nutrition and performance exercise and performance tutorial presentation
TRANSCRIPT
Who am I?• http://
www.youtube.com/watch?v=URghSgfHrh0
Types of Carbohydrates:Monosaccharides: (Simplest carbohydrate)-Glucose-Fructose (in fruit and honey)-Galactose Disaccharides: (a carbohydrate composed of 2
Monosaccharides)-Lactose (galactose and glucose)-Sucrose (fructose and glucose)-Maltose (glucose and glucose)Polysaccharides: (complex carbohydrates. Made up of many
Monosaccharides and bonded together.)-Glycogen (energy stores in animals and humans-primarily in
liver and muscles)-Starch and Fibre (carbohydrates stored in plants. In fruit,
seeds, rice, wheat, corn, grains etc)
Role of Carbohydrates in Sports:-Carbohydrates are a major energy source during
sport and exercise.-When consumed, blood glucose levels rise and are
used as energy for working muscles.-Glycogenesis- blood glucose is converted into
glycogen and stored in the muscles and liver.-Glycogen stores have a large impact on sports
performance, as muscle glycogen may decrease or increase due to carbohydrate consumption.
-Glycogenolysis, glycogen is broken down and converted back to the blood as glucose. This will be the primary source for the body’s energy.
Glycaemic Index:What is it?
Glycaemic Index (GI) is the index for comparing the blood glucose response from the ingestion of various foods.
The more complex the carbohydrate, and the more fat, protein and fibre in the food the lower the GI level will be.
Glycaemic Index: continued…
• GI values can be interpreted intuitively as percentages on an absolute scale and are commonly interpreted as follows:
Hyper and Hypoglycaemia:• Hyperglycaemia occurs when plasma glucose
levels are elevated, such as after a meal, the pancreas receives signals to release insulin into the blood. It is generally found in people with diabetes.
• Hypoglycaemia is caused by a low blood glucose level during and after exercise as the liver fails to release glucose at a rate that can keep up with glucose consumption. An example would be consuming too much sugar causes a come down effect.
Hyper and Hypoglycaemia:What is the difference between
hypoglycaemia and hyperglycaemia?
• Hypoglycaemia is caused by having low levels of glucose ie. Too much sugar causes a come down effect.
• Hyperglycaemia (high blood sugar) is a condition, in which an excessive amount of glucose circulates in the blood plasma.
Hyper and Hypoglycaemia:
How do we remember the difference between the two?
• Hypo = Low
• Hyper =High
Rebound Hypoglycaemia:How/why it happens?- Athletes consume High GI carbohydrates
15-45 minutes before exercise.- Insulin is released, and its levels within the
body elevated.- In response to these insulin levels, 'glucose
uptake by the muscles reaches an abnormally high rate' (Wilmore et al. 2008: 332) leading to low blood glucose levels = Hypoglycaemia.
Rebound Hypoglycaemia:Why is it detrimental to
sports performance?
- This 'can lead to early exhaustion by depriving the muscle of its primary energy sources' (Wilmore et al. 2008: 332).
(Wilmore et al. 2008: 333)
Rebound Hypoglycaemia: How to avoid it?- Ensure that High GI carbohydrates are not taken
within the 15 - 45 minute period before commencing exercise.
- Research indicates (Vegetarian Nutrition 2008) that endurance can be improved taking carbohydrates 1-4 hours before exercise.
- Take a lower concentrated carbohydrate substance, ie. less than 6%
- Liquid Carbohydrates can be consumed late in a long duration exercise, without causing Rebound Hypoglycaemia.
Blood Glucose Loading:• Is the carbohydrate intake directly before
competition.• A pre-competition meal should be
consumed at least two hours before competition.
• A pre-competition mal can prevent hunger and provide essential energy fuel for competition.
• Recommended pre-competition meal is 200-500 calories
Carbohydrate Loading:
• Is not just eating flat out!!• Rather it is the process used by
most endurance athletes to boost glycogen stored in days leading up to an event.
• Can increase the distance over a set period of time by 2-3% (AIS 2004)
Carbohydrate Loading:
Strict (6-7days):Day 1: Exhaustive bout off exercise
Days 2-4: Eat fat and protein foods 3 times per day with minimal exercise
Days 5-7: Eat a carbohydrate rich diet with minimal exercise
Taken from AIS (2004) and Wilmore et al. (2008)
Carbohydrate Loading:
General (3-4 days):• Similarly to step 3 of Strict just eat a
carbohydrate rich diet with minimal exercise for the 3-4 days leading up to an event.
• Research found that similar if not better results were produced by athletes using this variation of the strict protocol.
Taken from AIS (2004) and Wilmore et al. (2008)
Carbohydrate Loading:What does a high carbohydrate rich
diet look like?- 400-700g per day
- The following diet is suitable for a 70kg athlete aiming to carbohydrate load.
- Taken from AIS (2004)
Carbohydrate Loading:Breakfast:• 3 cups of low-fibre
breakfast cereal with 11/2 cups of reduced fat milk
• 1 medium banana• 250ml orange juice
Carbohydrate Loading:Lunch :• 2 sandwiches (4
slices of bread) with filling as desired
• 200g tub of low-fat fruit yoghurt
• 375ml can of soft drink
Carbohydrate Loading:Dinner:1 cup of pasta sauce
with 2 cups of cooked pasta
• 3 slices of garlic bread
• 2 glasses of cordial
Experiment Time:• 4 Volunteers • 2 Females & 2 Males• 2 x Placebo
substances• 2 x 12.6% glucose
substances (doubles strength energy drink)
Experiment Time:• Each volunteer will run
for 20 minutes.• Each volunteer will
wear a HR monitor (remember to spit on the pads)
• Then we will compare results and investigate the data.
Experiment Time:• Class split into 4
groups as a support team to each volunteer.
• Each team is responsible for collecting data shown on page 53 of lab manual.
Experiment Time:Team Roles:• 1 Timer keeper• 1 H/R monitor• 1 RPE monitor (refer to
graph on pg 52 of lab manual)
• 1 Warm up and 1 warm down coach (OHS)
• 1 lap counter• Encouragers/cheerers
Discussion Time:1. Fill in graph page 55 of lab manual 2. What effect did the ingestion of glucose have on
performance?3. What are the potential benefits of pre exercise
ingestion of glucose? Why?4. What are the potential negative consequences
of pre exercise glucose intake? Why?5. Based on what we have found, and the
information in the text, for what activities would you recommend pre exercise ingestion of glucose?
6. And at what concentration/amount?
ReferencesDepartment of Sport nutrition, AIS (2004) AIS Sports Nutrition: Carbohydrate Loading [online]. Available: http://www.trainingsmartonline.com/images/Free_Triathlon_Articles/carbohydrate_loading.pdf[Accessed 5 August 2008]
McArdle, W., Katch, F. & Katch, V. (2006) Essentials of Exercise Physiology. 3rd Ed. USA: Lippincott, Williams Wilkins.
Vegetarian Nutrition (2008)[online].Available: http://www.vegetariannutrition.info/vn/vn_athletes.htm [Accessed 09 Aug 2008].
W. B. Saunders Company (1999) Role of Carbohydrate in Physical Activity. Clinics in Sports Medicine. 18(3): 469-484
Wilmore, J.H., Costill, D. L., & W. Larry Kenney (2008) Physiology of Sport and Exercise, (4th Edition) Human Kinetics, Champaign, Ill
Yager, Zali (2008) In an email communication on 6 August 2008: Blood Glucose Loading. Available email: [email protected][Accessed 6 August 2008] Yager, Zali (August 2008) Exercise and Performance lecture [3] notes: Nutrition for Exercise. Available: http://webct.latrobe.edu.au/webct/urw/lc9140001.tp0/cobaltMainFrame.dowect [Accessed 4th August 2008]
All images sourced from Google Images and Microsoft Clip Art