Exercise machine with unstable user support

An unstable user support for supporting a user in a seated position while performing an exercise on an exercise machine, comprising:

• a base;
• an unstable user support platform configured to support the user in the seated position while performing the exercise;
• the unstable user support platform pivotally mounted on a U-shaped base mounting bracket for free rotational tilting movement about at least one non-vertical axis;
• and
• a joint which provides the pivotal connection between the base and the unstable user support platform;
• a stop assembly between the base and the unstable user support platform which limits tilting movement from a centered support position to a predetermined angular range;
• and
• a base support member positioned a vertical distance above the base, wherein the U-shaped base mounting bracket is secured to an upper surface of the base support member.

An exercise machine, comprising:

• a stationary main frame having a forward end, a rear end, and opposite sides;
• an unstable user support assembly mounted on the main frame and adapted to support a user in a seated position during an exercise;
• an exercise arm assembly movably mounted relative to the main frame and having a user engaging portion which is adapted for engagement by a part of the user's body to perform the exercise when the user is supported in the seated position on the unstable user support assembly,
• wherein the unstable user support assembly comprises:
• a base having a U-shaped base mounting bracket comprising a horizontal bottom member and two spaced apart vertical side members extending upwardly from the horizontal bottom member;
• an unstable user support platform configured to support the user in the seated position while performing the exercise;
• the unstable user support platform pivotally mounted on the U-shaped base mounting bracket for free rotational tilting movement about at least one non-vertical pivot axis in at least two opposite directions between first and second tilted end positions, the unstable user support platform having a centered support position between said first and second tilted end positions;
• and
• a stop assembly between the base and the unstable user support platform which defines the respective first and second tilted end positions and limits tilting movement from said centered support position in each direction to a predetermined angular range;
• and
• wherein the base is secured to the main frame.