Exercise physiology that teach more about the body's response for exercise What the cell, tissue, organ and system responds for exercise

1. Exercise metabolizm and
Bioenergetics
By Tesfalem(MSc PT)
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2. Objectives
Øexplain cell metabolism
Ødiscuss sources of energy for exercise
ØDiscuss ways of energy transduction during exercise
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3. Muscle Metabolism During Exercise
Ø Muscles are the ultimate source of energy where by body
perform all the work.
Ø Energy is extracted from foods in the body by converting the
chemical energy stored in chemical bonds to high energy
phosphate bonds in ATP (adenosine triphosphate).
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4. Ø Thishigh-energy bond can be used in a number of biochemical
reactions as a fuel withthe conversion of ATPto ADP (adenosine
diphosphate).
Ø IfADP begins to accumulate in muscle, then an enzyme is
activated in muscle to break down phosphocreatine (PCr) in
order to restore ATPlevels (PCr +ADP → ATP+Cr). The creatine
released from this reaction is converted to creatinine and
excreted in the urine.
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5. Aerobic and Anaerobic Metabolism
Ø The stores of PCr are extremely limited and can only support
muscle ATP levels for about 10 seconds if there were no other
sources of ATP.
Ø Because ATPisprovided from other sources, PCr ends up being a
major energy source in the firstminute of strenuous exercise. PCr
is localized in the muscle so that it can rapidly restore and
maintain ATP levels for intense exercises such as sprinting,
jumping, lifting and throwing.
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6. Ø During moderate exertion of the body, carbohydrate undergoes
aerobic metabolism. Under these conditions, oxygen isused and
the carbohydrate goes through both the Embden-Meyerhoff
pathway of anaerobic metabolism, in which glucose is
converted to lactate and aerobic metabolism( Krebs cycle).
Ø Butbefore the conversion of pyruvate to lactate, pyruvate enters
the Krebs C y c l e in mitochondria, where oxidative
phosphorylation results in a maximum extraction of energy from
each molecule of glucose.
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7. Ø Ifthere is plenty of oxygen available and the exercise is of low
to moderate intensity, then the pyruvate from glucose is converted
to carbon dioxide and water in the mitochondria.
Ø Approximately 42 ATP equivalents can be produced from a
single glucose molecule compared to only 4ATPwith anaerobic
metabolism.
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8. Continued…
Ø To replenish ATP levels quickly, muscle cells convert a high-
energy phosphate compound called creatine phosphate.
Ø The phosphate group isremoved from creatine phosphate by an
enzyme called creatine kinase, and is added to ADP to form
ATP.
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9. Ø Together, the ATP levels and creatine phosphate levels are
called the phosphagen system. As itworks, the cell turnsATP into
ADP, while the phosphagen rapidly turns the ADP back into ATP.
As the muscle continues to work, the creatine phosphate levels
begin to decrease.
Ø The phosphagen system can supply the energy needs of
working muscle at a high rate, but only for8to 10 seconds.
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10. Ø Aerobic metabolism supplies energy more slowly than
anaerobic metabolism, but can be sustained for long periods of
time –up to five hours.
Ø The major advantage of the less efficient anaerobic pathway is
that it more rapidly provides ATP in muscle by utilizing local
muscle glycogen. Other than PCr, itis the fastest way to resupply
muscle ATP levels.
Ø Anaerobic glycolysis supplies most energy for short-term intense
exercise ranging from 30 seconds to two minutes.
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11. Ø The disadvantages of anaerobic metabolism are that it cannot
be sustained for long periods, since the accumulation of lactic
acid in muscle decreases the pH and inactivates key enzymes in
the glycolysis pathway, leading to fatigue.
Ø The lactic acid released from muscle can be taken up by the
liver and converted to glucose again (Cori Cycle).
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12. Source of energy forworkdone
Sprinter Phosphagen
System 8-10Sec
(100m)
Swimmer
Glycogen-Lactic acid System
13-16mins(400m)
Marathon Runners
Aerobic Respiration 1-
2hrs(15km-30km)
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13. Bioenergetics
By Tesfalem(MSc PT)
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14. Bioenergetics
ØBioenergetics is the quantitative study of the energy
transductions that occur in living cells and of the nature and
function of the chemical process underlying these
transduction.
ØBiological energy transductions obey the same physical laws
that govern all other natural processes
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15. “High energy” bonds
Compounds with “high energy bonds” are said to
have high group transfer potential.
For example, Pi may be spontaneously cleaved from ATP for
transfer to another compound (e.g., to a hydroxyl group on
glucose).
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16. Potentially, 2 ~P bonds can be cleaved, as 2
phosphates are released by hydrolysis from ATP.
AMP~P~P AMP~P +
Pi AMP~P AMP + Pi
Alternatively:
AMP~P~P AMP + P~P
(ATP ADP +
Pi) (ADP AMP
+ Pi)
(ATP AMP +
PPi)
P~P 2 Pi (PPi 2Pi)
Contd..
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17. ATP often serves as an energy source.
Hydrolytic cleavage of one or both of the "high energy"
bonds of ATP is coupled to an energy- requiring (non-
spontaneous) reaction. (Examples presented earlier.)
AMP functions as an energy sensor & regulator of
metabolism.
When ATP production does not keep up with needs, a higher
portion of a cell's adenine nucleotide pool is AMP.
AMP stimulates metabolic pathways that produce ATP.
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18. High Energy Phosphates
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19. Anaerobic & aerobic ATP Synthesis
• What Does ATP Do forYou?
It supplies energy for the body.
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20. Chemical Structure of ATP
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21. cont
• The energy which coming
from ATP is by breaking
the high energy bonds
between the two
phosphates in ATP.
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22. How DoesThat Happen?
An
Enzyme!
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23. How is ATP Re-Made?
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24. The ADP-ATP Cycle
Dr. Rahul Krishnan Kutty
ATP-ase
ATP
Synthetase
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25. Cellular Respiration
Ø Includes pathways that require oxygen
Ø Glucose is oxidized and O2is reduced
Ø Glucose breakdown is therefore an
Ø oxidation-reduction reaction
Ø Breakdown of one glucose results in 36 to 38 ATP
molecules
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26. What Carries the Electrons?
 NAD+ (nicotinadenine
dinucleotide) acts as the
energy carrier
 NAD+ is a coenzyme
 It’s Reduced to NADH
when it picks up two
electrons and one hydrogen
ion
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27. What are the Stages of Cellular Respiration?
Ø Glycolysis
Ø The Krebs Cycle
Ø The Electron Transport Chain
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28. Where DoesCellular RespirationTake Place?
It actually takes place in
two parts of the cell.
glycolisis occurs in the
cytoplasm while krebs
cycle and ETC takes
place in the Mitochondria
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29. Diagram of the Process
Dr. Rahul Krishnan Kutty
Occurs in
Cytoplasm
Occurs in
Matrix
Occurs across
Cristae
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30. Glycolysis Summary
ü Takes place in the Cytoplasm
ü Anaerobic (Doesn’t Use Oxygen)
ü Requires input of 2 ATP
ü Glucose split into two molecules of Pyruvate or Pyruvic
Acid
ü Also produces 2 NADH and 4 ATP
ü Pyruvate is oxidized to Acetyl CoA and CO2 is removed
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31. Glycolysis
Diagram
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32. Krebs Cycle Summary
üRequires Oxygen (Aerobic)
üCyclical series of oxidation reactions that give off CO2 and
produce one ATP per cycle
üTurns twice per glucose molecule
üProduces two ATP
üTakes place in matrix of mitochondria
üEach turn of the Krebs Cycle also produces 3NADH,
1FADH2, and 2CO2
üTherefore, For each Glucose molecule, the Krebs Cycle
produces 6NADH, 2FADH2, 4CO2, and 2ATP
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33. Krebs Cycle
ATP
NETS: 3NADH, 1ATP, 1FADH2, & 2CO2
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34. Control of Bioenergetics
ØRate-limiting enzymes
– An enzyme that regulates the rate of a metabolic
pathway
Ø Modulators of rate-limiting enzymes
– Levels of ATP and ADP+Pi
High levels of ATP inhibit ATP production
Low levels of ATP and high levels of ADP+Pi
stimulate ATP production.
– Calcium may stimulate aerobic ATP production
ØMetabolism is regulated by enzymatic activity. An
enzyme that regulates a metabolic pathway is termed
a“rate-limiting” enzyme.
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35. Cont..
ØT h e r a t e - l i m i t i n g e n z y m e f o r g l y c o l y s i s i s
phosphofructokinase, while the rate-limiting
enzymes for the Krebs cycle and electron transport
chain are isocitrate dehydrogenase and cytochrome
oxidase, respectively.
ØIn general, cellular levels of ATP and ADP+Pi regulate
the rate of metabolic pathways involved in the
production of ATP.High levels of ATP inhibit further ATP
production, while low levels of ATP and high levels of
ADP+Pi stimulate ATP production.
ØEvidence also exists that calcium may stimulate aerobic
energy metabolism.
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36. 36

37. Exercise and Training
Principle
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38. Physical Activity
 The term “physical activity” describes many forms of
movement, including activities that involve the large
skeletal muscles.
 Activities that involve the small skeletal muscles (e.g. playing
board games, drawing, writing) are important, but they do not
provide the health benefits of activities that involve the large
skeletal muscles and require substantial energy expenditure.
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39. Physical activity is defined by its duration, intensity, and
frequency
 Duration is the amount of
time spent participating
in a physical activity
session
 Intensity is the rate of
energy expenditure
 Frequency is the
number of physical
activity sessions during a
specific time period (e.g.
one week).
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40. Types of Physical Activity
Aerobic - light to vigorous-intensity physical
activity that requires more oxygen than sedentary
behavior and thus promotes cardiovascular
fitness and other health benefits (e.g., jumping
rope, biking, swimming, running; playing soccer,
basketball, or volleyball).
Anaerobic – intense physical activity that is
short in duration and requires a breakdown of
energy sources in the absence of sufficient
oxygen. Energy sources are replenished as an
individual recovers from the activity.
Anaerobic activity (e.g., sprinting during
running, swimming, or biking) requires
maximal performance during the brief period.
Lifestyle – physical activity typically performed
on a routine basis (e.g., walking, climbing stairs,
mowing or raking the yard), which is usually
light to moderate in intensity.
Physical activity play – play activity that
requires substantial energy expenditure (e.g.,
playing tag, jumping rope).
Play – activity with flexible rules, usually
self-selected, for the purpose of having fun.
Sports – physical activity that involves
competition, scorekeeping, rules, and an outcome
that cannot be predetermined. There are two
categories of sports: individual and team.
Weight-bearing – physical activity that
requires people to move their own weight.
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41. Exercise
 Exercise consists of
activities that are planned
and structured, and that
maintain or improve one or
more of the components of
physical fitness.
 Physical activity suggests a
wide variety of activities that
promote health and well-
being.
 Exercise is often associated
with fitness maintenance or
improvement only.
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42. Types of Exercises
Calisthenics. Isotonic muscle-fitness
exercise that overloads muscles by
forcing the muscles to work at a
higher level than usual.
Flexibility (Stretching). Exercise
designed to stretch muscles and
tendons to increase joint flexibility or
range of motion. Specific flexibility
exercises need to be done for each
part of the body.
Isometric. Muscle-fitness exercise in
which the amount of force equals the
amount of resistance, so that no
movement occurs.
Isotonic. Muscle-fitness exercise in
which the amount of force exerted is
constant throughout the range of
motion, including muscle shortening
(concentric contractions), and muscle
lengthening (eccentric contractions).
Muscle-fitness. Exercise designed to
build muscle strength and endurance
by overloading the muscles; also
called progressive resistance exercise
(PRE). Common forms of muscle
fitness exercise include isokinetic,
isometric, and isotonic.
Isokinetic. The speed of movement
remains the same throught movement.
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43. Fitness
 Participating in physical activity is beneficial to people of
all ages. Physical activity contributes to fitness, a state in
which people’s health characteristics and behaviors
enhance the quality of their lives.
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44. Types of Fitness
Physical
fitness
Health-related
physical fitness
Skill-related
physical fitness
A set of physical
attributes related to a
person’s ability to
perform physical
activity successfully,
without undue strain
and with a margin of
safety.
A physiological state of
well-being that reduces the
risk of hypokinetic disease;
a basis for participation in
sports; and a vigor for the
tasks of daily living.
Components include
cardio-respiratory
endurance, muscle
strength , flexibility, and
body composition.
Common components of
physical fitness (e.g.,
agility, balance,
coordination, speed, power,
reaction time) that enable
participation in sports and
other physical activities;
also called performance or
motor fitness.
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45. Fitness is transitory – it increases with activity and
decreases with inactivity.
All training has some common features:
- It produces constant physical changes
- It takes time for these changes to occur, so training must take
place over a period of time
- The training response is directly related to the types of
training used
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Fitness futures

46. Principles of Fitness Training
Special emphasis
 Warm-up, workout, cooldown components
 Helps prevent injury and prepares body for exercise as
well as returns it to a normal state.
 Safety
 Information collected from medical screening, and
informing individual of environmental conditions
 Behavioral factors
 Motivation of individual to adhere to fitness program
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47. Principles of Training
Training programs should be developed to meet the needs of the
individual. However, the basic principles and guidelines for achieving a
desired level of fitness are the same for everyone.
1. SPECIFICITY
 “What you train for is what you get” i.e different forms of exercise
produce different effects.
 The outcomes of training don’t automatically translate from one activity
to another
** Peripheral training effects – those occurring at the muscle level
** Central training effects – those occurring in the cardiorespiratory
system, may transfer more quickly.
Training MUST include the physiological capacities that need
maintenance or improvement.
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48. Principles of Training
2. PROGRESSIVE OVERLOAD
 The body systems must be continually loaded with
progressively higher levels of work.
 The body adapts physiologically when training load is
greater it’s used to be.
 Overloading can be achieved by varying 3 factors in
training:
- increasing INTENSITY of exercise
- increasing FREQUENCY of activity
- increasing DURATION of exercise or number of
REPETITIONS
 The method used to achieve overload is dependent on the
specific fitness desired and the aim of the training program.
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49. Principles of Training
3. TRAINING THRESHOLDS
A minimum intensity and duration of stress must
be exceeded before adaptations in physiological
capacities are triggered.
Aerobic Threshold
- The level of intensity that allows you
to exercise
using the aerobic energy system
- Improvements can be achieved by training at
60 –85% max HR for at least 30 minutes.
- Can be increased by training at higher end of
training zone
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50. Principles of Training
Anaerobic Threshold
- Working above aerobic threshold you will
feel out of breath, possibly nausea and
cramping. At this
point you have reached anaerobic threshold.
- Can be increased by using short bursts of high
intensity activity, interspersed with aerobic
workout
* If you are able to have a conversation during
your workout you are working in the aerobic
zone
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51. Principles of Training
4. INDIVIDUAL DIFFERENCES
 Individuals will respond to the same training in
different ways
Factors affecting physiological responses to
training:
- fitness levels
- muscle mass
- fat distribution
- genetics
- heart size
- fibre type
- joint flexibility
 Optimal benefits result from programs geared to the
individual needs & capabilities of the athlete.
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52. Principles of Training
5. REVERSIBILITY
- Training effects are reversible
- If training stops, is done irregularly or with not
enough intensity then adaptations will be reversed.
- This process is also referred to as detraining
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53. Principles of Training
TYPES OF TRAINING
1. ANAEROBIC TRAINING
To improve anaerobic capacity we need to overload The
ATP-CP & Lactic Acid energy systems
ATP-CP System
- Engage specific muscles in repeated 5-10 second
bursts of activity
- The activity must use the specific muscles required for the
particular sport
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54. Principles of Training
Lactic Acid System
- Improving the capacity requires repeated bouts of up to 1
minute max effort, stop 30 seconds prior to exhaustion. Repeat
after 3-5 minutes recovery.
- This causes lactic acid build-up which overloads the
muscles and increases lactic acid tolerance.
- Activities chosen must engage the specific muscle
groups.
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55. Principles of Training
2. AEROBIC TRAINING
The aerobic energy system provides energy for
prolonged activities by producing ATP from
Glycogen, with oxygen
2 main goals of aerobic training are:
- Increase capacity of cardiorespiratory system (cardiac
output/ stroke volume) & efficiency of
respiratory system
- Enhance capacity of specific muscles to process oxygen
*brief bouts of repeated exercise & long-duration efforts
develop aerobic capacity.
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56. 3. STRENGTH TRAINING
Three types of muscular action:
- Concentric action – muscle shortens, joint move’t
occurs as tension develops eg raising dumbell
- Eccentric action – external resistance > muscle force &
muscle lengthens while developing tension eg lowering
dumbell (bicep lengthens)
- Isometric action – when muscle generates force & attempts to
contract but can’t overcome external force eg pressing against
a wall
Principles of Training
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57. Principles of Training
Basic principles of strength training:
- overload
- progressive resistance (reps or weights)
- specificity
- largest muscle groups first
- warm-up
- breathe when lifting
- technique
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58. Principles of Training
4. SPEED TRAINING
- Training methods best suited to improving speed are
circuit and interval training
- Progressive overload achieved by decreasing the
duration but increasing the reps
5. POWER TRAINING
- Power is combo of speed and strength
- Training methods best suited to improving it are
resistance training, interval & circuit training &
plyometrics
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59. Principles of Training
6. FLEXIBILITY TRAINING
There are 2 types of flexibility – static & dynamic.
Training should be specific:
- static exercises eg hold quad stretch for 20secs
-dynamic exercises that involve movement during the
stretch eg side bends
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60. Principles of Training
METHODS OF TRAINING
 Continuous Training
 Fartlek Training
 Interval Training
 Circuit Training
 Resistance Strength Training
 Isometric Strength Training
 Flexibility Training
 Plyometrics
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61. Principles of Training
1. CONTINUOUS TRAINING
 Involves sustained activity for between 20 – 60 minutes
 Improves cardio-respiratory endurance and muscular
endurance
In order to develop aerobic capacity through
continuous training the following variables must be
considered:
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62. Principles of Training
Intensity:
- How strenuous the exercise must be
- Between 60-85% of maximum heart rate
Duration:
- Length of the training session (at least 20 mins)
Frequency:
- Number of training sessions per week
Type of Activity:
- Depends on individual interests and objectives of training
program
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63. Principles of Training
2. FARTLEK TRAINING
- Modified form of continuous training involving
regular changes of pace
- The changes of pace increase the involvement of the
anaerobic energy systems while primarily using the
aerobic system
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64. Principles of Training
3. INTERVAL TRAINING
- Comprises a series of repeated short bouts of exercise
interrupted by periods of relief (rest or light exercise)
- Designed to improve speed, power, agility and anaerobic
capacity
Key Variables in Interval Training
Work Interval:
Refers to the exercise phase at a prescribed
intensity
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65. Principles of Training
Recovery Interval:
- Refers to the time between work bouts, and the type
of activity during the recovery
- Heart rate should drop to 120 beats per minute
- The recovery interval is expresses in relation to the work
interval as a ratio eg a 1:2 ratio means the recovery interval is
twice as long as the work interval
Set:
Refers to a series of work-recovery intervals
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66. Principles of Training
Repetition:
Refers to the number of work intervals in a given
set
4. CIRCUIT TRAINING
- A number of exercise stations that are consecutively
arranged in a given area, to be completed in as short a time
as possible
- Has potential to develop aerobic capacity, anaerobic capacity,
strength, power, agility, flexibility and muscular strength
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67. Principles of Training
- Activities included in circuit depend on objectives of the
training program
- 10 to 15 stations requiring 8 – 12 minutes to complete
- Usually repeated 2 or 3 times during a session
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68. Principles of Training
5. RESISTANCE STRENGTH TRAINING
 Involves performing a series of exercises with
resistance, using either free or machine weights
 Produces improvements in muscular strength and
muscular endurance
 3 types – Isotonic, Isometric, Isokinetic
TERMS TO KNOW
- Repetition (rep)
- Set
- Repetition Maximum (RM)
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69. Principles of Training
6. PLYOMETRICS
- A very specialised form of power training
- Rapid eccentric contraction (muscle lengthens)
followed by a rapid concentric contraction (muscle
shortens)
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70. QUESTIONS ?
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71. Thank You!!
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