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Reprinted from a USOC article written by:
Scott A. Riewald, PhD,CSCS and Michael R. Barnes, Med,CSCS/ USOC Coach National Strength and Conditioning Association
Competing and training to achieve peak performance requires a great deal of attention to detail, not only to athletes’ physical training but also to their lifestyle. Athletes and coaches are continually looking for any possible advantage, and fine tuning hydration and nutritional strategies for recovery should be part of the game plan.
It is the intent of this article to clarify some fundamental nutritional strategies to maximize performance and minimize recovery time. Different sports require different training demands; for example, training for triathlon is drastically different from training for Olympic weightlifting. As a result, the specific nutritional and hydration needs for each sport and athlete needs to be individualized. Special attention should be given to the topic of nutritional supplements as the marketing strategies of supplement companies often cloud coaches; and/or athletes’ perspective on designing a comprehensive nutritional strategy. This article presents some general guidelines that should be followed by most athletes, especially when sport-specific training is complemented by strength training.
Dehydration and Rehydration
Proper hydration and re-hydration is important to every athlete. It has been well documented that maintaining hydration is critical for ensuring optimal performance in all types of training, from aerobic training to strength training. However, hydration is especially important in those sports where large amounts of water are lost through sweat. Water accounts for up to seventy percent of an individual’s body weight, and muscle tissue actually is composed of seventy-five percent water. There are many factors that affect hydration status including an athlete’s fitness level, ambient conditions (heat and humidity), altitude, air travel and medications. It is easy to lose track of weight lost during a practice session, and athletes may forget to replenish lost fluid stores. Therefore, proper fluid replacement is important because fluid loss of only three percent of an athlete’s body weight (i.e. 4.5 pounds in a 150-pound athlete) significantly impairs performance.
Maintaining a proper electrolyte balance is a factor that must be considered in sports where large amounts of water are lost through sweat. Specifically it is important to replenish sodium, chloride and potassium as they play a major role in regulation of body temperature and hydration. Electrolyte imbalances, if left untreated, can also interfere with muscle contraction and possibly lead to cramping.
In particular, when sodium is lost in moderate-to-large amounts through sweat, its function of regulating fluid retention can be compromised. The average American consumes between four to six grams of sodium per day, and this amount is sufficient to replace sodium losses in most people. However, athletes who sweat profusely and/or are training in stressful conditions may require a daily intake of sodium that exceeds the average intake. Consuming healthy foods with high amounts of sodium, adding salt to food or drinking sports beverages that contain electrolytes are viable solutions to meeting additional sodium needs of athletes.
Replacing fluids after a practice or competition is essential to ensure optimal performance in subsequent practices or competition sessions. Some general fluid replacement guidelines are:
• Continually remind athletes to drink plenty of water or other appropriate beverages. Encourage athletes to hydrate properly before and during exercise, especially in a hot environment. They should drink at least 16 ounces of fluid two hours before practice or competition and six to eight ounces every 15 minutes during practice.
• Make cool beverages 9about 50-70 degrees Fahrenheit or 10-21 degrees Centigrade) available to athletes during and immediately after practice.
• After training, athletes should replenish fluids a t a rate of or exceeding one pint for every pound of body weight lost. Weight lost in training should be regained before the next training session. Encourage athletes to weigh themselves before and after practice. This helps them get a feel for how much water weight they lose during a workout, and if they need to change their hydration practices.
• Water is a good fluid replacement although flavored beverages that contain electrolytes may be more effective at promoting consumption. The sodium consumed in food a d sport beverages can promote re-hydration more readily than water when a significant amount of weight has been lost via sweat.
• A fluid replacement sport drink, that includes a six to eight percent carbohydrate concentration, is ideal for replenishing fluids and electrolytes during practice.
• Have athletes note the color of their urine. When properly hydrated, urine should be a pale yellow color. Dark yellow urine means that an athlete needs to drink more fluids.
What And When Should Athletes Eat To Recover From A Workout?
The bottom line is that both the timing and content of a post-exercise meal can have a significant impact on how well athletes recover for their next training session or competition. This is especially true for athletes who practice or compete multiple times per day. When considering nutrition, it is important to realize it is a day-to-day maintenance process that should focus on replenishing depleted energy stores. While it is vital to think about nutrition during a competition, what athletes do between practices on a day-to-day basis has a much greater effect on performance. If athletes are not replenishing their energy stores after every workout, they will be unable to practice with optimal intensity and concentration. By denying their bodies’ sufficient food to replenish energy stores, athletes’ performances ultimately will suffer. Here are some suggestions on proper eating habits that encourage athletes’ recovery.
• Eat carbohydrates (CHOs).
Intramuscular glycogen is the primary source of energy in almost every activity, from intense anaerobic activities such as strength training to endurance events like triathlon. Glycogen depletion may be a limiting factor on performance especially in endurance events, and it important to rebuild the muscle glycogen stores between workouts. CHOs contain sugar, and sugar molecules are the essential building blocks of glycogen, so athletes need to eat CHOs!
• Eat CHOs within the first two hours after a workout.
The highest rate of glycogen storage occurs in the two hours after exercise due to increased permeability of the muscle to glucose, an increased sensitivity to insulin (which stimulates glucose uptake into the muscle) and enzymatic activity. Rates of glycogen synthesis may be nearly two times faster than normal in the first two hours after a workout. After this two-hour time window, the rate of glycogen formation returns to normal levels.
• Do not delay, prepare for the next workout.
Glycogen resynthesis does not occur until CHOs are consumed. A high CHO meal after a workout stimulates an immediate replenishment of muscle glycogen stores. This effect significantly decreases the longer the meal is postponed. Research has demonstrated at two hours post-exercise, glycogen stores are three times greater when CHOs are eaten immediately after workout compared to eating the same meal two hours after workout. At four hours after workout, glycogen resynthesis was still two times greater in individuals who ate right after practice. These differences disappeared by 8 and 24 hours post-exercise. This data suggests that to properly recover, especially when athletes have more than one practice session per day, it is important to get the CHOs into their systems as soon as possible.
• Eat enough CHOs.
Perhaps even more important than when an athlete eats CHOs is how many they eat. The key to replenishing intramuscular glycogen is to eat sufficient carbohydrates. Seven to nine grams of CHO per kilogram of body weight (CHO/kg BW) should be eaten within 24 hours following an intense workout and then ensure the remaining CHOs are consumed throughout the remainder of the day. For example, a 150-pound athlete should consume approximately 50 grams of CHO immediately after workout and between 425 and 560 grams throughout the remainder of the day.
• Meal size and number are not important.
Studies show that as long as CHO needs of athletes are met, eating CHOs in many small meals or several larger meals does not affect the rate of glycogen resynthesis. At 24 hours post-exercise, the intramuscular glycogen stores were replenished in athletes who followed either meal plan.
• Eat high Glycemic Index (GI) CHOs after a workout.
The GI indicates how fast a food breaks down into sugar and enters the blood stream. High-GI CHOs enter the bloodstream rapidly and low-GI CHOs that will digest rapidly for glycogen resynthesis. The remaining CHOs consumed throughout the day should be a combination of high and low GI foods.
• Consume protein with carbohydrates.
Muscle damage frequently occurs during training sessions. Some researchers recommend consuming protein and/or essential amino acids before or after a workout. Protein consumption does not interfere with the rate of glycogen synthesis, and athletes may safely eat a low fat, protein rich food like lean lunchmeat or a low fat dairy product after a workout. Since amino acid mixes are considered a dietary supplement, be cautious in their use. Keep in mind that extra protein does not necessarily mean build extra muscle.
• Muscle damage may interfere with glycogen uptake
Exercises involving eccentric muscle contractions (lengthening contraction)cause more damage to muscle than concentric contractions. This damage may inhibit glycogen uptake during the first 24 hours after exercise. Following a practice where eccentric exercises are conducted, recognize that athletes may come to the next workout in a depleted state. To maximize muscle recovery, design volume, intensity and duration of training while taking into account prior training loads.
• Avoid dietary supplements. Supplements may contain prohibited substances that can lead to a positive drug test.
A recent IOC study showed that 94 of 634 supplement products (14.8 percent) tested worldwide-included substances not included on the label that could lead to a positive drug test. This rate was slightly higher in the United States (45 of 240 products or 18.8 percent). The best rule regarding dietary supplements is use supplements at your own risk.
• Avoid excessive alcohol.
Drinking alcoholic beverages may be a common social activity following an athletic event. However, athletes should avoid alcohol in the two hours after a practice or competition, and binge drinking should be avoided at all times. Alcohol interferes with rehydration and glycogen synthesis, and these two processes occur most rapidly in the first two hours after exercise. Athletes should take advantage of this two-hour window to refuel their bodies.
Conclusion:
The coaches’ main responsibility is to maximize athletes’ potential. This often means going the extra mile to research topics that are unfamiliar; nutrition may be one of these topics. Nutrition for athletic performance is a complicated and detailed topic. With basic knowledge, common sense and strategic approach, coaches can assist athletes in choosing the necessary fuel for peak performance.
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