<P> Anterior cruciate ligaments are particularly vulnerable in most types of football due to injuries that can be sustained during tackles . </P> <P> An increased incidence of osteoarthritis in the hip joint has been found in retired football players . </P> <P> A 2012 study of association football injuries found that 19% of all injuries were muscle injuries, of which 54% affected the thigh muscles . </P> <P> In a 2009 study, association football was found to be associated with favourable sleep patterns and psychological functioning in adolescent male football players . </P>

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