1 A stretch reflex, when the stretch is created by a blow upon a muscle tendon. 2  This is the usual definition of the term. 3  A common example is the standard knee-jerk response when visiting the doctor.4  Deep tendon reflex also usually refers to this sense.5  A deep tendon reflex is often associated with muscle stretching. A stretch reflex, when the stretch is created by a blow upon a muscle tendon. 2  This is the usual definition of the term. 3  A common example is the standard knee-jerk response when visiting the doctor.