The FENCING RESPONSE is a 100% indication that there has been a loss of consciousness (LOC) and a 100% indication that the person has sustained a concussion. Loss of consciousness is known to occur in less than 10% of all concussion injuries, and the fencing response is seen in approximately 2/3 of these. The fencing response can be seen from the sideline as a players arm or arms go rigid (extended straight up in the air as they are lying on their back, and is a tell-tale sign of LOC. This also