Definition: In table tennis, mechanical spin is an informal term used by players to describe how spin is produced with a rubber that does not have a very grippy or tacky topsheet. It is considered that the spin is produced by the ball sinking into the sponge underneath the topsheet, allowing more of the topsheet to wrap around the ball to produce spin.
In comparison, rubbers that have very grippy or tacky topsheets are said to produce topsheet spin.
