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 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: m dash, 100 m swim Aerobic Endurance: Beyond 800 m run Immediate/short-term Aerobic-oxidative non-oxidative systems system

Energy Systems 1. Alactic Anaerobic – ( without producing lactic acid / without O2) 1 ST FUEL THAT IS CALLED UPON TO RESYNTHESIZE ATP. Utilises Creatine Phosphate / Phosphocreatine (CP or PC) MAX STORES IN THE BODY (WITHOUT TRAINING) < 10 secs DURATION THIS IS THE LIMITING FACTOR FOR; INTENSITY EXERCISE / DURATION

Energy Systems 1.Alactic Anaerobic – ( without producing lactic acid / without O2) TRAINING – the levels of stored CP in the body can be increased by: SPEED TRAINING CREATINE 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 Energy a. Adenosine Triphosphate (ATP) b. The breakdown of ATP: P P P P P 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 P Energy High energy bond a. Creatine Phosphate (CP) b. CP = Creatine + energy for resynthesis of ATP + P Adenosine P P 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 Systems 3.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