Human power is work or energy that is produced from the human body. It can also refer to the power (rate of work per time) of a human. Power comes primarily from muscles, but body heat is also used to do work like warming shelters, food, or other humans.World records of power performance by humans are of interest to work planners and work-process engineers. The average level of human power that can be maintained over a certain duration of time is interesting to engineers designing work operations in industry.Human-powered transport includes bicycles, rowing, skiing and many other forms of mobility.Human-powered equipment is occasionally used to generate, and sometimes to store, electrical energy for use where no other source of power is available. These include the Gibson girl survival radio, wind-up or (clockwork) radio and pedal radio.