Abstract: A backstop or target particularly suited for use in athletic applications such as baseball or golf, and which includes a frame from which a flexible net is suspended at its corners and connected to a plurality of linear displacement sensors. As the net is displaced due to the impact of a projectile such as a ball, tension is applied to the cords which in turn move the axially-moveable components of each linear displacement sensor. In one embodiment, the linear displacement sensors utilize a light beam and photoelectric detector to plot the time intervals at which equally-spaced indices on the axially-moveable component pass a predetermined point. This data is used to determine position, velocity, or trajectory of the projectile relative to the initial plane of the net using direct geometric and trigonometric calculations.