Kinesiology Kinesiology is a multidisciplinary study focusing on exercise stress, movement efficiency, and fitness. The articular system is a series of joints that allows movement of the human body. Where two bones come into contact, a joint articulation is formed, which may be immovable, slightly moveable, or freely moveable. Arthrology is the study of joint structures and functions.

Classification of Joints Synarthroses are joints that lack a synovial cavity and are held closely together by fibrous connective tissue. They are immovable. –Sutures are the joints between skull bones, separated by a thin layer of dense fibrous connective tissue. They begin to fuse together shortly after birth. Once fused, the joints are immovable. –Syndesmoses joints are connected by ligaments and are very slightly moveable; sometimes classified as an amphiarthrosis joint. –A gomphosis is a joint in which a conical process fits into a socket and is held there by ligaments, like teeth held to the jaw bones.

Classification of Joints Amphiarthroses are slightly moveable joints connected by hyaline cartilage or fibrocartilage.

Classification of Joints Diarthroses (synovial joints) are freely movable, with bone ends covered with articular cartilage, and separated by a space called the joint cavity. –Within the joint is a joint capsule; its outer layer is made of ligaments and inner synovial membrane secretes synovial fluid for lubrication. –Piviot joints allow a bone to move around a central axis, creating rotational motion, as in the joint between the atlas and axis of the vertebral column. –Gliding joint allow movement in a sliding motion, as between carpals of the wrist and tarsals of the foot.

Classification of Joints Diarthroses cont. –Hinge joint allow only flexion and extension, as in the two distal joints of the fingers. –Condyloid or ellipsoidal joints can move in many directions, but cannot rotate, as in the joint between the metacarpals and phalanges of the hand or metatarsals and phalanges of the foot.

Classification of Joints Diarthroses cont. –Ball-and-socket joint include those in which one bone’s rounded end fits into a concave cavity on another bone, providing the widest range of movement possible in joints, as in the femur’s connection to the hip bones, or the humerus and the bones of the pectoral girdle. –The saddle joint occurs in the thumb, where the two bones have both concave and convex regions, and allows the thumb to touch each of the fingertips, plus many other movements.

Movements of Diarthroses (Synovial Joints) The stability of a joint is determined by the shape of the bones at the joints, the ligaments that join the bones, and muscle tone, which is usually the main stabilizing factor.

Open and Closed Kinematic Chains In a closed kinematic chain exercise, the end of the chain farthest from the body is in a fixed position. –Examples include squats, push-ups, or pull- ups. –These movements emphasize compression of joints, making the joint more stable. –More muscles and joints get involved, leading to better coordination around each structure.

Open and Closed Kinematic Chains In open kinematic chain exercises, the body part farthest from the body moves the most. –Examples include seated leg extensions and kicking a ball. –These movements involve more shearing force parallel to the joint, making the joint less stable.