Tic
A tic is a sudden, repetitive, nonrhythmic motor movement or vocalization involving discrete muscle groups. Tics can be invisible to the observer, such as abdominal tensing or toe crunching. Common motor and phonic tics are, respectively, eye blinking and throat clearing.
Mechanical doping
Motor doping, or mechanical doping, in competitive cycling terminology, is a method of cheating by using a hidden motor to help propel a racing bicycle. The term is an analogy to chemical doping in sport, cheating by using performance-enhancing drugs. As a form of "technological fraud" it is banned by the , the international governing body of cycling.