1st new concept: "secondary play" (ice & roller skating)

"secondary play" is the 1st new concept introduced, as intended & written (2/7/13)
(s.p. - conceptual approach, through cross industry knowledge)
it represents the axial and/or radial play of the:
(i. s.) - grinding wheel, relative to the shaft it is mounted on;
           (could appear when the grinding wheel is/becomes loose, or is fixed/becomes
           decentered, on its rotating shaft; dangerous, as the grinding wheel rotates at high speeds;
           serious injuries may occur, by flying grinding wheel pieces, if this breaks while
           rotating, due to this type of  play; always keep in safe distance  from a sharpening
           machine in operation.
           the grinding wheel's secondary play (axial and/or radial), even taken without any
           abnormal values of the axial and/or radial play of its shaft bearings, could mean damages,
           even beyond repair, to the ice skates' blades.
(r. s.) - rollers, relative to the bearings they are mounted on
            the rollers' secondary play (axial and/or radial), even taken without any abnormal
            values of the axial and/or radial play of  their respective bearings, could mean serious
            crashes, particulary in speed skating, downhill, etc....

bearings' axial and/or radial play, became so much more important in ice & roller skating
competitions, of any kind.

secondary play, as a new concept, for the first time defined, might only add up as information
for the casual skater; but in terms of competition & performance in skating, plays a role & has
to be dealt with, accordingly.