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
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