Transcript Fatigue and Recovery - rcs-pe

Fatigue and Recovery
Defining fatigue
How would you describe fatigue?
“ A reduction in muscular performance or a
failure to maintain expected power output”
 Muscular tiredness
 Shortness of breath
 Vary depending on activity

Causes of fatigue




Insufficient ATP
Lactic acid
Glycogen depletion
Fluid loss- low blood pressure
Recovery Process after
Exercise


Why does a 400m sprinter take the same
deep breaths as a marathon runner after the
race, even though they have run different
distances?
Why do we take deep breaths?
Recovery Process is needed
to….





Rebuild muscular stores of ATP and
PC that were used during exercise.
Remove lactic acid.
Replenish the myoglobin O2 stores
(Myoglobin has an important , if
small scale, role in carrying O2 from
haemoglobin to the mitochondria
thus ensuring the provision of
energy in muscles.
Complete restoration is thought to
be complete by the time needed to
recover the alactacid debt
component.
Replace Glycogen.
•
There are many other processes
involved in recovery. Processes
such as restoration of
cardiac/pulmonary functioning to
resting values, return to normal
body temperature etc. all require
additional O2 ( although
substantially less than that used
during the alactacid and lactacid
components) and therefore adds
time to paying back the O2 deficit to
reach the pre exercise level.
The oxygen debt


Oxygen Debt= “the amount
of oxygen consumed during
recovery above that which
normally would have been
consumed at rest in the
same period of time”
Excess Post-exercise
oxygen consumption
(EPOC) =The need for O2
to rapidly replace ATP and
remove lactic acid.



Oxygen debt will occur if
anaerobic activity has
occurred
Debt can be measured by
analysing oxygen
consumption before and
after exercise.
Oxygen debt used to
compensate for oxygen
deficit…..
Oxygen Deficit


Oxygen deficit is the difference between the
O2 required during the exercise and the O2
actually consumed during the activity
O2 is not available for the first few mins
approximately, so an oxygen deficit will
always occur.
Oxygen debt has 2 components:
1=Alactacid Debt



“It is the volume of
oxygen required to
restore phosphogens
used in the alactic or
ATP-PC energy
system.”
fast replenishment
1st component of
oxygen debt to be
replaced




2-3 mins to replenish
phosphocreatine
2-3 litres of 02
consumed to provide
energy
Intense work- this
recovery process can
occur to allow for
another set of reps.
Interval training doesn’t
allow full recovery
Effects of training on the
Alactacid Component

Increased stores of ATP and PC in muscle
cells.

Improved ability to provide O2.

Increase in size of alactic component
2= Lactacid Debt


“ It is the volume of oxygen
consumed during recovery
used to remove lactic acid
from muscles, which has
accumulated during
anaerobic work”
slow replenishment


Most lactic acid is
-removed into blood oxidised in mitochondria via
aerobic system to give CO2
and H20
-converted into muscle
and liver glycogen, glucose
and protein
-excreted from body as
sweat or urine.
Lactic acid removal takes
approx 1 hour
The Effect of Lactic Acid
Accumulation


During high intensity exercise, muscle fatigue
occurs at a pH of 6.4 and noticeably affects
muscle function. It is thought that protons
dissociate from lactic acid and associate with
glycolytic enzymes, thus making them acidic.
In this state, the enzymes lose their catalytic
ability and energy production through glycolysis
ceases. This coupled with the inhibition of the
transmission of neural impulses impairs muscle
contraction
Fate of the Lactic Acid




65% is oxidised to form carbon dioxide
and water.
20% is converted back into glucose by the
liver (gluconeogenesis). This is returned
to the liver and muscles to be stored as
glycogen.
10% is converted in the liver to form
protein.
5% is converted into glucose.