Eccentric – Lengthen and refers to movement down towards the earth
To remember what eccentric means use the following mnemonic:
The eccentric professor just seemed to keep lengthening the equation on the blackboard.
And to remember it's down:
Relate the first letter of eccentric to:
E= Look down to Earth
Eccentric = Lengthen
Eccentric = Down
Eccentric would be a lengthening of a muscle and is usually associated with a movement downwards towards earth.
An example of an eccentric contraction would be moving a dumbbell in a bicep curl back down towards the earth. Down being the memorable word.