Pump systems for use in suspension of a prosthetic device from a residual limb and methods of suspending a prosthetic device from a residual limb are disclosed. The pump systems include a mechanically activated pump having a first compression member coupled to a second compression member, a compressible bladder disposed between the first and second compression members, and coupling elements that engage and couple together the first and second compression members. The mechanically activated pump may be connected with an electrically activated pump within a fluid circuit of a hybrid pump system to provide vacuum engagement between a prosthetic device and a residual limb.