energy systems

Note by , created over 6 years ago

Physical Education Note on energy systems, created by hazellafernando on 05/18/2013.

Created by hazellafernando over 6 years ago
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Page 1

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 



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


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 lactatewhen 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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