A definition of exercise

I'm just posting this here as a reference.

Ken Hutchins has developed his very precise definition of exercise:

Exercise is a process whereby the body performs work of a demanding nature, in accordance with muscle and joint function, in a clinically controlled environment, within the constraints of safety, meaningfully loading the muscular structures to inroad their strength levels to stimulate a growth mechanism within minimum time.

(I copied this from Analyzing the Definition of Exercise but he has published this in lots of places before.

I have had some enjoyable correspondence with Ken in recent years - virtually all my training is now Timed Static Contraction - and I have refined the definition in my mind at least, trying to express the ideas in a way that I understand them.  Hopefully they are as precise as Ken would like

Exercise is the application of mechanical tension to muscles, in accordance with muscle and joint function, within the constraints of safety, loading the muscular structures optimally to inroad their strength levels with the aim of stimulating a mechanism that strengthens muscle and promotes beneficial change in other systems in the body.