|London Underground - Photo by Billy Haworth|
A 2009 paper addressed this exact question of action-perception linkage by asking: Does the odd sensation emerge because of the unfamiliar motor behaviour itself toward the irregular step-height of a stopped escalator or as a consequence of an automatic habitual motor program cued by the escalator itself (Takao Fukui, Toshitaka Kimura, Koji Kadota, Shinsuke Shimojo, & Hiroaki Gomi). They compared motor behaviour properties toward a stopped escalator with those toward moving escalators, and toward a wooden stairs that mimicked the stopped escalator.
"The results suggest a dissociation between conscious awareness and subconscious motor control: the former makes us perfectly aware of the current environmental situation, but the latter automatically emerges as a result of highly habituated visual input no matter how unsuitable the motor control is. This dissociation appears to yield an attribution conflict, resulting in the odd sensation." - Fukei et al., 2009.
So it seems in this instance at least I am not as awkward as I may have thought, and there is an explanation for this strange occurrence. The way we as people become accustomed to 'normals' in surroundings is interesting, particularly when something 'abnormal' occurs. And I'm sure there are probably other examples of similar odd sensations experienced by our interactions with the places around us, such as the feeling of motion experienced whilst sitting in a stationary train and seeing another train passing by. So if you find yourself one day awkwardly approaching a motionless escalator, you can take some comfort knowing there's an explanation for your odd behaviour.