high-intensity sessions, especially if you plan to cycle or go for a long, steady run later in the day.

During all periods of very heavy training and whenever you are significantly increasing your workout duration or total training volume, give the new carbo-loading scheme a try. Also employ the strategy during times when extensive hill training is a priority. It’s easy to figure out how to carbo-load using the Ohio State pattern.

Simply multiply your weight in pounds by three. Divide the result by 16 to determine the number of grams of carbohydrate to eat every 15 minutes. Example: Penny weighs 117 pounds. 117 x 3 = 351. 351/16 = 22. 22 grams of carbohydrate should be ingested every 15 minutes. Since you usually don’t think about how many grams of carbohydrate you’re actually ingesting, we’ve made things easier for you by listing food servings which provide about 20- 25 grams of carbohydrate: (1) Two cups of skim milk (2) A little more than half a bagel (3) A two-thirds cup serving of cooked pasta (4) An apple or a banana or a pear (5) Four dates (6) A cup of orange juice (7) One-fifth of a cup of raisins (or two half-ounce packets) (8) An ounce and one-half of corn chips (9) A medium baked potato (10) A slice and a quarter of most breads (11) Two slices of non-fat ‘diet’ bread (12) A cupcake (13) A muffin (14) A cup of oatmeal (15) One and one-half cups of Special K cereal (16) One-half cup of cooked rice (17) Three carrots (18) Two thirds of a cup of cooked lentils (19) A half-cup of cooked kidney or pinto beans (20) A cup of split pea or bean soup If ingesting 20-25 grams of carbohydrate every 15 minutes for four hours after a tough workout is just too much of a bother, a modified glycogen-storage plan may work almost as well.

According to Mike Sherman, Ph.D., one of the Ohio State investigators and an internationally acclaimed expert concerning carbohydrate’s role during exercise, taking in 40-50 grams every 30 minutes or 60-75 grams every 45 minutes might yield similar rates of carbohydrate warehousing. The new carbo-loading scheme requires some planning, and you’ll still want to eat some additional carbohydrates during your regular meals, but the effort should add fire to your training and competitive efforts. With extra carbohydrate in your muscles, you’ll simply be able to train or compete at a fast pace for longer periods of time.

Jim Bledsoe peak performance manuals

In sports, carbohydrate loading, commonly referred to as carbo-loading or carb-loading, is a strategy employed by endurance athletes such as marathon runners to maximize the storage of glycogen in the muscles.

Carbohydrate loading is generally recommended for endurance events lasting longer than 90 minutes. For many endurance athletes the food of choice for carbo-loading is pasta. Because of this, hundreds of marathons and triathlons have large pasta dinners the night before the race. This can only be done a couple times a year, such as for events, otherwise the body begins to adapt making carbo-loading useless.

There are several periods of carbohydrate loading, since the original one has several possible modifications

The protocol of carbohydrate loading was originally developed in 1967 by Swedish scientist Bengt Saltin. The original theory of carbohydrate loading was that, if the body's glycogen stores were depleted, it would store more glycogen than normal when carbohydrate intake returned to normal. Consequently, the original carbo-loading regimen began one week before the event, and called for three days of minimal carbohydrate intake (about 10% of total calories) and intense exercise to deplete the body's carbohydrate stores. Then for the next three days, the athlete would consume primarily carbohydrates (about 90% of total calories), and reduce the intensity of exercise to allow for maximum storage.[1] This is the way many Swedes prepare for Vasaloppet.[2]

Without depletion

In the 1980s, research led to a modified carbo-loading regimen that eliminates the depletion phase, instead calling for increased carbohydrate intake (to about 70% of total calories) and decreased training for three days prior to the event.[1] Most athletes now follow this modified regimen, and it is recommended by many coaches, although there are some athletes who still follow the original carbo-loading regimen.

Short workout

A new carbo-loading regimen developed by scientists at the University of Western Australia calls for a normal diet with light training until the day before the race. On the day before the race, the athlete performs a very short, extremely high-intensity workout (such as a few minutes of sprinting) then consumes 12 g of carbohydrate per kilogram of lean mass over the next 24 hours. The regimen reportedly resulted in a 90% increase in glycogen storage.[1]

source: http://en.wikipedia.org/wiki/Carbohydrate_loading