This is a multi-part series on BCAA supplementation for athletes. Please check out Part I if you haven't already. Last week I finished up by explaining how BCAAs are released from the liver after digestion and released into general circulation where they are taken up by the muscles. Once there, they are available to be used as building blocks for protein synthesis, act as energy substrates, or serve as donors to form other aminos such as glutamine. If you're looking to gain strength and size then ideally they will serve as building blocks for additional protein synthesis.
During normal conditions, 80-100% of the body's energy requirements are supplied by fats and carbohydrates. This means that even under normal sedentary conditions amino acids can provide up to 20% of your energy needs. During exercise, depending on your training, you will ideally burn mostly fat and stored carbohydrate (glycogen) as fuel but eventually your body will also turn to protein, particularly the BCAAs, as glycogen becomes depleted.
The muscle proteins are a rich source of BCAAs and the problem is that muscles can use the BCAAs directly as fuel, so in a pinch the BCAAs will cannibalize themselves and oxidize their own proteins as a fuel source. This happens during exercise as glycogen levels become depleted. Studies have shown that in weight training using sets of 10 repetitions for various exercises, individual muscle glycogen levels can become depleted by more than 10% with each set performed. So if one set can deplete glycogen levels by 10% you can probably imagine how much depletion of glycogen a typical higher set might lead to!
Studies Of BCAA Oxidation
In studies using moderate intensity exercise (an easy bicycle ride of 55% of VO2 max), the BCAA oxidation during the exercise period was 240% above baseline and the total BCAA oxidation during an easy 2 hour ride was 90% of the total requirement for various BCAAs listed in the RDA (recommended daily allowance) handbook. In another study it was found that during a 10 mile run more than 100% of the RDA for protein, and thus BCAA, was oxidized as fuel during the run! For an athlete this is not a good thing as it is virtually impossible to build or maintain muscle in this state.
One way you can ensure an adequate BCAA pool is by consuming enough protein at regular intervals on a daily basis. Remember that protein contains all the aminos, including the BCAAs, so it is imperative you take in enough protein. Intensely training athletes have long known they require more protein than sedentary people. Many people are under the misconception that they need all this extra protein strictly for fueling muscle growth.
Although it does require a bit of extra protein to fuel muscle growth, the truth is that athletes need additional protein because their intense exercise sessions burn more protein and amino acids for fuel during exercise. Because of this, endurance athletes actually have higher protein and amino acid requirements on a pound-for-pound basis than bodybuilders! If you neglect to consume enough protein to make up for that protein used as fuel during your training, your body will strip aminos, particularly branched chain aminos, from your muscles to be used as fuel. This is obviously not something you want to happen. (Not unless you want to look like a typical marathon runner!)
|Bodyweight (lbs)||Leucine (grams)||Valine (grams)||Isoleucine (grams)|
Source: The Colgan Institute
Some recent studies have shown that even sedentary men require significantly more BCAA than what the RDA recommends. Even at leucine intakes 40% higher than the RDA figure, these men were found to be in negative leucine balance. In this state, optimal muscle maintenance is not possible and the status of all the other amino acids is also compromised.
All athletes want to avoid the reduced muscle size and strength consequent of reduced muscle protein synthesis and breakdown. Keep in mind an adequate level of free BCAA won't turn you into superman (although higher targeted dosages may come close), but will enable you to avoid some of the negative effects of BCAA depletion including inadequate recovery and training stagnation.
First you should make sure you get an adequate level by consuming enough protein to ensure at least a homeostatic level. Then you can add to this through targeted supplementation.
If you already have an adequate level provided by your diet, you'll really be able to see the benefits. In addition to consuming enough protein, make sure you consume enough quality calories on a daily basis and get plenty of rest and recovery. By consuming adequate calories and carbohydrates you'll help spare the BCAAs.
The greater your glycogen storage the more likely your BCAA pool will be used for muscle growth and the less likely it will be oxidized as energy. Rest and recovery will further help direct your BCAA pool towards muscle growth. Following these steps will go a long way in enhancing your gains-and we haven't even covered the REAL supplemental benefits yet!
Next week I'll get into the specifics on how higher targeted and timely dosages of BCAA supplementation can induce rather drug-like anabolic and anti-catabolic effects in the body! Trust me, if your goals include improving strength, performance, muscularity, and dropping body fat, then you won't want to miss out on this!