Soccer is a unique game. It requires a wide range of specific fitness elements for a player to be successful. A match typically lasts 90 minutes at senior level and 60 minutes a junior level which requires a high level of stamina and endurance. Players also need to be strong, powerful, quick, to turn, jump, tackle and shoot, and to be able to make decisions, both individually and tactically within an ever-changing, fast moving environment. Soccer requires a range of different levels of fitness in all areas as opposed to requiring one specific area of fitness. The specific types of fitness also depend on the position the player plays. For example a central midfield player would need good stamina, decent pace and speed, good mobility. Whereas a central striker would need very good pace and mobility and perhaps not so much stamina.

Whilst players also need a number of other skills to be successful such as skill, technique, mental strength and talent, fitness has an very big influence on them all. Without fitness, individuals and the team will always fail, despite having an abundance of the other attributes required to be successful

Whilst the following information refers to a player at the top level of the game, the principles apply to all levels of players. The following research demonstrates how far and at what pace players run, jog, sprint and cruise during a game. The following is a summary of some of the findings, which all relate to senior players.

Match analysis has shown that the typical player at the top level may:

• Cover a total distance of between 10-12km within a game (Bangsbo 1994, Ohashi 1988)
• Work at 75% of their maximum endurance capacity on average throughout a game (Ekblom 1986)
• Cover 11% of the total distance in some form of sprint (Reilly and Thomas 1976). The majority of these sprints will last for less than seven seconds
• Cover different distances depending on position - midfield players cover the most distance (Bangsbo 1994)
• Cover less distance at the beginning of the second half than they do at the start of the first half.
• An interesting supplementary fact is that 23% of goals are scored in the last 15 mins of a game (Jinshan et al 1992).

The research reinforces the different types of fitness that are important for playing soccer. It is important to understand that the older and the higher the level the player plays at, the more important the fitness demands become.

It is useful to consider the types of actions a soccer player needs to perform, before we consider how and why we can improve soccer fitness. Soccer is not like going on a continuous steady run, it requires a great many changes of movement and frequent changes of speed and intensity as well as a wide variety of strength and power movements. Players need a mixture of aerobic and anaerobic energy to maintain peak performance. For example the following shows a range of players movements during a match and the percentage at which they perform each movement:

Before players can improve and develop different types of fitness, they need to have a solid stamina and endurance base. This primarily involves the aerobic system of the player. To develop this it is important that the coach understands what the aerobic system is and how it can be improved to develop and improve a players stamina and endurance level. It is also important that the coach understands what the anaerobic system is, how it can benefit a players fitness programme and how it must work alongside and compliment the aerobic system in any training programme.

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.