 As a brain researcher, this is my opinion on contact sports. Researchers suggest that people who play contact sports are prone to getting longer-term brain injuries and later in their life that might increase their risk of getting dementia. These kinds of sports include high impact sports such as AFL, rugby and boxing, but also lower impact sports such as soccer when you have the ball. The repeated blows and continued impact to the brain and spinal cord involved in these contact sports will ultimately cause the brain's natural protective mechanisms to fail over time causing brain injury. So whilst it's important to stay physically active and involved in the sports that you love to be involved in, there's still a lot of ongoing research to better understand the mechanisms behind the concussive effects on brain injury. So bottom line is it's better to prevent rather than to treat.