A liquid buoyancy muscle training device includes a liquid receiving tank receiving and holding liquid therein. A buoyantly submergible member is buoyantly submergible in the liquid contained in the liquid receiving tank and includes a regulation chamber formed therein. A bottom pulley is mounted inside the liquid receiving tank. A rope is connected to the buoyantly submergible member and wrapped around the bottom pulley and extends upward to project outside the liquid receiving tank. A liquid regulation tank is connected through a liquid supply tube to the regulation chamber to allow liquid to flow therebetween. A gas supplier is connected through a gas supply tube to the regulation chamber to selectively supply gas into the regulation chamber to change a ratio between liquid and gas inside the regulation chamber so as to change buoyance applied to the buoyantly submergible member by the liquid contained in the liquid receiving tank.

A weight system having at least one weight stack moveable in a vertical direction on a lift rod, and a bearing block for housing a linear bearing. The invention further includes a method and apparatus for aligning the linear bearing.

In described embodiments, a strength testing device that can be applied to a weight stack is provided. The strength testing device can be used in physical therapy, chiropractics, or other rehabilitation professionals to assess the strength of a patient. The strength testing device can also be used in the fitness industry by strength coaches and personal trainers.

An exercise apparatus comprising a base; a supporting surface carried by the base, the supporting surface to receive a weight bearing portion of a user's body; a support frame carried by the base; a stationary pelvic belt receiving frame carried by the support frame; a pelvic belt rotatably received within the stationary pelvic belt receiving frame and configured to securely receive a pelvic area of the user's body for rotation therewith; and one or more mechanical force resistors carried by the support frame and operably coupled to the pelvic belt so as to impart resistance to rotation of the pelvic belt relative to the stationary pelvic belt receiving frame.

A weight pin for use with a stacked weight exercise machine includes a handle portion, and a shaft portion extending outwardly from the handle portion. The shaft portion is configured to be removably positioned adjacent to one or more weights of the exercise machine to selectively engage the one or more weights during use of the exercise machine. The weight pin also includes interrogation circuitry arranged relative to the handle portion, the interrogation circuitry configured to read information from the adjacent one or more weights.

A permanently affixed and travelling selector pin, car and weight plate selection mechanism for use with physical fitness equipment is disclosed including a segmented track and/or cut out cavern within the plate body for the car to travel within in either vertically or horizontally in order to select a different weight plate or cumulatively, more or less weight for an exercise. The selector pin and car mechanism features a selector pin which is not removable from the car and is inserted through the car which is contained by the track and or plate body shape and into a throughbore in the weight plate in order to engage with the selector stem.

A weight system having at least one weight stack moveable in a vertical direction on a lift rod, and a bearing block for housing a linear bearing. The invention further includes a method and apparatus for aligning the linear bearing.

A selectable weight set apparatus includes a handle assembly including a handle having a first end portion and a second end portion opposite the first end portion. A first weight set is adapted to be supported on the first end portion of the handle and a second weight set is adapted to be supported on the second end portion of the handle. Each of the first and second weight sets includes a plurality of weight plates. An adjustment assembly selects a number of weight plates to be retained to the handle assembly. The adjustment assembly includes at least one selector for movement relative to at least one of the first and second weight sets to engage and select the weight plates in said at least one of the first and second weight sets. A locking assembly fixes the selector relative to said at least one of the first and second weight sets.

An exercise apparatus for performing a back extension exercise comprising: a frame, a seat having a seating surface and a pelvic stabilization pad having a lower back engagement surface, an input arm assembly interconnected by a first interconnection to a first resistance mechanism, the input arm assembly including a manually graspable mechanism and being arranged on the apparatus such that the input arm assembly is pivotable beginning from a start motionless position along a path of travel toward the pelvic stabilization pad under resistance exerted by one or both of the resistance mechanisms, wherein the first resistance mechanism is adapted to increase resistance as the degree of pivoting of the input arm assembly increases along the path of travel away from the start motionless position rearwardly toward the pelvic stabilization pad.

A more efficient exercise system can be facilitated by interactive components. The interactive components can communicate with mobile devices, users, server devices, weight lifting machines, etc. The interactive components can also generate exercise data and provide prompts to a user to facilitate a more efficient workout. Additionally, third parties can receive user workout data and manipulate, or provide guidance to the user to manipulate, exercise equipment remotely to assist a user in attaining his or her goals.