My friends says this:
"toning " is a process explained in 2 parts. the first of which is to reduce fat around the muscle tissue. The second step to "toning " is the low weight repetitive exercises . Some may argue that this is the same as "building " but it is not building more commonly refers to bulking of muscle or wieght while toning is used to create a more sleak and defined physique .
secondly to further back my point physiotherapists often use slow repetitive low wieght techniques to help there patients with poor muscle definition this is often refered to as "toning" the muscle.
Anyways can you tell him why it doesnt exist, i know he hasnt really backed up his information but dont be mean please just a simple explanation would be good thanks.