Pivot Machine: A resistance training machine with stacks of weights that the exerciser lifts by pushing or pulling a weight arm that is attached to a pivot point. These machines come as both single-unit machines for one exercise or body area, or multi-unit machines, with several stations for different exercises or body areas. They may use either a fixed pivot or a moving pivot. Some machines use both.
Pivot machines with fixed pivots do not provide equal resistance throughout the range of motion. Therefore the weight will feel lighter or heavier depending on the position of the body. As the weight arm is moved, it changes the position of the weight stack relative to the weight arm's pivot point. As the distance between the weight stack and the pivot point becomes shorter, the exercise requires less effort and as the distance becomes greater, more effort is required. Machines that use a fixed pivot, or a circular pulley, are called 'fixed-resistance' machines.
Pivot machines with moving pivots attempt to solve this problem by allowing the weight stack to move, via a roller, back and forth on a weight arm. This way, when the weight arm is moved to a position that would require less effort, the weight stack moves to a position on the arm requiring more effort. When the weight arm is moved to a position that requires more effort, the weight stack moves to a position requiring less. Like the cam-machine, this is an example of a 'variable-resistance' machine.
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This page created 07 May 2012 02:48
Last updated 07 May 2012 02:49