1. INTRODUCTIONF FOR BIOMECHANICS

2. When we study any part of knowledge we ask ourselves these questions
What
Is the application of mechanical principles on the living organisms.
Why
Via this science we able to solve many medical problems that face the patients
How
Using it on designing exercise programs, orthotics and prosthesis, application of a technique etc… even when we give an advice to a patient.

3. Course Contents Forces Centre of Gravity (COG).
Stability and Equilibrium.
Force Systems.
Simple Body Mechanics.
Motion and Newton’s laws.

4. Biomechanics of bone.
Behaviour of bone under stress.
Stress strain curve.
Possible fracture patterns.
Various loading modes.

5. Biomechanics of fracture fixation.
Soft tissue biomechanics(muscle and cartilage)
Regional biomechanics: hip, knee, shoulder, spine.
normal Gait.
Pathomechanics of Gait.
Mechanics of Posture.

6. Kinesiology &Biomechanics
Kinesiology is the scientific study of human motion. (kinesis and ology)
Biomechanics Is the application of mechanical principles on the living organisms.

7. Causal analysis of motion
Biomechanics
Kinematics
Descriptive analysis of motion e.g. displacement, velocities and acceleration
Kinetics
Causal analysis of motion
e.g. resultant forces

8. Quantitative analysis
kinetics
Study of body in state of rest or equilibrium
Statics
Study of body in state of motion.
Dynamics
Kinematics
Naming and evaluating movement components
Qualitative analysis
Counting and measuring movement components.
Quantitative analysis

9. Forces
Definition:
Physical quantity that tends to change state or shape of an object ( state means the speed or equilibrium). So force can generate, stop, or modify motion.
It’s unit is Newton (N).

10. Force is a vector quantity
That because it has a magnitude and direction. Represented graphically by an arrow(vector) has four characteristics: 1-Magnitude  length 2-Direction  head 3-point of application tail 4-line of application angle with the horizontal (angle of pull).

11. A Vector representing a force
(2)
(1)
(4)
(3)

12. Types of Forces External forces Internal forces G.R.F friction
Gravitational force
G.R.F
friction
pressure
resistance
Internal forces
Muscle forces
J.R.F
Ligaments and tendons

13. Gravitational force
The force that attract any object to the Earth. The force by the gravity on an object is equal to its weight . W = M x (g) (in Newton) (in kg) Where g=9.8m/s or =10 N/kg 2

14. Magnitude= the weight of the body. Direction= downward.
Point of application= the center of gravity.
Line of application= 90 angle (perpendicular to the ground)
(COG is an imaginary point that the body weight can be assumed to be concentrated and equally distributed.)

15. Ground Reaction Force Magnitude = gravity.
Direction opposite to gravity.
Line of application= gravity.
Point of application= point of contact to the ground.

16. Frictional force
It’s the resistance force generated when two surfaces pressed and slide on each others.
Magnitude= the pressure and coefficient of friction (µ) roughness.
Direction=lateral.
Point of application= the surface of contact.
Line of application= parallel to the surface

17. pressure
Definition: It is the total force applied per unit area. P=F/A Measured in (N/m2 ) or pascal

18. Resistance
force that tends to reduce or stop a moving object As air or water resistance, it depends mostly on the surface area

19. Center Of Gravity(COG)
Definition:(center of mass) COG is an imaginary point that the body weight can be assumed to be concentrated and equally distributed, around which body can rotate freely in all direction. At which summation of all moments equal zero

20. Location of COG Depends on the body’s shape and position.
In objects possess a symmetrical shape and it’s mass are equally distributed it is located exactly in the center.
For asymmetrical irregular bodies the COG will be nearer the larger and heavier end.
In normal standing adult person its located anterior to the second sacral vertebra.

21. Factors affect the location of COG in the human body
Age
In newborn: above the umbilicus.
At two years: at level of umbilicus.
At five years: below the level of the umbilicus.
In adults: anterior to the 2nd sacral vertebra.

22. 2-Sex
The COG in males is higher than in females Because of The different mass distribution

23. 3- position of any part in relation to the others
COG is always shifts to the heavy mass e.g. flexion and extension running.

24. 4-Addition and subtraction of weight
By carrying a weight
Pregnancy
amputation