Current Concepts in Sports Nutrition - Australian Sports Commission

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DURING EXERCISE Commercially available sports drinks (4–8 per cent carbohydrate, 10–25mmol/L sodium) promote effective rehydration during exercise and simultaneously deliver an additional source of fuel for the muscle and brain. The inclusion of sodium and flavouring in sports drinks has been shown to improve voluntary fluid intake, making it easier for athletes to achieve fluid intake goals. Water can be a suitable choice in lower-intensity exercise or exercise lasting less than 60 minutes. Carbohydrate Many studies have shown that consumption of carbohydrate during prolonged (>60–90 minutes) exercise enhances endurance and performance. More recently, carbohydrate intake has also been shown to benefit performance during shorter (~60 minutes) events and ‘stop and go’ intermittent sports such as tennis and soccer. The performance benefit may occur due to sparing of muscle glycogen stores, the prevention of low blood-glucose levels (hypoglycaemia) or effects on the central nervous system that are not well explained as yet. The benefits can translate into faster race times, a delay in the onset of fatigue towards the end of the event, ability to cover more ground at faster speeds in the last half or quarter of a game, and better maintenance of skills and concentration right to the final siren. The optimal rate of carbohydrate ingestion during exercise is unknown. However, in events lasting longer than 60 minutes, athletes are encouraged to consume carbohydrate at a rate of 30–60g per hour. Experimentation in training or less important events may allow the athlete to finetune this plan for their specific needs and opportunities. It makes sense for refuelling during the event to start well before fatigue is experienced and before a fluid deficit can build to a level where gastric emptying is reduced. The effects of consuming fluid and carbohydrate during exercise are additive. A variety of options exist for carbohydrate intake, however sports drinks offer a convenient strategy for meeting fluid and carbohydrate needs simultaneously. If other carbohydrate choices are used, care should be taken to consume adequate amounts of fluid.
Application to sport During Exercise / 28 Guidelines for endurance sports (for example, long-distance running, cycling, triathlon) Strategies for refuelling and rehydration during these sports need to be individualised for each event and each athlete. Assessment of likely sweat losses and the general guidelines for carbohydrate intake during prolonged exercise provide a starting point for experimentation. Supplies may be provided at aid stations or may need to be carried by the athlete. Examples of how to meet both carbohydrate and fluid requirements per hour of moderate intensity exercise lasting longer than 60 minutes. 750ml sports drink (CHO ~ 50g) 400ml sports drink, 400ml water, and 1 PowerBar PowerGel (CHO ~ 50g) 1000ml water with 1 PowerBar Performance bar, or a banana and 1 PowerBar PowerGel (CHO ~ 40–50g) Longer events, such as Ironman triathlon or multi-discipline adventure races, may allow for the inclusion of a greater variety of food options such as a sandwich (made with vegemite, honey or jam), instant soup, PowerBar ProteinPlus drink or degassed soft drink. Team sports (for example, netball, AFL, soccer, basketball, waterpolo) Opportunities to drink are usually limited to breaks in play and at half or quarter time. Each person should have their own drink bottle and monitor their weight before and after games (and training) to get an understanding of their fluid losses. Sports drinks provide a convenient means to meet fluid and carbohydrate needs simultaneously during exercise. Some team sport athletes, particularly those drinking water during the game, may benefit from consuming a PowerBar PowerGel at half-time as an easily digested, immediate source of carbohydrate.
Page 1 and 2: Current Concepts in Sports Nutritio
Page 3 and 4: Introduction INTRODUCTION Whether y
Page 5 and 6: Energy balance Energy Balance / 2 M
Page 7 and 8: Other food choices providing 30g of
Page 9 and 10: Energy Balance / 6 What about prote
Page 11 and 12: Reading list Energy Balance / 8 Ame
Page 13 and 14: Tips for achieving a high-energy di
Page 15 and 16: Case study: Men’s Basketball and
Page 17 and 18: How low can you go? Impact of low-c
Page 19 and 20: Long-term energy restriction — th
Page 21 and 22: Fuelling Up / 18 In many sports, co
Page 23 and 24: Fuelling Up / 20 Timing Food item C
Page 25 and 26: Pre-event Preparation / 22 The exac
Page 27 and 28: Fluid requirements Pre-event Prepar
Page 29: During Exercise / 26 When sweat los
Page 33 and 34: Reading list During Exercise / 30 B
Page 35 and 36: Refuelling post-exercise Recovery /
Page 37 and 38: Recovery / 34 consumption after tra
Page 39 and 40: Reading list Recovery / 36 Armstron
Page 41 and 42: Immune Function / 38 • Maintain (
Page 43 and 44: Dietary Supplements / 40 PowerBar h
Page 45 and 46: Reading list Dietary Supplements /
Page 47 and 48: Recommended uses by the AIS Departm

Current Concepts in Sports Nutrition - Australian Sports Commission

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