The three macronutrients (with examples) and what percentages of them a normal person needs vs an endurance athlete
- Carbohydrates
Simple sugars (such as honey, table sugar and fruit juice)
Complex carbohydrates (such as potatoes, bread, cereal, rice and pasta). - Fats
Saturated fatty acids (found in full cream milk, cheese and fatty meats) are considered unhealthy.
Unsaturated fatty acids (avocados, fish, nuts and olive oil) can be beneficial. - Proteins
Eggs, dairy products, nuts and seeds
For a normal person, approximately;
55‐60% Carbohydrates
25‐30% Fats
10‐15% Proteins
For athletes involved in heavy endurance training, approximately;
70% Carbohydrates
- to account for the energy used when training/competing
15% Fats
15% Protein (this may increase to up to 30% for body builders)
What is carbohydrate loading? Advantage and disadvantages
Increasing carbohydrate intake in the days before competition to increase glycogen stores within the muscle and liver. Means there is more fuel stores to be broken down into energy
Advantage:
- Enables endurance athletes to work for longer at a higher intensity
Disadvantage:
- Gastrointestinal upset
- Weight gain
What should an athlete consume pre-competition?
Weeks leading up:
- Carbohydrate loading
Day of competition:
- 3-4 hours before competition, so that it can be digested, athlete should consume a low GI meal as it provides a slow release of energy
- Immediately before competition, an athlete should consume a high GI snack like lollies to maximise glucose levels
What should an athlete consume during competition?
- Ingest high GI carbohydrates as they are broken down quickly into glucose absorbed into the bloodstream as an energy source (eg, gels and energy bars)
- Consume sports drinks that contain electrolytes and carbohydrates are benficial as they prevent dehyrdation and replenish salts
400-800mL of fluid an hour - during exercise
200mL of fluid every 15 minutes - for short duration events
What should an athlete consume post-competition?
- Ingest high GI carbohydrates within 30 minutes to replenish blood glucose levels
- Drink 1.5 times the fluid lost during exercise to aid recovery and prevent dehydration
- Low GI meal containing protein should be consumed a few hours after competition to replinish glycogen stores and assist the repair of muscle tissue
How are carbohydrates utilised by the body?
Carbohydrates are digested to glucose. Glucose is either:
- Released into the bloodstream for circulation (energy for bodily functions)
- Converted into glycogen for storage in the muscle and in the liver.
How are fats utilised by the body
Dietary fats are broken down in the digestive system to free fatty acids. Free fatty acids obtained from dietary fat are either:
- Released into the bloodstream for circulation
- Stored as triglycerides (a molecule resulting from the combination of three fatty acids) in adipose tissue. Fat stored as triglycerides in the body provides a plentiful source of energy.
Protein supplementation
- The consumption of extra protein or amino acids in the form of a powder.
what are the advantages and disadvantages of protein supplementation?
Advantages
- increased muscle bulk
- improved rate of muscle repair and recovery
Disadvantages
- increased risk of osteoporosis
- increased risk of colonic cancers
- increased risk of impaired kidney function
- increase in water retention.
What are anabolic steroids?
- Artificial/synthetic form of testosterone usually taken via injection of orally.
- banned in sport and illegal without a prescription
what are the advantages and disadvantages of anabolic steroids?
Advantages
- increased muscle mass
- improve recovery rate/ muscular repair rate
- decreased muscle breakdown
Disadvantages
- reduced sperm count/infertility
- high blood pressure
- decreased testicular volume
- increased risk of hear disease/ sudden heart attack
- increased aggression, deepening of voice facial hair growth
what is caffeine?
- A widely available substance found in many foods that stimulates the central nervous system.
What are the advantages and disadvantages of taking caffine?
Advantages
- increased CNS activity/ increased alertness
- increased arousal
- increased heart rate
- increased metabolism
- improved reaction time
Disadvantages
- increased heart rate
-increased muscle twitches/shakes
-increased CNS activity
-increased anxiety
-High blood pressure
-inability to sleep/insomnia
What is creatine?
-Creatine is a compound that comes from 3 amino acids. It is found naturally in muscle cells and stored as phosphocreatine. Normally ingested in capsule/pill or powder forms.
Advantages and disadvantages of taking creatine?
Advantages
-increased energy production during exercises
-improved strength
-muscle hypertrophy/increased lean muscle mass
-improved recovery
Disadvantages
-fluid retention
-weight gain
-gastrointestinal upset
-fatigue
-kidney problems
What is EPO?
A form of blood doping which involves taking the hormone erythropoietin (EPO) which is a type of protein growth factor. EPO stimulates the production of red blood cells in bone marrow.
Normally injected under the skin.
What are the advantages and disadvantages of taking EPO?
Advantages
-Boost RBC production
-Increase 02 transport around body
-Improve performance
-improve V02 max
-increase of haemoglobin in body
Disadvantages
-High blood pressure
-Blood clotting
-strokes
-Heart attacks
-Pulmonary embolism
What is blood doping?
Increasing the number of RBC in the blood stream. Primarily done through blood transfusions either from another person or back to the same individual, or by using blood substitutes.
What are the advantages and disadvantages of blood doping?
Advantages
-Increase number and concentration of RBC
-Increased haemoglobin
-Increased V02 max
Disadvantages
-Allergic reactions
-Fevers
-Blood clotting
-Strokes
-Heart attacks
-Pulmonary embolism
What is the glycemic index
- A measure of the speed at which glucose is released into the blood stream after eating carbs.
- Low GI = slow breakdown and release of glucose eat these foods 2-4 hours before an activity.
- High GI = fast breakdown and release of glucose, eat this immediately before a match.
What are the acute effects of being in a high altitude environment?
Due to the reduced pressure difference at altitude less 02 diffuses from the alveoli into the blood thus less 02 is flowing to working muscles.
The acute effects of being at altitude are
- increased breathing rate - to increase the amount of 02 getting into the lungs
- Increased heart rate and cardiac output during rest and submaximal exercise - as the amount of 02 entering the bloodstream is reduced so the body will increase heart rate in attempt to increase the amount of 02 getting to working muscles.
- decreased V02max (aerobic capacity)
What are the effects of altitude on the performance of a athlete?
- Negative for endurance athletes and team sport athletes as
- low humidity at altitude = greater risk of dehydration
and there’s a reduced ability to provide oxygen to the muscles via the aerobic pathway as there is less oxygen uptake and pulmonary diffusion. - positive effect on power athletes - as less drag due to thinner air causing less resistance and decreased gravitational effect on objects.
What are the chronic adaptations to altitude?
- These occur after 2-4 weeks and last for a few weeks.
- increased percentage of RBC due to increased EPO, thus blood can carry more O2.
- Increase in haemoglobin concentration in blood as more RBC, meaning blood can carry more O2
- increased mitochondria, increased ability to use O2 to create energy
- increased aerobic enzymes. improve ability to utilise O2.
Define Acclimatisation
- The process or result of becoming accustomed to a new climate or new conditions.
