Although newer carpet is dense enough to allow a chair to roll, carpet fibers and backing are not designed to handle the extreme pressure generated by casters. The down force of a chair is nearly 100 times greater than a footstep! Under this stress, unprotected carpet will lose fibers and backing will break down, shortening the life of the carpet. A chair mat spreads this down-force and prevents damage to carpeting.
Use of a chair mat can significantly reduce lower back and joint strain because casters move more easily across a hard surface. In an eight hour workday, an office worker moves his or her chair more than 250 times per day. Some of these movements may be just inches, but they require up to twice as much effort without a chair mat. Given the frequency of these movements, a workspace without a chair mat is more susceptible to Repetitive Strain Injury (RSI).