why is a turbo trainer called a turbo trainer?

sloxam

is it because of the resistance increase from road riding?

john ponting

http://en.wikipedia.org/wiki/Bicycle_trainer

suggests there is no valid reason - marketing speak to differentiate from older style roller trainers

term1te

Perhaps it is because originally the resistance was generated by a turbine, spinning blades in air or a liquid? Turbo is a diminutive of turbine.

Monty Dog

Yup, the first ones used a wind-fan or turbine for resistance, hence turbo-trainer as opposed to a set of rollers.