1. بسم الله الرحمن الرحيم
الحمد لله والصلاة
والسلام على رسول الله

2. Gad El-Mawla Abd El-Aziz
Professor of Physiology
Mansoura University
M.B., B.Ch. 1974 Mansoura University, Egypt.
M.Sc. (Physiology) 1980.
PhD. (Physiology) 1984.
Professor of Physiology (1994).
E-mail: elmawla@hotmail.com

3. Sources of energy
During rest and Exercises

4. Energy: is the capacity to perform work
Cells in the body need energy to function
FOOD = ENERGY (E)
 Cells don’t get Energy directly from food,
it must be broken down into:
ATP - Adenosine Triphosphate
ATP: The energy “currency” of the cells.

5. ATP :
ATP : is a high energy compound stored in
our cells and is the source of all energy used
at rest and during exercise.
Energy in food is released within the
cells then stored in the form of ATP.
 Formation of ATP provides the cells
with a high-energy compound for storing
energy.

6. Nutrients which give us energy:
Carbohydrates
Fats
Proteins
Digestion
Glucose
Fatty acids
Amino Acids
Carbohydrates
Common Pathway Energy

7.  These nutrients are absorbed into the blood &
transported to cells (muscle, liver & nerve).
 They are used to produce ATP or stored.
 ATP is stored in small amounts, therefore the
rest is stored as:
 Glucose = Glycogen (muscle & liver).
 Fatty Acids = Body fat.
 Amino Acids = Growth, repair or excreted as waste.

8. Carbohydrate:
(Body’s primary energy source for most activities)

9. Carbohydrate:
 Readily available and easily metabolized by
muscles.
 It is transported as glucose and taken up by
muscles and liver and converted to glycogen.
 Glycogen stored in the liver is converted back to
glucose as needed and transported by the blood to
the muscles where it is used to form ATP.
 Glycogen stores are limited.

10. Fat :
 Provides energy at rest and during
prolonged, low-intensity activity.
 Body stores of fat are larger than
carbohydrate reserves.

11. Fat :
 Less accessible for metabolism because it
must be reduced to glycerol and FFA.
 FFAs are used to form ATP.
 Trained muscle has a greater ability to use fat
as fuel.
 As exercise is prolonged, fat becomes the
main fuel.
 Requires more oxygen for aerobic breakdown.

12. Protein:
 Can only supply up to 5% to 10% of the
energy needed to sustain prolonged exercise.
 Amino acids are broken down into glucose
(gluconeogenesis).

13. Protein :
 A gram of protein yields about 4 Kcal.
 Can be used as an energy source if
converted to glucose via gluconeogenesis.
 Only basic units of protein (amino acids) can
be sued for energy.

14. Sources of Energy
during & after exercises

15. Energy Systems:
Three basic energy systems:
1. Phosphagen energy system:
(Immediate energy system).
2. Anaerobic or glycolysis energy system:
(Glycolytic or non-oxidative system).
3. Aerobic or Oxidative energy system:
(Mitochondrial respiration )

16. I- Phosphagen energy system
 It is utilized during transition from rest
to exercise, and also during the transition
from one exercise intensity to a higher
intensity.
 It does not need oxygen.
 It leaves no waste products.

17. I- Phosphagen energy system
During a contraction:
 Myosin cross-bridge breaks down ATP,
producing ADP and a phosphate group.
 Creatine phosphate is then used to
"recharge" ADP, converting it back to ATP :
 ADP + creatine phosphate  ATP + creatine.
 ATP  ADP+ P (phosphoric acid) + energy

18. The Phosphagen system is active during all-out
exercise that lasts about 5 to 10 seconds, such
as a 100-meter dash, lifting a heavy weight, or
any other activity that involves a maximum, short
burst of power.

19. This system relies on stored ATP and to a larger
extent, creatine phosphate, to provide immediate
energy.
 For any exercise lasting longer than 10
seconds, assistance from other systems is
required.

21. II- Anaerobic or glycolysis energy system
 Breakdown of glucose into pyruvic acid in
the sarcoplasm of the muscle.
Glucose ( muscle glycogen )
Anaerobic
oxidation
2 pyruvic acid + 2 ATP
 Pyruvic acid produced is converted into
lactic acid which diffuses out of the muscle
and accumulate in the blood.
 When the muscle is doing work at faster rate,
more than the blood can supply O2 and nutrients,
the muscle depends on local glycogen stores
and anaerobic glycolysis.

22. II- Anaerobic or glycolysis energy system
The advantage: it is able to supply ATP at
a high rate and within a short time.
The disadvantage: it provides only 2 ATP
molecules from each molecule of glucose. So,
anaerobic glycolysis is rapid but not
economic.

23. o Anaerobic glycolysis supplies the total
energy requirements for moderate to high
intensity exercise lasting about one to two
minutes.
o Anaerobic Glycolysis continues to supply
energy during exercise lasting up to ten
minutes.
o This system breaks down muscle and
liver glycogen stores without the use of
oxygen.

24. Micheal Gohnson
200 meter run

25.  Production of ATP by anaerobic glycolysis is
not as fast as Phosphagen system, which
makes muscle contraction slower.
When oxygen is not available the lactic acid,
produced causes rapid muscle fatigue.
 Anaerobic glycolysis supplies ATP at high rate
and within short time but it is not economic.

26. Anaerobic glycolysis
Oxygen cannot reach the muscles fast enough.
Glucose Produces

27. Glucose produces
Lactic acid is formed
quickly which makes
muscles feel tired &
painful.
Part is used for muscle
contractions, creating
movement.
Anaerobic glycolysis
Oxygen cannot reach the muscles fast enough.

28. Glucose produces
The rest is
converted into heat.
Lactic acid is formed
quickly which makes
muscles feel tired &
painful.
Part is used for muscle
contractions, creating
movement.
Anaerobic glycolysis
Oxygen cannot reach the muscles fast enough.

29. Anaerobic glycolysis
In Anaerobic glycolysis lactic acid accumulate
in blood and fatigue occurs early

30. Function of lactic acid
 It stimulates respiratory and
circulatory systems to increase their
activities.
 It is converted to glucose in the liver.
 Lactic acid is the preferable fuel to
the heart.

31. Function of lactic acid:
 In the muscles it causes capillary
dilation and  blood flow.
 It causes shift of O2 dissociation
curve to right i.e. giving O2 easily to
active muscles.
 It is oxidized in the recovery period
to replenish ATP and energy stores.

32. Aerobic or Oxidative energy system:
 It is used during lower levels of activity
(as in marathon) when there is enough
energy being delivered to the working
muscles.
 Depends on O2 for break down of fuels
to energy.
 Produces ATP in mitochondria of cells.
 Can yield much more energy (ATP) than
anaerobic systems.

34.  It is used for energy production during
endurance events ( economic).
 As a rule, the more intense the activity,
the more glucose is used instead of FAT.
 At lower levels of activity fats can be
used as muscle fuel.
 During exercise, VO2 rises rapidly until
“steady rate”.

35.  Aerobic oxidation of CHT and fat produce
ATP, CO2, H2O, and heat.
 CO2 is transported to lungs while heat and
water are released through sweat.
 Provides energy for 2 minutes to 3 hours
of work.
 Supply ATP slowly to the active muscles.

36. Relative rates of ATP utilized by aerobic,
anaerobic and Phosphagen systems
 Aerobic system 1.0 M of ATP / min.
 Anaerobic system 2.5 M ATP / min.
 Phosphagen system 4.0 M ATP / min.

37. Comparing the 3 energy systems for
endurance:
 Phosphagen system 10 – 15 sec.
 Anaerobic system 30 – 40 sec.
 Aerobic system unlimited time (as
long as nutrients last)

38. Energy systems used in sports:
 Phosphagen system: 100 meter dash,
jumping, weight lifting, and diving.
 Phosphagen and anaerobic systems: 200
meter dash.
 Anaerobic system mainly: 400 meter dash,
100 meter swim, 800 – 1,500 meter dash, 200
– 400 meter swim, and boxing.
 Aerobic system: 10,000 meter skating,
marathon run, and Jogging ( 42.2 Km.)

39. Oxidation of Carbohydrate:
 Pyruvic acid from glycolysis is converted
to acetyl CoA.
 Acetyl CoA enters the Krebs cycle and
forms ATP, carbon dioxide, and hydrogen.
 One molecule of glucose can generate up
to 38 molecules of ATP.
Blood gulcose+ 6o2
Aerobic oxidation
6co2 +6H2O + 38ATP
Keb’s cycle

40. Oxidation of Fat :
 Lypolysis – breakdown of triglycerides
into glycerol and free fatty acids (FFA’s).
 FFA’s are broken down in the
mitochondria into acetyl CoA.
 Acetyl CoA enters the Krebs cycle for
oxidation.
 Fat oxidation requires more oxygen and
generates more energy than carbohydrate
oxidation.
Free fatty acid +O2
Aerobic oxidation
CO2 +H2O + ATP

41. Aerobic oxidation
In Aerobic glycolysis fatigue is delayed

42. Aerobic oxidation
Glucose and
O2 produce

43. Aerobic oxidation
Glucose and
O2 produce
Some is used for
muscle contractions,
creating movement.

44. Aerobic oxidation
Glucose and
O2 produce
Carbon dioxide,
which is carried
away by the blood
& excreted through
the lungs.
Some is used for
muscle contractions,
creating movement.
The rest is converted
into heat to warm
the body.
Water, which is
carried away by the
blood and excreted
through the lungs,
sweat and urine.

45. Oxygen Debt

46. Oxygen Debt
It is the difference between oxygen needed by the
contracting muscle and the oxygen available by the
cardiovascular and respiratory systems.
O2 debt is paid at the end
of the exercise. Sprinters
will continue to breath
more deeply and rapidly
for minutes. This will
enable them to pay back
the oxygen debt, and allow
lactic acid levels to fall.

47. Oxygen Debt
Measurement of oxygen debt :
O2 debt: O2 consumption during recovery – O2
consumption during similar period of rest.
Importance of oxygen debt:
It helps the muscle to do an
exercise which is much greater
than would be possible if they
depend completely on energy
from oxygen consumption.

48. In exhausted muscles:
 There is an emergency metabolism for the
supply of ATP.
 This is done by combining two ADP
molecules to reform one ATP molecule, and one
AMP molecule.
ADP + ADP ATP + AMP

49. Metabolic changes
During Recovery

50. Metabolic changes During Recovery
 At the end of the muscle activity ,the energy stores in
the muscle are depleted , and lactic acid is increased in
blood .
 Recovery occurs by removal of the lactic acid and
regeneration of the energy stores.
A) Part of lactic acid is oxidized into CO2 and H2O.
The energy produced from this oxidation is
used for reformation of ATP and by turn Cr-p.
Lactic acid
oxidation
Pyruvic acid
Oxidation
Kreb’s cycle
CO2+H2O+ATP
ATP + creatine Cr-P + ADP

51. B) The other part of the lactic acid diffuses to
the blood stream and then to the liver where it’s
converted into blood glucose. Muscles take
glucose from the blood stream and changes it
into muscle glycogen.
 At the end of recovery , the energy stores in
the muscle (ATP, Cr-P, and muscle glycogen )
are reformed again and the lactic acid is
removed.

52. وآخر دعوانا أن الحمد لله رب العالمين