A weight plate to be coupled to a post of a weight lifting apparatus so that said weight plate can be lifted by said post in response to a lifting force applied thereto, said weight plate comprising: a weight plate body; a bore hole extending through said weight plate in which to receive the post; a hollow channel that extends in the weight plate body communicating with said bore hole at a first side of the bore hole; a locking cavity formed within the weight plate body and communicating with said bore hole at an opposite side of the bore hole such that said hollow channel and said locking cavity are aligned with one another; and a pivotal switch arm having first and opposite ends and being rotatable through said weight plate, the first end of said pivotal switch arm receiving a force for causing said switch arm to rotate through said hollow channel in either a first direction to an unlocked position at which the weight plate is uncoupled from the post or in an opposite direction to a locked position at which the weight plate is coupled to the post so as to be lifted thereby, the opposite end of said pivotal switch arm being sized to move into locking engagement with said post within said bore hole and to extend completely through said bore hole for receipt by said locking cavity when said pivotal switch arm is in said locked position wherein the opposite end of said pivotal switch arm is a fork having first and second fingers and a space lying between said first and second fingers, said first and second fingers extending completely through said bore hole for receipt by said locking cavity such that said post is located within the space between and engaged by said first and second fingers when said pivotal switch arm is rotated to said locked position. a weight plate body; a bore hole extending through said weight plate in which to receive the post; a hollow channel that extends in the weight plate body communicating with said bore hole at a first side of the bore hole; a locking cavity formed within the weight plate body and communicating with said bore hole at an opposite side of the bore hole such that said hollow channel and said locking cavity are aligned with one another; and a pivotal switch arm having first and opposite ends and being rotatable through said weight plate, the first end of said pivotal switch arm receiving a force for causing said switch arm to rotate through said hollow channel in either a first direction to an unlocked position at which the weight plate is uncoupled from the post or in an opposite direction to a locked position at which the weight plate is coupled to the post so as to be lifted thereby, the opposite end of said pivotal switch arm being sized to move into locking engagement with said post within said bore hole and to extend completely through said bore hole for receipt by said locking cavity when said pivotal switch arm is in said locked position wherein the opposite end of said pivotal switch arm is a fork having first and second fingers and a space lying between said first and second fingers, said first and second fingers extending completely through said bore hole for receipt by said locking cavity such that said post is located within the space between and engaged by said first and second fingers when said pivotal switch arm is rotated to said locked position.