Patent ID: 8419600

Claim:
Resistance training exercise apparatus comprising a load system for providing resistance comprising an axially extending tubular housing having an inner cylinder wall extending axially from an axial end wall, a piston in said housing and engaging said cylinder wall in sealing relation and axially slidable therealong, a connector link extending from said piston and coupled to a user-engaged exercise member, said piston defining a vacuum load chamber in said housing between said piston and said end wall, said piston moving in a first axial direction away from said end wall to increase the volume of said vacuum load chamber, said piston moving in a second opposite axial direction toward said end wall to decrease the volume of said vacuum load chamber, wherein movement of said piston in said first axial direction creates vacuum in said vacuum load chamber, which vacuum provides load resistance resisting exercise movement of said user-engaged exercise member, wherein said piston has an axial travel stroke between a rest position and a loaded position, wherein said piston moves in said first axial direction from said rest position to said loaded position and is resisted by vacuum load resistance due to said vacuum created in said vacuum load chamber, wherein said vacuum urges said piston to move in a second axial direction to return to said rest position from said loaded position, wherein said vacuum load chamber has a one-way valve blocking ingress of air into said vacuum load chamber and permitting egress of air from said vacuum load chamber, whereby to accommodate leakage of air past said piston into said vacuum load chamber and permit expulsion of such leakage air from said vacuum load chamber upon movement of said piston in said second axial direction, to facilitate movement of said piston to said rest position.