Shoulder strengthening systems

An exercise apparatus comprising:

• a frame;
• a base coupled to the frame;
• a shaft assembly that is moveable around each of a first axis and a second axis relative to the base;
• a joint assembly coupling the telescoping shaft assembly to the base, the joint assembly comprising:
• a bracket, wherein the bracket is rotatable about the first axis;
• a first pinion shaft comprising a first shaft portion and a first pinion portion, wherein the first shaft portion is coupled to the bracket, and wherein the first pinion portion is rotatably coupled to the base;
• a first rack having a plurality of teeth meshed with the first pinion portion;
• a second pinion shaft comprising a second shaft portion and a second pinion portion, wherein the second shaft portion is coupled to a base portion of the shaft assembly and the second pinion portion is rotatably coupled to the bracket;
• and
• a second rack having a second plurality of teeth meshed with the second pinion portion;
• and
• a resistance mechanism comprising:
• a first hydraulic member comprising a first housing coupled to the first rack and a first shaft coupled to the base;
• and
• a second hydraulic member comprising a second housing coupled to the second rack and a second shaft coupled to the bracket;
• wherein the first and second hydraulic members are each coupled to one or more flow valves configured to control a flow rate of hydraulic fluid delivered the first and second hydraulic members, wherein the flow rate of hydraulic fluid modifies a degree in which relative motion of the bracket relative to the base is restricted by the first hydraulic member and a degree in which relative motion of the base portion of the shaft assembly relative to the base is restricted by the second hydraulic member.