2. ADENOSINE TRIPHOSPHATE AND
PHOSPHOCREATINE / CREATINE
PHOSPHATE (ATP-PC/CP)
• High power x short duration.
• Energy system that provides immediate energy (by breaking down of these stored
high energy phosphates).
• If this energy system is 'fully stocked' it will provide energy for maximal intensity,
short duration exercise for between 10-15 seconds before it fatigues.
• First few seconds of exercise regardless of intensity, ATP-PC system is relied on
almost exclusively, with energy coming from the breakdown of the ATP stores within
the muscles.
3. •PROS: Provides the most 'power' =
produces ATP more quickly than any
other system & fuels all very high
intensity activities.
•CONS: It burns out very quickly.
4. ON THE BACKGROUND: ATP
• ATP must be present for muscles to contract. Produced via ATP-PC system,
glycolytic system, or oxidative system. If depleted, it must be replenished if further
muscle contraction is to continue.
• Under anaerobic system, with Lactic acid.
• All energy systems work together, but the intensity and type of activity is the one
that determines which system is predominant.
• ATP is the usable form of chemical energy for muscular activity. It is stored in most
cells, particularly in muscle cells. Other forms of chemical energy, such as those
available from food, must be transformed into ATP before they can be utilized by the
muscle cells.
5. THE ATP-PC ENERGY SYSTEM
• Phosphagen system.
• Immediate and functions without oxygen.
• ATP - High energy molecule which is broken down to form Adenosine Diphosphate
(ADP) and release energy.
• PC: - High energy molecule, found in the sarcoplasm of muscle fibres.
• The breakdown of ATP and so increase in volume of ADP triggers an enzyme
known as Creatine Kinase to initiate the breakdown of PC into Phosphate and
Creatine. Being an exothermic reaction, this provides the energy required to
resynthesize ATP at a fast rate.
6. • - ATP stores last only a few seconds after which the breakdown of PC provides
energy for another 5-8 seconds of activity.
• - Combined, the ATP-PC system can sustain all-out exercise for up to 10-15
seconds and it is during this time that the potential rate for power output is at its
greatest.
• - Replenished after about two minutes rest.
• - We only have 120g of Creatine within our bodies and so this repeated breaking
down of PC in order to produce energy to resynthesise ATP is temporary and can
only last a maximum of 10 seconds.
• - ATP-PC system is used mainly for bursts of speed.
7. HOW DOES THE ATP-PC SYSTEM
WORK?
STEPS:
1. ATP in the myosin cross-bridges (microscopic contractile parts of muscle) is broken
down to release energy for muscle contraction. This leaves the by-products of ATP
breakdown: adenosine diphosphate (ADP) and one single phosphate (Pi) all on its
own.
2. Phosphocreatine (PC) is then broken down by the enzyme creatine kinase into
Creatine and Pi.
3. The energy released in the breakdown of PC allows ADP and Pi to rejoin forming
more ATP. This newly formed ATP can now be broken down to release energy to fuel
activity.
8. Examples of training that focuses primarily
on the ATP-PC system:
- Lifting the heaviest weight you possibly can for one or two repetitions.personal
training stopwatch
- Sprinting as fast as you can for 50 – 100 meters with 2-3 minute recovery
intervals before repeating.
- Punching a boxing bag as hard as you possibly can for 2 – 3 punches.
- Getting up out of your chair to go and make a coffee (alright it’s not really
‘training’ but as it requires immediate energy for movement the energy comes
exclusively from the ATP-PC system).
9. REMINDERS:
• Conditioning the ATP-PC system you must build in adequate rest and stop the session if the
quality of the movements or their power decreases significantly.
• When this happens you are starting to work on power endurance (as fatigue is evident) and
that is counter productive if your goal is purely to increase the ATP-PC system's capacity.
• For example, if you were training to increase your explosive leaping ability (say for
basketball) by jumping as high as you could you would notice that after two or three leaps
the next leap may not get you the same height.
• You would then stop and rest as your ATP-PC system is depleted. If you continue you will
be starting to train endurance which will be counterproductive to developing explosive
leaping power.
