Mechanics 1 Axis and planes of the body

MECHANICS Study of Forces, and the motions produced by their actions Mechanics can be divided to 2 main areas Statics - associate with non moving systems

Dynamics - associate with moving systems � Kinetics � kinematics

Kinetics ◦ Deals with forces causing movement in a system

Kinematics � Motion of bodies (objects) and systems (groups of objects) without consideration of the forces that cause the motion. � Mainly devided in to two parts, ◦ Osteokinematics ◦ Arthrokinematics

BIO MECHANICS � Application body of mechanics to the living human

KINESIOLOGY ◦ Study of motion How does a person walk ? How does a animal run ? How does a car accelerate / decelerate ?

CLINICAL KINESIOLOGY � The purpose of studying clinical kinesiology is to understand the forces acting on the human body and to manipulate these forces in treatment procedures so that human performance may be improved and further injury may be prevented.

Osteokinematics � Movements � Voluntary � Ex taking place at bones shoulder flexion / extension Hip medial / lateral rotation

Arthrokinematics � Movement taking place at the joint surfaces during osteokinematic movement � Involuntary movements � Main 3 types of movements ◦ Rolling ◦ Gliding ◦ Spinning

Analysis of Osteokinematic movements Anatomical body position � Standing erect � Head, toes and palm of hands facing foreword � Fingers extended

Planes and axis of the body � Three imaginary axes perpendicular to each other � Intersecting each other at the center of gravity �X axis �Y axis �Z axis

Planes of the body � Three imaginary planes � Also called cardinal planes ◦ Frontal plane ◦ Sagittal plane ◦ Horizontal plane

Frontal plane � Coronal plane / XY plane � Parallel to frontal bone � Divide the body in to front and back � Motions occur in this plane are ◦ Abduction and Adduction ◦ Occurs around the Z axis

Sagittal plane � Mid saggital plane / YZ plane � Vertical � Divides the body in to right and left sides � Motion occur in this plane are, ◦ Flexion and Extension ◦ Occur around the X axis

Horizontal plane � Horizontal plane / XZ plane � Divide the body in to upper and lower parts � Movements occur are rotation � Around the Y axis

What are the planes and axis for the following movements ? � A. shoulder abduction � B. trunk flexion � C. 1 st metacarpo phalangeal joint flexion � D. cervical rotation Frontal Saggital Frontal Transverse

FORCES � Simple way of push(compression) or a pull (tension) � Forces acting in the human body, ◦ Gravity ◦ Muscles ◦ Externally applied resistances ◦ Friction Lead to 3 secondary consequences of Joint compression, distraction and pressure

Characteristics of a Force � Created by one object acting on another � Vector quantity � Characteristics of force ◦ Magnitude ◦ Direction ◦ Point of application � 2 types of force that cause motion of the body ◦ INTERNAL �Muscle contraction, ligaments, bone ◦ EXTERNAL �Gravity, weight, friction

Think about a tug of war � If both teams pulls in equal forces – Equilibrium � If one team pulls harder the other slips – Unequal forces � Ground to feet and feet to ground – Action reaction forces

Explain the forces acting on following examples � Person standing on ground � Person hanging from a rope � A man sitting on a chair � A man pushing a wheel chair with a patient � A man riding a motor cycle

Types of forces � Linear forces � Parallel forces � Concurrent forces

Force Couple � 2 forces acting in equal and opposite directions ◦ Creates turning

Newton’s Laws of Motion � Law of Inertia: � Law of Acceleration: � Law of Action–Reaction: ◦ Body at rest tends to stay at rest; body in motion tends to stay in motion. ◦ Acceleration of an object is dependent on the strength of the force applied to it. ◦ For every action there is an equal and opposite reaction.

Forces acting in Angles