If you are a coach and you work with high-intensity team sports you need to read Carbohydrate Nutrition and Team Sport Performance. If you are an athlete who plays any of the sports below you need to read this paper. The best part is – it’s free.

That means: football, hockey, soccer, basketball, baseball (maybe), tennis, swimming, volleyball, rowing, most of track and field, CrossFit, or anything else where you sprint around, rest, and then sprint around some more.

Below are my favorite quotes and commentary for each.

 “In a single 6-s sprint, glycogen degradation (glycogenolysis) contributes 50 % of the ATP production, whereas PCr contributes 48 % and the remaining 2 % is provided by the muscle’s small store of ATP.”

This isn’t something you are going to be able change. This is the fuel you need to get that job done. We cannot lose sight of that, this is the nutritional ground we walk on when we are messing with athlete’s who run hott and do cool shit.

“During recovery between sprints, aerobic metabolism is responsible for the re-synthesis of PCr as well as covering the energy cost of submaximal running.”

The PCr system is refueled by the aerobic system, meaning the aerobic system is still important for all athletes. Remember, none of these systems work independently or in isolation. If you look at MOXY the body starts using up Oxygen immediately AKA it is already sensing what it will need to do in milliseconds.

“Although an up-regulation of fatty acid oxidation will never cover the high demands for ATP re-synthesis required during sprints, the oxidation of fat will play a supporting role during periods of recovery between repeated high-intensity efforts.”

Metabolic Flexibility still wins. And let’s remember that when you are fat adapted you are actually less metabolically flexible, just the other way around in that you can’t burn carbs good. Perhaps amazing for an ultra-endurance runner or someone who never leaves their desk, but for anyone playing under the lights – not so much.

“Peripheral depletion of muscle glycogen in sub-cellular compartments such as the sarcoplasmic reticulum will influence the flux of calcium and impair the contractile property of the muscle.”

There a lot of limiters when it comes to exercise performance. From a nutritional standpoint – glycogen repletion is a big one when we are stomping around in the world of performance.

“Following a competitive soccer match muscle glycogen stores are reduced by 50–60 % of pre-match values. It should be noted that the loss of glycogen during intermittent variable running is not even across both type 1 and type 2 fibres.”

We can assume similar loses from basketball and football (will likely depend on position) and other field sports. Matches are 45 min to 90 min depending on the sport. But how much time do these players spend practicing? We are talking likely a minimum of three hours a day plus the weight room. That is a glycogen massacre (especially in type II fibers) at least six days a week and replenishing it becomes one of your top priorities.

“Early studies of work rates during soccer matches revealed the link between muscle glycogen stores and activity patterns of players: those players with low prematch glycogen levels covered less ground than those with high values.”

Want to cut out your athlete’s legs – try some carb restricted diet that doesn’t adequately fuel them for their sport…because you read it on the internet. There has been a lot of chatter about this in the blogosphere and podcastmundo, but in the published research, only a few studies have stood the test of peer-review in the last decade and the ground we walk on in anything with repeating high-intensity efforts is still the same.

For more on this read the tremendous review by Dr. Burke – Re-Examining High-Fat Diets for Sports Performance: Did We Call the ‘Nail in the Coffin’ Too Soon?

“Eating a high glycemic index carbohydrate meal, that provided 2.5 g/kg body mass (BM), 3 h before exercise, increases muscle glycogen levels by about 11–15 %.”

It has to be high GI and if you are chasing performance in an insulin sensitive individual this is likely a tool you use selectively. But, if you are riding the bench – you are not crushing pancakes.

“One consequence is that athletes may consume less carbohydrate when recommended to eat low glycemic index foods and so do not sufficiently restock their glycogen stores.”

This sentence literally encompasses the bane of the exercising Paleo community over the last decade. When you increase food quality you invariably decrease food quantity. This is not always good. Play the game and know you are playing it.

“Games players who performed five blocks of the LIST (75 min) followed by alternate 20-m sprints with jogging recovery to fatigue, and 22 h later they attempted to repeat their performance. During the recovery they consumed their normal diet with either additional carbohydrate to achieve a total intake of 9 g/kg BM or their normal carbohydrate intake (5 g/kg BM) plus extra protein so as to match energy intake of the carbohydrate diet. After the high-carbohydrate recovery diet, the games players were able to match their previous day’s performance. In contrast when they consumed their normal amount of carbohydrate, and an equal energy intake, the players failed to reproduce their previous day’s performance. When this study was repeated using energy- and macronutrient-matched HGI and LGI carbohydrate meals during the 24-h recovery, there were no differences in performance of the games players.”

5 g/kg is not going to be met with broccoli and brussels and 9g/kg isn’t going to be met unless you eat a little dirty and get in liquid calories. For an 85 kilo male this is 340 and 765 grams of CHO, respectively. Yet, we should strive to meet the athletes need with the highest percentage of real food as possible and only use our high GI hammer in and around training.

The upcoming study in Costa Rica will carb cycle athletes and average around 3g/kg to see if muscle glycogen can be replenished while undergoing one of the harder protocols you will find in the lifting realm.

*a side note most competitive CrossFitters I work with, especially females aren’t within shouting distance of 5 g/kg and it is killing them softly.

“More recent studies suggest that ingesting sufficient carbohydrate (1.2 g/kg BM) during post-exercise recovery can maximize the rate of glycogen storage and improve subsequent performance.”

If weight is stable and performance is the goal. Do it. Rice cakes. Powders. I don’t really care just get it done and if you want measure blood sugar to see what happens and assess if you need to spread it out. The likelihood of your 9% body fat 220 pound running back being anywhere close to diabetic is slim to none.

And to finish.

“Prolonged periods of multiple sprints drain muscle glycogen stores, leading to a decrease in power output and a reduction in the general work rate during training and competition. Adopting nutritional strategies to ensure that muscle glycogen stores are well stocked prior to training and competition helps delay fatigue.”

Go Packers!

*The meme for this post is by @ScottcerJance. Follow him. It is quite amusing.