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The foundation of enhancing athletic performance is essentially the same goal that health-care providers have for their in their patients, which is to optimize health. For the athlete, detailed sports-specific training regimens should be recommended as well as appropriate sports-specific caloric and macronutrient needs. Furthermore, every athlete should at least be on an appropriate multivitamin, no matter what the lifestyle deficiencies may be. The fact that JAMA in 2002 stated, "It appears prudent for all adults to take vitamin supplements," applies even more so to athletic populations.1 Once the basic needs of the athlete are addressed (i.e., sports-specific training, caloric needs, and lifestyle optimization), then the athlete and associated team will be in a better position to determine appropriate supplemental ergogenic aids. Part 3 of this article briefly details specifics on the known natural ergogenic aids, most of which are deemed unbanned by athletic organizations, and then lists banned substances in international sports competition.
The ISSN has called creatine "the most effective nutritional available to athletes to increase high intensity exercise capacity and muscle mass during training."2 This supplement is one of the most extensively studied for its performance-enhancing effects. The ergogenic effects appear to be (1) increasing the amount of energy available in the form of ATP and (2) increasing cellular hydration.
More than 95% of the body's creatine is stored in muscle tissue in a readily available phosphorylated form, phosphocreatine. Hence, creatine is especially rich in animal protein. While creatine can be made in the body, it requires significant resources, including the amino acids (AA), magnesium, methionine, B12, and folate among others. Phosphocreatine is able to supply ATP, the body's energy currency, for quick bursts of high-intensity activity lasting around 10 sec. Once these high energy phosphates are depleted, the body relies more heavily on anaerobic metabolism. Supplementation of creatine is thought to "supersaturate muscle" and allows for greater performance of short, explosive movements. Creatine appears to increase muscle water content, and research appears to show that hydrated muscle tissue is able to both synthesize new muscle tissue and resist protein breakdown.2-4
Studies on weight training and high-intensity interval exercise show creatine as a reliable and beneficial training aid. Kerksick et al. showed that 4 weeks of creatine supplementation significantly improved both strength and lean body mass when loaded at 20 g/d for 5 days followed by 5 g/d.5
Another study, on 23 untrained males divided into a creatine group or a placebo group, showed greater power output and less fatigue in the creatine group.6 The creatine dose was 5 g 4×/d for 6 days. Both before supplementation and 7 days after supplementation, participants did a 30 sec of maximal sprinting on a bicycle ergometer. This was repeated 5× with 2 min rest in between. There was a 7.6% increased power obtained in the creatine group, while the placebo group saw no improvement.
Lean body mass gains can be significantly greater with creatine than with controls while weight training. A review by Kreider et al. says that most evidence shows that short-term creatine supplementation can generate greater muscle gain and greater power output, thus enhancing performance.7
Creatine has now been studied extensively in several reviews, and long-term studies on safety show it to be safe in adults and adolescents without renal disease.8 Creatine increases recovery from intense exercise and increases lean body mass.2
Dosing is typically done in divided doses of 20 to 30 g/d for 5 days followed by a maintenance dose of 2 to 5 g/d for 3 wks. Taking creatine postworkout with small amounts of glucose, such as grape juice, can improve muscle saturation benefits.2
Beta-alanine is a precursor, along with histidine, of carnosine, which is found in high concentrations in skeletal muscle. Beta-alanine has been shown to increase carnosine levels.9,10 It is widely assumed that carnosine has performance benefits in its ability to resist pH changes in muscle. Ergogenic effects include greater number of repetitions during resistance exercise, fatigue resistance, generation of greater force with the legs, optimization of hormonal response to exercise, and improvement in body composition.10-14
Common side effects are a "pins and needles" sensation (acute paresthesias), burning, itching, or a flushing on the ears and scalp. Many people use these side effects to adjust their dosing, reducing it if they experience them.
Dosages range from 800 mg to 7 g daily in divided doses.
Branched-Chain Amino Acids (BCAAs)
BCAAs (leucine, isoleucine, and valine) have been shown to increase protein synthesis, decrease protein breakdown, and speed recovery from exercise. BCAAs are probably the most beneficial aspect of protein intake for the athlete. Research suggests they may have some acute performance enhancement effects and play a key role in body composition. BCAAs have been shown to spare muscle protein breakdown and promote muscle protein synthesis.15-17 They have some impact on exercise performance, perceived exertion, optimization of body composition, and recovery. 16,18-22
Suggested doses of BCAAs are between 6 and 12 g/d. Given that dosages of BCAAs are so high, it may be more practical to recommend this supplement in powder form rather than capsule. Mixing BCAAs powder into a small amount of high-glucose fruit juice, such as grape juice, may help increase compliance by masking the bitter taste and increasing absorption and utilization.
Beta-Hydroxy Beta-Methylbutyrate (HMB)
HMB is derived from the BCAA leucine. Using HMB at levels from 1 to 3 g/d while undergoing weight training may increase strength results and have positive impacts on lean muscle gains.23-25 Older or untrained individuals can also benefit from supplementation.26 Vukovich et al. in 2001 showed that 3 g of HMB daily over 8 wks given to elderly men and women led to significantly greater loss in fat compared with a placebo group.26
A study by Knitter et al. showed that HMB might protect against muscle damage from exercise.27 Well-trained runners were supplemented with 3 g/d over 6 wks. Compared with placebo, HMB-supplemented runners had lower markers of muscle damage.
HMB supplementation along with creatine may behave in a synergistic fashion.28
The dose of HMB shown to be effective is 1 to 3 g/d.
The consensus of studies show that caffeine, as opposed to coffee, has value in endurance exercise performance, anaerobic exercise outcomes, exercise recovery, and weight loss.29-32 Research on pure caffeine consumption shows an ergogenic effect, whereas coffee consumption is equivocal. Users of caffeine will develop some tolerance, whereas nonhabitual users may experience slightly better benefits. Concerns about caffeine and risk of dehydration are unfounded, according to the research. Caffeine's absorption occurs rapidly and is detectable in blood within 15 min of intake, reaching peak levels at 1 hr. Caffeine is cleared from the system in about 6 to 12 hrs, depending on the individual's metabolism.29-31
Caffeine exerts strong influence on the nervous system, affecting both the CNS and PNS. It acts to increase mental focus and fine motor skills. B-endorphin concentrations also rise with caffeine consumption, possibly resulting in decreased pain perception during intense activity.33 Nervous system activation by caffeine plays a strong role in sports requiring bursts of speed and intensity.33,34
Caffeine spares muscle glycogen and shifts metabolism toward the increased use of fat both from subcutaneous and intramuscular compartments.35 Given that fat oxidation is a key component of endurance sports, caffeine can improve outcomes in long-distance events.36 It also has an interesting impact when dosed along with carbohydrate. A carbohydrate beverage spiked with caffeine can significantly bolster carbohydrate oxidation and muscle glycogen synthesis more than carbohydrate alone.37,39 This may be due to caffeine's ability to hasten the absorption of glucose from the digestive tract to the bloodstream.
In high-intensity exercise, caffeine increases catecholamine production, increasing both lipolysis and glycogenolysis.29-31 This along with increased activation of the CNS may be the mechanism responsible for better performance in high-intensity endeavors. Schneiker et al. showed that caffeine intake increased sprint performance 8.5% and 7.6% over placebo in the first and second bouts, respectively. It also increased power output compared with placebo.38
Caffeine's suspected activity as a fat-loss aid comes from its epinephrine-inducing effects. Studies as far back as 1990 showed that as little as 100 mg of caffeine, the equivalent in 1/3 cup of coffee, could increase thermogenesis in even habitual coffee drinkers.40 Studies on caffeine have repeatedly shown increased fat oxidation, making it a known fat-loss aid.29-32
Caffeine consumption shows impact when taken 15 to 60 min prior to exercise at a dose of 6 mg/kg bodyweight. For a 160-pound individual, this is the equivalent of about 430 mg of caffeine.29-31
Green Tea Extract (GTE)
Green tea has been consumed in Asian countries for centuries. Habitual green tea consumption is correlated with lower weights and less body fat.44 Studies have shown that extracts of green tea catechins can increase oxidation of fat both at rest and during exercise.42,43
Dulloo et al. showed that GTE intake elevated 24-hr resting energy expenditure with increase fatty acid oxidation when compared with an equal amount of caffeine taken alone.42 A 90-day clinical trial combining GTE with a low-calorie diet resulted in significantly greater weight loss compared with a nontreatment group (30 lbs vs. 11 lbs).41 Interestingly, the activity of GTE may have particular use against abdominal fat.45
Ichnose et al. conducted a double-blind, placebo-controlled trial of GTE intake over 10 wks.46 Exercise testing was done before and after the 10 wks supplementation. Both the placebo and GTE contained equal amounts of caffeine content. At the conclusion, no changes in performance parameters were noted between groups. However, there was a statistically significant increase in fat utilization for the GTE group, but no change in the placebo group.
GTE can cause a transient feeling of nausea in susceptible populations. It also frequently comes along with caffeine, both of which separately can aid in fat loss.44
GTE dosage is usually 300 mg to 500 mg daily.
Sodium Bicarbonate (Baking Soda)
Due to the fast accumulation of protons (H+) and carbon dioxide (CO2) during high-intensity anaerobic activity, buffering capacity in muscle and blood is essential. The chief buffering compound is the bicarbonate ion (HCO3−).
Sodium bicarbonate appears to provide a reservoir of bicarbonate ions and thus gives one greater capacity to resist fatigue-induced pH changes at the muscle cell. Several studies have shown that supplemental sodium bicarbonate can stabilize pH changes for exercise lasting from 1 to several min.2,47-50
There appear to be no safety issues with sodium bicarbonate intake aside from occasional digestive upset; therefore, one should acclimate to dosing before using it in competition.
Sodium bicarbonate can be taken prior to exercise or as a loading dose several days before an event. The pre-exercise dose is 0.3 g/kg body weight taken in water between 60 and 90 min before an exercise bout.2 The loading dose of bicarbonate is taken over a 5-day period and consists of 5 g taken 2×/d for 5 days.2
Studies indicate that supplementation with sodium phosphate can increase maximal oxygen uptake/maximal aerobic capacity and anaerobic threshold, thus enhancing endurance exercise capacity.2,51-53,56 Sodium phosphate loading also seems to improve mean power output and oxygen uptake.2,54-56 Other forms of phosphate (i.e., calcium phosphate, potassium phosphate) do not appear to have ergogenic effect. The dosage is 1 g taken 4×/d for 3 to 6 days 2
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