The Aerobic system

A simple scientific description of the aerobic system is the body is at its most efficient when it burns fuel in the presence of oxygen (ie aerobically). As we have seen from the previous information, the distances covered by players in the game and the length of the game, classify soccer as primarily an endurance sport. Aerobic endurance to develop stamina is very important so that players can:

• Work hard throughout a game, with less fatigue - for 69% of the game the players are running at different paces
• Recover quickly between periods of very hard work during a game, such as a series of repeated sprints.
• In soccer terminology "get around the pitch better"

Simply put, a well developed aerobic energy system in a player provides the fitness platform for the player to maintain a high maintain a higher work rate and cover more distance during a game and, therefore, utilise their skills and ability to influence the game more often. They will be in a position to get to the ball quicker and more often. They can pressure and win more tackles and "get round the pitch" better.

Although the aerobic system is very important to develop a players overall endurance and stamina, it isn't very good at providing energy very quickly and when it is needed instantly, i.e a very quick sprint or a sharp change of direction, or a powerful jump. It also takes time to get going or warm up before it works best, which is why it is important that players warm up correctly. Players who are over trained using the aerobic system tend to be very one paced and lack a great deal of power, strength and dynamic mobility

Therefore a fitness programme should also include training to develop the ability to very quickly work hard or fast. As we have seen from the research, players can spend 11% of the game sprinting, with the majority of the sprints lasting less than 7 seconds. In addition players will need to be able to jump to challenge for the ball, turn and sprint, tackle and be strong in body contact situations. In these situations, the body must supply energy anaerobically.

The anaerobic system

A simple explanation of the anaerobic system is that enables the body to supply energy by burning fuel without oxygen to produce energy quickly when needed. The anaerobic system is vitally important for soccer players, but it also is very tiring and takes a lot out of the players.

There are many situations in the game when the body needs to produce a lot of energy quickly (eg tackling, sprinting for a ball or continually sprinting with short rest periods). In these situations, the aerobic energy system cannot supply all of the energy needed, as it cannot provide the energy quickly enough.

Anaerobic fitness is very important so that players can produce short, sharp, intense efforts required throughout a game. It is important that they not only can produce these efforts, but can also recover quickly and repeat them with only short recovery periods. Soccer requires many of these types of intense efforts and these can prove crucial to a player being first to the ball or winning the ball. Improving and developing anaerobic fitness can help players to be able to withstand longer periods of high-intensity work, recover more quickly from these hard efforts and enable them to be able to repeat their efforts again.

The main disadvantage of the anaerobic system is that it takes a real toll on the body and requires time to replace the energy used. Another major problem is that when anaerobic work is prolonged, like in a match, the body produces waste products, such as lactic acid, which leads to fatigue and stops the body working efficiently. One of the symptoms of excess lactic acid is when the legs are very heavy and tired after a game. This is one of the reasons that a proper cool down is conducted, because it enables the body to rid itself of a degree of lactic acid and waste product enabling the player to recover more quickly from a tiring game or training session.

Younger players have a well-developed aerobic system and can readily supply energy in this way. Young players naturally have a high supply of energy and can seem to run for ever. However, in young developing players, the anaerobic system is less mature and not as efficient at supplying energy as quickly as it would to a fully developed player. Young developing players need to take periods of rest frequently when they perform high-intensity sprint-type work anaerobic training. This is because their bodies are not fully developed and cannot supply the energy for this work easily and as a result they find this sort of training a lot more tiring.

It is very important that anaerobic training is strictly monitored with young players. It should not form a significant part of players' training until they have reached puberty and can cope well with the intensity of work involved. Even at this stage, the anaerobic training should be introduced gradually, with plenty of rest periods.

Guide to aerobic and anaerobic match requirements

As we can see, players need a combination of both aerobic and anaerobic fitness due to the nature of the game and the type of movements the players need to perform.

It is important that the coach recognises that players are different and have different training requirements. The requirements will revolve around the age and ability of the player, the position they play, their inherent physical abilities, their commitment and desire to train along with the level they play at. Soccer is by it's nature a a team game and for most of the time, players train together as a team. This is important for many reasons, but it also means that not all conditioning type sessions or activities have equal benefits to all the players. Sometimes coaches need to recognise that individual players will need specific fitness training.

If we are going to ask players to work hard to develop and improve fitness levels, then we must also understand that rest and recovery is crucial in the fitness training process. Players will need time to recover properly from tough training sessions. As coaches we can help this process by conducting an appropriate cool - down, ensuring the players are re-hydrated and re-nourished and aren't expected to train too hard too soon.