Proform Treadmills

treadmills
(treadmill) an exercise device consisting of an endless belt on which a person can walk or jog without changing place
(treadmill) a mill that is powered by men or animals walking on a circular belt or climbing steps
An exercise machine, typically with a continuous belt, that allows one to walk or run in place
(treadmill) a job involving drudgery and confinement
A device formerly used for driving machinery, consisting of a large wheel with steps fitted into its inner surface. It was turned by the weight of people or animals treading the steps
A job or situation that is tiring, boring, or unpleasant and from which it is hard to escape

proform
A pro-form is a type of function word or expression that stands in for (expresses the same content as) another word, phrase, clause or sentence where the meaning is recoverable from the context.
A proform is an expression (typically a word) which has no specific content of its own, but which derives its content from its antecedent.
a form representing another constituent. Pronouns are common proforms, e.g. My little sister saw herself in the mirror.