Energy Systems

Energy Systems

Storage of Food Fuels in the Body

Digestion 101

http://www.youtube.com/watch?v=q3986Yfl5cU

The Animal Cell

ATP Requirements

ATP Requirements of 70kg male in a 24 hr period

Amount of Stored ATP available 50g Required ATP in 24hr period

190kg

ATP and Muscle Contraction

Adenosine Triphosphate MoleculeChemical Structure

Adenosine Triphosphate

adenosine Pi PiPi

Adenosine Triphosphate Molecule: the bonds between the phosphate molecules break – energy is liberated.

End product = ADP (Adenosine Diphosphate)+ Free Phosphate Molecule

Energy SystemsThe systems used to resynthesis of ATP depend on a number of factors including:

•Duration•Intensity•If sufficient level of oxygen is present•Urgency of energy required•Athletes level of training

The Energy SystemsThe Energy Systems and their alternative names

1. The ATP-PC Energy System Alactacid System Creatine Phosphate or Phosphate Creatine System Phosphagen system

2. The Lactic Acid Energy System Anaerobic glycolysis Lactacid System

3. The Aerobic Energy System Oxygen system Aerobic glycolysis

The ATP-PC Energy System

Quickest ENERGY system – simple chemical reactions that occur in the cytoplasm of the cell

Breaks down phosphocreatine (PC) to form ATP anaerobically.However, PC stores require time to replenish.Dominant system for the first 10-15 seconds of high intensity exerciseUsed in fast, powerful movements.

PC releases a free phosphate

The ATP-PC Energy System

The LACTIC ACID Energy System

Activated at the start of intense exercise:

• More complex reactions than the ATP-PC system – occurs in the cytoplasm

• Peak power until it fatigues (2-3 minutes)

• Predominant energy supplier in events 85% of maximum Heart Rate eg. 200m sprint.

The LACTIC ACID Energy SystemGlycogen is broken down in the absence of sufficient levels of oxygen at the cell site (Anaerobic glycolysis)

The lactic acid system provides twice as much energy for ATP resynthesis than the ATP-PC system.

This produces a fatigue causing by product called lactic acid.

Lactic acid makes the muscle pH decrease (More acidic), reducing ATP resynthesis.

The LACTIC ACID Energy System

ANAEROBIC Respiration

The AEROBIC Energy SystemThe aerobic system

Slowest contributor to ATP resynthesis – occurs in the MitochondriaProduces more ATP than the two anaerobic pathwaysBecomes the predominant pathway for ATP production once the lactic system decreases.Major contributor in prolonged exercise eg. Endurance events.Aerobic system does contribute in maximal intensity exercise (Eg. Between 55-65% in 800m)

Comparison of Aerobic and Anaerobic Glycolysis

Interplay of the Energy Systems All energy systems start contributing ATP at the onset of work. At different times during the activity one energy pathway will be the

predominant pathway for generating ATP. The predominant pathway depends upon the intensity and duration of

the work phase.

Oxygen Uptake & Delivery

Oxygen Deficit The period after the onset of exercise where the ATP demands are

being met via anerobic pathways

The available oxygen is less than that required to produce all the ATP via aerobic pathways

Oxygen Uptake & DeliverySteady State A period of time where oxygen supply to the working muscles equals

the demand of the muscle

A steady state can occur at various stages throughout an event in response to the oxygen demands until the intensity reaches a point where the body cannot deliver enough oxygen to the muscles to meet the demand.

Oxygen Uptake & DeliveryEPOC (Excess Post Exercise Oxygen

Consumption) An activity performed at a lower intensity will have a longer steady state

and a smaller oxygen debt

A person who has undertaken aerobic training will be able to: Consume a greater amount of oxygen during steady stateThe anaerobic pathways contribute less to work in the early stages of

the event.

Oxygen Uptake & Delivery

EPOC (Excess Post Exercise Oxygen Consumption)

The oxygen that is consumed above resting levels to deliver to the working muscles in response to anaerobic work.

There are two components to EPOC – alactacid debt and lactacid debt The body can repay the debt simultaneously

Oxygen Uptake & DeliveryAlactacid debt – replenishing the Creatine-Phosphate stores (Passive recovery)

Lactacid debt – involves the removal of the lactic acid (active recovery)