Abstract: A method to automatically calibrate a load cell without the need to remove the loading on the load cell. This method takes advantage of the fact that weight stack strength equipment uses generally known discrete weight increments, and any signal drift in the load cell can be automatically recalibrated by offsetting the load cell signal to accurately reflect the expected discrete weight increments without the need for unloading the load cell and without the need for a manual recalibration of the load cells.

Abstract: A method to automatically calibrate a load cell without the need to remove the loading on the load cell. This method takes advantage of the fact that weight stack strength equipment uses generally known discrete weight increments, and any signal drift in the load cell can be automatically recalibrated by offsetting the load cell signal to accurately reflect the expected discrete weight increments without the need for unloading the load cell and without the need for a manual recalibration of the load cells.

Abstract: Disclosed is an exercise machine providing an upper body exerciser portion adapted for use with a lower body exerciser and having a semi-dependent retraction system. The exercise machine generally includes a frame adapted to be mounted on a lower body exerciser (though standalone versions are also disclosed) and the upper body exerciser consisting of first and second user members for pulling by a user to provide pull forces, single retraction means for providing retraction forces to the user members sufficient to retract them back to their start positions after being pulled out, and, non-floating combining means coupled to the single retraction means for making the retraction forces semi-dependent on the pull forces, and thereby reducing travel of the retraction means, by coupling the single retraction means to both user members. Drive and resistance means are further provided.