A complex of proteins that is responsible for energy, usually ATP hydrolysis-dependent, intracellular movement of an organelle or smaller structure along a cytoskeletal filament; e.g. the microtubule-anchored spindle motor, the actomyosin engine. The action of a motor is conceived as a duty cycle of working and recovery strokes, like the action of oars in a rowboat. During the recovery stroke, a point of contact is broken ('the oars come out of the water') to prevent reversal. The duty ratio, then is the fraction of total cycle time that contact at any single point is maintained; it can vary between 0 and 1, and for a bundle of myosin filaments with many heads (like the many oars of a trireme, approaches 0.