Motion resistance mechanism and treadmill adjustable resistance device composed of same

A motion resistance mechanism comprises a stand column, an upper installation base and a lower installation base are installed on the stand column, an adjustable elastic pull rope resistance mechanism is arranged on the upper installation base and the lower installation base, the mechanism comprises an upper wheel base and a lower wheel base, the upper wheel base is rotationally connected to the upper installation base, and a first fixed pulley and a second fixed pulley are rotationally installed on the upper wheel base; the third fixed pulley is rotationally connected to the lower portion of the upper mounting base, the lower wheel base is rotationally connected to the lower mounting base, and a fourth fixed pulley and a fifth fixed pulley are rotationally mounted on the lower wheel base; the sixth fixed pulley is rotationally connected to the upper part of the lower wheel seat; and the elastic pull rope passes through the space between the first fixed pulley and the second fixed pulley, downwards bypasses t