Effect of the moon on soccer injuries

What is it about?

According to folklore, full moons are traditionally associated with insomnia, insanity (hence the terms lunacy and lunatic) and various magical phenomena such as lycanthropy. However, although there are numerous references in the literature to humans shapeshifting into wolves dating back 2 millennia, recent scientific literature reported that the moon cycle does actually impact several psychological and physiological variables in humans. For instance, full moon has been related to reduced sleep quality and an increase in the aggressive behaviour of humans. To establish if lunar phases somehow do affect injuries in soccer players, an international group of researchers studied the effects of circa-lunar periodicity on the risk of football injuries. The results were published in Chronobiology international journal. The study team monitored injuries and player exposure in the premier professional league in Qatar during four consecutive seasons (2013–2014 through 2016–2017). Data were collected according to standardized tools under the ASPREV program (Aspetar injury and illness prevention). Acute injuries (sudden-onset (traumatic) were analyzed while gradual onset injuries (overuse) were excluded. Over the 4 seasons, 1184 injuries (587 from contact with another player and 597 without player contact) were recorded during matches and training and were thereafter classified according to the following lunar cycle characteristics on the date of injury: (i) moon illumination, (ii) lunar distance from earth and (iii) tidal coefficient, acquired from the lunar calendar and tide tables from Qatar. Authors explained that to maximize the potential effects of moon illumination, we analysed data from Qatar, characterized by less than 2 weeks of overcast skies per year and where football players typically train and play matches after dark to avoid sun radiation during hot periods of the year. In this context, and on a funny note, data from the Premier League in England would have been of limited value; indeed, British football fans are haunted not only by limited success in recent World Cups, but frequently also by fog, clouds and rain. Geography and weather conditions therefore also be borne in mind when interpreting results from previous studies investigating the effects of moon on humans and/or animals. Daily injury count was modelled using Poisson regression to reveal no relation between injury-rates and: moonlight (i.e. % of moon illumination), the gravitational pull of both moon and earth (i.e. tidal coefficient) and both apogee and perigee (i.e. moon earth distance). So, as far as these results are considered, any link between a football player injury and the moon cycle remain spurious.

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Photo by v2osk on Unsplash

Photo by v2osk on Unsplash

Why is it important?

Playing football (soccer) is by many regarded as a modern expression of ‘lunacy’, as regularly expressed through the behaviour of fans, players, and managers alike. An equally consistent consequence of playing football is injuries which have been shown to be impacted by poor sleep and/or aggressive playing style. But is there any impact of Lunar myth on football players’ injuries? "Stellar cases of sports injuries serve to highlight the current research question. For instance, the Swedish striker Zlatan Ibrahimovic suffered an adductor injury on the 12th September 2011, which corresponded to a perfect full moon night. However, when, he severely injured his right knee on the 20th April 2017, marking his career end, moon illumination was of only 43%. On the 12th August 2017, Usain Bolt, the world’s premier sprinter, suffered a hamstring injury on the way into his career-final appearance, while the moon was at 82% illumination". So, this question of potential link between moon and sport injury deserves more attention.

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