Biomechanics Activity Analysis

One thing I do everyday is get out of my bed in the morning. I sleep on my side usually, so my starting position would be on my right side with my knees and hips already in a slightly flexed position. The first thing I do to begin getting out of bed is sit up. In order to do this, I use my right arm which is on the bed to push myself up. During this, my wrist, elbow, and shoulder joints are all extending until I am sitting up right. My shoulder joint is also abducting as my torso moves away from my arm. My hips are flexing more to allow my legs to fall over the side of my bed to put my feet on the floor upon sitting up. In order to stand up, I have to flex at my hip joint slightly to bend forward and then slightly dorsiflex my feet (to maintain balance) and extend at the knee and hip joints to stand upright. My end position is standing upright with my elbow, hip, and knee joints in a neutral position.

All actions that are flexion and extension in the knee, hip, wrist, elbow, and shoulder occur in the sagittal plane on a frontal axis. The abduction of my shoulder occurs in the frontal plane on a sagittal axis. The osteokinematics of my elbow joint from flexion to extension to push myself to a seated position are in a closed kinematic chain. Regarding arthrokinematics, the convex humeral segment glides posteriorly and rolls anteriorly on the concave ulnar surface. The prime mover for elbow extension is the triceps brachii muscle and it is performing a concentric contraction.