soccer There have been some studies investigating the effects of heading the ball on the brain[0]. [0] For example: http://www.ncbi.nlm.nih.gov/pubmed/1134768

soccer There have been some studies investigating the effects of heading the ball on the brain[0]. [0] For example: http://www.ncbi.nlm.nih.gov/pubmed/11347686 http://www.ncbi.nlm.nih.gov/pubmed/11347686