**1. Introduction**

Soccer is a high intensity intermittent contact sport exposing elite level players to contin‐ ual physical, technical, tactical, psychological, and physiological demands (Owen et al, 2011; Dellal et al, 2011). Due to the huge financial rewards of being successful at the elite level of the sport, the demands placed upon the players are ever growing because of increased fixture schedules that generally include less recovery periods between train‐ ing and competitive match play, disposing players to a greater risk of injury (Dellal at al, 2013; Dupont et al, 2010; Rey et al, 2010; Morgan and Oberlander 2001; Junge and Dvorak 2004). The number of competitive matches played by elite European soccer play‐ ers (Table 1) during one season can be >80, with 1.6 to 2 matches per week throughout its entirety (excluding friendly games) (Figure 1). It should be noted that, a player com‐ peting at the higher echelons of world soccer such as Lionel Messi has accumulated be‐ tween 64 to 69 official competitive games throughout seasons 2011-2012, 2010-2011, and 2009-2010 as shown in Table 2. As reported in this context, modern day soccer involves a continued, intensive cycle and predisposes players to greater injury risks due to accu‐ mulative fatigue or overload. Previous research has already found a correlation between low training and match availability due to injury, with decreased team success (Arnason et al, 2004). This is of particular importance for teams unable to replace players due to limited funds or resources, and subsequently highlights the need for all clubs irrespec‐ tive of budgets, resources and funding potential to minimize injury risk of players in or‐ der to be more successful. After all, there seems to be no point in pushing players constantly to be physically, technically and tactically better if they are consistently un‐ available to play.

© 2013 Dellal et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**Players Season 2011-2012 Season 2010-2011 Season 2009-2010**

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 Messi Lionel **69** 66 64 Ronaldo Cristiano **69** 59 46 Iniesta Andres 47 **50** 41 Xavi 51 50 **53** Falcao Radamel **52** 42 43 Pirlo Andrea **56** 36 51 Drogba Didier 47 49 **57** Van Persie Robin **60** 38 34 Ibrahimovic Zlatan **55** 49 49 Alonso Xabi 54 **63** 56 Yaya Touré 49 **52** 37 Neymar 59 **67** 62 Osil Mesut 62 **64** 62 Rooney Wayne **50** 48 49

**Table 2.** Official matches played by the 14 best players during the 3 last seasons (according to the official "Ballon

The financial outlay clubs make season upon season in order to gain success is well into the high percentages of club turnover (wages, transfer fees and contractual terms agreed). The expense of a player being out through a non-contact injury could be substantial and seen as a negative investment or non-efficient with every game missed through a preventable injury. Consequently, the need to implement a sport-specific injury prevention structure within the organization that technical, conditioning coaches and other individuals involved with the player training status is of paramount importance. According to previous research the most significant injury predictor of soccer players is their injury history (Olsen et al, 2004). The fact that players have some type of chronic problem or low training or match availability over numerous seasons will more than likely manifest itself moving forward unless appropriate

It is however, questionable whether some types of exercise-based injury prevention programs actually facilitate true learning of new biomechanical and neuromuscular characteristics (Padua et al, 2012; Paterno et al, 2004). Whereas the effects of short duration exercise-based injury prevention programs may induce transient changes in the performance of functional tasks that regress following cessation of the program. In order to experience biomechanical and/or neuromuscular changes it is likely that extended-duration training periods are necessary to facilitate long-term retention of movement control (Padua et al, 2012). Yet, performing injury prevention drills over a prolonged period, as performed by Owen et al (2013b), may still be insufficient to induce large reductions in the incidence of specific injuries.

d'Or" ranking).

injury prevention steps are taken.

**Table 1.** Official match played by elite soccer players from European teams.

**Figure 1.** Mean number of official matches per week played across the 5 best European Leagues (excluding the friendly games).


**Country Match**

242 Muscle Injuries in Sport Medicine

Spain, *La Liga*

England, *Premier League*

Germany *Bundesliga*

France *Ligue 1*

Italy *Calcio*

friendly games).

**played in 1st League**

**Match played in League cup**

**Match played in National cup**

**Table 1.** Official match played by elite soccer players from European teams.

**Match played in UEFA Champions League or Europa League**

**Other games (National or European super cup, champions cup, etc)**

38 1 to 10 0 6 to 15 2 to 4 4 to 11 51 78 30 to 41

38 1 to 9 1 to 9 6 to 15 2 4 to 11 52 84 40 to 55

34 1 to 5 1 to 6 6 to 15 1 4 to 11 47 72 41 to 53

38 1 to 5 1 to 6 6 to 15 2 4 to 11 50 77 25 to 35

38 2 to 11 0 6 to 15 1 4 to 11 51 76 41 to 53

**Figure 1.** Mean number of official matches per week played across the 5 best European Leagues (excluding the

**National team**

**Minimal rate of match per years**

**Maximal rate of match per years**

**Summer holidays**

days

days

days

days

days

**Table 2.** Official matches played by the 14 best players during the 3 last seasons (according to the official "Ballon d'Or" ranking).

The financial outlay clubs make season upon season in order to gain success is well into the high percentages of club turnover (wages, transfer fees and contractual terms agreed). The expense of a player being out through a non-contact injury could be substantial and seen as a negative investment or non-efficient with every game missed through a preventable injury. Consequently, the need to implement a sport-specific injury prevention structure within the organization that technical, conditioning coaches and other individuals involved with the player training status is of paramount importance. According to previous research the most significant injury predictor of soccer players is their injury history (Olsen et al, 2004). The fact that players have some type of chronic problem or low training or match availability over numerous seasons will more than likely manifest itself moving forward unless appropriate injury prevention steps are taken.

It is however, questionable whether some types of exercise-based injury prevention programs actually facilitate true learning of new biomechanical and neuromuscular characteristics (Padua et al, 2012; Paterno et al, 2004). Whereas the effects of short duration exercise-based injury prevention programs may induce transient changes in the performance of functional tasks that regress following cessation of the program. In order to experience biomechanical and/or neuromuscular changes it is likely that extended-duration training periods are necessary to facilitate long-term retention of movement control (Padua et al, 2012). Yet, performing injury prevention drills over a prolonged period, as performed by Owen et al (2013b), may still be insufficient to induce large reductions in the incidence of specific injuries. Essentially, players may respond differently to intervention programs and this should be a consideration for further detailed investigations. Alternatively, despite certain programs being performed during the entirety of the season, it is possible that specific prevention sessions or individual exercises may have been insufficient in terms of longevity and duration required to elicit large training adaptations. This is pertinent to elite level athletes who generally possess relatively high levels of general fitness and would unlikely experience gains similar to lesser skilled individuals despite being at a greater risk of injury (Ekstrand et al, 1983).

normal differences in strength between compared to contra-lateral muscle groups. Further‐ more, an unfavorable difference between agonist and antagonist muscle groups is considered to leave the weaker muscle group at a disadvantage and such an example, hypertrophy of the quadriceps at the expense of the hamstring may lead to hamstring injuries. Indeed, Croisier et al (2008) and Knapik et al (1991) suggested that players with a strength imbalance greater than

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Ekstrand and Gillquist (1984) have showed that intervention prevention strategies allowed players to have 75% fewer injuries than a control group (ankle, sprain, strain). **In this context, the aim of the present book chapter will be to present the literature review showing how different prevention methods and strategies appear to result in the reduction of injuries to soccer players both during training and matches.** However, the combination of concurrent prevention programs could further positively affect the injury rate, especially the high incidence of lower extremity non-contact muscle injuries. Therefore, based on all the previous research findings and suggestions, the importance of injury prevention at the elite level of professional soccer led to the development of this review. The current review aims to examine the impact a 4-part structured injury prevention intervention would have on injuries occurring

The majority of injury prevention training studies have generally examined the effects of individual components on injury incidence. However, this is not representative of a soccer specific environment where the time constraints dealt necessitates the development of a mixed conditioning approach that allows for the simultaneous development of several fitness qualities. From a practical perspective, injury prevention programs are implemented with the expectation that they will elicit improvements in performance (through increasing players' availability and reducing lay-off durations when injury occur) and reduce the incidence of injury, however, this is not always representative of research findings. Recently, it has been suggested that a multicomponent injury prevention intervention may increase motivation through an integrated approach within a team sport environment (Owen et al, 2013b). This particular investigation recently reported that significantly less muscle injuries were observed during integration of a 4-part injury prevention program concomitant with a bigger squad size (large effect, p<0.001) when compared to a control season (Owen et al, 2013). It was reported during this investigation that high levels of contusion injuries were apparent within this study, which led the author to suggest that the multicomponent prevention technique is beneficial when integrated in order to reduce muscle injuries but may not be able to prevent other types of injuries (contact injuries). Prevention exercise is commonly included before, during or/and after the training sessions and matches. Within this chapter, we are going to describe the most common prevention technique used in soccer specific, especially by fitness coach. Sometimes one out of these is enough to reduce the injury occurrence, sometimes it is the combination of

15% were 2.6 times more likely to suffer injury in the weaker leg.

within elite level professional soccer clubs.

2 or more that appears necessary.

**2. Prevention techniques used in soccer**

The incidence of injuries among elite adult male soccer players during competitive match-play was described to be approximately between 24.6 and 34.8 per 1000 match hours (Walden et al, 2005; Arnason et al, 2008; Parry and Drust, 2006), and training injuries ranging between 5.8 to 7.6 per 1000 training hours (Walden et al, 2005; Arnason et al, 2008) even if some studies report values outside these ranges. Walden et al (2005) revealed that the risk of injury in European professional soccer is high with the most common injury being the posterior thigh strain. Hawkins et al (2001) reported an average of 1.3 injuries per player per season in English professional soccer, with the propensity of injuries occurring in the final 15min period of each half. Comparatively, fewer injuries occur during the first half of matches compared to the second (Hoy et al, 1992; Hawkins and Fuller 1996, 1999). The stressors encountered during actual match play have been suggested to show no detrimental effect of consecutive games on physical performance, but a greater injury risk (Carling et al, 2012; Dupont et al, 2010; Rey et al, 2010).

Almost one third of all soccer related injuries are muscle related and the majority (92%) affect the major muscle groups of the lower extremity: hamstrings, 37%; adductors, 23%; quadriceps, 19%; and calf muscles, 13% (Ekstrand, 2011). Over a period of two seasons, the Football Association Audit of Injuries also showed the hamstrings to be the most commonly injured muscles, constituting 12% of all strains (Hawkins et al, 2001). The implications manifesting in players being 2.5 times more likely to sustain a hamstring strain than a quadriceps strain during a game (Hawkins et al, 2001). This is clear evidence as to why clubs invest heavily in time and resources of injury prevention in an attempt to reduce the prevalence of injuries (injury rate). However, eagerness to return to play resulting in an incomplete rehabilitation has shown the increase the re-injury rate for hamstring injuries thus, questioning the success of current injury prevention programs (Croisier, 2004; Hagglund et al, 2005).

Previous research has suggested that muscle strains may occur due to insufficient warm-up (Kujala et al, 1997; Worrell, 1994), poor flexibility (Kujala et al, 1997; Worrell, 1994; Hartig and Henderson, 1999) even if some recent research are conflicting in this regard, muscle imbalances (Worrell, 1994), muscle weakness (Croisier et al, 2002), neural tension (Turl and George, 1998), fatigue (Kujala et al, 1997; Worrell, 1994), previous injury (Engebretsen et al, 2008), increasing age and poor running technique although the evidence to represent these findings are both minimal and conflicting. Chamari et al (2012) has recently showed Ramadan Inter‐ mittent Fasting to induce higher injury rates in Muslim elite soccer players with a higher number of contractures for muscles themselves, and some tendinosis for tendons. Overemphasis on one-sided activities, such as kicking, lateral movements and single-leg jumping, may also lead to asymmetry and dominance of one leg, which in turn may cause greater than normal differences in strength between compared to contra-lateral muscle groups. Further‐ more, an unfavorable difference between agonist and antagonist muscle groups is considered to leave the weaker muscle group at a disadvantage and such an example, hypertrophy of the quadriceps at the expense of the hamstring may lead to hamstring injuries. Indeed, Croisier et al (2008) and Knapik et al (1991) suggested that players with a strength imbalance greater than 15% were 2.6 times more likely to suffer injury in the weaker leg.

Ekstrand and Gillquist (1984) have showed that intervention prevention strategies allowed players to have 75% fewer injuries than a control group (ankle, sprain, strain). **In this context, the aim of the present book chapter will be to present the literature review showing how different prevention methods and strategies appear to result in the reduction of injuries to soccer players both during training and matches.** However, the combination of concurrent prevention programs could further positively affect the injury rate, especially the high incidence of lower extremity non-contact muscle injuries. Therefore, based on all the previous research findings and suggestions, the importance of injury prevention at the elite level of professional soccer led to the development of this review. The current review aims to examine the impact a 4-part structured injury prevention intervention would have on injuries occurring within elite level professional soccer clubs.
