The World Cup and Ramadan - the ninth month of the Muslim year, during which fasting is observed from sunrise to sunset - last clashed in 1986. This year, they do so again in spectacular fashion, with both the fasting month and the tournament's Round of 16 beginning last Saturday.

Prior to Brazil 2014, Muslims in a range of sports fasted during their regular club competitions, with seemingly little or no impact. In Australia, Sonny Bill Williams joins Hazem El Masri as rugby league stars who have fasted during a National Rugby League season, and Bachar Houli in Aussie Rules.

National Basketball Association great Hakeem Olajuwon's playing statistics famously improved while fasting in Ramadan. Liverpool and Cote d'Ivoire defender Kolo Toure says his body adjusts after the first few days.

This year, there are several Muslims in teams which have made it to the knockout stages of the World Cup, including at least five players from France, seven from Switzerland's diverse squad, two from Nigeria, three from Belgium, two or three from Germany and most of the Algerian team.

There are several factors that suggest the clash of the World Cup and Ramadan this year won't present a problem.

For a start, there's a general agreement among Muslim scholars that anyone who is travelling is included in the list of Muslims who are exempt from fasting, along with the sick, young children and the elderly.

Several players have said they will still be fasting, and would not be seeking to make up the missed fasting days after Ramadan, as those claiming the travel exemption must do.

Algerian captain Madjid Bougherra has played for a number of European clubs and fasted while doing so.

There is a growing body of research on coping strategies that Muslim athletes can undertake if they wish to continue fasting while playing, as football's governing body Fifa found out.

Ramadan changes not just the amount of food and drink consumed by a fasting Muslim (none at all during daylight hours) but also his or her sleeping patterns (as a fasting person will get up pre-dawn for an early breakfast).

Muslims in general, not just those who play professional sport, are advised to consume a pre-dawn meal consisting of foods that release energy slowly throughout the day, as a listicle widely shared on social media in the days before Ramadan suggests.

Imagine the impact that a change in sleeping patterns and the timing of food and drink consumption might have on a professional athlete's training regimen. Some studies suggest an increase in fatigue and a decline in speed and agility among Muslim athletes.

Others indicate that performance isn't affected by fasting in Ramadan as long as regular training is maintained, and the same amount of nutrients are consumed (at night).

Finally, the Muslim world doesn't have a central authority acknowledged by everyone who follows the faith. This makes the fasting/sport equation even more complex because some religious figures looked up to by the players say that because of the nature of their jobs, they don't have to fast even if they aren't travelling and can make it up later or otherwise compensate for the fast.

Fasting exemptions for sports people are, of course, hotly debated and will probably continue to be discussed at the 2018 World Cup in Russia, scheduled for June 8 to July 8 in a year when Ramadan is expected to last until the first week of the tournament.

In a nutshell, it shouldn't be an issue if Ramadan and the World Cup clash this year, as the players will be covered by the travelling exemption.

Those who don't want to claim this exemption and still fast will be able to draw on the emerging research into how the body is able to adapt to fasting while maintaining physical performance.

The writer is senior lecturer at the School of Media, Film and Journalism at Monash University. This article first appeared in The Conversation (http://theconversation.com), a website which carries analysis by academics and researchers in Australia and Britain.