Bone mass fortifies and regenerates as repeated stress is placed on them. Shape/type of articulation: explain what a rigid segment model is. Shows where the joints are and how long the segments are which helps to define the basic properties of movement. Dorsal back of the hand, top of the foot. A plane is a flat surface in which movement occurs in. An axis is the point at which body segments rotate around. Explain what the x, y and z axes refer to. The mechanics of structure and function for the process of biological movement. Statics -> remain still and not moving (bridge) Acceleration is the change in velocity over a period of time. Velocity is the change in displacement over a period of time. To provide analysis to improve both effectiveness and efficiency. Effective movement -> getting the results expected from the movement performed. Efficient -> getting the maximum amount of output for the effort put in.