Sources of Energy for Exercise Kevin Browne

The human body is made to move in many ways:• Quick and powerful• Graceful & coordinated• Sustained for many hours

And is dependent upon the capacity to produce energy

We have a great amount of diversity

• Quick movements-lasts a few seconds• Reduced speed-lasts for several minutes• Reduced intensity(50%)-lasts for several

hours

The body uses different energy systems for each activity

Cells don’t get Energy directly from food, it must be broken down into:

ATP-Adensosine TRIphosphate

ATP = a form of energy one can immediately use, it is needed for cells to function & muscles to contract

Energy Sources

•From Food:▫CHO = 4 kcal▫Fat = 9 kcal▫Protein = 4 kcal

•For Exercise:• ATP ADP + P +

energy (for muscle contraction)

Energy Systems

ADENOSINE TRI-PHOSPHATE (ATP) is the UNIVERSAL ENERGY CURRENCY for humans.

ADENOSINE Tri-PHOSPHATE

ADENOSINE Di-PHOSPHATE

High energy bond breaks to release energy

ADENOSINE P P P

ADENOSINE P P

P

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

Predominant Energy Pathways

•ATP (2-3 seconds)

•ATP-CP Energy System (8-10 seconds) (also known as the Alactic Energy system)

•Anaerobic Energy System (2-3 minutes)

•Aerobic Energy System (3 minutes +)

0 sec 4 sec 10 sec 1.5 min 3 min +

Strength – Power:power lift, shot put, golf swing

Sustained Power:sprints, fast breaks, football

Anaerobic Power – Endurance:200-400 m dash, 100 m swim

Aerobic Endurance:Beyond 800 m run

Immediate/short-term Aerobic-oxidativenon-oxidative systems system

Energy Systems

1. Alactic Anaerobic – (without producing lactic acid / without O2)

1ST FUEL THAT IS CALLED UPON TO RESYNTHESIZE

ATP.Utilises Creatine Phosphate / Phosphocreatine (CP or PC)

MAX STORES IN THE BODY (WITHOUT TRAINING) < 10 secs DURATIONTHIS IS THE LIMITING FACTOR FOR;

INTENSITY EXERCISE / DURATION

Energy Systems1. Alactic Anaerobic – (without producing lactic acid / without

O2)

TRAINING – the levels of stored CP in the body can be increased by:

SPEED TRAININGCREATINE LOADING

Both the above delay the use of the lactic anaerobic system

CAN GIVE > 30 secs STORE IN THE BODY.

ATP-CP Energy System

ATP is stored in the muscle & liver for “Quick Energy”

• Nerve impulses trigger breakdown of ATP into ADP

• ADP = Adenosine Diphosphate & 1 Phosphate

• The splitting of the Phosphate bond = Energy for work

Ex. Muscle Contraction, Moving hand from a hot stove, Jumping & Throwing

The ATP Molecule

Adenosine

Adenosine

Energy

a. Adenosine Triphosphate (ATP)

b. The breakdown of ATP:

PP

P

PP P

ATP = ADP + energy for biological work + P

(ADP = Adenosine Diphosphate)

Energy for cellular function

For contractions to continue… ATP must be REBUILT

This comes from the splitting of CP (Creatine Phosphate a Hi energy source, automatic)

When ATP is used – it is rebuilt – as long as there is CP

Energy released from CP breaking down, resynthesizes the ADP & P

REMEMBER – only small amounts of ATP are stored = only 2-3 sec. of Energy

ATP-CP = 8-10 sec. of Energy

The usefulness isn’t the AMOUNT of Energy but the QUICK & POWERFUL movements

For longer periods of work = The Aerobic & Anaerobic Energy System must be utilized

The Immediate Resynthesis of ATP by CP

Creatine

P

Creatine P

Energy

High energy bond

a. Creatine Phosphate (CP)

b. CP = Creatine + energy for resynthesis of ATP + P

Adenosine PP

P

c. ADP + energy from CP + P = ATP (reversal of ATP = ADP + P + energy for work)

Anaerobic Energy System• Without oxygen = Activities that require a

large burst of energy over a short period of time

• Anaerobic Glycolysis = Production of ATP from Carbohydrates without oxygen

(breakdown of glucose)

Since glycogen is stored in the muscle & liver, it is available quickly

This system provides ATP when ATP-CP runs out

Again, ATP-CP lasts for a few seconds, the Anaerobic Energy System allows for 2-3 minutes of work

1.The process to produce ATP is not as fast as ATP-CP, which makes muscle contraction slower

2.When oxygen is not present the end product of glycolisis is lactic acid, which causes the muscles to fatigue

3.Anaerobic Glycolisis is less efficient in producing ATP than Aerobic Glycolisis, BUT is needed for a large burst of energy lasting a few minutes

Oxygen Deficit = The body can not supply enough O2 to the muscles that the muscles demand

•When the muscle does not get enough oxygen, exhaustion is reached causing immediate and involuntary reduction in intensity

Oxygen Debt = “pays back” the deficit

recovery time

Aerobic Energy System

• With Oxygen = Using large muscle groups continuously over a period of time

•Aerobic Glycolisis & Fatty Acid Oxidation = The production of ATP from Carbohydrates & Fat

Energy Systems3. Aerobic – (with O2)

INTENSITY EXERCISE / DURATION

UNLIMITED DURATION at LOW INTENSITY

Uses Glycogen (long chain stores of Glucose) and breaks up into Glucose which can then be used as fuel. Goes through the process of GLYCOLYSIS and into the KREBS CYCLE for complete oxidation of glucose. This creates more ATP.

TASK: MAKE A LIST OF ALL SPORTS PERFORMANCES THAT COULD POSSIBLY UTILISE THIS SYSTEM.

1.O2 enters the system, stopping the breakdown of glycogen to lactic acid

2.With oxygen, glycogen breaks down into: ATP + CO2 + H20

3.These byproducts are easier to get rid of

CO2 is expelled by the lungs

H20 is used in the muscle