By Dr. Christopher Mohr
Christopher Mohr, PhD, RD, is the President of Mohr Results, Inc., based in Louisville, Ky., where he provides nutrition and training consultations for individuals and corporations. He can be reached through his Web site at: www.MohrResults.com.
Training & Conditioning, 15.7, October 2005, http://www.momentummedia.com/articles/tc/tc1507/acsm.htm
Testing High-Energy Drinks
Energy drinks seem to be all the rage. They are popular across many age groups and sometimes used in athletics for a performance boost. Most beverages in this category include similar ingredients: hefty doses of caffeine and sugar, some B-vitamins, and a sprinkle of amino acids. This particular study tested Red Bull, the self-described “original” drink in this category. Red Bull contains taurine, glucoronolactone, caffeine, niacin, vitamin B-6, pantothenic acid, vitamin B-12, sucrose, and glucose.
The purpose of this study (“The Effects of a Commercial Energy Drink on Repeated High Intensity Anaerobic Cycling Performance,” by Stefan M. Pasiakos, Robert Petrancosta, John Wygand, and Robert M. Otto) was to measure the effects of Red Bull on anaerobic cycling performance. The study was a double-blind, placebo controlled, crossover trial in which 13 male subjects participated. Trials consisted of a modified Wingate Anaerobic Power Test after consumption of either Red Bull or a Red Bull-flavored placebo drink. The Wingate Anaerobic Power Test used in this trial consisted of six bouts of 15-second supramaximal cycling with a load equal to 0.1 kg/body weight with 45 seconds of recovery time between bouts. The data from this test can be extrapolated to other high intensity sports, such as sprinting, basketball, and soccer.
The results showed that some of the resting metabolic variables, including heart rate and respiratory exchange ratio, were significantly higher in the group that consumed Red Bull vs. the placebo group. In addition, exercising heart rate and lactate levels were significantly higher in the experimental vs. the placebo group. There were no significant differences seen, however, in repeated anaerobic cycling performance in the two groups.
Take home message: Considering there were no differences in performance outcomes, it is recommended that athletes not rely on Red Bull or similar energy drinks when looking for performance assistance. Because such drinks raise athletes’ heart rates and respiratory exchange ratios, they should especially be avoided by athletes exercising in extreme heat.
Supplementing Soccer Players
Soccer is considered a power-endurance sport, and in preseason and in-season training, soccer players’ bodies are under a great deal of stress as they attempt to maintain high levels of both strength and endurance. This maintenance is obviously crucial so that athletes can perform near maximal capacity in season. This study (“The Impact of Nutritional Supplementation on Performance and Muscle Breakdown in Collegiate Soccer Players,” by Shawn M. Arent, Joseph Pellegrino, David DiFabio, John Greenwood, and Carey A. Williams) was conducted to examine the physiological changes and metabolic parameters in collegiate soccer players in preseason training if a particular dietary supplement was introduced.
The subjects in the study included 24 NCAA Division I male soccer players. VO2max, the onset of blood lactate accumulation (which could determine onset of fatigue), the time to fatigue, and the creatine kinase (CK) response (which is a marker of muscle damage) were all measured. Athletes were given either a dietary supplement containing three ingredients—superoxide dismutase, coenzyme Q10, and branched chain amino acids (BCAAs)—or an isocaloric placebo. Superoxide dismutase can act as an antioxidant. Coenzyme Q10 (COQ10) is produced endogenously and used in an energy pathway in the body—some suggest additional COQ10 is useful as an antioxidant and for energy production. BCAA are amino acids that are often recommended for recovery.
Results showed significant changes from the beginning to end of preseason in all the measurements across groups. This is not surprising since the athletes are in much better shape after intense training. CK levels also increased significantly, meaning muscle breakdown was higher, so the improvements in the first three outcome parameters came despite the increased muscle breakdown.
In terms of the use of dietary supplements, there did appear to be modest differences between the experimental and control groups—better cardiovascular capacity, increased VO2max, and longer time to fatigue for the experimental group—but these differences were not significant. The researchers drew the conclusion that this particular combination of ingredients may enhance some of the parameters measured. But the short-term effects were moderate.
Take home message: More research is necessary with this particular concoction of ingredients, as the effects were only moderate, and the study was completed on a small test group. The best advice for enhancing recovery from high-intensity training is still to eat a varied diet, drink plenty of fluids, and ensure adequate rest.
Caffeine & Agility
Caffeine is a known ergogenic aid. It has been shown through numerous studies to enhance endurance performance and increase mental focus. This study (“The Effects of Caffeine on Athletic Agility,” by Andrew J. Lorino, Lisa K. Lloyd, Sylvia H. Crixell, John L. Walker, and Jack W. Ransone) was conducted to examine whether caffeine also has an effect on athletic agility and, therefore, on overall anaerobic performance.
Sixteen adult men performed two trials of two drills with two to three days of rest in between. They participated in a pro-agility run test (to measure agility) and a 30-second Wingate test (to measure anaerobic power). Subjects were not blinded for this study. They all received six mg of caffeine per kg of body weight before one of the testing days, and a placebo on the other. The order in which they received the supplement was random.
The researchers found no significant differences between either the placebo or caffeine trials in either of the outcome measurements. They suggested a number of possible limitations to this study, however. The caffeine dosage may have been too low, habitual caffeine use by some of the athletes may have hindered the results, and training status of subjects could have influenced the results.
Take home message: Caffeine does work for many outcome parameters, but this study did not prove it affects agility and anaerobic performance. Most researchers suggest that athletes be very careful before using caffeine as an ergogenic aid, and this study reiterates that view.
All three of these studies were also published in the May 2005 issue of Medicine and Science in Sports and Exercise, the official journal of the ACSM. It can be accessed at: www.ms-se.com.