Energy Systems

During exercise the body uses up large amounts of energy in three different ways. The ATP/CP system, anaerobic system and the Aerobic system all combine during periods of exercise to allow our bodies to continue exercise or playing sport. Most sports have a major system which takes up the bulk of the energy production during the activity and the timing in switching from one to another. This plays a major role in success in the playing arena. In a sport such as Australian Rules football it is important that the systems can switch back and forth between one another. Whilst in marathon running or 100m sprinting one system provides the bulk of energy production. This is why training energy systems to function at an optimal level is so important when striving to become an elite athlete.

The three energy systems work as follow. The ATP/PC system last for around 10 secs and requires no oxygen. This system is when the phosphate from phosphocreatine (PC) is broken away and joins with Adenosine Diphosphate (ADP) to form Adenosine Triphosphate (ATP). The ATP/PC produces no waste product which is a benefit. The Anaerobic Glycolysis/Lactic Acid System takes over once the alactic threshold is reached. The lactic acid system relies on glycolysis which is the break down of carbohydrates into glucose. Glycolysis occurs without oxygen and produces 2 ATP molecules. It unfortunately produces lactic acid as a waste product which has to be cleared to avoid muscle fatigue. After roughly 4 minutes the Aerobic system takes full effect of energy production. This system use proteins, carbohydrates and fats to resynthesize ATP molecules. The difference between this cycle and the Lactic acid system is because oxygen is required to complete the break down of glucose, with no lactic acid production, instead carbon dioxide and water are produced which are much easier to remove. This system can be used continuously for extended periods of time and yields at total 38 molecules of ATP pre glucose molecule.

ATP/CP system ATP Re-synthesis

Lactic Acid System Aerobic System

With these three energy systems providing the drive for your body it is important to be able to train them, specialize for your sport. For example, a marathon runner would receive minimal gain in competition if he or she trained their ATP/CP system to a high level because this system only provides energy to the body for roughly 10 seconds. A marathon runner would receive a much better gain in competition if the aerobic energy system was trained to a higher level. Because a marathon takes longer than 2-3 minutes the event primarily uses the aerobic system. At the beginning of the event the ATP/CP would begin before switching to the aerobic system quickly. The lactic acid system would come in when the athlete bursts to pass an opponent or to sprint home in the final stages. Therefore a marathon runner would be much better suited to train his/hers aerobic system to achieve the best result. A runner of any long distance would benefit from this and can train the aerobic system in multiple ways. To improve all systems it is best to undergo progressive overload to keep the body improving. To train your aerobic system the body should be working at 70-80% of maximum HR for a prolonged period of time (more than 30 minutes). In most average people their heart rate will be between 142-162 bpm, however in elite athletes their resting heart rate will be lower and maximal heart rate will be higher, so in their case they would have to work at a higher rate and have a higher heart rate to achieve results.

The best type of training for the aerobic system is continuous training. This training must go for at least 15 minutes and can last up to an hour. The aim is to reach the zone for inducing cardiovascular effect which is between 70-80% of max heart rate. The intensity should remain below the anaerobic threshold so to not cause an overload of lactic acid in the muscle which would fatigue the muscles. Some examples of continuous training are swimming, cycling, rowing, jogging and running. Obviously the best way for a marathon runner to train their aerobic system is to jog and run because not only does it train the energy system it is the type of event they will be competing so it would be possible to concentrate on other components in the sport whilst training. A good example would be running style or technique, if a change in technique has been made by coach, the athlete would be able to become more accustomed to it whilst training the aerobic energy system. To continue training and still improve the athlete must continue to increase work load and under go a progressive overload. This stops the body allows the body to keep improving at a consistent level. For the marathon runner, timing practice runs is a good place to start. Once the athlete begins to finish the runs in faster times, it is time to increase distance or decrease target time to keep the body improving. To build muscular endurance weights are an excellent training method. The best weights session for muscular endurance is one where the athlete is lifting 40-60% of maximum weight, with 25-40 reps and 2-5 sets. This will increase your muscle endurance which will help improve overall running times.

Another very popular sport in Australia is Australian Rules football (AFL). The game requires you to not only have very good skills but at elite levels have a high level of fitness as well. Unlike marathon running which uses one energy system for the majority of the event, AFL uses a mixture of all three energy systems consistently through out a game. Some players cover up to 30 kilometres a game in running so it is very important to have a solid base of aerobic fitness as a foundation. Through out the game players are required to make multiple efforts at the ball. Whilst these sprints are only small with usually a max of 30 metres, a player may still be required to do upwards of 50 of these sprints in one game. This means for a player to reach the elite level speed as well as endurance are both vital parts of a footballer’s skills. Of course the level of endurance vs. speed also varies from each position. An onballer or follower is required to follow the ball continuously around the ground and therefore need a much higher aerobic capacity to cover more ground. A player who plays a more stationary position such as fullfoward needs to be able to sprint away from his opponent on a lead multiple times in a game. Once the ball is cleared away from the forward 50 a forward can rest until the next forward thrust. A Forward also needs greater muscular strength