Figure 2.

Diagram of methods used to add inertia and weight to the backboard. (a) Inertia was added by adding masses (plate weights used for resistance training depicted as black circles) symmetrically about the pin support. The added inertia from each plate weight was md², so the added inertia of all four plate weights was 4md². (b) Weight was added by applying a horizontal force (F) to the back end of the arms, which resulted in a moment about the pin support that tended to rotate the body forward.