**4. Which factors affecting injury risk?**

duration, and intensity of training and ensure maximum player freshness pre-game (Owen et

The previous review of literature presented in this book chapter and describing the different methods of prevention strategies, should help the coach, the technical staff and the medical staff to reduce the injury occurrence. They have to adapt the prevention program according to the sport, the athletes' morphology, age, gender, their injury history, and the period of the

First of all, all players should to be tested at the beginning of the pre-season in order to detect what prevention program they eventually need. They should be tested in isokinetic, functional strength, mobility (lumbar-pelvic, ankle, knee, hip), flexibility, balance and theirs morpholo‐ gies. These results have to be combined to their injury history. All of these information will allow to draw the needs for each player, and therefore designing individual specific prevention

A Cochrane review by Goldman and Jones (2010) on such interventions concluded that there was insufficient evidence from randomized controlled trials to draw conclusions as to the effectiveness of interventions used to prevent injuries. This current lack of evidence for interventions and the current high incidence of injuries seen in the game could also suggest that injuries should be considered multifactorial in their etiology. Therefore, we have yet to understand how works the interplay between all of the intrinsic and extrinsic factors that may contribute to each specific injury. It could also be suggested that there is some element, be it intrinsic or extrinsic, in the day to day management of the players that maybe a significant contributing factor in the aetiology of these injuries and we have yet to establish what this

For example, a recent large scaled randomized controlled trial by Petersen et al (2011) ad‐ dressed the efficacy of the Nordic hamstring exercise program for preventing acute hamstring injuries in soccer players. They found that introducing this ten weeks program to reduce eccentric weakness, a common intrinsic factor associated with hamstring injuries, reduced the incident of these injuries by 70%. This backed up previous findings by Arnason et al (2008). Using a larger sample size Arnason's study looked at a total of 24 teams, with over 650 soccer players, over a four years period. These players were from professional soccer teams in the Icelandic and Norwegian leagues. The study showed that teams combining the Nordic eccentric exercise protocol and the stretching program were on average seeing 65% fewer hamstring injuries. However, when we look closely at the Nordic hamstring exercise it's clear to see that it only involves movement at one joint-the knee. We know that the hamstrings work over two joints, the hip and knee, and when we consider the mechanism of hamstring injuries then the Nordic hamstring exercise clearly doesn't replicate any of the functional activities

**3. Which prevention program should be used?**

al, 2013a).

260 Muscle Injuries in Sport Medicine

season.

programs.

might be.

used in football specific training.

It has been identified in two studies by Heiderscheit et al (2010) and Orchard et al (2005) that clinical experience shows us that it is extremely difficult to decide at which point during rehabilitation the athlete is ready to a return to sport, and thus this is usually based on subjective evidence. These difficulties may well be the reason why there is a conspicuously high injury recurrence rate, particularly within the first few weeks of a return, as identified by Walden et al (2005). Additionally, there are a difference of risk injury according to the age (adult vs. youth soccer players) and gender (male vs. female). Indeed, it was clearly showed that female players presented between 2 and 3 times higher risks of ACL injuries than soccer male players (Vescovi and Van Heest, 2010; Walden et al, 2011). It is cause by different knee morphology with especially an impaired alignment. All these information show that different factors could affect and be at the origin of an injury

#### **4.1. Factors impacting the injury risk**

**• Warm up.** Adapted warm up is considering as a prevention strategies because it reduces the injury risk (Fields et al, 2010; Soligard et al, 2010). These studies showed that a specific intervention program based on specific "The11" FIFA warm up focusing on core stability, eccentric training of thigh muscles, proprioceptive training, dynamic stabilization and plyometrics with straight leg alignment induce lower knee injuries in comparison to a

7

control group. This is contrasted by Junge et al (2002) who did not find that "the11" had a preventive effect on youth soccer players, probably due to the fact that youth players are growing and they don't have a control of a large pattern. Olsen et al (2004) confirmed that specific warm up and cool down, adapted training shoes analyzed, prophylactic taping (especially in players formers sprain and ankle instability), reduce the injury risk.

However, Debedo et al (2004) demonstrated the opposite results with forwards sustained 10% more hamstring strains than defenders. Whatever, the prevention program has to be plan according to the playing position, the region, the country and the championship.

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**• Injury history and re-injury.** As it was previously described, the injury history is a deter‐ minant factor to design the prevention training for players (Hagglund et al, 2006). The different adaptation resulting from previous injuries will direct the manner to manage the prevention program and to be careful for one or more specific players. Previous injuries, which are not well treated, could be the origin of a re-injury (in the same scarb area). In this context, it is very important to take the time in order to the organism recover totally its physiological and biomechanical components. The rehabilitation work, the prevention exercises and the re-training needs to pay a special attention after players took part in the collective training. The high risk of re-injury concerns the hamstring strain, and indirectly, after an ACL, there are a possibility of compensation and of re-injury on the same knee, and

**• Nutrition and dehydration.** A bad management of the food and the fluid intake could increase the risk of injury according to the period of the season and external conditions. Appropriate nutrition, regular and adapted hydration is the basic behavior to have.

**• The period of the season.** The risk of injury differs according to the period of the season. To illustrate it, the highest incidence of sprains was achieved during pre-season and the beginning of the competition period. The risk to sustain a muscular strain peaked at the beginning and in the final weeks of the competition period and was related (*r*=0.72; *P*<0.05) to mean heart rate during training. (Mallo and Dellal, 2012). Concerning the in-season, recent research has shown that performing an injury prevention program twice weekly for the entirety of the entire season (58 prevention sessions) can lead to significantly less muscle injuries. The findings from this study identified a multi component injury prevention training program may be appropriate for reducing the number of muscle injuries during a season but may not be adequate to reduce all other injuries. A recent study by Mendiguchia and Brughelli (2012) has attempted to provide a return-to-sport algorithm. In general, the pre-season requires a greater proprioception (ankle and knee), eccentrics, core stability and stretching program whereas the in-season needs to increase the attention to prevent the sprain with each player participating in a specific preventive training. However, sometimes it is no chance due to player-to-player contact, because it could reach 32% of the injury

The injury risk and the type of injury are age dependent. Soligard et al (2010) suggested that most earlier the prevention program is started, greater will be the effect. Literature showed that youth soccer players have between 61-82% of overall injuries located at the lower extremity especially at the ankle (28%) and knee (19%) (Emery and Meeuwisse, 2010; Junge et al, 2002). The incidence of injuries decreases with a specific strength program (resistance training) in youth soccer players during in-season and off-season (Lehnhard et al, 1996). Emery and

the contro-lateral knee, or muscle (hamstring, quadriceps, gastrocnemius).

causes.

**4.2. Prevention in young soccer players**


However, Debedo et al (2004) demonstrated the opposite results with forwards sustained 10% more hamstring strains than defenders. Whatever, the prevention program has to be plan according to the playing position, the region, the country and the championship.


#### **4.2. Prevention in young soccer players**

control group. This is contrasted by Junge et al (2002) who did not find that "the11" had a preventive effect on youth soccer players, probably due to the fact that youth players are growing and they don't have a control of a large pattern. Olsen et al (2004) confirmed that specific warm up and cool down, adapted training shoes analyzed, prophylactic taping

(especially in players formers sprain and ankle instability), reduce the injury risk.

hot water immersion for example)

investigated this.

262 Muscle Injuries in Sport Medicine

**• Congested period.**Dellal et al (2013) and Dupont et al (2010) have shown that a congested period could affect and increase the injury risk. Consequently, when a team plays 6 or 7 matches in about 20 days for example, a global preventive plan has to be settled including the training load monitoring, the use of post-efforts recovery method (alternating cold and

**• Change of temperature and external conditions.** To the best of our knowledge, no study has ever attempted to show if the brutal change of external temperature has any effect on the injury occurrence. However, it is suggested that several fast change of temperature from heat to cold induce a greater risk of injury, especially hamstring strain (personal unpub‐ lished observations). Moreover, the external conditions could modify the type of grass pitch and therefore, the run and the footstep will be altered too. When the pitch is firm, hard or soft, it affects the players' muscle contraction pattern at ground contact and thus could increase the risk of injury. For example, when the pitch is "heavy" the fatigue appears more quickly, especially at the hamstrings but to the best of our knowledge, no study has ever

**• Equipment modification and playing surface.** Specific running shoes adapted to the players' anatomy (if the players is under pronation, supination, genu varus and rear foot with varus) could possibly be a preventive injury risk factor to be a determinant factor (Fields et al, 2010), but this has not been widely investigated. However, it is essential for the staff to pay a special attention that each player having the adequate equipment for playing football, running, to perform strength exercise training (belt), or stretching (carpet). The playing surface has a essential roles (Ekstrand et al, 2006), but as it was showed, this is the

**• Fatigue and training monitoring.** The workload is the key factor to prevent injury. Period‐ ization, and the capacity to plan and to design a schedule with the appropriate intensity and frequency of training is a key factor to avoid injury and in this context, it should be consider as a prevention strategy. Every coach, technical staff and fitness training have a special view of the planning design but whatsoever the method used, the final target is to manage and manipulate the players fatigue and level performance and to avoid injury. Technical staff

**• Playing positions.** It was showed that the frequency of injuries was not uniformly distrib‐ uted by playing positions with forwards and central defenders sustained the greatest number of injury episodes and the highest match absence (Mallo and Dellal, (2012) whereas it was the wide and central midfielders who have the lowest number of injuries during two consecutive season in Spanish professional soccer players. Complementarily, Woods et al (2004) revealed that defenders sustained 15% more hamstring strains than forwards.

has to determine and control precisely the training and the match performance.

change of playing surface which induce an increase of the injury risk.

The injury risk and the type of injury are age dependent. Soligard et al (2010) suggested that most earlier the prevention program is started, greater will be the effect. Literature showed that youth soccer players have between 61-82% of overall injuries located at the lower extremity especially at the ankle (28%) and knee (19%) (Emery and Meeuwisse, 2010; Junge et al, 2002). The incidence of injuries decreases with a specific strength program (resistance training) in youth soccer players during in-season and off-season (Lehnhard et al, 1996). Emery and

adjustment according to the collective training in positioned the exercises before, during or

How and when to use an injury prevention intervention in soccer

http://dx.doi.org/10.5772/56452

265

Additionally, recovery strategies have constituted a prevention strategy in order to reduce injury risk because they decrease the soreness. In, this context, hydrotherapy (after training and matches), a good nutrition and hydration with supplements for some players (during, before or after the training and matches). The technical staff should also considered the warm up, the number of match played (congested period), the change of temperature, the type and

Finally, all these prevention strategies will be efficient if they are include in the training, and considering the individual characteristics of all players as a unique person. However a complementary question is when the players could take part in the collective training after a

and Adam Owen3,5

1 FIFA Medical Excellence Centre, Santy Orthopedicae Clinical, Sport Science and Research

3 Centre de recherche et d'Innovation sur le Sport (CRIS), Université de Lyon 1, Lyon,

4 Research and Education Centre, Aspetar, Qatar Orthopaedic and Sports Medicine Hospi‐

[1] Aagaard P, Simonsen EB, Trolle M, Bangsbo J, Klausen K. Isokinetic hamstring/quad‐ riceps strength ratio: influence from joint angular velocity, gravity correction and

[2] Alonso JM, Tscholl PM, Engebretsen L et al. Occurrence of injuries and illness during the 2009 IAAF World Athletics Championships. Br J Sports Med 2010, 44: 1100-5.

[3] Andersen JC. Stretching before and after exercise: effect on muscle soreness and in‐

5 Glasgow Rangers Sport Science Department (soccer), Glasgow, Scotland

contraction mode. Acta Physiol Scand 1995, 154: 421-427.

jury risk. J Ath Training 2005, 40(3): 218-220.

change of playing surface, and adapted shoes as a preventive strategies.

after the training (or before and after games).

specific injury.

**Author details**

France

tal, Doha, Qatar

**References**

Alexandre Dellal1,2,3, Karim Chamari4

2 OGC Nice, Fitness Training Department, Nice, France

Department, Lyon, France

**Figure 6.** Ligament sprains and muscle strains incidence (per 1000 hours) during each training stage during two con‐ secutive seasons (from Mallo and Dellal, 2012)

Meeuwisse (2010) added that most studies showed a high effect of an intervention until 88% reduction in injuries. Specifically, they showed that prevention strategies including hamstring eccentric exercise, neuromuscular training, warm up, balance board exercise, and core stability induced lower risks for acute injuries, lower extremity injuries, ankle sprain and knee sprains than no intervention strategy in youth soccer players (U13-U18). In this context, injury prevention strategies should be applied very early in youth soccer players' categories.

#### **5. Conclusion**

This particular book chapter has tried to provide an analysis of the main injury prevention strategies commonly used in soccer with the primary aim being to decrease the injury rates during both soccer training and matches. The combination of different prevention methods (functional strength, eccentric strength, isokinetic ratio, core stability, balance, proprioception, stretching, flexibility, stability, work on sand) have not been discussed due to the fact that each of them as a separate method has been reported to reduce the risk of injury.

However, the key point running throughout the chapter is the necessity to individualize prevention programs according to the athlete or players injury history, morphology, gender, age, testing data (e.g. medical and fitness tests) and their playing position. As suggested, preseason training allows a foundation to be provided through general and sport specific training (i.e. specific musculature, joints, tendons) whereas the competitive period needs individual preventive exercises (i.e. aimed at hamstring/quads). Moreover, the prevention exercises need adjustment according to the collective training in positioned the exercises before, during or after the training (or before and after games).

Additionally, recovery strategies have constituted a prevention strategy in order to reduce injury risk because they decrease the soreness. In, this context, hydrotherapy (after training and matches), a good nutrition and hydration with supplements for some players (during, before or after the training and matches). The technical staff should also considered the warm up, the number of match played (congested period), the change of temperature, the type and change of playing surface, and adapted shoes as a preventive strategies.

Finally, all these prevention strategies will be efficient if they are include in the training, and considering the individual characteristics of all players as a unique person. However a complementary question is when the players could take part in the collective training after a specific injury.
