Biomechanics Activity Analysis: Packing a Backpack

Every morning I pack my backpack for school. When I reach my arm, forearm, and hand out to grab my materials, I am starting in a full extension position in a sagittal plane. After I have grabbed my materials, my fingers are in a flexed position also occurring in the sagittal plane, around a frontal axis. My arm then moves into flexion as the materials get to my bag. The Osteokinematics of the arm and fingers include extension to flexion, specifically when the arm is extended and the fingers are moving into flexion with the arm then moving into flexion during an Open Kinematic Chain. In regards to Arthrokinematics and the Convex/Cocave Rule, the moving surface, such as the Ulna, is concave and is moving closer to the Humerus, which is Convex. The Concave surface is rolling and gliding in the same direction in order to move the two closer together. The prime movers for the arm while moving into flexion in order to bring the materials to the bag would be the coracobrachialis, biceps brachii, and the brachialis which are performing a concentric contraction. The biceps Brachii would be in charge of arm extension during the eccentric contraction.