Transcript How can nutrition and recovery strategies affect

Nutritional considerations
Supplementation
Recovery strategies
Overview
Programs designed to improve performance must be supported by
solid nutritional practices. This involves many factors such as
what to eat and drink, being aware of the most appropriate time
for food intake and having recovery strategies in place to recoup
expended energy. The specific roles of carbohydrates and
hydration are important considerations for optimal physical
performance.
Foods are the life source of energy supply. Different foods have
differing amounts of energy. Carbohydrates supplies 16kJ/gm,
protein supplies 17kJ/gm and fat supplies 37kJ/gm. Therefore the
type of food consumed prior to competition directly affects the
quantity of energy available.
Overview cont.
Fluid is also important as it is the body’s medium for
cooling heated muscles and ultimately preventing
dehydration. It assists in temperature regulation by
transporting heat to the outside of the body , prevents
damage to organs by diluting toxic waste, ids oxygen
transportation to cells, assists the transportation of
wastes from the body and helps eliminate carbon
dioxide via the blood plasma.
Thus a deficiency in food and fluid supply can place the
health of an athlete at risk.
Nutritional Considerations:
Pre-Performance
Recommendations for pre-performance nutrition and
hydration include:
- Avoid foods that take a long period of time to digest such
as foods high in fats, protein and fibre. Athletes are advised
to eat meals high in complex carbohydrates (pasta, breads,
cereals, fruits) because these provide slow energy release.
- To avoid discomfort the appropriate amount of food to
consume relates to the type of competition. Sustained,
endurance type competitions (triathlons) require more
kilojoules to fuel their metabolism than those in less
demanding events.
Nutritional Considerations:
Pre-Performance cont.
- It is advised that a normal meal should be consumed
three to four hours prior to competition. Small snacks
and liquid preparations consumed within two hours of
the competition with only carbohydrate solution
drinks advisable in the last 30 minutes prior to
competition.
Nutritional Considerations:
Pre-Performance cont.
- Adequate fluid intake should be consumed in the
preceding days, particularly for endurance events. A
side effect of this can be weight gain, particularly if
carbohydrate intake has also increased ( each gram of
glycogen stores 2.6 grams of water with it).
- As a general rule, 500-600 mL of fluid should be
consumed in the two to three hour period prior to
endurance performance and a further 250-300 mL in
the last quarter hour period.
Nutritional Considerations:
Pre-Performance cont.
Carbohydrate Loading:
Is the technique of loading the muscles with glycogen in preparation for a
high intensity endurance activity of more than 90 minutes.
Average muscle glycogen levels are approximately 100-120 mmol/Kg, but
can increase by up to one-third in response to carbohydrate loading.
In the past it has been viewed that the correct process of carbohydrate
loading is to deplete glycogen stores in the body through intense
training followed by a loading stage of rest and the consumption of
large quantities of carbohydrates.
However, new research suggests that a normal diet supplies sufficient
amounts of carbohydrate to fuel athletes (7-12 grams of carbohydrate
per kilo of body mass). People who need to carbohydrate load will
already be involved in training schedules that regularly utilise stored
glycogen , so the body’s ability to store fuel will be greater than that of
non-athletes.
Nutritional Considerations:
Pre-Performance cont.
The process of carbohydrate loading should now be
completed by maintaining a normal diet rich in
carbohydrates and ensuring that athletes have a taper
phase leading up to major competition.
The taper phase is essential as it allows an athlete’s body to
rest and reduce the utilisation of glycogen for energy whilst
the consumption of carbohydrates through a normal diet
boosts storage levels of glycogen in the liver and muscles.
Carbohydrate loading has the benefit of delaying the point at
which the muscles being repeatedly used run out of fuel.
Nutritional Considerations:
During Performance
Endurance events in hot and humid conditions can have
a significant impact on the body’s fuel and fluid
supplies.
The need for carbohydrate and electrolyte replacement
depends on a number of factors including intensity,
duration, humidity, clothing type and individual sweat
rates.
The aim during performance is to conserve muscle
glycogen and maintain blood glucose levels.
Nutritional Considerations:
During Performance
The following are nutritional considerations during
performance:
- Carbohydrate supplementation is only needed for exercise
intensities 75% and above for prolonged periods of time (in
excess of an hour).
- Glycogen supplementation is not needed for low intensity,
short duration exercise.
- Adequate hydration by regular fluid intake must be
maintained. It is suggested that 200-300 mL of fluid,
preferably in the form of a sports drink, be taken every 1520 minutes during exercise. An athlete should not wait
until thirst develops before replenishing lost fluid.
Nutritional Considerations:
During Performance
The following are also considerations regarding hydration and
performance during exercise:
- Hydrate before and after physical activity.
- Drink every 15-20 minutes while running. Runners lose between three
and five cups each hour .
- Drink water or low-carbohydrate concentration sports drinks. Cool
plain water or sports drinks that have less than 8% carbohydrate
content is best. Anything above 8% slows the body’s absorption rate.
- Ensure that you have trained properly and acclimatised to race
conditions.
- Wear clothing that breathes.
- Avoid activities in times of high temperature and high humidity.
- Avoid excess fat, salt and alcohol which act as diuretics.
- Do not run if suffering a fever.
- Learn to recognise the symptoms of heat stress.
Nutritional Considerations:
Post-Performance
A post performance nutrition plan aims to return the body to its pre-event state as
quickly as possible, enabling full training to resume in preparation for the next
phase of competition.
The following recommendations should be considered:
- Following endurance activity carbohydrate intake of 50-100 grams in the first
two hours is highly beneficial. This intake is then followed by intakes of 50-75
grams every two hours until a total of 500-600 grams of carbohydrate have
been consumed.
- Consume foods and drinks that are high in carbohydrate content and have a
high Glycemic Index as apposed to a low one. (Glycemic index is a ranking
system for carbohydrates based on how they affect blood sugar). High glycemic
index carbohydrates increase blood glucose levels at a faster rate than low
glycemic index carbohydrates.
- Rehydrate your body, up to 150% of your normal intake levels.
- Incorporate active rest after exercise as it assists with the manufacturing of red
blood cells and new proteins.
Supplementation
Dietary supplementation is found in many forms,
including vitamins, minerals, protein, caffeine and
creatine products.
Why Supplement?????
Supplement intake is routine for many competitors
because it is believed to improve athletic performance.
However, while perhaps supplying a psychological boost,
supplements may be of little value if the diet is already
well balanced in terms of nutritional requirements.
Supplementation
Vitamins and Minerals
Vitamins:
 Are inorganic compounds that are essential to maintaining bodily functions.
 They are required in very small quantities.
 They do not contain energy but act as catalysts that help the body use energy
nutrients.
 They also assist with metabolic regulation and tissue building.
 The body is unable to manufacture vitamins, so diet must supply them.
 Some athletes take vitamins even though their normal diet contains all the
necessary vitamins.
 The unnecessary intake of vitamins through supplementation is not only
expensive but also potentially dangerous. Can lead to body aches, nausea,
headaches and fatigue.
 Research shows that super-supplementation does not improve performance
and that supplementation should not be a response to a desire for improved
performance.
 Supplementation of vitamins should only be used to address health related
matters such as vitamin deficiencies.
Supplementation
Vitamins and Minerals
Minerals:
 Are inorganic substances found in the body that are necessary for it to function
adequately.
 They do not provide energy.
 Iron and calcium are most commonly deficient in athletes and inadequate supplies will
affect performance.
 Iron is important as it is found in haemoglobin in red blood cells and assist with the
transportation of oxygen and carbon dioxide around the body. Lack of iron is known as
the deficiency ‘sports anaemia’ and reduces performance. Characterised by a lack of
energy and general fatigue. People most at risk include endurance athletes, females,
vegetarians and adolescent males. Athletes should look to dietary sources rather than
supplementation to prevent this condition i.e. Lean meats, particularly red and dark
green leafy vegetables such as spinach and lettuce.
 Calcium deficiency is more specific to health. It is vital for strong bone structure and
regular intake prevents the onset on osteoporosis (brittle bones) which can be developed
later in life (particularly females). Adequate calcium intake through dairy products
during childhood and adolescents has a positive effect on bone quality during later life.
Athletes should look to dietary sources rather than supplementation to prevent this
condition i.e. Milk, yoghurt and cheeses, leafy green vegetables and fish.
Supplementation
Protein
Protein supplements have been used widely by weight lifters, body builders and strength
athletes for a long time. These supplements may be natural or synthetic and available in
powder, fluid or solid formulations.
The belief associated with protein is that a higher intake will positively affect muscle size.
However, research suggests the idea that most athletes do not need or benefit from
protein supplementation. This is because the majority of the population, including
athletes, are getting on average more than the daily requirements through a normal
balanced diet.
Surveys reveal that most athletes consume well in excess of 1.2-2.0g/Kg body mass per a day
(thats the equivolent of 23 extra eggs a day for a 70kg person), making supplementation
both needless and wasteful. Additionally many protein supplements have many additives
that pose health problems and may increase the risk of cancer.
Furthermore, excess protein can increase the amount of calcium excreted in the urine and
possible contribute to osteoporosis. Unlike excess carbohydrates which can be stored,
excess protein must be eliminated from the body. This process can interfere with kidney
function.
Supplementation
Caffeine
Much of the evidence relating to caffeine and performance is
inconclusive. However caffeine does appear to improve cognitive
processes such as alertness, concentration, clear headedness,
improved memory and reasoning.
Caffeine does not appear to improve the performance in short-term
high intensity activities such as sprinting.
Some studies also indicate that caffeine acts as a diuretic. A diuretic
is a drug that increases the amount of fluid (water and urine)
passing from the body.
Caffeine has ergogenic aid properties. This means that it has the
ability to improve performance by assisting specific metabolic
processes. In the case of endurance activities, the ability of
caffeine to mobilise fat stores in the body and convert them into
free fatty acids is important for energy production.
Supplementation
Creatine
The body has two sources of creatine, one is produced by body cells
and the other is found in meat.
Creatine found in the body and eaten from meat is converted to
creatine phosphate and thereafter assists in the resynthesis of
ATP.
It is important in making energy available to sustain short duration
explosive activity.
While many manufacturers claim its performance enhancing
abilities, such as delayed fatigue and sustained energy, increased
strength and fat burning properties, research suggests otherwise,
finding very little benefit from supplementation. This is because
creatine supplementation has very little effect on athletes who
are already consuming excessive amounts of protein.
Recovery Strategies
Physiological Strategies
These strategies aim to address physiological fatigue and
tissue damage. Issues such as replenishment of energy
supplies, hydration and the dissipation of metabolic by
product of competing e.g. lactic acid, are facilitated by
techniques such as nutritional recovery plans and
appropriate cool downs.
Recovery Strategies
Neural Strategies
Neural Strategies involve a number of aspects such as the
restoration of key neural transmitters, which are
chemicals that are used to relay, amplify and modulate
signals between a neuron and another cell. Neural
recovery can be aided by appropriate hydrotherapy
and self massage strategies. A hydrotherapy strategy
that is available to most sporting clubs are contrast
showers i.e. one minute of hot shower followed by 30
seconds of cold, repeat several times.
Recovery Strategies
Tissue Damage Strategies
Icing, cold baths, cold ocean dips etc. are popular
methods of constricting blood flow to areas of the
body which may have suffered soft tissue damage
through direct and indirect contact during
competition or training.
Recovery Strategies
Psychological Strategies
Post game relaxation allows the athlete to wind down
from the excitement of the game and deal with stress
and fatigue. It facilitates sleep and provides a balance
by focusing the athlete on issues other than the sport.
While relaxation techniques will vary considerable
from individual to individual, it is important that
athletes learn to disengage their thoughts from their
sport at times so that they are psychologically fresh
when required to refocus when training resumes.