Food is eaten andconverted to fuel/waste fuel is transported in the blood and can be

used direct from the blood (glucose, free fatty acids) or stored for future use (glycogen in muscles,triglycerides in fat cells)

These fuels provide the energy needed for the re-synthesis of ATP in the aerobic energy system(glycogen is also used in anaerobic glycolysis ie:the Lactic Acid System)

is stored in muscles is made up of one adenosine molecule and three phosphate molecules the splitting of one of the phosphate

molecules produces the energy required for muscular contraction and leaves behind ADP and one free phosphate

are there to re-connect the free phosphate OR create a new phosphate to replace the one used. So the energy systems re-synthesise ATP

the blood borne and stored fuels are used to provide the energy for that re- synthesis (glucose, free-fatty acids glycogen, triglycerides, creatine-phosphate, adipose fat)

Circulatory/Respiratory systems•Volume of left ventricle increases after aerobic training•Hypertrophy of the left ventricle occurs after anaerobic training•Capillary network of the lungs increases•Haemoglobin count (in blood) increases•Elasticity of lungs improves•Lung volumes increase

Aerobic training effects at the working muscles•Capillarisation to muscle increases•Mitochondria increase in size and number•Myoglobin concentration increases•Triglyceride stores increase•Glycogen stores increase•Oxidative enzymes increase

Anaerobic training effects at the working muscles•Hypertrophy of the muscle occurs (mainly reflecting an increase in the size of the fast-twitch fibres)•Glycogen stores increase•Glycolytic enzymes increase in number•Capillarisation increases•Phospho-creatine stores increase•Muscle stores of adenosine triphosphate increase•Production of lactic acid at sub-maximal workloads falls•Speed and force of contraction increases•Connective tissue strength (tendons and ligaments) increases

Increased lung volume means more air in lungs therefore more O2

available to the bloodIncreased haemoglobin in blood means greater potential for O2 absorption into the

bloodBroadened network of capillaries on lungs means bigger surface area for direct contact

between blood and the O2 in the lungs

Cardiac hypertrophy means thicker/stronger heart walls & larger left

ventricular chamber a greater stroke volume

a greater volume of blood can be pumped with the same number of beats at rest, the heart will beat fewer times

Increased stroke volume means maximum cardiac output (Q) is increased potential VO2 maximum increase

Increased myoglobin concentration in the muscles meansgreater potential for O2 extraction from blood, therefore

increased a-VO2 difference

Increased size & number of mitochondria in the muscles means

greater potential for aerobic re-synthesis of ATP as there are more aerobic energy production sites and each can produce more

Increased glycogen storage in muscles means more immediately available fuel for ATP re-synthesis

(both aerobic & anaerobic)

Increased concentration of glycolytic enzymes means

greater potential for immediate glycolysis (Lactic Acid System)

therefore less demand on PC stores (ATP-PC system)

more efficient activation and ongoing energy production by the Aerobic system

When we exercise, the most efficient way of re- synthesising ATP is through our aerobic system, where O2 is used and the muscles during the re-synthesis

The O2 needed comes from the blood The changes mentioned provide for

…greater O2 absorption into the blood…and therefore, increased volume of O2 delivery to muscles…and also, increased extraction of O2 by the muscles

…and that makes for greater aerobic fitness as shown by a higher VO2 max

being able to exercise at the same level of performance for longer periods before fatiguing being able to work at a higher level of performance for at least the same period of time being able to work at higher level of performance without crossing the lactate threshold

reducing the need to use the lactic acid system more efficient energy production at higher levels of performance and therefore less stress on the body greater potential for using fat as an aerobic fuel source instead of glycogen (glycogen sparing), so also greater potential for extended surges of effort (eg: end of race or late in the match) which rely predominantly on the lactic acid system

being able to recover more efficiently (quicker) in terms of systems returning to resting levels (breathing, HR, fuel storage, ATP levels, blood lactate)