treadmill（n.）
踏车是1822年发明（并命名）的，最初是一种监狱惩罚工具，源自于 tread（v.）+ mill（n.1）。类似于驱动机械的 Treadwheel 方法可以追溯到1570年代。
As a corrective punishment, the discipline of the stepping mill has had a most salutary effect upon the prisoners, and is not likely to be easily forgotten, while it is an occupation which by no means interferes with, nor is calculated to lessen the value of, those branches of prison regulation which provide for the moral and religious improvement of the criminal. ["Description of the Tread Mill Invented by Mr. William Cubitt of Ipswich for the Employment of Prisoners," London, 1822]
作为一种纠正惩罚，踏车对犯人产生了极为有益的影响，并且不太可能被轻易遗忘，同时这种职业并不会干扰，也不会减少监狱管理的其他方面，这些方面提供了对罪犯的道德和宗教改造。["Description of the Tread Mill Invented by Mr. William Cubitt of Ipswich for the Employment of Prisoners," London, 1822]
后来被后代视为一种健身方式。
该词起源时间：1822年