a disruption in neurological functioning following a significant impact to the head or elsewhere on the body resulting in extreme acceleration or deceleration of the brain within the skull.
This causes a biochemical imbalance within brain cells as well as decreased blood flow and temporary energy deficits within the brain.
Following a suspected concussion, a player should be immediately removed from play, assessed and placed on complete rest in order to recover from the energy deficit. Studies have shown that any activity, both mental and physical, in the immediate days following a concussion can delay the process of recovery and should be avoided until the athlete is completely symptom free.