Right, a concussion is caused by sudden acceleration of the skull relative to the brain. The acceleration is the result of momemtum transfer, not energy transfe

Right, a concussion is caused by sudden acceleration of the skull relative to the brain. The acceleration is the result of momemtum transfer, not energy transfer, and momentum is always conserved. Therefore, to first order, the key factors should be the mass of the projectile, the speed of the projectile, and the combined mass of the skull+helmet. Spreading the impulse over a slightly longer time with energy absorbers should help a little, but im skeptical of the size of the effect without making the helmet significantly larger. Given the comparison with military helmets, It sounds like this design might be more about bleeding energy from projectiles to prevent penetration, so the sports claims seem confusing.