1. A method of using an acceleration responsive device for providing an indication of the acceleration attained when the device is moved, which comprises the steps of: preparing a graph which has values appearing along the abscissa thereof relating to an indication of the acceleration attained by the moving device and has values appearing along the ordinate thereof representing the stiffnesses of implements which stiffnesses correlate to the indications of acceleration attained when the device is moved by a user thereof, plotting at least one line on the graph based on data showing the correlation between the various acceleration values and the stiffness values, moving the acceleration responsive device in a prescribed direction to obtain a reading indicative of the acceleration attained during the movement thereof, applying the reading to the acceleration values of the graph, visualizing a perpendicular line from the acceleration reading on the graph to an intersection with the plotted line, and visualizing a line perpendicular to the ordinate from the intersection of the plotted line to the ordinate to obtain a stiffness value reading representing the appropriate stiffness of the implement most suited for use by the user of the device.