When the biceps is used to lower the elbow to a straight position, it is called eccentric extension.
What is eccentric extension?
Eccentric extension is the slowing down of body movements when you try to resist gravity.
These involve lengthening muscle contractions which are specific for a muscle.
When you are squatting, the slow motion of you going from a standing position to sitting one is an example of eccentric contraction.
Examples of eccentric contraction for the bicep muscles include extension of elbow during a bicep curl and lowering of the forearm away from the shoulder.
Our body muscles are stronger in the lengthening (eccentric) phase of its motion, as compared to the shortening (concentric) phase.
