1 sport and metabolism hendra wijaya. sport books publisher2 learning objectives: to develop an...

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SPORT AND METABOLISM

HENDRA WIJAYA

Sport Books Publisher 2

Learning Objectives:

To develop an awareness of the basic chemical process that the body uses to produce energy in the muscles

To develop an understanding of the body’s three main energy systems

To introduce the energy requirements and source of energy for skeletal muscle( Resting vs. Working)

To introduce the effect of training and exercise on the energy systems


The Chemistry of Energy Production

Energy in the human body is derived from the breakdown of complex nutrients like carbohydrates, fats, and proteins.

The end result of this breakdown is production of the adenosine triphosphate (ATP) molecule.

ATP provides energy necessary for body functions

Carbohydrates

Fats

Proteins

ATP Muscular Work

Digesting Food

Thermoregulation

Breakdown of Energy currency Biochemical processes


ATP Cycle Overview

a) ATP breakdown

b) Phosphorylation

c) ATP resynthesis


1. Hydrolysis of the unstable phosphate groups of

ATP molecule by H2O

3. Energy is released (38-42 kJ, or 9-10kcal/ mol ATP)

ATP H2O++ Energy++ P++

2. Phosphate molecule (P) is released from ATP (ATP ADP)

ADP

a) ATP breakdown (ATP turnover)


1. Energy released by ATP turnover can be used by body when a free P group is transferred to another molecule (phosphorylation)

Energy for muscle contractionMolecule P++

b) Phosphorylation


1. Initial stores of ATP in the muscles are used up very quickly and ATP must be regenerated

2. ATP is formed by recombination of ADP and P

ATPADP Energy++ P++

3. Regeneration of ATP requires energy (from breakdown of food molecules)

c) ATP resynthesis

Human Energy Systems ATP-PC System

– adenosine triphosphate

– phosphocreatine Lactic Acid System

– anaerobic glycolytic pathwayOxygen System

– aerobic metabolic pathways


The Energy Systemsa) the high energy phosphate system (ATP-PC)

1. Adenosintriphosphate2. Phosphocreatine

b) the anaerobic glycolytic system (Lactic acid system)

c) the aerobic oxidative system


The Roles of the Three Energy The Roles of the Three Energy Systems in Competitive Systems in Competitive

SportSport


The High Energy Phosphate System Overview

Primary energy source:

Duration of activity:

Sporting events:

Advantages:

Limiting factors:

Stored ATP, CP

7-12 s

Weight lifting, high jump, long jump, 100m run, 25m swim

Produce very large amount of energy in a short amount of time

Initial concentration of high energy phosphates (ATP, PC)

ATP-PC Energy SystemATP – Energy for muscle contraction


Training the High Energy Phosphate System

a) Interval training:

- 20% increase in CP (creatine phosphate) stores- no change in ATP stores- increase in ATPase function (ATP -> ADP+P)- increase in CPK (creatine phosphokinase) function

(CPK breaks down CP molecule and allows ATP resynthesis)

b) Sprint training:

- increase in CP stores up to 40%

- 100% increase in resting ATP stores


The Anaerobic Glycolytic System Overview



Sporting events:

Advantages:

Limiting factors:

Stored glycogen, blood glucose

12 s – 3 min

Lactic acid build up, H+ ions build up (decrease of pH)

800m run, 200m swim, downhill ski racing, 1500 speed skating

Ability to produce energy under conditions of inadequate oxygen


The Anaerobic Glycolytic System

ADP + Pi ATPADP + Pi ATP

ENERGYENERGY

Lactic AcidLactic Acid

GlycogenGlycogen


Glycolysis

A biochemical process that releases energy in the form of ATP

from glycogen and glucose

anaerobic process (in the absence of oxygen)

The products of glycolysis (per molecule of glycogen):

- 2 molecules of ATP

- 2 molecules of pyruvic acid

The by-product of glycolysis (per molecule of glycogen):

- 2 molecules of lactic acid


Anaerobic Threshold The exercise intensity at which lactic acid begins to accumulate within

the blood The point during exercise where the person begins to feel discomfort

and burning sensations in their muscles Lactic acid is used to store pyruvate and hydrogen ions until they can

be processed by the aerobic system


The Anaerobic Glycolytic System cont. Starts when:

– the reserves of high energy phosphate compounds fall to a low level

– the rate of glycolysis is high and there is a buildup of pyruvic acid


Substrates for the anaerobic energy system

The primary source of substrates is carbohydrate

Carbohydrates: – primary dietary source

of glucose

– primary energy fuels for brain, muscles, heart, liver


Glucose stored in blood

Glycogen stored in muscle or liver

Complex Carbohydrates

Digestive system

Glycogen

Gluconeogenesis

Circulation of glucose around body

Glucose

Blood Stream

Carbohydrate breakdown and storage


Effect of Training on the Anaerobic Glycolytic System

Rate of lactic acid accumulation is increased in the trained individual

This rate can be decreased by:

a) reducing the rate of lactate production - increase in the effectiveness of the aerobic oxidative system

b) increasing the rate of lactate elimination

- increased rate of lactic acid diffusion from active muscles

- increased muscle blood flow

- increased ability to metabolize lactate in the heart, liver and in non-working muscle

Oxygen Energy System




Sporting events:

Advantages:

Limiting factors:

Glycogen, glucose, fats, proteins

> 3 min

Lung function, max.blood flow, oxygen availability, excess. energy demands

Walking, jogging, swimming,

walking up stairs

Large output of energy over a long period of time, removal of lactic acid

The Aerobic Oxidative System Overview


Aerobic Oxidative System

ADP + Pi ATPADP + Pi ATP

ENERGYENERGY

Carbon Dioxide

Carbon Dioxide WaterWater

GlycogenGlycogenO2O2

ProteinProtein

FatFat


The Aerobic Oxidative System

The most important energy system in the human body Blood lactate levels remain relatively low (3-6mmol/L bl) Primary source of energy (70-95%) for exercise lasting longer than 10

minutes provided that:

a) working muscles have sufficient mitochondria to meet energy requirements

b) sufficient oxygen is supplied to the mitochondria

c) enzymes or intermediate products do not limit the Kreb’s cycle Primary source of energy for the exercise that is performed at an

intensity lower than that of the anaerobic oxidative system

Glucose

Plasmamembrane

Extracellular fluid

09.06 Aerobic Respiration Overview

Slide number: 6

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Mitochondrion

Cytoplasm

PyruvateGlycolysis

ATP

NADH

ATP

H2O

O2

Electron transport system

ATP

NADH

CO2

Krebscycle

NADHAcetyl-CoA


The Oxidative Phosphorylation System

Two Pathways: Krebs Cycle & Electron Transport Chain

Biochemical process used to resynthesize ATP by combining ADP

and P in the presence of oxygen

Takes place in mitochondrion (contains enzymes, co-enzymes)

Energy yield from 1 molecule of glucose is 36 ATP molecules

Energy yield from 1 molecule of fat up to 169 ATP molecules

By-products of this reaction: carbon dioxide, water

INTERACTION OF ENERGY SYSTEMS

Immediate Short-term Long-term

Energy Systemsfor Exercise

Energy SystemsEnergy Systems Mole of Mole of ATP/minATP/min

Time to Time to FatigueFatigue

Immediate:Immediate: ATP - PCr ATP - PCr

(ATP & phosphocreatine)(ATP & phosphocreatine)44 5 to 10 sec5 to 10 sec

Short Term:Short Term: Glycolytic Glycolytic

(Glycogen-Lactic Acid)(Glycogen-Lactic Acid)2.52.5 1 to 2 min1 to 2 min

Long Term:Long Term: Oxidative Oxidative 11Unlimited Unlimited

timetime


Summary of the three energy systemsCharacteristic High energy phosphate Anaerobic glycolytic Aerobic oxidative

Other names phosphagen, ATP/CP lactic acid steady stateFuel source(s) stored ATP, PC stored glycogen, blood

glucoseglycogen, glucose, fats,

proteinsEnzyme sytem used in breakdown

single enzyme single enzyme multiple enzymes

Muscle fibre type(s) recruited SO, FOG, FG SO, FOG, FG depends on level of effortPower output requirement high high lowMetbolic byproducts ADP, P, C lactic acid CO2, H2Omaximum rate of ATP production (mmol/min)

3.6 1.6 1

Time to maximal ATP production

1 sec 5-10 sec 2-3 min

Maintenance time of maximal ATP production

6-10 sec 20-30 sec 3 min

Time to exhaustion of system 10 sec 3040 sec 5-6 minATP production capacity (mol) 0.6 1.2 theoretically unlimited

Relative % ATP contribution to efforts of 10 sec

50 35 15

Relative % ATP contribution to efforts of 30 sec

15 65 20

Relative % ATP contribution to efforts of 2 min

4 46 50

Relative % ATP contribution to efforts of 10 min

1 9 90

Time for total recovery (sec) 3 min 1-2 hr 30-60 minTime for one half recovery (sec)

20-30 sec 15-20 min 5-10 min

Ultimate limiting factor(s) Depletion of ATP / creatine phosphate stores

Lactic acid accumulation resulting from production

exceeding buffer capacity.

Depletion of carbohydrate stores, insufficient oxygen,

heat accumulation


The Role of Three Energy Systems During an All-out Exercise Activity of Different Duration


Factors Affecting Physical Performance

Somatic Factors Nature of the Work Psychic Factors Environmental FactorsSex Intensity Attitude DietAge Duration Motivation Temperature

Body distribution Technique (efficiency) Air pressure (hypobaric and hyperbaric)State of health Body position Air pollution

Drugs Mode NoiseStrength Type

Fibre type distibution Work:rest schedule

ENERGY REQUIREMENTS AND SOURCE OF ENERGY FOR SKELETAL MUSCLE

( Resting vs. Working)

ATP Use in the Resting Muscle Cell

ATP is necessary for cellular housekeeping duties, e.g.:– ATP is used for glycogenesisglycogenesis (storage form of

glucose)– ATP is used to create another energy storage

compound called creatine phosphatecreatine phosphate

Resting Muscle and the Krebs Cycle

Resting muscle fibers typically takes up fatty acids from the blood stream.

Inside the muscle fiber, the FA’s are oxidized (in the mitochondriamitochondria) to produce Acetyl-CoAAcetyl-CoA & several molecules of NADH and FADH2

Acetyl-CoA will then enter the Krebs cycle Krebs cycle (in the mitochondriamitochondria) CO2, ATP,ATP, NADH, FADH2, and oxaloacetate

NADH and FADH2 will enter the Electron Transport the Electron Transport Chain. Chain. (in the inner mitochondrialmitochondrial membrane) synthesis of ATPATP

Figure 10–20a

ATP use in Working Muscle

As we begin to exercise, we almost immediately use our stored ATP

For the next 15 secondsnext 15 seconds or so, we turn to the creatine-phosphate.

This system dominates in events such as the This system dominates in events such as the 100m dash or lifting weights.100m dash or lifting weights.

Working Muscle After the phosphagen system is depleted, the muscles must

find another ATP source. **The process of anaerobic metabolism anaerobic metabolism can maintain ATP

supply for about 45-60s.about 45-60s. Glycogen Glucose 2 pyruvic acid pyruvic acid (2 ATP + 2 NADH) 2 Pyruvic acid 2 lactic acid lactic acid (2 NAD+) Lactic acid diffuses out of muscles blood taken by the

liver Glucose (by gluconeogenesis) blood taken by the muscle again

* * It usually takes a little time for the respiratory and cardiovascular systems to catch up with the muscles and supply O2 for aerobic metabolism.

Muscle Metabolism

Figure 10–20c

Anaerobic Metabolism, continued…

Anaerobic metabolism is inefficient… Why?Anaerobic metabolism is inefficient… Why?– Large amounts of glucose are used for very small ATP

returns.– Lactic acid is produced whose presence contributes to

muscle fatigue

Which type of sports uses anaerobic metabolism?Which type of sports uses anaerobic metabolism?– Sports that requires bursts of speed and activity, e.g.,

basketball.

Aerobic Metabolism Occurs when the respiratory and cardiovascular

systems have “caught up with” the working muscles.– Prior to this, some aerobic respiration will occur thanks

to the muscle protein, myoglobinmyoglobin, which binds and stores oxygen.

During restrest and light to moderate light to moderate exercise, aerobic metabolism contributes 95% of the necessary ATP.

Compounds which can be aerobically metabolized include:– Fatty acids, Fatty acids, Pyruvic acid (made via glycolysis), and

amino acids.


Cori Cycle

Lactic acid is taken to the liver to be metabolized back into pyruvic acid and then glucose

GlucoseGlucose

GlycogenGlycogen

LactateLactate

GlucoseGlucose

GlycogenGlycogen

LactateLactate

Blood Glucose

Blood Lactate

Glucose alanine cycle


The Power Of The Aerobic System

Evaluated by measuring the maximal volume of oxygen that can be consumed per kilogram of mass in a given amount of time

This measure is called aerobic power or VO2 max (ml/min/kg) Factors that contribute to a high aerobic power:

a) arterial oxygen content (CaO2)- depends on adequate ventilation and the O2-carrying capacity of

bloodb) cardiac output (Q = HR x stroke volume)- increased by elevation of the work of heart and increased

peripheral blood flow

c) tissue oxygen extraction (a-vO2 diff)- depends upon the rate of O2 diffusion from capillaries and the rate

of O2 utilization


The Substrates for the Aerobic System

Carbohydrates ( glycogen and glucose) and fats (triglycerides and fatty acids)

Fats:– found in dairy products, meats, table fats, nuts, and

some vegetables– body’s largest store of energy, cushion the vital organs,

protect the body from cold, and serve to transport vitamins

– each gram of fat contains 9 calories of energy


Effect of Training on Aerobic Systems

Endurance training is the most effective method (long duration several times per week):

- increases vascularization within muscles

- increases number and size of mitochondria within the muscle fibres

- increases the activity of enzymes (Krebs cycle)

- preferential use of fats over glycogen during exercise

Endurance training increases the max aerobic power of a sedentary individual by 15-25% regardless of age

An older individual adapts more slowly

Aerobic or Anaerobic?


Discussion Questions:

1. What are the differences between the 3 energy systems?

2. List one advantage and one disadvantage of each of the 3 energy systems.

3. Give an example of three activities or sports that use each of (a) the high energy phosphate system, (b) the anaerobic glycolytic system, and (c) the aerobic oxidative system as their primary source of energy (one sport for each energy system).

4. What is the most important source of fuel in the body for all types of energy production - a substance also known as the energy currency of the body?

5. Define ATP turnover and ATP resynthesis.

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