How does Vibrocore work? 
The low density foam is able to ''reduce the frequency, amplitude, and duration of energy waves traveling through the handlebar. Not only does the low density of the Vibrocore impede the transfer of energy, but as energy waves cross material boundaries from high density to low density within the bar, they are refracted and reflected, reducing their ability to build on oneanother or sustain vibrational frequencies.'' It's all about dealing with energy transfer, which is something that motorbike riders have know for years and are able to somewhat remedy by using weighted bar plugs or other devices to dissipate the buzz of their motor and the terrain. However, those methods are obviously not suitable on a mountain bike that only weighs thirty some odd pounds, which is why the 25 gram weight penalty of the Vibrocore foam over a standard Spike handlebar is so appealing - can it do a similar job while basically weighing next to nothing? Let's also keep in mind that we don't have to deal with high RPM motors, only the terrain under us, so is it really needed?

This cutaway, protected behind a plexiglass case, shows the low density foam that disperse's the buzz that travels up through a rider's hands.