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MECHANICS AND BASIC BIOMECHANICS ppt.pptx
- 1. MECHANICS AND BASIC BIOMECHANICS BY-DR. RISHIKAYADAV MPT CARDIOPULMONARY
- 2. Biomechanics A humanbody is a complex of structure and has many function, the study of mechanics in human body is termed as Biomechanics. It consist of two areas :- Kinetics :- area of biomechanic s which includes study of motions Kinematics :- It is defined as the study of function or forces which are producing that motion to maintain it in equilibrium.
- 3. Kinetics Study offorces Forces are of two types Internal force:- forces that are arise from sources with the human body. E.g. muscles, bones, ligament. External forces:- These are the pushes and pulls of the body arises from sources outside the human body. E.g. Gravitational forces. (there are some other forces like friction and atmospheric pressure which act both internally and externally)
- 4. kinematics Study ofmotions There are three types of motions Angular motion Translatory motion Curvilinear motion
- 5. Angular motion:- the movement of the motion to the joint axis each point on the object moves through the same angle at the same time and constant distance on the axis of rotation. Translatory Movement:- when the movement of the object at the straight line and each point of the object moves through same angle and same time and in parallel direction. Curvilinear Motion :- when an object rotate about an axis and moves through space at the same time is known as Curvilinear Motion.
- 6. Arthokinematics It refersto the movement of joint surface in this one joint surface is more stable and serves as a base for motion while other surface moves on this fixed base. It thas three types of Motions Roll:- it refers to the rolling of one joint surface on another as a tier rolling on the road. Spins :- it refers to a rotation of a movable component as when a top spins Gliding:- it is pure translatory motion refers to gliding of one component to another.
- 7. Osteokinematics Movement ofbone rather than movement of articulating surface. The normal ROM sometimes known as anatomic and physiological ROM because the normal range refers to the amount of motion available at a joint within an anatomical limit of joint structure. ROM is considered to be pathological when a motion of the joint either exceed or decrease to reach the normal anatomical limit of motion. When ROM increase normal limits the joint is hypermobile and when ROM decreases the joint is hypermobile.
- 8. Kinematic chain Thetype of motion that occur in the joints of limb and when a person is standing can be described by kinematic chain which are of two types Open kinematic chain :- when the ends or distal parts of the limb are free without causing motion on another joint is called open kinematic chain. Close kinematic chain :- when the ends or distal parts of the limb are fixed on the ground is called close kinematics chain.
- 9. Forces Force isthat which alters the state of rest of a body or its uniform motion in a straight line. A single force applied to a body, which is free to move, causes movement in the direction of the force. a. Two forces acting in the same direction and at a common pointare equivalent to a single force acting in that direction, whose magni- tude is equal to the sum of the magnitudes of the individual forces. b. Two equal forces acting at a common point, and in opposite directions, will result in a state of equilibrium. c. Two unequal forces acting at a common point and in opposite directions will result in movement in the direction of the greater force.
- 10. Continue.... d. Sometimesit is inconvenient to apply force in a particular direction and in these circumstances two forces acting at an angle to each other may be compounded to produce the desired effect. e. Two unequal forces acting at different points and in opposite direc- tions produce rotation of the body
- 11. WORK Workis defined as the product of force and the distance through which the force acts. It is measured in joules or ergs. ENERGY Energy is the capacity of a body for doing work. Potential Energy is the capacity for doing work by virtue of position and a body's capacity for doing work because of its velocity is called Kinetic Energy. FRICTION Friction is the force which opposes motion when one surface slides upon another. It may be sufficient to prevent movement altogether, e.g. as in the case of rough surfaces or substances, such as rubber, when they are in contact with one another.
- 12. POWER Poweris the rate of doing work or the rate of energy expenditure. It is measured in joules per second or ergs per second. ACCELERATION Acceleration is the rate of change of velocity. A positive accelera- tion causes an increase and a deceleration, or retardation, a decrease in velocity. MOMENTUM The momentum of a body is the quantity of motion it possesses, and it is represented by the product of mass and velocity. The force responsible for the momentum will generate movement slowly in a relatively heavy body and more rapidly in a lighter body. INERTIA Inertia is the resistance of a body to any change in its state of rest or motion. A body at rest tends to remain at rest indefinitely, while a moving body tends to continue moving at a constant speed and in a straight line unless acted upon by a force. Inertia may be defined as the reversed effective force of a body.
- 13. NEWTON'S LAW Newton'slaw of Inertia :- the object will remain at rest or in uniform motion unless acted by unbalance force . Newton's law of acceleration:- it states that acceleration is proportional to unbalanced force acting on it and inversely proportional to the mass of an object A=F/M Newton's law of reaction :- To every action there is equal and opposite reaction.
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