Abstract: A brake assembly comprising a spindle, two components having concave part-cylindrical bearing faces embracing a cylindrical portion of the spindle, and a housing accommodating the components and carrying an adjuster for urging the bearing faces of the components into engagement with the surface of said portion of the spindle. The bearing face of each component either comprises a single material or surface portions of different materials having relatively high and relatively low coefficients of friction so that when the bearing faces of the components are urged into engagement with the spindle they provide resistance to turning of the spindle while at the same time providing a low friction bearing for the spindle. The assembly may be incorporated in an exercising apparatus comprising a frame, a seat and a handlebar, the assembly being supported by the frame and the spindle carrying pedals to be turned by a user to rotate the spindle against resistance to turning of the spindle.