Hardscience of concussions

rapid acceleration and deceleration of brain can be estimated as follows
a=(v2-v0)/2sg, easily calculates deceleration based on initial speed v0, final speed v2, and distance travelled s. The result obtained is in terms of g, which is equivalent to 10.73 yards per second (Varney and Roberts 1999). Since the final speed is zero after player stops, formula becomes a= -v0squared/2sg. Then, calculate force applies by F=mg. The number 200g force has been proposed as the amount to cause permanent damage but is not really known.