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Put your flag up - he's just offside!

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We all hear it; "he was just offside"... But is he?

There is a theory which is used and applied at all levels of football, all the way from the FIFA select referees at the top of teh game to the likes of myself when lining on the SWPL. The Flash-Lag Effect.

So, what is it?

The Flash Lag Effect is a misconception of a position of a flash relative to that of a moving object. Even when both are at the same position, the flash is reported to lag behind the moving object. It is an error in localization that consists of perceiving a flashed object to lag behind a moving one when both are presented in physical alignment.
    Previous studies have addressed the question if it is the predictability of the flash, or the moving object, that modulates the amount of error. Scientific studies have proved that the human eye and brain function tells the person [in this case the AR] that the moving object [the forward] is far more advanced than the stationary object or the object moving in the opposite direction [the defender].
    Top ARs are aware of the Flash Lag Effect and practice hard to factor it into their thought process when considering whether a player is in an offside position. They also know that the faster the players are moving, the more tolerance they have to factor in to their decision making. This is why close offsides are the most difficult calls in the game. The AR has to override what his own eyes and brain are telling him and, if they make a correct call, when it appears to every person in the stadium including himself that he is incorrect, then that call is of genius proportions


Basically, due to light and the way our brain interprets information that it recieves from our eyes, it is easy for us to create a picture in our mind which isn't a true representation of the actual event. Basically, our eyes pick up changes in light. Light has a speed in which it travels (300,000 km/s). If you have an item moving at a constant speed, and another item beyond it (further away from us) travelling slightly faster, when they are alligned, it appears to us that the faster item is in front of the slower item, when in reality (because of the light and our brain's processes), they would actually be in-line.

Have I lost you yet? Basically, by understand and accepting the flash-lag effect, Assistants are able to be confident in their understanding that if a player looks "just" offside, he is actually onside (obviously depending on speed). 


I'm a bit crap at explaining this as I really only understand the concept, not the theory behind it. If you're interested in seeing what the hell I'm on about, take a look at the two websites below. View them in order. Let me know what you think


Have a play with the speeds. Believe it or not, they are pulsing in-line every single time.


How the Flash-Lag effect is applied to football:





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There's a lot more to it @TheolderIgetthebetterIwas. I only learnt about this at a Development Day at the beginning of the season which was taken by Premier League Assistant (and Cornwall's most senior official), Simon Long. Whe. It's applied correctly, it really is fantastic. Of course there can be times when it's not as clear as I've made out, but it right a lot more often than it is wrong. And it's been proven that it's much more effective than guessing whether he's inside or not. 

Hopefully, those that don't run the line or officiate will see this (and hopefully kinda grasp the concept) and realise that there's so much more to offside than meets the eye. The laws themselves take a lot of understanding, particularly the "is the player active and interfering" concept. 

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I would have got that right every time - hawk eye they used to call me.:thumbsup:

Used to run the line until a couple of minor altercations with spectators....nobody  calls me a cheat - ever.

I used to say to the players....you don't stand offside - and I won't flag you.

Trouble with running the line...you don't watch the game.

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