Golgi tendon organs are a type of stretch receptor (similar to motor spindles) which are nerve cells activated by the stretching of tendons. Tendons are stretched when the connected muscle fibres are contracted, and therefore the golgi tendon organs increase activity in an exact opposite manner in relation to muscle spindles (which are activated by the stretching of muscles). Golgi tendon organs are responsible for the conscious perception of the weight of an object when held or lifted.