Probably due to the repeated trauma associated with heading balls, professional association football has been suggested to increase the incidence of amyotrophic lateral sclerosis.[22] In a 1987 study of former Norwegian association football national team players, one third of the players were found to have central cerebral atrophy, i.e. brain damage.[23] A 1999 study connected soccer to chronic traumatic head injury (CTHI):[24]
[P]articipation in amateur soccer in general and concussion specifically is associated with impaired performance in memory and planning functions. Due to the worldwide popularity of soccer, these observations may have important public health implications
Knee
Anterior cruciate ligaments are particularly vulnerable in most types of football due to injuriesaws of the Game[1] are the codified rules that help define association football. These rules were first played by members of the Cambridge University Football Club on Parker's Piece, Cambridge in 1848, and adopted by the Football Association in 1863. "They embrace the true principles of the game, with the greatest simplicity" (E. C. Morley, F.A. Hon. Sec. 1863) These laws are written and maintained by the International Football Association Board and published by the sport's governing body FIFA. The laws mention: the number of players a team should have, the game length, the size of the field and ball, the type and nature of fouls that referees may penalize, the frequently misinterpreted offside law, and many other laws that define the sport.Today, the above 17 laws are less than 50 pages of a 140 by 215 mm (roughly A5-size) pamphlet. In 1997, a major revision dropped whole paragraphs and clarified many sections to simplify and strengthen the principles. These laws are written in English Common Law style and are meant to be guidelines and goals of principle that are then clarified through practice, tradition, and enforcement by the referees.
The actual law book has long contained 50 pages more of material, organized in numerous sections, that contain many diagrams but did not fit with the main 17 laws. In 2007, many of these additional sections along with much of the material from the FIFA Questions and Answers (Q&A), were restructured and put into a new Additional Instructions and Guidelines for the Referee section. This section is organized under the same 17 law points, consists of concise paragraphs and phrases like the laws themselves, and adds much clarifying material that previously was only available from National organizations and word of mouth among referees.
