Rototranslational forces that act on the helmet as a result of a shock or an impact are transmitted to the fixing system of the helmet (the retention chinstrap). Those forces, in order to avoid possible damages to the brain or neck due to the acceleration or deceleration , must be reduced by slowing down the rotation of the helmet on the head. The rotation is prevented by the retention chinstrap of the helmet itself (a helmet not equipped with a chinstrap would rotate freely).
During an impact the helmet, thanks to the low friction coefficient with the head - determined both by the presence of the inner comfort padding and by the natural movement of the skin, accentuated by the presence of the hair - is free to rotate till a certain limit, beyond which, to the persistence of force, the chinstrap reacts.
It is just after that process that becomes important to absorb the inertial forces to which the user's head is subjected, and it is just in that situation that SMART STRAP works by modifying its shape and acts as a shock absorber.