It has been suggested that taking proper quantities of carbohydrates at the right time could improve athletic performance by ensuring adequate energy stores are available when necessary. Research Loading, or increasing the carbohydrate content of the diet for several days before an event, has been promoted as a means to prolong exercise endurance. One study 29 evaluated its impact on continuous, short-term events of less than one hour and found no benefit, because muscle glycogen content was not depleted at the end of the exercise. A meal prior to exercise will ensure that muscle and liver glycogen stores are maximized.
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It has been suggested that taking proper quantities of carbohydrates at the right time could improve athletic performance by ensuring adequate energy stores are available when necessary. Research Loading, or increasing the carbohydrate content of the diet for several days before an event, has been promoted as a means to prolong exercise endurance. One study 29 evaluated its impact on continuous, short-term events of less than one hour and found no benefit, because muscle glycogen content was not depleted at the end of the exercise.
A meal prior to exercise will ensure that muscle and liver glycogen stores are maximized. Evaluation of six endurance athletes ingesting carbohydrates only 45 minutes prior to a two-hour exercise test revealed no benefit. Thirty marathon runners in a double-blind study 33 described decreased subjective exertion when ingesting 60 g per hour of a liquid carbohydrate solution during a two and one-half hour run.
Another study 34 found that ingesting a carbohydrate-electrolyte drink during one hour of high-intensity exercise improved performance in 19 bicyclists. Many studies have demonstrated similar results. One study 35 that evaluated solid versus liquid carbohydrate replenishment showed no difference, as long as adequate water intake was maintained. Eating a mixture of carbohydrates and protein within two hours after an activity has also been associated with benefits, including replenishment of depleted muscle and liver glycogen stores and decreased muscle catabolism.
A study 36 of nine weight lifters showed increased levels of plasma growth hormone and insulin when athletes ingested protein and carbohydrate immediately and two hours after exercise, which would theoretically provide a physiologic environment favorable for muscle growth.
Another placebo-controlled study 37 of endurance athletes ingesting a carbohydrate-containing solution after exercise reported increased glycogen resynthesis.
Adverse Effects Theoretic disadvantages have been reported with carbohydrate supplementation. Increased insulin levels after carbohydrate consumption were shown to significantly decrease blood glucose levels in some athletes, though not all athletes seem to be subjectively sensitive to these decreased levels. Many other dietary supplements have been advertised for their purported ergogenic properties, and the list grows each year. Table 3 provides a brief summary of the most common agents that physicians may hear about from their patients who are athletes.
When counseling patients about ergogenic aids, it is important that the physician be knowledgeable about the topic. The intervention that carries the most impact is ensuring optimal dietary habits.
Supplying adequate energy intake, carbohydrates and protein in the diet, and timing these to be efficiently used by the body, will provide the most effective and safe results.
Performance Enhancers: The Safe and the Deadly
Some substances are banned in competition only, others are banned at all times, and some may be banned in specific sports. Strict Liability The Athlete is solely responsible for any prohibited substance found in their body. Who does it apply to and when? Mobile App "Clean Sport" which provides up to date anti-doping advice is a free application available in both iOS and Android versions. Do not assume that because a substance is not listed, it is not prohibited. Lists of prohibited substances are periodically revised. Always check with the medical officer of the sport or the Sports Council if you are in doubt.
Overview People use performance enhancers to improve their performance during high-intensity physical exercise. A performance enhancer, or ergogenic aid, is anything that gives you a mental or physical edge while exercising or competing. This can range from caffeine and sports drinks to illegal substances. There are a variety of both safe and harmful ergogenic aids. However, scientific proof of their effectiveness is sometimes lacking or contradictory. There are other ergogenic aids that are generally recognized as safe by the U.
Ergogenic Aids: Counseling the Athlete