Transcript File - twynham a level pe

Recovery Process
Excess post exercise oxygen
consumption (EPOC)
The total volume of oxygen that is
consumed during recovery above that
which would have been consumed at
rest during the same period. It enables
the body to fully recover, and return it
to its pre exercise state.
Used to be O2 Debt
Made up of….?
EPOC/Oxygen Debt

When we start to exercise, not enough oxygen is
distributed to the tissues for all energy production to be
met aerobically. Anaerobic systems need to supply
energy..

This accrues an oxygen deficit-This is the amount
oxygen the subject was short of during the exercise
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EPOC (Oxygen debt) is used to compensate for the
oxygen deficit.

As oxygen is not available for 3 minutes, a deficit will
always build up.
 Oxygen
debt does not always equal
oxygen deficit because it also has to do
the following….
 Supply
oxygen to help restore the oxy
haemoglobin link
 Supply energy for the increased
respiratory and cardiac rates
Two stages of the oxygen debt
 Alactacid
(Fast Replenishment)
Mainly to restore phosphocreatine
2-3 mins, 2-3 litres of O2
50% restored in 30 seconds
Restore oxy myoglobin link (role of myoglobin?)
 Lactacid
(Slow Replenishment)
Removal of lactic acid
Helped by a cool down
Replenishment of glycogen
Removal of Lactic Acid through
buffering
 The
removal of LA relies on the buffering
capacity of the blood.
 Quite good at this as hydrogen carbonate
ions are produced by the kidneys- which
absorbs hydrogen ions from the lactic acid
-to form carbonic acid and eventually
carbon dioxide.
 Breathed out!
The fate of lactic acid
Conversion into carbon dioxide and
water
Conversion into glycogen
65%
Conversion into protein
10%
Conversion into glucose
5%
20%
Removal of Lactic Acid
 Lactate
is removed
quicker with an
active cool down.
Oxygen is needed
to remove it.
Removal of Lactic Acid
 Some
athletes try to improve their
buffering capacity by ‘soda loading’
 Training
with small amount of lactic acid in
the system may also improve resistance
and buffering capacity of the body.
Effect of lactic acid
accumulation
 Blood
will always contain a bit of lactic
acid
 1-2 millimole/litre of blood at rest
 30 millimole/litres of blood 400m run
? What are the effects on the performer?
 Muscle
fatigue occurs at a pH of 6.4
 This affects muscle function
 Inhibits the cross bridge
 Inhibits the enzyme activity, and energy
production by glycolysis stops.
 High acidity may also impair neural
transmission between muscles.
OBLA

Onset of Blood Lactate Accumulation
 Point at which lactate begins to
accumulate in the blood, usually taken as
when it reaches 4mmol/litre of blood.
 Used to predict endurance capabilities/
potentials
 As longer an athlete can delay build up of
blood lactate the longer they can keep
going.
OBLA
 Lactate
Threshold- point at which lactate
is being produced quicker than the body
can get rid of it.
 Exercise
is anaerobic

Usually measured by a test that gets
progressively harder. i.e. treadmill

Person takes place in progressively harder task i.e.
bleep test, a point is reached where energy can no
longer be sustained completely by aerobic means.

If intensity increases further the deficits in energy must
be met by the anaerobic metabolism.

By doing so, blood lactate concentration rises until a
point where it causes muscle fatigue.

The point at which lactic acid begins to accumulate in the
muscles is the OBLA and is measured as a percentage
of VO2max reached.
VO2 max
 Maximum
volume of oxygen that can be
taken and utilised or consumed by the
working muscles per minute
 Mathew
 High
Pinsent 8.5 litres/min
VO2max = great endurance
performances
OBLA and V02
 Lactate
threshold (OBLA) is a percentage
of your VO2max
 The higher your VO2max, the more the
delay in lactic acid build up
 So delaying OBLA/ lactate threshold
VO2max and Training
 As
fitness increases (training) you delay
OBLA (lactate threshold).
 This is why trained athletes can exercise
for a longer period/ train at a higher
intensity for longer.
 They can utilise much more of their
Vo2max
http://www.youtube.com/watch?v=VOLfQ_8ROTg
http://www.youtube.com/watch?v=qJNtFKRWVJQ&NR=1&feature=endscreen
Exam Questions

Outline the relationship between ‘VO2 max’ and
‘lactate threshold’. (3 marks)
Answer
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VO2 max – the maximum amount of oxygen utilised/equiv per unit of
time/per minute
Lactate threshold – the point at which lactic acid starts to accumulate in the
blood/OBLA
Lactate threshold is a percentage of VO2max
The higher the VO2 max, the more the delay in lactic acid build-up/as
VO2max increases, so does lactate threshold
Trained athletes can exercise for longer periods at the same/higher intensity
compared to an untrained athlete/lactate threshold a much higher
percentage of VO2 max
Has to be utilised, not just taken in
Alternative words for utilised are uptake, used, consumed
OBLA must be written in full initially
During a game, performers may suffer
fatigue because they have a low lactate
threshold(OBLA).
 What
do you understand by the term
lactate threshold and how is this
related to VO2 max?
(3 marks)
Answer
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Levels at which lactate/lactic acid accumulates in blood;
Exercise has become anaerobic/without oxygen;
Lactate threshold is some proportion/percentage of VO2 max;
Proportion/percentage of lactate threshold increases as fitness
increases/delayed lactate threshold/OBLA.
3 marks
Exam Questions
In terms of recovery, explain the relationship between
lactate threshold and the functions of Excess Postexercise Oxygen Consumption (EPOC).
(5 marks)
Answer
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Lactate removed during EPOC
Slow/ lactacid component
Oxygen used/needed for aerobic energy/ATP production formation
Lactate mainly converted back into pyruvate
Mitochondria/Kreb’s cycle/to CO2 and H2O
In inactive muscles/other organs (liver)
Some lactate converted to glucose/glycogen/protein
Some excreted in urine and sweat
Measurement of lactic acid
 Lactate
and lactic acid are
interchangeable terms but not same thing
 Lactate is a product of lactic acid that
splits to give a lactate molecule and
hydrogen ions
 Blood lactate measurement is easier than
taking muscle biopsies this is the most
common method used.
Why measure?

Can determine and assess training intensities to
ensure athlete is working at suitable level and is
producing energy by the most effective energy
system
 Provides information current work capacity and
fitness
 Assesses effectiveness of current training
regime
 Main use is to establish anaerobic threshold or
point of ‘onset blood lactate accumulation’ which
gives an indication of endurance capacities.
Fatigue
 This
is when we can no longer sustain a
level of work.
 Muscle fatigue- inability of a muscle to
maintain contractile force as a result of
repeated contractions
What causes fatigue
when we exercise?
Causes of Fatigue
 Build
up of lactic acid /accumulation of
hydrogen ions/OBLA
 Glycogen depletion/needed for glycolysis
 Dehydration/reduces blood flow/loss of
electrolytes/increase body temperature
 Lack of PC stores
Competitive swimmers will often compete in
several events and suffer from fatigue due to
limited recovery time.
Explain the possible causes of fatigue during
a race.
(3 marks)
Delayed onset of muscle
soreness
DOMS

Tender, painful muscle soreness usually 48 hrs
after intense or unaccustomed exercise.
 Soreness is a result of damage to muscle fibres
and connective tissue and increased tissue
fluids.
 Usually goes in couple days and muscles repair
themselves.
 In the meantime it has a negative effect in the
amount of force the muscle is able to generate.

Most likely to occur following eccentric contractions
 Weight training, walking done steep slopes and
plyometrics
Reducing the effect
 Warm up, cool down
 In a training session you progress from low intensity to
high intensity exercise.
 Avoid eccentric contractions early on in session
 Ice baths
 Massage
Other factors affecting recovery
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Restoring muscle glycogen
stores
During exercise glycogen has
been depleted.
Repletion of muscle glycogen is
a long process and takes up to
48 hours.
Re fuelling with a high carb meal
within one hour of exercise will
speed up the process.
Other factors affecting recovery

Restoring oxymyoglobin link
The saturation of myoglobin so that oxygen can
again be transported to the mitochondria.
During exercise oxygen is dissociated from
myoglobin to enable aerobic gylcolosis and
energy to be supplied aerobically.
During recovery oxygen must be re associated
with myoglobin.
To ensure a continuous supply of oxygen this
happens very quickly in the first minute and is
part of the alactacid debt.