Injuries Have a Negative Impact on Player Progression in an Elite Football Academy

FEATURE / JON LARRUSKAIN

Jon Larruskain, PhD

Football Scientist, Athletic Club jlarruskain@hotmail.com @TheJonLa

Background

Professional football clubs aim to develop future First team players in their youth academies. We, as Sports Medicine and Science practitioners, perceive that remaining injury-free is one of the many important aspects in player development (McCall et al., 2016). However, we often find that players, coaches and academy directors are not aware of the importance of working towards maximizing player availability, or that a gap between awareness and actual practice exists. The impact of injuries on team performance, economy and player health are well established (Ekstrand et al., 2013), but little is known about the influence of injuries on player progression in an academy (Le Gall et al., 2008).

Data exploring the potential consequences of injuries on player progression could be helpful in the challenging task of persuading these key stakeholders of the importance of directing sufcient resources to injury prevention and rehabilitation. Thus, we aimed to investigate the association of injuries with football player continuity, progression and chances of reaching the First team in an elite academy.

Data collection and analysis

Time-loss injuries and exposure time were prospectively recorded following the FIFA consensus (Fuller et al., 2006) in all male players from Athletic Club for over 6 seasons (2011-2017). The First team of Athletic Club plays in the Spanish LaLiga, and the development of academy players is key for the club’s success as the Club’s policy states that only home-grown players or Basque players can play for the First team. The academy has diferent levels or categories according to age: U(Under)12, U14, U16 and U19, with 2 teams in each of these levels; in addition to a Third and a Second team (2nd/3rd teams) comprising 17-23 year-old players (Spanish 4th and 3rd division, respectively). A player obtains First team status after playing 10 ofcial matches with the First team.

Two types of analyses were performed: 1. The aggregated injury data while playing at a certain level was compared between players that progressed and did not progress to the next level. 2. The injury data of individual seasons was compared between players that continued and did not continue in the academy at the end of each season. The impact of injuries sufered in the previous season on player continuity was also investigated.

The main injury-related variables were: • Injury burden (number of days lost/1000 hours; Bahr et al., 2018). • % match availability: (total number of matches – number of matches unavailable due to injury or illness) × 100 / total number of matches. • Whether players sustained the following specific injuries or not: Hamstring muscle injuries, groin pain, anterior cruciate ligament (ACL) ruptures, ankle joint/ligament injuries, severe injuries (+28 days), and injuries requiring more than 100 days (+100 days) or 200 days (+200 days) to return to play.

Injury incidence and burden were compared by calculating rate ratios with 95% confidence intervals and tested using z-statistics. Mixed linear models were used to estimate the influence of match availability and specific injuries on the odds of progressing to the next level or continuing in the academy each season.

Injuries were negatively associated with player progression

Figure 1 shows the burden of injuries and the % of match availability in players that progressed and did not progress to the next level. The main findings show that: • Injury burden was lower and match availability was higher in players progressing from the 2nd/3rd teams to the First team, and from U19 to the 2nd/3rd teams compared to players who did not progress.

Figure 1 - Injury burden (days lost/1000 h) and % of match availability in players that progressed and players that did not progress to the next level. Statistically significant diferences (p < 0.05) are denoted with an asterisk.

• Injury burden was lower in players progressing from U12 to U14. • Injury burden was higher in in players progressing from U14 to U16, and there were no statistically significant diferences in U16 players.

Several factors might explain the negative influence of injuries. Absence from training and matches cause players to lose valuable development time. Some injuries might also have long-lasting physical or psychological consequences, and often-injured players might be perceived as fragile by coaches and directors (Podlog et al., 2011). These factors may result in decreased future playing opportunities and performance compared to their peers.

In contrast, injuries appear to have a lesser efect in the lower levels of the academy. At such young ages, injured players are not required to perform immediately, and they may be promoted based on perceived talent. In addition, all players tend to have equal playing opportunities and sufer fewer long-lasting injuries compared to higher levels.

The injury profle of players reaching the First team

Players reaching the First team had a relatively low injury profile in the 2nd/3rd teams, with: 1. A match availability higher than 84% (Figure 2). 2. No ACL ruptures. 3. No injuries requiring more than 200 days to return to play.

2nd/3rd team players with a match availability higher than 84% had almost 25 times higher odds of progressing to the First team compared to those with a match availability lower than 84%. At this advanced stage availability is crucial, as the First team coach may be looking for new players to improve the squad or fill the position of an injured player. Players have to be on the pitch to showcase and develop their skills, and an unavailable player may lose the opportunity to train or play with the First team. Therefore, although many qualities are required to become a professional player and avoiding injuries is not solely sufcient, injuries and low availability can prevent a talented young football player from playing at the highest level.

Very severe injuries decrease the chances of player continuity

Higher odds of continuing in the academy each season were observed for U19 and 2nd/3rd team players who sustained a +100 days injury compared to players remaining free of such an injury, and there was a similar non-significant trend for +200 days

Figure 2 - The percentage of match availability in 2nd/3rd team players that progressed to the First team and players that did not progress. Each dot represents a player.

injuries and ACL ruptures (Figure 3). This might happen either because they are still recovering from these injuries or because they may be given a second chance to display their potential.

However, players sustaining these injuries had lower odds of continuing in the academy at the end of the ensuing season, suggesting that the time lost or the consequences of these injuries ended up having a negative effect. For instance, ACL ruptures can lead to long-lasting physical and psychological disturbances, in addition to a high risk of reinjury. This results in a high proportion of players not returning to their previous playing level, while those returning might have lower performance and a shortened playing career (Waldén et al., 2016).

Moreover, there was a statistical trend for groin pain to decrease the chances of continuing in the academy in U19 and 2nd/3rd team players. Nevertheless, a better recording system beyond the time-loss definition is needed to understand the burden of overuse injuries. Ankle ligament injuries and hamstring injuries were not negatively associated with player continuity or progression.

Football academies should invest in injury prevention and rehabilitation

In our view, this study presents important messages to football academies: • Preventing injuries and maximizing player availability is important in developing First team players. • Adequate return-to-play strategies are fundamental to get injured players back to their level as safely and quickly as possible and minimize the negative consequences of injuries. • Considering that 9 out of 10 players entering an academy will not become professional footballers, a conscious efort has to be made to protect young players from the negative consequences that injuries could have on their footballing career and future lives.

The results from the present study, when communicated to players, coaches and directors, could help increase their buy-in in injury prevention and rehabilitation. In addition, key decision makers should be educated and discouraged from

Figure 3 - The influence of injuries requiring more than 100 days (+100 days) or more than 200 days (+200 days) to return to play, and anterior cruciate ligament (ACL) ruptures on U19 and 2nd/3rd team players continuing or not in the academy at the end of each season. Statistically significant diferences are denoted with an asterisk (p < 0.05).

using injury data in isolation to assess player potential and decide on player continuity and progression.

Considerations for future work

• Considering the unique policy of the present club, findings might not generalize to other football academies; and it is not possible to infer causality from such a descriptive study. • Injuries occurring in the early years might impair skill acquisition and player development, negatively afecting the likelihood of reaching the highest levels in the future. A larger follow-up period is required to investigate this hypothesis. • Player progression in football is a complex multifactorial process where many other factors interact with injuries to determine future success (e.g., talent, training load, coaching, life stress, schoolwork, psychosocial environment or personality). • Research in young football players is scarce, and large collaborative studies are needed to understand the injury problem in each age group, and to implement tailored prevention and return-to-play strategies (Hall et al., 2020).

Key points

• This is the first study to present data supporting the perception that remaining free of injury is an important factor for academy player progression, especially in U19 and 2nd/3rd team players. • Players progressing from the 2nd/3rd teams to the First team had a match availability higher than 84% and did not sustain an ACL rupture or an injury requiring more than 200 days of recovery. • In U19 and 2nd/3rd team players, very severe injuries were associated with lower odds of continuing in the academy each season, although this efect might not be immediate. • The data from the present study, when communicated appropriately to players, coaches and academy directors, could help increase their buy-in to injury prevention and rehabilitation strategies.

The full scientific article can be found at: https://doi.org/10.1080/24733938.20

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