The following is an excerpt from <a href="http://www.hpv.org/">HPV Deutschland e.V.</a>. "Human-powered vehicles include land, air and aquatic vehicles. These vehicles are powered solely by human muscles. They don't use any form of stored energy." HPVs can be divided into three main categories: Air = Human Powered Aircraft (HPA), Sea = Human Powered Boats (HPB), Land = <a href="/Sports/Cycling/Human_Powered_Vehicles/Recumbent/">Recumbents</a> and <a href="/Sports/Cycling/Human_Powered_Vehicles/Handcycling/">Handcycling</a>.