You've heard of glutamine, the branched-chain amino acids and taurine. They're major players in the which-amino-acids-are-best-for-bodybuilding-and-exercise game. But there are two other amino acids that haven't gotten quite as much press. I call them the A team'aspartate and asparagine. In a study from S'o Paulo University in Brazil, investigators tested rodents after supplementation with aspartate and asparagines (A+A). The rodents got the A+A in their drinking water, so it isn't clear how much, in milligrams, they took in. Nevertheless, the results are fascinating.
After seven days of supplementation the animals performed a swim test to exhaustion. No, the supplement-fed rats didn't have to put on rat Speedos, nor did they have time to train for this event; however, rats have an uncanny ability to exercise like crazy, particularly if you put 'em in a vat of water to sink or swim. When researchers compared swim time to exhaustion, the results were dramatic. The A+A group swam for 68 minutes, while the placebo group lasted 41 minutes. That's a 66 percent difference. The A+A rats also had lower levels of blood lactate, which suggests that the A+A combination had a buffering effect. Another interesting finding was that the A+A group had lower rates of glycogen degradation in the lower-limb muscles as well as in the liver, which suggests that A+A improved the oxidative capacity (aerobic power) of the rats' muscles.
The next step is finding out what the effective dose might be in humans. I can foresee an A+A preworkout supplement that'll make for killer sessions in the gym.
Ribose revisited. Professor Rick Kreider of Baylor University is perhaps the most prolific scientist in the field of sports supplementation. His latest paper on ribose sheds further light on this unique sugar: Although high doses of ribose might improve performance in certain clinical populations, it isn't clear how much it can help the healthy athletic population. In a short-term study subjects got 10 grams of ribose or dextrose per day for five days. They took 10 capsules in the morning, or five grams, and 10 capsules in the evening, another five grams.
The researchers found no side effects to taking ribose for five days. Also, when they had subjects perform sprint cycling (two sprints, before and after) under laboratory conditions, they found that during the postsupplementation sprint test the placebo group had a greater rate of decline than the ribose group. In essence, the ribose group could maintain work output while the placebo group could not. Nevertheless, peak power, average power, torque, fatigue index, lactate, ammonia and uric acid levels did not differ between groups. The authors concluded that short-term ribose supplementation (10 grams a day for five days) has no effect on anaerobic exercise capacity or metabolic markers in trained subjects. Keep in mind that this was a short-term study; perhaps a longer treatment period is needed. Previous work by Antonio, et al., showed that the identical dose given for one month improved bench press'endurance performance.
Optimal creatine dosing. Cool science from the Land Down Under examined three different creatine-dosing protocols. Researchers divided 18 physically active males into three groups: 1) those who took five-gram creatine doses four times a day (separated by two-hour intervals) for five days; 2) those who took creatine (same dose) plus glucose (one gram per kilogram of glucose per kilogram of bodyweight twice daily, with the glucose dissolved in 500 milliliters of water and taken 30 minutes after the second and fourth doses of creatine); and 3) those who did exercise and took creatine (60 minutes of cycling on each of the five days of the loading phase). The subjects did their exercise sessions approximately one hour after taking the second creatine dose.
So which loading protocol worked best?
Phosphocreatine levels improved in the glucose-plus-creatine group (by 7.8 percent) and the exercise-plus-creatine group (by 9.2 percent) but not significantly in the creatine-only group (by 5.3 percent). Total muscle-creatine levels increased for all conditions, with the greatest change occurring in the glucose-plus-creatine group (by 25.2 percent) compared to the creatine-only (by 15.7 percent) and exercise-plus-creatine (by 18 percent) groups.
So carbs plus creatine do significantly better than either creatine alone or exercise plus creatine, at least during the loading phase. My guess is that if you combine exercise with carbohydrate consumption 30 minutes after taking creatine, you'll get an even greater effect.
What about the maintenance dose? How much do you really need? Well, get this: There was no difference in postloading creatine concentrations between a two-gram and five-gram maintenance dose. Interestingly, in the group that took no creatine after the loading phase, levels of creatine stores were still higher than baseline at six weeks out. So if you take creatine regularly and then go on a so-called off cycle, it'll take more than six weeks to get back to presupplementation levels.
Bottom line: If you choose to load, combine exercise and high-glycemic sugar consumption 30 minutes after taking in creatine. And for maintenance, a teaspoon of it will do just fine.
Marquezi, M.L., et al. (2003). Effect of aspartate and asparagines supplementation on fatigue determinants in intense exercise. Int Jour of Sprt Nutr and Exer Metab. 13:65-75.
Antonio, J., et al. (2001). Ribose administration in recreational bodybuilders. Med Sci in Sprts and Exer. 35:S166, 2001 abstract.
Kreider, R., et al. (2003). Effects of oral D-ribose supplementation on anaerobic capacity and selected metabolic markers in healthy males. Int Jour of Sprts Nutr and Metab. 13:76-86.
Preen, D., et al. (2003). Creatine supplementation: a comparison of loading and maintenance protocols on creatine uptake by human skeletal muscle. Int Jour of Sprt Nutr and Exer Metab. 13:97-111.
Editor's note: Jose Antonio, Ph.D., CSCS, earned his doctorate at the University of Texas Southwestern Medical Center. He is a co-editor (with Jeffrey R. Stout, Ph.D.) of and contributor to Sports Supplements (Lippincott Williams & Wilkins), Sports Supplement Encyclopedia (Nutricia), Supplements for Strength-Power Athletes (Human Kinetics) and Supplements for Endurance Athletes (Human Kinetics). For more information visit www.supplementbooks.com. IM