Callum Scotson in the context of "Human-powered land vehicle"

Human-powered land vehicles are land vehicles propelled over ground by human power, The main ways to support the weight of a human-powered land vehicle and its contents above the ground are rolling contact; sliding contact; intermittent contact; no contact at all as with anything carried; or some combination of the above. The main methods of using human power to propel a land vehicle are some kind of drivetrain; pushing laterally against the ground with a wheel, skate, or ski that simultaneously moves forward; by pushing against the ground directly with an appendage opposite to the direction of travel; or by propeller. Human-powered land vehicles can be propelled by persons riding in the vehicle or by persons walking or running and not supported by the vehicle.

Many human-powered land vehicles can also be gravity-powered land vehicles, and vice versa, although some of the latter are quite awkward to use as the former. For example: street luges, gravity racers, and snow boards.