Biomechanics

Basics Biomechanics - study of how forces affect a living body Kinesiology – Study of Human movement Ground Reaction Force – a force that is equal to the force you are pushing into the ground. Anatomic Position

Anatomic Position/Locations Anterior - front of body (Chest is located on body’s anterior surface) Posterior - back of body (latissimus dorsi are located on body’s posterior surface) Superior - located above a landmark or closest to head (knee is superior to foot) Inferior - located toward or closest to bottom part of body (foot is inferior to knee) Proximal - located closest to center of body or landmark (she sprained the proximal end of her thumb near her palm while playing softball) Distal - located farthest from center of body (the ankle is distal to the hip) Medial - located closest to midline of body (the nose is medial to the ear) Lateral - located away from the midline (ear is lateral to the nose) Contralateral & Ipsilateral - located on opposite (contralateral) or same side (ipsilateral)

Planes of motion & Axes of rotation Saggital plane Bisects the body into left and right halves Movements: flexion and extension Frontal plane Bisects the body into front and back halves Movements: adduction and abduction Transverse plane Bisects body into top and bottom halves Movements: internal and external rotation, pronation and supination, horizontal abduction and horizontal adduction

Planes of motion & Axes of rotation cont... Medial-lateral axis (Frontal Axis) Rotational axis that runs from right to left Longitudinal axis (Vertical Axis) Rotational Axis that runs vertically Anterior-posterior axis (Sagittal Axis) Rotational axis that runs front to back Rotary Motion: Rotational movement around an axis. (How joint movement occurs) Torque: A force that produces rotational motion. (Muscles produce torque)

Types of Muscle Actions Isometric Activation Muscle produces active force while maintaining same length Concentric Activation Muscle produces active force during shortening cycle Eccentric Activation lengthening cycle

Muscle Origins and Insertion points Origin - stationary attachment site where skeletal muscle attaches/begins Insertion - mobile attachment site Tendons - connective tissues that attach muscle to bone and provide an anchor for muscles to produce force Muscle belly - mid-region in between the origin and insertion

Muscular Dysfunction Muscle Imbalance - incorrect or improper alignment of joints in a body without movements Overactive- state of having disrupted neuromuscular recruitment patterns that lead a muscle to be more active during a joint action Underactive - state of having disrupted neuromuscular recruitment patterns that lead a muscle to be relatively less active during a joint action

Efficiency and Flexibility Flexibility - normal extensibility of soft tissue, which allows a joint to be moved through its full range of motion Relative flexibility - human movement system’s way of finding the path of least resistance during movement Corrective exercise - programming process that identifies neuromuscular dysfunction, develops a plan of action, and implements a corrective strategy as part of an exercise program Neuromuscular efficiency - when the neuromuscular system allows agonists, antagonists and stabilizers to synergistically produce muscle actions in all three planes of motion