energy systems

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the three energy systems:

ATP-PC

Anaerobic glycolysis

aerobic system

ATP is needed for muscular contractions

muscular contractions or movement is produced either anaerobically or aerobically

VERY IMPORTANT! any activity carried out above 100% VO2 max depend on anaerobic energy supply

the most rapidly available source of ATP (SO RATE = FASTEST)

NOTE!

That anaerobically means ATP-PC AND Anaerobic glycolysis

interplay:

the three energy systems do not work independently they work together

the three systems are activated at the start of exercise

to determine which energy system is predominant depends on:

the duration of the exercise

the intensity of the exercise

whether or not oxygen is present

the depletion of fuels

At rest our demands for ATP is low however at exercise the demand is much higher

AT THE EARLY STAGES OF EXERCISE: (oxygen deficit)

Blood CAN NOT transport oxygen quickly enough to the working muscles

therefore the body calls upon the anaerobic systems

the anaerobic systems require no oxygen

the ATP-PC system

fuel: creatine phosphate

ATP is already stored in the muscles, and is broken down.

however ATP stored in the muscles can only last for 2-3 seconds

the PC, which is also stored in the muscles, resynethsises ADP+Pi to ATP.

broken down by an enzyme called: creatine kinase

the ATP-PC system does not require oxygen

only predominant for 0-10 seconds

mainly utilized for sports that require quick sharp movements.

when ATP is balanced with resyntheisis it is quite possible that a person could perform at high intensities for a long period of time

ATP

ADP+Pi

step1: ATP is broken down to ADP+Pi

step 2: This would last for about three seconds

step3: the PC stored in the muscles will break down to resynthesis ADP+Pi to ATP

PC

P (energy) C

ADP+Pi ----> ATP

PC will be replenished within 3 minutes after activity finishes with PASSIVE recovery

The anaerobic glycolysis

anaerobic glycolysis refers to the incomplete breakdown of glucose without the presence of oxygen.

there is enough glycogen stored in the muscles to provide the body with energy for 90 seconds, yet maximal activity efforts can be sustained only for about 20 seconds

glucose is broken down further to pyruvic acid, and pyruvic acid is further broken down to lactic acid.

the by-products of this process are hydrogen ions.

the accumlation of hydrogen ions can cause fatigue (increase in muscle acidity)

this can inhibit glycolysis (interupt glycolitic enzymes from breaking down glycogen to glucose)

the hydrogen ions combine with pyruvate to form glycogen

the breakdown of glycogen to glucose produces energy to rebuild ATP.

Lactate Inflection Point: (LIP)

the exercise intensity beyond which lactate production exceeds removal, sometimes referred to as lactate threshold

OR

LIP refers to the movement when the body is unable to prevent the accumalation of hydrogen ions

this occurs around 2-3 mmol/L

OBLA- Onset of blood lactate

when lactate levels reach 4 mmol/L

aerobic system:

aerobic glycolysis refers to energy provided by the complete breakdown of glucose when plenty of oxygen is available

fatty acids and proteins can be broken down if the glycogen stores are depleted

glycogen BREAK down to glucose (energy) is used to re synthesis ATP

aerobic energy production takes even more chemical reactions to produce ATP in comparison to the other aerobic systems

slower rate but greater yeild

when oxygen demand meets oxygen supply the person would of reached steady state

only occurs when a person is working submaximally

when working maximally there is a 50% aerobic contribution at the 75th mark

when there is an accumulation of lactic acid it has the opportunity to be oxidized or removed

fats are not the preferred source of energy as they require high levels of oxygen to be broken down, therefore they are broken down during rest.

if the glycogen stores are depleted then the athlete/individual are forced to drop their intensity because they require more oxygen

by products: co2 heat and water

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