1. Basic Biomechanical Factors and Concepts
Anatomy and Physiology
Zgabay

2. Outline
Introduction
Levers
Anatomical Levers
Laws of Motion

3. Biomechanics
________________- study of the mechanics as it relates to the functional and anatomical analysis of biological systems and especially humans
Necessary to study the body’s mechanical characteristics & principles to understand its movements

4. Biomechanics ____________- study of physical actions of forces
Mechanics is divided into:
____________

5. Biomechanics
_____________- study of systems that are in a constant state of motion, whether at rest with no motion or moving at a constant velocity without acceleration
Statics involves all forces acting on the body being in balance resulting in the body being in equilibrium
_____________- study of systems in motion with acceleration
A system in acceleration is unbalanced due to unequal forces acting on the body

6. Biomechanics Kinematics & kinetics Mechanical advantage
___________- description of motion and includes consideration of time, displacement, velocity, acceleration, and space factors of a system‘s motion
___________- study of forces associated with the motion of a body
Mechanical advantage
Load/effort or load divided by effort
Ideally using a relatively small force, or effort to move a much greater resistance

7. Outline
Introduction
Levers
Anatomical Levers
Laws of Motion

8. Introduction to Levers
__________: Simple machine that operates according to principle of torques
__________: The turning effect of a force
T = _____

9. d F How can you change torque? 1. __________ 2. __________
3. ________________ F

10. d
Optimal direction = 90 degrees F

11. Function of Levers
Two functions:
1. __________
2. __________

12. Function of Levers Force Common traits? Examples? ____________
____________ vs. ________________

13. F R

14. Function of Levers Speed/ROM Common traits? Examples? Rigid bar
Fixed point
Lever movement vs. resistance movement

15. F R

16. Components of a Lever System
Fulcrum: _______________________
Force:
______________________
Moment arm: d
_________________

17. More Concepts ____________ advantage ____________ disadvantage
Levers designed for force
____________ disadvantage
Levers designed for speed/ROM

18. F R Mechanical advantage or disadvantage?
How does mechanical advantage affect movement of the lever?

19. Advantage: Small effort moves big resistance
Disadvantage: Big movement required to move resistance a small distance

20. Human Application? Lever? ________________________ Fulcrum?
Applied force?
Resistance force?

21. Classification of Levers
Lever classification based on the relative location of:
1. Axis of rotation/fulcrum (A)
2. Resistance force (R)
3. Applied force (F)
A R F

22. First Class Lever ____________: (A) – Axis of rotation/fulcrum
Mechanical advantage
Mechanical disadvantage
Examples
___________

23. Advantage or disadvantage?

24. Second Class Lever ___________: (R) – Resistance force
Mechanical advantage
Always
Mechanical disadvantage
Never
Examples
_______________

26. Third Class Lever ___________: (F) – Applied force
Mechanical advantage
Never
Mechanical disadvantage
Always
Examples
______________

27. Baseball, tennis?

28. Human Application First class lever
_____________________________________

29. Mechanical advantage or disadvantage
(R) – Resistance force
(F) – Applied force
(A) – Axis of rotation/fulcrum

30. Human Application
Second class lever
_____________________

31. Mechanical advantage or disadvantage?
Not many in the body

32. Human Application
Third class lever
______________________

33. Mechanical advantage or disadvantage?
Many of these in body

34. In general, is the human body built for force application or speed/ROM?