Shoulder strengthening systems

1 . An exercise apparatus comprising:

a frame;

a joint pivotably coupled to the frame;

a resistance mechanism coupled to the joint and comprising a first hydraulic member and a second hydraulic member, the first hydraulic member configured to restrict relative motion of the joint about a first axis and the second hydraulic member configured to restrict relative motion of the joint about a second axis; and

a shaft coupled to the joint,

wherein the shaft and the joint are configured to move together relative to the frame about the first and second axes; and

wherein the shaft and the joint move together relative to the frame about a third axis.

2 . The apparatus of claim 1 , wherein the first hydraulic member and the second hydraulic member are coupled to one or more flow valves configured to increase and/or decrease a flow rate of hydraulic fluid delivered to the first and second hydraulic members.

3 . The apparatus of claim 2 , wherein the flow rate of hydraulic fluid modifies the degree in which the relative motion of the joint is restricted by the first hydraulic member and the second hydraulic member.

4 . The apparatus of claim 2 , wherein the degree in which the relative motion of the joint is restricted is directly proportional to the flow rate of hydraulic fluid delivered to the first and second hydraulic members.

5 . The apparatus of claim 1 , wherein the resistance mechanism further comprises a first rotational position sensor and a second rotational position sensor, the first rotational position sensor configured to measure the angular rotation of the joint about the first axis and the second rotational position sensor configured to measure the angular rotation of the joint about the second axis.

6 . The apparatus of claim 1 , wherein the joint is a universal joint, the universal joint having a first pivot axis and a second pivot axis perpendicular to the first pivot axis.

7 . The apparatus of claim 1 , further comprising a wrist-ring structure coupled to the shaft, wherein the wrist-ring structure moves with the shaft and joint about the first and second axes.

8 . The apparatus of claim 7 , wherein the wrist-ring structure comprises a ring, a shuttle movably coupled to the ring, and a brace coupled to the shuttle, the shuttle and brace configured to move along a circumference of the ring and about a first axis of the wrist-ring structure.

9 . The apparatus of claim 8 , wherein the ring is configured to pivot about a second axis of the wrist-ring structure such that the shuttle and brace also pivot about the second axis.

10 . The apparatus of claim 9 , wherein the ring, shuttle, and brace rotate about a third axis of the wrist-ring structure.

11 . The apparatus of claim 1 , wherein the shaft is a telescoping shaft assembly comprising at least a first member coupled to the joint and a second member coaxially aligned with and slidably coupled to the first member.

12 . The apparatus of claim 11 , wherein the telescoping shaft assembly further comprises an adjustment mechanism configured to restrict relative movement between the first member and the second member.

13 . The apparatus of claim 1 , further comprising a support coupled to the frame and configured to abut an arm of a user of the apparatus.

14 . The apparatus of claim 13 , wherein the support is rotatably coupled to the frame such that the support is configured to rotate 360 degrees about a vertical axis of the frame.

15 . An exercise apparatus comprising:

a frame;

a joint pivotably coupled to the frame;

a resistance mechanism coupled to the joint;

a shaft coupled to the joint;

a wrist-ring structure coupled to the shaft, wherein the resistance mechanism is configured to restrict movement of the joint relative to the frame; and

an outwardly extending arm coupled to the resistance system, wherein the outwardly extending arm is hinged to the post and is configured to rotate clockwise and counterclockwise relative to the frame about an axis of the post such that the shaft, the wrist-ring structure, the resistance mechanism, and the joint move together about the axis of the post relative to the frame.

16 . The apparatus of claim 15 , wherein the wrist-ring structure comprises a ring, a shuttle movably coupled to the ring, and a brace coupled to the shuttle, the shuttle and brace configured to move along a circumference of the ring and about a first axis of the wrist-ring structure.

17 . The apparatus of claim 16 , wherein the ring is configured to pivot about a second axis of the wrist-ring structure such that the shuttle and brace also pivot about the second axis.

18 . The apparatus of claim 17 , wherein the ring, shuttle, and brace are rotatable about a third axis of the wrist-ring structure.

19 . The apparatus of claim 18 , wherein the apparatus further comprising a support coupled to the frame and configured to abut an arm of a user of the apparatus, and wherein the support comprises a telescoping shaft and is rotatably coupled to the frame such that the support is configured to rotate 360 degrees about a vertical axis of the frame.

20 . An exercise apparatus comprising:

a frame comprising a post;

a resistance system comprising:

a joint;

a resistance mechanism coupled to the joint and comprising a first hydraulic member and a second hydraulic member, the first hydraulic member configured to restrict relative motion of the joint about a first axis and the second hydraulic member configured to restrict relative motion of the joint about a second axis; and

a shaft coupled to the joint; and

an outwardly extending arm coupled to the resistance system;

wherein the shaft and the joint are configured to move together relative to the frame about the first and second axes;

wherein the outwardly extending arm is hinged to the post and is configured to rotate clockwise and counterclockwise relative to the frame about a third axis.