Technique
I definitely consider technique a key component of football, the importance of the technique of tackling and passing is identified through achieving and retention of possession for sustained periods of time. The best passing teams dictate play, conserve energy, make the best of their resources and therefore score goals (Clarke)
Hook and Hughes (2001) found that successful teams utilised longer possessions than unsuccessful teams in Euro 2000
Jones et al. (2004) showed that successful teams in the English Premier league typically had longer possessions than unsuccessful teams.
Incorrect passing technique creates turnovers in possession allows the other team to attack and creates pressure on the team.

Decision making
The importance of decision making is highlighted by (McGreskin) the thing that separates the best from the rest, is that the best players consistently make better decisions while under pressure. Decision making is quite simply, the process to find the optimum pass, whether that be a 40 yard switch of play to attack from the other side (where the space is) or passing the ball into the strikers feet to play a one-two or allow him to turn and run at the oppositions defence, decision making is a complex process (the best players know what they are going to do before) the process involved highlighting the number of players where the pass is intended for, both the opposition and your own team, as well as the obstacles in the way of the pass, the amount of pressure on yourself to release the ball.
Football compared to other sports is an open continuous game; it is ever-changing which means that making decisions quickly is important before the scenario changes again. Without correct decision making they are more likely to panic and therefore concede possession.

In football balance is significant http://sportsscientists.com/2010/06/physiology-of-football-profile-of-the-game/ Balance
ASHLEY'S TIP
"Balance is vitally important in football - it helps you beat your man when you want to ink left or right. It's a component you need in your locker when you go out on the football pitch. You don't spend a lot of time on two legs during a game; you're always running about and moving so it's important to be able to balance on one leg. This exercise will help you improve that." As a modern full back the demands of the game now include them to have the capability of creating an option, normally this is done by overlapping (running round the outside of the winger) due to this defenders need to have the capability of beating a man, and the use of balance is extremely useful in order to deceive the oppositions defence.

Many researchers have noted that control over balance and posture paces the emergence of all other skills, as skilful activity can occur only if infants can consistently regulate that relationship to the environment.3,5,6,33-35 What this is saying is that controlling your balance allows you to use your other skills to full effect.

Because kicking places considerable demands on postural control, it would seem to be an ideal task for studying the contribution that balance makes to skilled performance. Researchers are beginning to pay greater attention to the importance of dynamic balance in a range of different sports39 and some evidence suggests that highly skilled soccer players have better general balance control than less-skilled players.40

In one of the only studies to address an aspect of balance control during kicking, Shan and Westerhoff 41 examined the role of horizontal elevation of the arm on the nonkicking side on the maximal instep kick in skilled soccer players. While many researchers have assumed the arm plays a pivotal role in maintenance of balance during the kick,9 Shan and Westerhoff 41 argued that its primary function is to create a diagonal “tension arc” that helps generate velocity in the kicking leg by taking advantage of the stretch–shorten cycle in the hip flexors.

When a player is running and then stops quickly, the ability to maintain your balance will affect how quickly the athlete is able to recover and turn a new direction. http://www.elitesoccerconditioning.com/BalanceTraining/BalanceTraining.htm http://expertfootball.com/forum/viewtopic.php?t=11748
Muscular strength
The development of strength is critical for laying the foundation to perform work specific to soccer (Schmid & Alejo, 2002). Further to this, developing optimal strength levels in soccer may increase the availability of force for muscular contraction in appropriate muscles or muscle groups, thus the acceleration and speed of skills critical to soccer such as turning, sprinting, and accelerating may improve. What's more, high levels of maximal strength in upper and lower limbs may prevent injuries in soccer by increasing the cross-section area of muscles and strength and mobility of tendon and ligaments according to Ekblom (1994).

Strength can be defined in terms of the maximal force that a muscle or muscle group can generate at a specified velocity (Knutten & Kraemer, 1987). Literature (Kraemer & Gomez, 2001) suggests that all sports require the development of strength but for potentially different reasons, for example the need for strength of a wrestler in comparison to a long distance runner will be very different. This statement therefore implies that there are different types of strength. Strength is particularly important for two different reasons in a defender; muscular strength in the legs but also upper body. The strength in the legs is to generate force in your legs, mainly used for kicking the ball – strength is important because although you rarely have to use maximal, having strength allows you to kick the correct distance but you can still maintain the correct technique and therefore have greater accuracy with the pass. (Because the strike of the ball is not at full strength you can be focused on other parts of the pass).

http://www.thestrengthandconditioningblog.com/2013/09/application-of-strength-in-soccer.html

Muscular/strength endurance
The sport of soccer requires players to repeatedly produce maximal or very near maximal movements of short duration, which are separated with short recovery periods over the 90-minute duration of a match (Bangsbo, 1994). Therefore the capacity to activate muscles under conditions of fatigue, for example near the end of the match, is another important element of strength often referred to as strength endurance. The application of this is a player with optimal levels of strength endurance will be the player who will be able to make powerful turns, sprints, jumps etc late on in the game when counterpart’s muscles may be fatiguing. Research shows that strength endurance will aid a player buffer by products from the muscle and improve intramuscular co-ordination which in turn makes the athlete better equipped to more fully activate (contract) fatigued motor units in the muscle (Gamble, 2010).

To conclude, it has been established that strength is a key fitness component of the sport soccer. It has also been shown that due to diverse physical demands of the sport that it requires different elements of strength. Therefore it is important for a soccer player who wants to perform at their highest potential to develop all these different elements in order to establish their sport specific strength. This is the ability of a player to express their strength qualities during the execution of game-related activities or sport skills in the context of a match situation (Smith, 2003) and should remain the most important factor when considering the application of strength in sport.

http://www.brianmac.co.uk/football/strength.htm

Decision making
Before some movement happens, it is necessary to quickly understand and anticipate the situation and make a decision. Speed of reaction then appears as the fourth sub model, also known as explosiveness, and it takes place in the first three to four steps. After that we have the speed of movement, actions and activities.
Demonstrations of speed that are visible on the field and classify players from fastest to slowest can be divided into three categories. The first category refers to the speed of movement without the ball or so-called "pure speed", the second is the speed with the ball and the third is characterized as the speed of the first step.

The last is perhaps the most important and most widely-used category of speed at every football player. It allows him, while dribbling, in playing one to one, the possibility of easier passing his opponent and creating position for adding a teammate, still moving with the ball or shot at goal.
Speed of the first step is the closest connection with the technical and tactical tasks of players.
Although it sometimes seems that pure speed can compensate for many of the elements of football game, it is not enough only to be fast, but also knowing how to deal with the ball, especially as football is one of the technically difficult sport, because less accurate, lower limbs are used.

Speed
In 2009, there was a research performed under the auspices of the german magazine Der Spiegel in order to determine who the fastest player in the world is. Measurements were done during a game at a time until the player has the ball under the pressure from his opponents. The results showed that the fastest player was portuguese striker
Cristiano Ronaldo, Real Madrid player with a speed of 33.6 km/h. Followed by Dutchman Arjen Robben with a 32.9 km/h, then Theo Walcott (32.7 km/h) and Wayne Rooney (32.6 km/h) from England, while the fifth was another Dutchman Robin Van
Persie with achieved speed of 32.1 km/h . Coach of Manchester United, Alex Ferguson gave very interesting statement about his now former player Cristiano Ronaldo describing him as a football player that is just as fast with the ball as without it, if not faster.

If we consider that these players are one of the finest and best paid players of the world (Cristiano
Ronaldo is officially best paid football player in the world), then we will examine how the components of physical abilities, such as motor speed, make their game better, which is reflected on the price of one player on the market. The concept of football (according to Bisanz & Vieth, 2000) is reflecting in the fact that everything that today is a top form and success in football, tomorrow can be easily overcome, so it should not follow the same concept of play and training too long. The main objective in developing the game puts the success to the forefront without neglecting the play. One of the trends suggests that the speed of play will continue to increase, also the pace of play in the narrowest space around the ball that is controlled skilfully. In this way, the player with the ball will have less time to orient, before looking at a situation, deciding and executing oriented with fast actions during the whole game in all positions and in all situations, such as dribbling with the final shot on goal, sliding of defender in the full course, sudden change of speed or free running. In almost all the actions, their performance based on speed is the base of success or failure. The teams that adhere to this trend can continue to count on good results.
Many studies was dealing with the speed in football, often through a variety of programs for its development (Impellizzeri et al., 2008; Jullien et al., 2008) or in relations with other anthropological areas and physical indicators (Mujika et al., 2000;
Newman, Tarpenning & Marino, 2004; Aziz et al.,
2007). Milenković, D.: Speed as important component of football game Acta Kinesiologica 5 (2011) 1: 57-61
60
As already mentioned, the speed itself is difficult to develop, but with the help of some other dimensions, it can be influenced in order to achieve better results. Alternative is usually required in strength developing, which can compensate in certain percentage for the lack of the required speed in task executing. However, speed is also associated with the agility that incorporates the components of velocity and it is considered as changing movement direction but with maintaining the achieved speed (Smythe, 1995). All this points to the need for comprehensive planning, programming and implementation of training process, to a final product, a football player who has a highly developed motor ability such as speed.

Composure
Many players suffer from a common emotional problem of worrying or fretting about how they are going to perform, will they let people and themselves down. This fear can cause physical and mental distress, which will do little to improve a player’s performance.

This anxiety can cause muscle tension and tightness, increase the feeling of tiredness and can reduce fluency of movement. In addition the player’s minds are full of negative thoughts, which make it very difficult for the players to focus positively on the game and their jobs. If the coach has a good understanding of how a player normally behaves then they have a much better chance of identifying this emotional anxiety. If coaches can spot the signs, such as players who are normally talkative being quite or vice versa, players suddenly becoming very aggressive, when it is not in their nature to do so, then it becomes easier for coaches to assist their players in overcoming this form of emotional anxiety by encouraging them to remain calm and by turning negative thoughts into positive ones http://www.grassrootscoaching.com/members/page.phtml?id=142 Motivation
Motivation is a key means to achieving success. It greatly depends on the coaches' personality, attitude and means of getting players interested in bettering themselves and accepting the means by which they can develop. Generally, the coach should try to understand what motivation is and the ways to turn under or extrinsically motivated players into intrinsically highly motivated successful players.

In the end, Bill Besick (sports psychologist for Manchester Utd) states that the strongest motivation must be because the player wants to win and in a team sport the motivation must be because the players want to win together. http://www.footy4kids.co.uk/motivation-and-soccer-performance.htm# Just as there’s a winning habit, there is also a losing habit. It just shows the importance of mentality, whatever level you play at: footballers are 75 per cent confidence. If you’ve got the same team week in, week out, that’s the only area really to turn it round – the team’s mental preparation going into each game is crucial. You can change the mentality by changing the team around or asking the players to follow slightly different tactics until you get back on course; if you’re losing games by the odd goal then the first thing to do is to stop conceding. Focus on your strengths and ask them to remember what they felt like when they won nine on the trot – put that in their minds as a positive.

http://performance.fourfourtwo.com/health/psychology/big-sams-guide-to-motivation

http://www.mantralux.com/2010/11/player-attributes-explained/

tactical awareness

Author: Shane Pill, Flinders University School of Education
Issue: Volume 31 Number 1

To be successful in game play requires players to do more than execute sport-specific movement skills well. Players must be able to read the game situation off the ball, respond with appropriate movement to relocate themselves for the advantage of their team or self, react to produce appropriate skill execution, andrecover with off-the-ball movement to set up further game involvement. Coaching using a tactical games approach facilitates the development of player understanding of this totality of game play, whereas traditional direct instruction drill approaches primarily centre on skill execution in isolation.

http://www.actakin.com/PDFS/BR0501/SVEE/04%20CL%2012%20DM.pdf
Aggression
Most people view aggression as a negative psychological characteristic, however some sport psychologists agree that aggression can improve performance (Widmeyer & Birch, 1984). This is called an assertive behaviour (Bredemeier, 1994), where a player will play within the rules of the sport at a very high intensity, but will have no intention to harm an opponent. In sport, aggression has been defined into two categories: hostile aggression and instrumental aggression (Silva, 1983). Hostile aggression is when the main aim is to cause harm or injury to your opponent. Instrumental aggression is when the main aim is to be non-aggressive but to win the ball. Coulomb and Pfister (1998) conducted a study looking at aggression in high-level sport. They found that experienced athletes used more instrumental aggression in which they used to their advantage and that hostile aggression was less frequently used. Experienced athletes used self-control to help them with their aggression.

The single most important personal characteristic named by business people and sports persons as the key to their success, is tenacity. Tenacity is the ability to keep going when the situation seems hopeless and progress difficult. In most sporting fields talent is important but tenacity is essential. No matter what, the tenacious athlete will progress to fulfil his or her potential. In football tenacity will encourage an athlete to train rigorously, it will develop ’match toughness’, that ability to never give up no matter how hopeless the situation may seem to be and it develops a disposition to perform to their utmost ability at all times.

Bourgase (2010) in a research on footballers found that there was a significant relationship between self-efficiency feeling, motivation and performance of the athletes. Results of this research regarding the claim suggesting that the higher the self-efficiency is, the better the performance will be and vice versa are consistent with those found by Feltz, Landers & Reader (1979), Berg (1981), Gomez, Hill & Ackerman (2007), Sharififar&Tedjari (2007), Robinson (2000), Hilson& Cle (2006), Jao, Siebert & Hills (2012), Selentano (2012),Bradly& Wildman (2002), Afkhami (2011) and Tojari,Sharifnegad&Nemati (2007

In conclusion, professional soccer players' running speed and agility performances are higher than amateur soccer players. In addition, these results indicate that all soccer players have the same running speed and agility performance in accordance with their different playing positions. Coaches should consider individual training programs based on the positional role of soccer players.

The Evaluation of the Running Speed and Agility Performance in Professional and Amateur Soccer Players
Kaplan, Turgut; Erkmen, Nurtekin; Taskin, Halil

Athletic performance in soccer is a function of aerobic fitness, anaerobic fitness, speed, muscular strength, muscular power, and agility (Bangsbo, Mohr, Poulsen, Perez-Gomez, & Krustrup, 2006; Stolen, Charmari, Castagna, & Wisloff, 2005). During a match a player frequently performs activities that require rapid development of force, such as sprinting or quickly changing direction (Bangsbo, 1996). Although high-speed actions only contribute to 11% of the total distance covered in soccer, they actually contribute directly to winning possession of the ball and to scoring or conceding of goals (Reilly, Bangsbo & Franks, 2000). High-speed actions in soccer can be categorized into actions requiring acceleration, maximal speed or agility (Gambetta, 1996).
Consequently, the SAQ (speed, agility and quickness) method has become dominant in soccer training (Pearson, 2001). Similar morphological and biochemical determinants of acceleration, maximal speed and agility have led to the assumption that these qualities are highly related (Little and Williams, 2005).
For example, elite young players (as compared with the sub-elite ones) could be characterized by high agility (Gil, Ruiz, Irazusta, Gil & Irazusta, 2007; Reilly, Bangsbo & Franks, 2000) and running speed (Gil, et al., 2007; Reilly, et al., 2000; Rosch, et al., 2000). Furthermore the soccer specific skill could also be distinguished among the elite and non-elite young competitors (Davids, Lees & Burwitz, 2000; Mirkov, Nedeljković, Kukolj, Ugarković & Jarić, 2008; Vaeyens, et al., 2006),

Ramos, et al. (2009) investigated performance of youth elite soccer players through physical tests according to positional roles and did not find significant differences between positional roles in the agility test.
The need for agility with the ball is of great importance for dribbling and one-on-one game situations.

The factors of perception and decision making quite often specify an elite soccer player who performs with greater agility on the field than the non-elite ones (Young and Farrow, 2006).
The statement is endorsed by research which implies that better athletes have quicker and more precise reactions due to their ability to choose anticipated information (Abernethy, Wann & Parks, 1998) and is extremely important in the course of the agility test performance

A recent study by prominent Norwegian researchers examined the effect of aerobic training on VO 2max and soccer match performance (Helgerud et al. 2001) in 19 high-level youth soccer players.

Match analysis results showed that the increased aerobic fitness:
Increased work intensity during a game
Prevented a second-half reduction in work during the game
Doubled the number of sprints completed in a game
Allowed players to be involved in more ‘decisive’ plays
Allowed players to cover a greater distance during a game.
High-intensity interval training has previously been used to show large improvements in team-sport athletes’ aerobic fitness in relatively short time periods (Hoff and Helgerud 2004)

Research suggests that increasing aerobic capacity will improve performance in team players and officials by allowing them to cover greater distance during a game at higher intensity. Furthermore, they will also increase the number of sprints completed throughout a game, decrease fatigue levels at the end of a game and increase their involvement with ‘the play’. As a coach, you can improve aerobic capacity through well-planned high-intensity training using either interval training or modified games. By implementing these sessions carefully into your training program, you will be able to increase your athletes’ on-field performance.

Training aerobic capacity for improved performance in team sports
Female Soccer player
Author: Aaron Coutts and Grant Abt

Physiological, technical, and tactical skills are all important to soccer performance. Factors such as acceleration, running velocity, jumping height, and capacity to release energy are of major importance. Because of the length of a soccer match, at least 90% of the energy release must be aerobic1; during a 90 minute match, players run about 10 km2,3 at an intensity close to anaerobic threshold or 80–90% of maximal heart rate.1,3,4 http://bjsm.bmj.com/content/36/3/218.full http://www.fcalliance.net/docs/Girls/White94g/06-Qualities_Of_Soccer_Player.pdf

Belgian university players were found to cover on average a distance of 444 m more in the first half than in the second half (Van Gool et al., 1988). Bangsbo et al. (1991) reported that the distance covered in the first half was 5% greater than in the second. This decrement does not necessarily occur in all players. Reilly and Thomas (1976) noted an inverse relation between aerobic fitness (V·O2max) and decrement in work-rate.

The players with the higher V·O2max values, those in midfield and full-back positions, did not exhibit a significant drop in distance covered in the second half. In contrast, all the centre-backs and 86% of the strikers had higher figures for the first half, the difference between halves being significant. It does seem that the benefits of a high aerobic fitness level are especially evident in the later stages of a match.
The amount of glycogen stored in the thigh muscles pre-match appears to have an important protective function against fatigue. Swedish club players with low glycogen content in the vastus lateralis muscle were found to cover 25% less overall distance that the other players (Saltin, 1973). A more marked effect was noted for running speed; those with low muscle glycogen stores pre-match covered 50% of the total distance walking and 15% at top speed compared to 27% walking and 24% sprinting for players who started with high muscle glycogen concentrations. Attention to diet and maintaining muscle glycogen stores by not training too severely are recommended in the immediate build-up for competition. These considerations would be most important in deciders where drawn matches are extended into 30-min extra time

http://spartan.ac.brocku.ca/~jmandigo/inclusionOC.pdf

Individual defending requires good 1v1 play and a good understanding of basic defensive principles.
‘Defending requires far more than being tough and determined; it also demands intelligence and tactical awareness. Good positioning is crucial – the ability to press the ball at the right place and time will often suffice.’
The skill must be mastered for anyone wishes to play effective defence.
Poor decision making by defenders who are impatient in trying to win the ball back often leads to free kicks being given away in a dangerous are of the field

https://books.google.co.uk/books?id=SqgymRsnpegC&pg=PA70&lpg=PA70&dq=the+importance+of+tackling+for+a+defender&source=bl&ots=jFwgPzr9aY&sig=WomDTfce8DrJsVBH0FxGMZLGQZo&hl=en&sa=X&ei=1veOVLzULMvtaJW6gKgD&ved=0CEoQ6AEwBg#v=onepage&q=the%20importance%20of%20tackling%20for%20a%20defender&f=false

Individual defensive tactics are based on players’ skills in reading the game, positioning, marking, and challenging for the ball. For example, if a very quick and left-footed opponent operates on the left flank, a right fullback may, by his positioning, prevent the winger from progressing with the ball between the defender and the touchline. He directs the winger infield to prevent him from immediately using his left foot to cross the ball. The positioning of the fullback’s feet and body when the winger receives the ball will largely influence the direction in which the winger moves. With a right-footed winger on the left flank, the same principles apply, but the intention of the fullback is now to prevent the opponent from coming infield and perhaps attacking the central areas of the defense. The fullback will push the winger outside so he has to operate near to the touchline in a reduced space. This simple individual defending tactic can reduce the winger’s effectiveness. The negation of the winger’s contribution can constitute part of an overall team defending tactic of reducing the number of crosses delivered into the defending team’s penalty box.

http://www.humankinetics.com/excerpts/excerpts/soccer-defensive-tactics-vary

In football, the mode of communication is a critical component of success and can be performed in several ways – speech, body language, sign language and eye contact (If you know any other modes of communication please share your thoughts in the comments section). It is good to understand all modes of communication because footballers have their own style of play. Some of you may run into open spaces – body language. Whereas, some of you ask for the ball – speech. You may raise your hands during free kicks or long passes indicating to your team mate you are open – sign language, or for throw-ins you make eye contact to your team mate indicating to pass the ball.
“The most important tactic in football is “Communication.”

No matter how good your team, if you’re not communicating effectively you’re not playing effectively

http://www.gurkhafc.com/2009/11/27/the-most-important-tactic-in-football/

http://www.worldofsoccer.com/index.php?option=com_content&task=view&id=928&Itemid=2

It is harder for a goalkeeper to judge and hold a shot struck with power and swerve, especially if directed at the far post. A FIFA report analysing goals scored in the 1982 World Cup, showed that 38% of goals came from shots outside the penalty area.
http://www.soccerperformance.org/training/shooting.htm