LONDON, Feb. 29 (Xinhua) -- Concussion substitutes will give a go in trials, agreed the International Football Association Board (IFAB) in Belfast on Saturday.

IFAB held its 134th Annual General Meeting in Belfast. The world football's rule-making body agreed to draw up protocols to be used in trials for substitutions in cases of concussion. The men's and women's football matches at this year's Tokyo Olympic Games would probably take part in the trials.

The Annual General Meeting also agreed to review the offside Law to foster the spirit of attacking play and to continually look at measures within the Laws of the Game to tackle mobbing of match officials and confrontations between players which should have no place in the game.

Members were updated on the use of video assistant referees (VARs) around the world, highlighting the success of this innovation, while also considering future developments, including improving communication and potential technological advances.

The IFAB is made up of the four British football associations (England, Scotland, Wales and Northern Ireland) and FIFA. It is the only body authorized to decide and agree changes to the Laws of the Game.