Transcript ERP 10 - Haiku Learning

AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(1) ATP
• ATP is the only form of usable energy in the body.
• Energy is released from ATP when it is broken
down into ADP + Pi.
• Stores of ATP last for only 3 seconds.
• When ATP stores are depleted, they need to be
replenished immediately.
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(2) Energy systems
There are three energy systems that can regenerate
ATP:
• the ATP–PC system (anaerobic)
• the lactic acid system (anaerobic)
• the aerobic system
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(3) Energy systems
The use of each of these systems depends on the intensity and
duration of the activity:
• If the activity is short duration (less than 10 seconds) and
high intensity, we use the ATP–PC system.
• If the activity is longer than 10 seconds and up to
3 minutes at high intensity, we use the lactic acid
system
• If the activity is long duration and submaximal pace, we
use the aerobic system.
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(4) The energy continuum
Sometimes we need to use all three systems to
regenerate ATP because the demands of an activity
are varied. For example, in rugby:
• a short sprint to tackle a player uses the ATP–PC
system
• a long sprint the length of the pitch to score a try
uses the lactic acid system
• positional play will use the aerobic system
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(5) What you need to know about
energy systems
• Type of reaction
• The chemical or food fuel used
• Where the reaction occurs
• The energy yield (how many ATP molecules)
• Specific stages in a system
• The by-products
• When the system is predominant
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(6) The ATP–PC system
Type of reaction — anaerobic coupled
Fuel used — phosphocreatine
The reaction occurs — in the sarcoplasm
Energy yield — 1 ATP
Specific stages in the system — PC is stored in the muscle
and broken down to release energy; this energy is used to
regenerate ATP
• By-products — none
• The system is predominant in high-intensity activity lasting
less than 10 s, e.g. 100 m sprint or a slam dunk
•
•
•
•
•
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(7) The ATP–PC system
Advantages
• Phosphocreatine stores can be regenerated
quickly (50% replenishment in 30 s; 100% in
3 mins)
• No fatiguing by-products
• Creatine supplementation extends the time that
the ATP–PC system can be utilised
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(8) The ATP–PC system
Disadvantages
• There is a limited supply of phosphocreatine in
the muscle cells, i.e. it can only last for 10 s
• Only 1 molecule of ATP can be regenerated for
every molecule of PC
• PC regeneration can only take place in the
presence of oxygen (i.e. when the intensity of the
exercise is reduced)
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(9) The lactic acid system
Type of reaction — anaerobic coupled
Fuel used — glycogen
The reaction occurs — in the sarcoplasm
Energy yield — 2 ATP
• Specific stages in the system — glycogen is broken down into
glucose and in the absence of oxygen forms pyruvic acid
• By-product — lactic acid
• The system is predominant — in high-intensity activity
lasting between 10 s and 3 min, e.g. a succession of tackles
in rugby, or a full court press followed by a fast break in
basketball
•
•
•
•
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(10) The lactic acid system
Advantages
• ATP can be regenerated quite quickly because few
chemical reactions are involved.
• In the presence of oxygen, lactic acid can be
converted back into liver glycogen, or used as a
fuel by oxidation into carbon dioxide and water.
• It can be used for a sprint finish (i.e. to produce
an extra burst of energy).
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(11) The lactic acid system
Disadvantages
• Lactic acid is the by-product! The accumulation of
acid in the body denatures enzymes and prevents
them increasing the rate at which chemical
reactions take place.
• Only a small amount of energy (5%) can be
released from glycogen under anaerobic
conditions (as opposed to 95% under aerobic
conditions).
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(12) The aerobic system
• Type of reaction — anaerobic coupled
• Fuel used — glycogen/fats
• The reaction occurs — stage 1 (glycolysis) in the
sarcoplasm; stage 2 (Kreb’s cycle) in the matrix
of the mitochondria; stage 3 (electron transport)
in the cristae of the mitochondria
• Energy yield — stage 1: 2 ATP; stage 2: 2 ATP;
stage 3: 34 ATP
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(13) The aerobic system
• Specific stages in the system — stage 1
glycolysis; stage 2 Kreb’s cycle; stage 3 electron
transport
• By-products — carbon dioxide (stage 2); water
(stage 3)
• The system is predominant in sub-maximal
exercise such as keeping up with play
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(14) The aerobic system
Advantages
• More ATP can be produced — 38 ATP from the
complete breakdown of one glucose molecule.
• There are no fatiguing by-products (only carbon
dioxide and water).
• Stores of of glycogen and triglyceride are
plentiful, so exercise can last for a long time.
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(15) The aerobic system
Disadvantages
• This is a complicated system so it cannot be used
immediately. It takes time for enough oxygen to
become available to meet the demands of the
activity and ensure glycogen and fatty acids are
completely broken down.
• Fatty acid transportation to muscles is low and
fatty acids require 15% more oxygen to break
them down than glycogen.
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(16) Food fuels
Food is the basic form of energy for ATP regeneration. The main
energy foods are:
• carbohydrates — stored as glycogen and converted into
glucose during exercise
• glycogen — a complex sugar supplied from muscle or liver
stores
• glucose — a simple sugar supplied from the blood
• fats — stored as triglycerides in adipose tissue under the
skin and converted by the enzyme lipase to free fatty acids
when required
AS/A2 PE: Anatomy & Applied Exercise Physiology
ERP 10
(17) When are these fuels used
during exercise?
• The intensity and duration of exercise play a
huge a role in determining whether fats or
carbohydrates are used.
• The breakdown of fats to free fatty acids requires
more oxygen than that required to breakdown
glycogen. It is also a much slower process.
• Therefore, during high-intensity exercise when
oxygen is in limited supply, glycogen will be the
preferred source of energy.