Abstract: Apparatus is provided for measuring the ability of an athlete to jump vertically from a standing or running position. Such apparatus is useful, for example, in enabling coaches to determine the ability of athletes for such sports as basketball, volleyball, and even competitive swimming. The apparatus includes an upright frame which can be positioned away from any wall or other structure which could interfere with the use of the apparatus. A series of horizontally extending vanes are pivotally mounted one above the other in spaced parallel relationship at the upper end of the frame for individual angular movement about a vertical axis. The vanes are retained in their uniformly spaced and parallel relationship by, for example, a stack of precision spacers, or accurately spaced retaining rings, and axial-loading spring washers, or coil springs. The vanes are mounted so that they may pivot freely about the vertical axis on an individual basis, independent of all the other vanes.