2. PHOSPHOCREATINE
• Phosphocreatine allows the making of small quantities of ATP extremely rapidly, this boosts short duration activities.
Muscles are much less prone to fatigue and the capacity to undertake strenuous exercise is increased. Activities such
as repetition weight training, short sprints, and repeated jumping are all enhanced and therefore the quality of
training increases which allows higher competitive performances.
• Creatine is both made by the body (from amino acids arginine, glycine and methionine) and gained from the diet. It
occurs naturally in meats and fish. An athlete who is eats a lot of meat may have in his muscle five grams of creatine
per kilogram of muscle, which is near the limit. This same athlete must take in approximately 2.5g of creatine per
day to replace the natural degradation of creatine that takes place each day.
• In this process, ATP is usually made without the presence of oxygen. Explosive work can be achieved, but only for
short periods (up to about 10 seconds) at maximum intensity, as the supply of PCr is very limited.
• Creatine phosphate is readily available to the cells and rapidly produces ATP. It also exists in limited concentrations
and it is estimated that there is only about 100g of ATP and about 120g of creatine phosphate stored in the body,
mostly within the muscles. Together ATP and creatine phosphate are called the high-energy phosphogens
• ADP + creatine phosphate --> ATP + creatine
3. TWO FACTORS OF ANY ACTIVITY CARRIED OUT AFFECT ENERGY SYSTEMS MORE THAN ANY
OTHER VARIABLE THEY ARE THE INTENSITY AND DURATION OF EXERCISE. HERE IS A LIST OF
SPORTS AND APPROXIMATELY HOW THE EACH OF THE ENERGY SYSTEMS CONTRIBUTES TO
MEET THE PHYSICAL DEMANDS:
GOT THIS PICTURE FROM -
HTTP://GLOXDALEBTECSPORT.BLOGSPOT.CO.UK/2011/06/ENERGY-SYSTEMS.HTML
4. LACTIC ACID SYSTEM
• This is the short-term energy system. To meet energy requirements for higher intensity over a long period, such as during a 400-
metre race, ATP can be made by the partial breakdown of glucose and glycogen. This is an anaerobic process (it does not include
oxygen) and therefore is not sustainable over a long duration. Around 60 to 90 seconds of maximal work is possible using this
system.
• Lactic acid is the limiting factor of the anaerobic system. it goes into the tissue fluid and blood. if this substance is not removed by
the circulatory system, it builds up to stop muscle contraction and cause fatigue. This happens during intense exercise as an
uncomfortable burning sensation in your muscles.
• Glucose --> 2ATP + 2 lactic acid + heat
• Glycogen --> 3 ATP + 2 lactic acid + heat
• Light activity such as walking or jogging following intense efforts speeds up the removal of lactic acid. The first ten minutes of active
recovery produces the greatest reduction in lactic acid levels.
• Not enough oxygen may reach the muscles during exercise. When this happens, they use anaerobic respiration to obtain energy.
• Anaerobic respiration involves the incomplete breakdown of glucose. It releases around 5% of the energy released by aerobic
respiration, per molecule of glucose. The waste product is lactic acid rather than carbon dioxide and water:
• glucose → lactic acid (+ little energy)
• Muscles become fatigued (tired) during long periods of vigorous activity. This means that they stop contracting efficiently. One
cause of this is the build-up of lactic acid in the muscles from anaerobic respiration. The lactic acid is removed from the muscles by
blood flowing through them.
5. HERE IS A SPORT WHERE LACTIC ACID
HITS ATHLETES THE MOST… THE 400M
6. AEROBIC ENERGY SYSTEM
• The aerobic system produces far more ATP than either of the other energy systems but it produces the ATP much more slowly, therefore it cannot fuel
intense exercise that demands the fast production of ATP.
• While the aerobic system doesn’t produce nearly as much power as the other systems, a major feature is its capacity which is virtually limitless, as it just
keeps on producing ATP.
• The aerobic system consists of three processes or ‘stages’ each of which produce ATP.
• These stages involve more complex chemical reactions than the other energy systems which is why ATP production is much slower. (The more complex the
process - the longer it takes to produce ATP)
• The three stages are:
• 1. Aerobic glycolysis (slow glycolysis)
• 2. Krebs cycle (also known as the citric acid cycle)
• 3. Electron transport chain
• Aerobic sports – jogging, marathons and cycling
