Transcript Core 2 - MrBettiol

Core 2
Nutrition, recovery strategies and
performance
How can nutrition and recovery strategies
affect performance?
• Nutrition is a major influencing factor on
an athlete’s performance, and on their
successful recovery.
• If the body can draw on the nutrients it
requires when it requires them, an
athlete has a significantly higher chance
of optimal performance and recovery.
• When we understand the nutrients that are needed
for better performance before, during and after
competition, we are able to adjust an athlete’s eating
plan for their maximum benefit.
• The intake of supplements has become increasingly
popular to help maintain the essential nutrients in the
body, but research shows that a good, tailored eating
plan can eliminate the need for most supplements.
• Coaches and athletes must also be aware of effective
recovery techniques and adopt them as a critical
component of their planning and programming.
• By using these strategies, athletes can accelerate
their training and achieve optimal performance.
Nutritional considerations
An athlete’s body must be fuelled
appropriately if the athlete is to maintain
optimal training regimes and give
themselves the opportunity to compete
at their best.
This ‘fuel’ will generally involve a diet
composed of a variety of foods.
• Energy intake
– A person’s energy expenditure will also influence
the number of kilojoules they need to consume—
elite athletes who train more than five hours a day
require more fuel than sedentary people.
– Research indicates that athletes should eat
frequently throughout the day. This helps to
stabilise blood sugar levels, and to maintain lower
levels of body fat and higher muscle mass.
Athletes who train at least 20 hours a week need
7 grams of carbohydrate per kilogram of body weight,
while a recreational athlete training 3–5 hours per
week needs 4–5 grams of carbohydrate per kilogram
of body weight.
Carbohydrates
Training commitments only lead to a small increase in protein
requirements for most athletes—that is, 1 gram per kilogram of
body weight compared to 0.8 grams for a sedentary person—
unless they are endurance or strength athletes in a heavy
phase of training, and therefore
need additional protein (1.4–1.7 grams per kilogram of body
weight) for muscle growth and repair.
Protein
Controlling fatigue
Athletes need to examine the type of fatigue that will impact
their training and performance, and develop nutritional
Strategies that will delay or reduce the onset of:
• glycogen depletion
• low blood sugar levels
• low blood sodium levels
• dehydration
• gastrointestinal upset.
The nutritional routine for any athlete will encompass what
should be consumed before, during and after their
performance.
Athletes need to develop a competition nutritional plan for all
major events, and tested the strategies - before, during and
after their event.
Pre performance
• Fuelling up
– A major cause of fatigue and decline in
performance is the depletion of fuels (in
particular the glycogen stores in muscles).
– One of the main aims of pre-performance
nutrition is ‘fuelling up’ and supplying
enough carbohydrates to maximise the
body’s glycogen stores in the final 24–36
hours before an event
Carbohydrate loading
• The duration of the event will also
influence the nutrition plan.
• If the event is completed under an hour
(or is a team sport), an athlete will look
at increasing glycogen stores over the
final 24–36 hours before the event.
• This may be achieved by consuming 7–
12 grams of carbohydrate per kilogram
of body mass, and reducing training—
called ‘tapering’—to ensure the athlete
does not expend as much glycogen as
they normally would in the days before
competition.
• For example, an athlete weighing 60
kilograms would consume 420–720
grams of carbohydrate on the day
before the event.
• If the event is over 90 minutes, the
athlete can also try carbohydrate
loading over 2–4 days.
• Research suggests that carbohydrate
loading 36–72 hours before an event
can increase performance over a set
distance by 2–3 per cent.
• This is achieved because an additional
50–100 per cent of glycogen can be
stored in the muscle and be available
for energy during the race..
• To achieve this increase in glycogen
stores the athlete must also be on a
taper—if they continue to train at the
same volume and intensity, their
carbohydrate loading will be
compromised.
• Athletes in events such as road cycling,
marathon running,
and endurance swimming
would all benefit from
carbohydrate loading
This diet is suitable
for a 70-kilogram
athlete aiming to
carbohydrate load
Carbohydrate loading does not mean ‘pigging out’ on any foods.
It is best to reduce high-fat foods and foods rich in fibre to maximise
carbohydrate intake.
The eating plan contains compact sources of carbohydrates such as sports
drinks, cordial, soft drink, jam and honey, and the meals are small and
frequent.
This also assists an athlete in achieving a high carbohydrate intake.
Questions
1. Would all athletes benefit from carbohydrate
loading before competition? Explain
2. Explain how glycogen depletion leads to
fatigue.
The pre-event meal
• The final hours prior to competition are
also important, and an athlete’s
nutritional plan at this time can play a
vital role in performance.
• This is an opportunity for athletes to:
• top up glycogen stores (both liver and muscle)
• make sure they are well hydrated
• ward off feelings of hunger without causing
gastrointestinal discomfort
• consume foods that give them a psychological
edge.
• Research indicates that eating a highcarbohydrate meal (2.5 grams of
carbohydrate per kilogram of body
weight) about 3 hours before exercising
can increase muscle glycogen
concentration by 11–17 per cent.
• The more fat, fibre and protein in the
meal, however, the more time it will take
to digest, and the higher the likelihood
that it will cause stomach upsets.
• This is also the case for the volume of
food consumed.
The timing of the pre performance
meal will depend on the competition
schedule and individual tolerance.
It is generally consumed 3–4 hours before
competition, but this is not always practical. If
the competition commences at 9 am, an athlete
will not want to eat at 5 am.
They may adjust their pre-event meal to 2 hours
before competition, and have a cereal bar,
yoghurt, smoothie or sports drink that can be
easily digested.
Some athletes will be able to have a light breakfast (cereal, toast,
juice) but this will depend on the individual.
Athletes will need to determine how much
and what type of food they can stomach prior to competition.
Athletes competing in sports that involve running are often more
sensitive to food at this time.
Liquid meals (smoothies, juices, shakes) or sports bars can be a
good alternative for these athletes, as well as those who are too
nervous to eat.
• Athletes need to eat something close to
competition (within one hour), a sports drink,
sports bar, jelly lollies or a carbohydrate gel
might be ideal.
• For most athletes, consuming carbohydrates
during this time will not have a negative
effect on performance, but a small number
of athletes do react with a drop in blood
glucose at the start of exercise, and feelings
of fatigue.
Glycaemic Index (GI)
• This is a ranking of carbohydrates in foods, in relation
to their effect on blood glucose (sugar) levels within 2
hours of consuming 50 grams of that food.
(The benchmark used to compare foods is white bread,
which has been given an arbitrary GI of 100.)
• Foods with a low GI(e.g. peanuts, low-fat yoghurt)
cause a slow release of glucose into the blood,
whereas high-GI foods (e.g. potatoes, fruit bars)
cause a quick but brief rise in blood glucose.
• There is no scientific evidence that
indicates the consumption of low-GI
foods in the pre-event meal will
enhance performance.
• In addition, some low GI foods (e.g.
porridge) can cause stomach distress.
Instead, athletes attempting to maintain
fuel levels will consume a sports drink
during the event
Hydration
• Hydration is the process of taking sufficient
fluid into the body. It is important that athletes
start their competition in a well-hydrated
state, as dehydration leads to a decrease in
blood volume and a drop in performance.
• Starting the competition in a slightly
dehydrated state will have an adverse effect
on heart rate, stroke volume and temperature
regulation
• Athletes can generally tolerate 300–500
millilitres of fluid (that is, 5 millilitres per
kilogram of body weight) before
exercise.
• For events of less than 60 minutes,
water is adequate, but athletes
competing in longer events may benefit
from sports drinks.
• A high fluid intake over several days
before competition will assist an athlete
in reaching a hydrated state.
During performance
• During an event, it is important for
athletes to refuel and rehydrate.
• An athlete’s fuel and fluid needs while
competing will be affected by:
– the duration and intensity of the activity
– the environmental conditions
– the athlete’s starting glycogen and hydration
status
– the athlete’s body size and metabolism.
• Refuelling
– Consuming carbohydrates during exercise
enhances performance, possibly by sparing
glycogen stores and preventing low blood sugar
levels.
– athletes attempt to consume 30–60 grams of
carbohydrate per hour during their performance,
but this will depend on their tolerance level, their
needs, and the opportunities within their sport.
– Examples include bananas, sports bars and
carbohydrate gels.
– Sports drinks, with 6–8 per cent carbohydrate and
10–25 millimoles per litre (mmol/L) of sodium, can
be effective exercise.
• Rehydration
– To effectively rehydrate during a sporting
event or exercise, an athlete should
– be aware of how much fluid they lose
under various conditions.
– This can be monitored by calculating the
difference between their body weight
before an event or exercise session with
their weight after the session
– this can be expressed as a percentage of
body weight:
• Becoming dehydrated during
competition increases an athlete’s heart
rate and core temperature, and
decreased blood volume, so dehydrated
athletes will feel more fatigued and are
likely to slow down during competition.
• A runner who would usually complete a 10kilometre run in 35 minutes when in a hydrated
state would slow to almost 38 minutes when
dehydrated by 4 per cent body weight—that’s
an 8 per cent decrease in performance.
Post performance
• Post-performance nutrition is a major
component of any athlete’s recovery
routine.
• The training or competition situation will
influence the amount of refuelling,
rehydration and muscle tissue repair
needed to boost adaptations and get
their body ready for the next event.
Refuelling and muscle
rebuilding
An athlete can kickstart the glycogen
replenishment and muscle rebuilding process
immediately following competition.
This involves having at least 1 gram of highGI food per kilogram of body weight, with 10–
20 grams of protein, within 30 minutes of
glycogen-depleting exercise.
This initial snack will contribute to a total
intake of 6–10 grams of carbohydrate per
kilogram of body weight over the next 24
hours.
Athletes expending large amounts of energy
will have more latitude in choice of food.
Some athletes will choose lollies as their
recovery food but these should be
supplemented with something else as they
do not provide fluid, protein or other nutrients.
Rehydration
• Weighing athletes before and after exercise
will give some indication of their fluid deficit,
and approximate how much they need to
replace.
• A good guide is that an athlete needs to take
in 1.5 litres of fluid for every 1 kilogram of
body weight lost
• A sports drink is recommended as the sodium
and potassium stimulates thirst, whereas
when consuming plain water the body thinks it
is over hydrated.
Supplementation
Vitamins/minerals
• Regular, strenuous exercise can create
the need for increased dietary intake of
some vitamins and minerals.
• These increased levels of vitamins and
minerals can be achieved through
correct food choices, so ordinarily
supplements are not required.
Vitamins
• The human body needs only small
amounts of vitamins to sustain our
bodily functions and perform well.
• Vitamins assist the body to use energy
nutrients, but do not contain or provide
energy themselves.
• Since the body only uses the vitamins
that it needs and cannot store the
excess, the benefits of vitamin
supplements seems negligible.
• In the case of fat-soluble vitamins,
supplements can even be dangerous.
Vitamins A and D can accumulate in the
body, and excessive quantities can
result in joint pain, headaches, nausea,
fatigue and loss of appetite.
Minerals
• The main mineral areas to consider are
calcium and iron, as many athletes tend
to be deficient in these, resulting in poor
performance.
• Females are also more likely to be
calcium- or iron-deficient.
• Calcium
– Calcium is a key mineral in healthy bones
and teeth.
– The quality of bone tissue is built up during
our younger years and starts to gradually
deteriorate from our mid-20s.
– A more rapid deterioration occurs later in
life, which may result in osteoporosis.
• Key sources of calcium include dairy products,
fish such as salmon, and green leafy
vegetables.
• Iron
– Haemoglobin is a protein in our red blood
cells that collects and transports oxygen to
where the body needs it.
– Low levels of haemoglobin can
dramatically affect performance, since the
muscles are deprived of oxygen which is
needed for energy production.
– This can result in symptoms of fatigue and
lack of energy.
– Iron is found in haemoglobin, and so is
very important in maintaining peak
performance. High amounts are found
naturally in lean meat and green leafy
– Iron is found in haemoglobin, and so is
very important in maintaining peak
performance.
– High amounts are found naturally in lean
meat and green leafy vegetables, including
spinach and grains.
Protein
• Protein is important for its structural
(building and repairing muscle tissue)
and functional (immune system) role, as
well as for its role as an energy source.
• Strength and endurance athletes need
more protein than the sedentary person.
Protein supplements
• Food is the best source of protein, and
most athletes do not need expensive
protein supplements.
• Research indicates that there is no
advantage in taking protein
supplements over everyday protein-rich
foods.
• Protein products tend to have large
amounts of protein and little else of
nutritional value.
• Lack of protein, however, does have a
detrimental effect on performance— slow
recovery, loss of muscle and reduced
immune function.
• Liquid meals and protein powders (containing
protein and carbohydrates) are low-bulk and
convenient, and so may assist athletes who:
• have difficulty in meeting daily protein requirements
because of poor or restricted diet
• are vegetarian and want more variety
• don’t feel like eating a steak directly after weight training
• have trouble getting their protein requirements for the
day from natural sources (e.g. may be fussy eaters).
Caffeine
• Caffeine is a drug that is socially accepted
and widely used around the world.
• Since it has been taken off the World AntiDoping Agency’s banned substances list,
many athletes are starting to experiment with
its effects on their performance.
• Caffeine can be found in teas, coffee, cola,
chocolate and energy drinks, ranging from
about 5 to 200 milligrams in each serve.
• Effects of caffeine
– For some individual athletes, it has been
proven to have a positive effect in some
circumstances, such as:
• alterations to the central nervous system to
amend perceptions of fatigue
• effects on the cardiac muscle
• stimulation and release of adrenaline
mobilisation of fats from the adipose tissue and
the muscle cell
• changes to muscle contractions.
– These effects result in an enhanced
performance during short-duration, highintensity events; prolonged high-intensity
events; and endurance events.
• Large doses of caffeine may result in:
– over arousal, which inhibits good sleep
patterns and jeopardises recovery
– an increased heart rate
– an impairment of fine motor control, which
can affect an athlete’s performance
depending on the sport.
• The most beneficial time to ingest
caffeine is 1 hour before an event, as
research shows increased performance
for up to 6 hours after intake.
Creatine products
• Creatine supplements have been
gaining popularity for the last 15 years.
• Many scientific studies also support the
positive effects of creatine supplements
on an athlete’s performance.
• Creatine is a muscle fuel, derived from
amino acids and stored in skeletal
muscle.
• Most important is creatine’s role as a
source of phosphate to regenerate ATP
• Creatine supplements can benefit
athletes in sports relying on their
ATP/PC energy system, e.g. short
sprints.
Creatine can benefit athletes
who are undergoing resistance
training to increase body mass,
those who perform short sprint
events, or athletes competing
in intermittent intense activities,
such as football and tennis.
Recovery strategies
• Recovery strategies are approaches used by
athletes to manage fatigue between one
training session or event and the next one.
• By using appropriate recovery strategies,
athletes can achieve accelerated training and
optimal performance.
• Recovery strategies are administered to
accelerate recovery from fatigue and
enhance either training adaptations or an
athlete’s readiness for competition.
• Identifying the type of fatigue will assist
coaches in implementing the most effective
recovery strategies for their athletes so that
they can start their session or competition in a
non fatigued state.
• This would be another use of the specificity
principle - specific recovery strategies can
meet the needs of specific training demands.
• Before selecting and implementing recovery
routines coaches need to consider the
following factors:
• age of the athlete—older athletes often take
longer to recover
• demands of the sport or training session and
possible causes of fatigue
• environmental conditions—climate (hot, cool,
humid); time zone differences
• recovery time before the next event or training
session
• access to facilities (e.g. ice bath, spa, pool,
massage)
• available time for recovery for all team
members.
Physiological strategies
• Cool down (active recovery)
– Active recovery, or the traditional ‘cooldown’, involves any mode of low-intensity
exercise.
– The most commonly used cool-down
involves a combination of jogging, walking
and stretching, although any cardio
exercise (e.g. cycling or swimming) can be
used.
• The suggested benefits of a cool-down,
when compared to a passive recovery
(i.e. doing nothing) include:
– a decrease in blood lactate
– decreased likelihood of delayed-onset
muscle soreness (DOMS)
– better heat dissipation after exercise
– reducing muscle soreness after eccentric
exercise
• Rehydration
• Stretching
• Compression garments
– decrease swelling and muscle soreness
– increase venous return and blood flow
(increasing oxygen to muscles)
– improve endurance, power and temperature
regulation
– increase force production.
Hydrotherapy
Cold-water immersion (CWI), hot-water immersion (spas),
contrast water therapy (CWT), and pool and beach recovery
sessions are examples of hydrotherapy strategies used by
athletes.
• Cold-water immersion (CWI)
– Applying cold water and ice are common
strategies for treating acute soft tissue
injuries
– Examples include the use of baths, ice
baths, and bins filled with water and ice to
a depth where the athlete is submerged at
least to their waist.
– The water temperature and duration of
CWI varies depending on the facility and
time available, and the needs of the
athlete.
• Benefits of CWI include:
– decreased temperature (core, muscle and
skin)
– reduced soreness and swelling
– decreased perception of pain and
discomfort
– increased perception of recovery.
• Contrast water therapy (CWT)
– Contrast water therapy involves alternating 60second periods in cold water (10–15°C) with 60second periods in hot water (38°C) for 3–7 cycles
– This recovery strategy is not recommended if the
athlete has an illness, open wound or acute injury.
– Suggested benefits of CWT include:
• increased blood flow
• increased lactate clearance
• decreased swelling, stiffness and pain
• decreased muscle soreness and damage
• stimulated central nervous system
• greater sense of wellbeing.
• Hot-water immersion (HWI)
– An example of hot-water immersion is the
use of spas.
– This generally involves the athlete
immersing themselves in water with a
temperature of 38°C for a maximum of 15
minutes.
– This is not recommended for athletes with
an injury or in hot, humid environments.
• Benefits include increased blood flow, and
reduced stiffness and muscle spasms.
• Pool/beach sessions
– Pool recovery sessions are frequently used
by team sport athletes and can be
scheduled immediately after competition or
the following morning.
– These sessions generally include light
exercise (walking, jogging, swimming,
kicking and stretching) for 10–30 minutes.
• Suggested benefits include reduced muscle
soreness and stiffness following contact sport
or eccentric exercise.
• Tissue damage strategies
– Cryotherapy - generally refers to the use of
ice or cold for therapy or recovery.
• Psychological strategies
• Relaxation
• Sleep
• A lack of sleep has a number of implications for
athletes:
– reduced focus and decision-making ability in skill
sports
– reduced memory, communication skills and learning
– increased likelihood of overtraining
– decrease in physical performance (after 3 days of
sleep deprivation).