Nutrition for endurance and power sports(60)

Supattra Silapabanleng

endurance exercise lasting 30 min or more the most likely contributors to fatigue are -dehydration - carbohydrate depletion (gastrointestinal problems) -Hyperthermia -hyponatraemia *****can reduce endurance*****

 Fatigue during prolonged exercise is often associated with muscle glycogen depletion and reduced blood glucose concentrations  dehydration can also impair endurance performance. American College of Sports Medicine stating that dehydration of more than 2–3% of body weight should be prevented

 Requirements can vary from around 5 to 12 g /kg/day depending on the athlete and their activity.



 It should be noted that even if a higher carbohydrate intake can achieve higher glycogen stores, this might not always result in better performance.  Another consideration for some athletes is that glycogen storage is associated with weight gain as a result of water retention (approximately 3 g per gram of glycogen) and this may not be desirable in some cases.

Carbohydrate loading. It was suggested that super compensated muscle glycogen levels can improve performance compared with low to normal glycogen (non- supercompensated) by 2–3% in events lasting more than 90 min. There seems to be little or no performance benefit of super compensated muscle glycogen when the exercise duration is less than 90 min. The amount of dietary carbohydrate depends on the duration and intensity of the athlete’s exercise program. Jeukendrup AE.Nutrition for endurance sports: marathon, triathlon, and road cycling.J Sports Sci.2011;29 Suppl1:S91-9.



 Carbohydrate ingestion before exercise the consumption of a high-carbohydrate diet before exercise as well as ingestion of carbohydrate meals 3–4 h before exercise can have positive effects on exercise performance (Hargreaves, M., Hawley, J. A., & Jeukendrup, A. (2004). Preexercise carbohydrate and fat ingestion: Effects on metabolism and performance. Journal of Sports Sciences, 22, 31–38.) the intake of carbohydrate 30–60 min before exercise may adversely affect performance

the intake of carbohydrate 30–60 min before exercise may adversely affect performance Glucose ingestion in the hour before exercise can result in hyperglycaemia and hyperinsulinaemia, which is often followed by a rapid decline in blood glucose 15–30 min after the onset of exercise (Rebound hypoglycemia) However, only two studies have found reduced performance capacity, while the majority of studies have reported no change or an improvement in performance following pre-exercise carbohydrate ingestion

 This suggests that there is no need to avoid carbohydrate intake in the hour before exercise.  It is interesting to note that rebound hypoglycaemia occurs in some triathletes but not in others  To minimize symptoms of hypoglycaemia, an individual approach may be desirable, which could include ingesting carbohydrate just before exercise or during warm-up and selection of low-to-moderate glycaemic index carbohydrates





 When hydrating prior to exercise ‘‘the individual should slowly drink beverages (for example, 5–7 mL/kg BW [body weight]) at least 4 h before the exercise task.  If the individual does not produce urine, or the urine is dark or highly concentrated And should slowly drink more beverage (for example, another 3–5 mL/kg) about 2 h before the event’’ Sawka, M. N., Burke, L. M., Eichner, E. R., Maughan, R. J.,Montain, S. J., & Stachenfeld, N. S. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine and Science in Sports and Exercise, 39, 377–390.

 carbohydrate ingestion during exercise can increase exercise capacity and improve exercise performance  carbohydrate ingestion during exercise has also been demonstrated to improve exercise performance even when the exercise is of high intensity (>75% _V O2max) and relatively short duration (1 h)  This do not from metabolic effect but it from the central nervous system.

 the beneficial effects of carbohydrate feeding during exercise are not confined to its conventional metabolic advantage but may also serve as a positive afferent signal capable of modifying motor output (Gant, Stinear, Byblow, 2010).  it has been convincingly demonstrated that carbohydrate is detected in the oral cavity by unidentified receptors and this can be linked to improvements in exercise performance  There is a guideline for carpohydrate taking during exercise (for a review,see Jeukendrup & Chambers, 2010)

 it is not necessary to ingest large amounts of carbohydrate during exercise lasting approximately 30–60 min and a mouth rinse with carbohydrate may be sufficient to obtain a performance benefit  When the exercise is more prolonged (2 h or more), carbohydrate becomes a very important fuel and it is essential to ingest carbohydrate.  that these guidelines for carbohydrate intake during exercise are expressed in grams per hour of exercise and that these figures are not corrected for body mass.

Jeukendrup AE.Nutrition for endurance sports: marathon, triathlon, and road cycling.J Sports Sci.2011;29 Suppl1:S91-9.





 Multiple transportable carbohydrates (MTC) refers to a combination of saccharides that rely on distinct transporters for intestinal absorption.  Ingestion of MTC during prolonged exercise has been purported to - increase carbohydrate absorption efficiency, - increase exogenous carbohydrate oxidation, - reduce gastrointestinal (GI) distress - improve athletic performance Multiple Transportable Carbohydrates During Exercise: Current Limitations and Directions for Future Research.

dextrin containing maltose, used as a food additive. The gel contains a mixture of glucose and maltodextrin - a complex carbohydrate - along with fat and a trace of protein.

 The goals of maintaining hydration status and providing carbohydrate to the working muscle.  The addition of sodium and carbohydrate to sports drinks is widely recommended to enhance the absorption of water.  A drink should contain sodium (10–30 mmol/L) (Maughan, 1998) for optimal fluid absorption and prevention of hyponatraemia.

 Protein should make up around 15 - 20% of the calories you eat every day  Don't eat TOO MUCH protein. Replacing carbohydrate with protein may limit your body's ability to recover and have a negative impact on your health and performance Good protein sources include chicken, turkey, beef, fish, dairy (milk, cheese, cottage cheese), and eggs

• Adding a little protein to a carbohydrate source may help speed up recovery and minimize muscle damage • Ingesting 3 - 4 grams of carbohydrate for every gram of protein may be the most beneficial and an important combination for recovery • Whey protein is a popular, high quality form of protein found in milk • 15 - 25 grams of a high quality protein source provide adequate nutrients to maximally stimulate recovery and muscle growth

 A very important nutrient! DON'T AVOID or eliminate fat from your diet • Your brain, nerves, and muscles all NEED fat to function • Minimize your intake of saturated fats and trans fats. Cookies, donuts, and potato chips all contain high amounts of saturated and trans fats

 Caffeine is one of the most common supplements used in endurance sports.  Caffeine has been consumed in various foods and beverages for centuries due to its perceived work-enhancing (ergogenic) and alertness effects.  The vast majority of the studies that reported ergogenic effects used caffeine doses in the range 3–6 mg/kg taken approximately 1 h before exercise.

 More recently, studies have reported that much lower doses of caffeine (1.0–2.0 mg /kg), especially when taken later during an endurance exercise task, have also enhanced performance  an effective strategy might be to ingest a dose close to 3 mg/kg 60 min before the start of exercise followed by 1 mg /kg every 2 h after that.

 To provide metabolic fuel that will generate energy in the right quantity at the right time for specific sport training  To provide energy for competition  To support training adaptation, include muscle hypertrophy, repair and maintain lean body mass  To support recovery from training and competition

LOW GLYCOGEN AVAILABILITY HAS ALSO BEEN SHOWN TO MEDIATE MUSCLE BREAK DOWN AND THIS WAY TO DIMINISH THE EFFICIENCY OF RESISTANCE TRAINING Blomstrand E, Saltin B. Effect of muscle glycogen on glucose, lactate and amino acid metabolism during exercise and recovery in human subjects. J Physiol. 1999 Jan 1;514 ( Pt 1):293-302.

 Daily carbohydrate intake - In power and strength group of athlete have shown highly variable number in the range 3-7 g/kg BW/day - In general preparation period(High training volume): 6-12 g/kg BW/day - In specific preparation and competition phase: 6-10 g/kg BW/day

 Carbohydrate intake during exercise -At high intensity exercise, Gastrointestinal tract function is often compromise. -In this case, carbohydrate mouth rinse could be a potential nutrition strategy for improving performance. - In an experiment on multiple 5 seconds cycle sprints with 6% glucose mouth rise, improvement in peak and mean power output in the first of five sprints

 Carbohydrate intake after exercise - The IOC, ISSN, ACSM all recommence post-exercise carbohydrate intake range 1.0-1.5 g/kg BW to increase recovery from exercise and should be ingest within 30 minute after exercise in order to achieve higher glycogen level - Athlete who perform high training volume with high intensity more than once aday, carbohydrate should be ingest within 30 minute after exercise and again every 2 hrs. for 4-6 hrs.

 Daily protein intake - Depend on the quantity and quality of training - Elite athlete who effectuate a large amount and intensity of training, generally need protein intake 1.6-1.7 g/kg BW per day (ACSM recommendation = 1.4-2.0 g/kg BW per day) - Protein intake larger than 1.7 g/kg BW per day increase catabolism of amino acid without an additional hypertrophic effect (Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI,Wilkinson SB, Prior T, Tarnopolsky MA & Phillips SM (2009a). Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr 89, 161–168.)

 Protein intake before and during strength and power training - There are not enough data to support general guideline for protein intake - Protein should be include with carbohydrates in the pre-event meal before resistance exercise. this can be achieve by including 0.15-0.25 g/kg BW of protein with the recommended 1-2 g/kg BW carbohydrates in pre-event meal 3-4 hours before training (\"IOC consensus statement on sports nutrition 2010.\" Journal of Sports Sciences, 29(sup1), pp. S3–S4)

 Protein intake after exercise - It seem that 20-25 g of proteins maximally stimulates protein synthesis. - Larger and older athletes probably need more protein synthesis, up to 40g this recommendation valid when training start more that 3-4 hours after the preceding meal - Co-ingest carbohydrate and protein the athlete can maximize training adaptation and restore muscle glycogen( 0.4g/kg of protein combine with 0.8g/kg of carbohydrate)







 An ISSN recommendation (2010) regarding the use of dietary supplement base on scientific literature, the following substance are recognize as effective and safe in strength and power : Caffeine,Creatine monohydrate, B-alalnine and sodium bicarbonate (Kreider RB1, Wilborn CD, Taylor L et.al ISSN exercise & sport nutrition review: research & recommendations. J Int Soc Sports Nutr. 2010 Feb 2;7:7. doi: 10.1186/1550-2783-7-7.)

 Caffeine - The optimal effective dosage is not clear,the ergogenic effect was reported with buccal administration of only 100mg caffeine (Chewing gum) - The ergogenic effect 3 mg/kg BW stimulate nervous system(not regular caffeine consumer) 5 mg/kg BW increase the intestine absorption of carbohydrate during exercise and stimulate resynthesis of muscle glycogen 10 mg/kg BW unlikely to increase performance because of side effect(headaches, anxiety, gastrointestinal discomfort, increase urination

 Creatine monohydrate the most effective nutritional supplement strength and power sport. Ingestion of creatine support an increase muscle mass result from improve ability to perform high intensity exercise, a more intense work out can promote greater training adaptation. The most useful form : creatine+carbohydrate+protein, increase muscle retention of creatine Dosage(fastest method to increase creatine): 0.3 g/kg BW per day at least 3 day followed by 3-5 g/day 2-3 g/day will increase the muscular creatine concentration in 3-4 weeks.

 B-alanine Is a non essential amino acid(dipeptide form with histidine it form carnosine) Carnosine is a potent intramuscular buffer,it slow down ph during intensive exercise. Dosage: 3-6 g for 4-8 weeks can increase the amount of carnosine 40-50% of its normal level The basis for positive anaerobic performance during intense exercise lasting 1-6 min

Sodium bicarbonate Ingest of sodium bicarbonate can increase plasma bicarbonate and may slow the development of acidosis relate to fatigue of exercise Dosage: 0.3g/kg BW or 20g 1-3 hr before exercise or 5g take twice per day for 5 days *Nut suitable for everyone 50% athlete develop gastrointestinal discomfort.