Last month we explored the evidence base supporting the notion that athlete availability reduces your team’s chance of success. That post included a number of sources that demonstrated an association between injury rates and success. It may seem obvious but it is important to have the evidence to back up this notion. This information can help support the need for, and implementation of, strategies that may help to reduce the risk of injury.
With that post fresh in mind, I was interested to see the publication of the following paper online:
Windt, J., Ekstrand, J., Khan, K. M., McCall, A., & Zumbo, B. D. (2017). Does player unavailability affect football teams’ match physical outputs? A two-season study of the UEFA champions league. Journal of Science and Medicine in Sport.
Johann Windt is publishing some fantastic papers as part of his PhD, including:
It is interesting to investigate the association between availability and success in more detail. Here the authors have started to explore what might mediate this relationship. The study used two seasons worth of data from the UEFA Champions League.
It has been established that match-to-match variability of physical outputs, particularly high-speed activities, are high. This was reported by Professor Warren Gregson and colleagues in 2011. To account for this variability, Windt and colleagues used linear mixed modelling to calculate within-team variation and included stage (group stage/knockout), venue (home/away), score differential, ball possession (%), team ranking (UEFA Club Coefficient), and average team age as covariates.
The results of the study (as per the abstract) were as follows:
Teams’ average player unavailability was positively associated with the average number of sprints they performed in matches across two seasons. Multilevel models similarly demonstrated that having 4 unavailable players was associated with 20.8 more sprints during matches in 2015/2016, and with an estimated 0.60–0.77% increase in the proportion of total distance run above 14 km/h in both seasons. Player unavailability had a possibly positive and likely positive association with total match distances in the two respective seasons.
They concluded that player unavailability was associated with an increase in teams’ match physical outputs. This reinforces the need to maintain high levels of fitness throughout the entire squad. Players coming into the starting lineup need to be prepared to meet the demands of a game. At times of greater unavailability, players may need to be prepared to potentially meet even higher physical game demands. Maintaining a high chronic workload in substitute and fringe players, despite low match minutes, is an important albeit challenging prospect for support staff, in order to avoid spikes in workload when others become unavailable. Of course this is only one study, in one sport and one competition, but further highlights the implications of injuries beyond unavailability for selection alone.