Effects Of Pre-Exercise Carbohydrate Supplementation For Mountain Bikers

This week I review a recent research publication on preexercise carbohydrate supplementation and mountain bike performance; if this doesn't specifically relate to you, there may be some information you can extrapolate to your current workout ...

The bodybuilding.com audience is primarily weight trainers; however, since I have started writing for this site, I have also received a number of reader letters with questions about endurance training too.

Therefore, this week I am going to review a recent research publication on preexercise carbohydrate supplementation and mountain bike performance; if this doesn't specifically relate to you, there may be some information you can extrapolate to your current workout regimen.

Effects Of Pre-Exercise Carbohydrate Ingestion On Mountain Bike Performance

Medicine & Science in Sports & Exercise, 36(9),1602-1609, 2004

If you don't know by now that carbohydrates are important for exercise, you might want to take up a new hobby. Yes, the low-carb diets are currently all the rage, but those of you who have tried them can surely attest to the fact that your energy levels are much higher when eating some hearty, whole grains on a regular basis. Carbs are particularly of importance in endurance activities, such as cycling, running or in this case, mountain biking.

Meal timing is all the rage right now; is it best to eat before, during, and/or after an event? What types of foods/beverages should be consumed? How much of each foods should I eat? Therefore, the purpose of this study was to examine the performance effects of high and low carbohydrate intakes (1 and 3 grams carbohydrate/kg bodyweight), taken before exercise, on a simulated mountain bike race.

There have been a number of recent publications on post-exercise meal timing; many of which I have reviewed for this very site, but few have considered pre-exercise nutrition.

The Study

Eight male subjects participated in this study. The subjects were all in training for the competitive mountain biking season, meaning that they all had some training history. The subjects were approximately 22 years of age and competed in a club mountain biking team.

The researchers in this study had the subjects complete two familiarization trials and two experimental trials. Because this study was a "simulated" mountain bike trial, it was not actually performed outdoors on a trail, but instead on an indoor cycle. Therefore, although it is the same type of movement, per se, it is not going to be exactly like a mountain bike race.

Because of this, researchers often give the subjects a "familiarization" trial to get the subjects accustomed to the specific protocol. The goal is to minimize the learning effect of the protocol, which can affect the end result.

Subjects were given food diaries to complete so the researchers could get a better idea of the foods and beverages they were consuming leading up to the actual trial. Of course previous glycogen stores could have an effect on the outcome, so this information was crucial. On the morning of the trial, the subjects arrived at the laboratory and were provided either a higher carbohydrate or lower carbohydrate meal that correlated to their bodyweight.

Both meals consisted of white rice with pasta sauce, but the higher carbohydrate group had added, tasteless, maltodextrin (form of carbohydrate) to their sauce to add carbohydrates. All meals purposefully looked identical, but differed only in the total amount of carbohydrate.

The Results

After the trials, the researchers found that those consuming the 3 grams carbohydrate/kilogram of bodyweight versus the 1 gram carbohydrate/kilogram of bodyweight had no significant differences in most outcome variables. Just to give you an idea, a 154 lb male is 70 kg. This weight is around that for many competitive cyclists. Therefore, to follow through with this exact protocol, you would have to determine your specific needs according to your bodyweight.

It is also important to note that although there were no statistically significant values, it does not mean there were no clinically significant values. For example, with this study it was determined that the higher carbohydrate group improved their performance by 3% or 2.48 minutes.

This may not seem like a lot, but in the world of competitive cycling or any competitive endurance event, this can mean the difference between first and second, gold and silver, or million-dollar contracts compared with nothing.

The moral of the story with this article is that higher carbohydrate intakes may be beneficial before an exercise event. This particular study had subjects consume these meals 3 hours before their event giving enough time to digest and have the consumed carbohydrate readily available for the working muscles. This correlates nicely with the resistance training studies that demonstrate pre-exercise intake to be just as important, if not more important, than post-exercise nutrition.

Therefore, to take this and extrapolate to resistance training, I'm going to say that a higher carbohydrate intake prior to exercising will absolutely help your performance in the gym; if you want great results, don't lay off the carbs!

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