Looking at the body in rob(ot) form.

Every night before going to bed I do a quick workout; I do 50 sit ups, 30 lunges on each leg, and 30 bicep curls.  When I start my bicep workout, my elbows are in full extension. Once I lift the weights closer to my shoulders my elbows are in a flexed position. Flexion is done in the sagittal plane and that occurs around the frontal axis. The osteokinamtics of this action would be considered an open chain because the distal regions of my arms are moving; however my scapula or trunk remains stable. In reference to arthokinamatics, the radius would be considered concave and the distal region of the humerus would be considered convex. In this activity the humerus would be the stable bone, and the radius would be the moving bone. In essence, the concave bone moves on the convex bone; meaning they are rolling in the same direction anteriorly. The primary mover for this activity are the biceps, and they are doing concentric movements. The antagonist, are the triceps.