Christian Alliance S C Chan Memorial College

Physical Education Department

F.3 Theory – Energy Systems

The Importance of ATP

Energy for muscle contraction comes from the breakdown of a chemical compound named adenosine triphosphate (ATP)

The breakdown of ATP releases energy which stimulate muscles to work

Sources of ATP

1.Protein – used to produce ATP only under prolonged starvation condition

E.g. people compete in marathon running events

2.Carbohydrates – are broken down to glucose and stored as glycogen in muscles and liverChemical reactions involving glucose produce ATPIf excess carbohydrate, it is converted to adipose and stored

3.Fats – broken down to fatty acids and triglycerides

Fatty acids are stored as adipose (fat) tissue or circulate in blood

Triglycerides are stored in the muscles and these can produce ATP through chemical reactions

Chemical systems that produce ATP

Three WaysBy the Stored Phosphagens (ATP & PC System)

By the Lactic Acid (Anaerobic) System

By the Aerobic System

ATP production during resting conditions (Aerobic System)

ATP is produced aerobically

Glucose + oxygen or triglycerides + oxygen to release ATP

ATP production during exercise

During exercise, the energy system being used to produce ATP depends on how long you have been exercising, and at what intensity

ATP production during exercise

The ATP-PC SystemATP stored is broken down to release energy for contraction

Exhausted after about 10 seconds (provides energy for tasks of only about 0-10 seconds duration

The CP and the stored ATP are restored after about two minutes’ rest

ATP production during exercise

The Lactic Acid SystemGlucose is converted to lactic acid, giving ATP

Lactic acid is slowly removed and broken down into carbon dioxide and water; it is toxic in large amounts and produces fatigue

This system provides energy for a high-intensity task of 30-seconds to 2-minutes duration (submaximal exercise)

ATP production during exercise

The Aerobic SystemUses glucose (main) or triglycerides to release energyProvides energy for muscle contraction for low-intensity tasks lasting five-minutes or moreProduce far more ATP than does the lactic acid system, but does not produce toxic waste

Energy sources for particular sports

The energy sources needed for each sport are specific to the sport being played; its duration and its intensityE.g. The 5000m Race:First 10 sec.: ATP/PC system10sec – 30sec: transition from ATP/PC to Lactic Acid System2-5min: Transition from Lactic Acid system to aerobic system5+min: Aerobic systemFinal sprint: combined aerobic / lactic acid system

The energy continuum and various sports activities

Although both aerobic and anaerobic energy systems contribute some ATP during the performance of various

sports, one system usually contributes more.

Aerobic System (In the order of higher percentage)Marathon > 10000m Run > 10000m Skating > 3-mile Run > 2-mile Run > 1-mile Run > Rowing (2000m) > Boxing > 800m Dash > Field Hockey > Tennis > 100m Swim > Fencing > Wrestling and Ice hockey > Weight-lifting, Diving, Gymnastics, 200m Dash

Anaerobic System (In the order of higher percentage)

100m Dash, Golf and tennis swings, American football > Basketball, baseball, volleyball, skating (550m), 400m Dash > Soccer > 200m Swim, Skating (1500m) > 1500m Run > 800m Swim > Cross-country running > Cross-country skiing > Jogging

The End