Patent attributes
An impact-absorbing assembly includes a covering layer being one or more of artificial turf, rubber mats, polymer mats, short pile carpeting, particulate infill, wood chips, and ground rubber chips. Also included is a layer of underlayment panels positioned beneath the covering layer. The panels have a panel section with a plurality of drain holes formed therethrough. A top surface of the panels is configured to support the covering layer. A bottom surface of the panels has a plurality of bottom projections that cooperate to define bottom channels suitable to permit water flow across the bottom surface, the bottom channels being in fluid communication with the panel drain holes. The bottom projections define a first spring rate characteristic that is part of a first stage and a second spring rate characteristic is part of a second stage, the first stage having a smaller volume of material than the second stage.