Understanding the concept of levers and their types can be highly beneficial to people in various ways.

1. 2015/2016
[ Levers in human
body ]
Vinod Baitha
Sports Sciences & Biomechanics

2.  Introduction
 When person is moving his leg -
arms - any part of his body
He depend on his Skelton
system (muscle forces)
by contraction or extension
muscles.
 In fact the bone in moving work
as A lever
 Levers cannot be changed, but they
can be utilized more efficiently .

3.  levers
 Definition of levers
A rigid bar that turns about an axis of rotation or a
fulcrum .
 Parts of a lever
- FulcrumAxis of rotation of the lever .
- Effort Arm The part of the lever that the effort force .
- Resistance Arm The part of thelever
that applies the resistance force .

4.  Classification of levers
 First Class Lever
A first-class lever is a lever in which the fulcrum (Axis) is located
between the input effort (Force) and the output load (Resistance).
 Second Class Lever
Resistance (load) is located between the effort arm and the
fulcrum .
 Third Class Lever
The effort force is located between the fulcrum and the resistance .

5.  The 3 Classes of
Levers
| |
ForceArm |
A
R
F
| ForceArm | | ResistanceArm |
R
| Resistance Arm |
A
|
F
A
R
| ForceArm
ResistanceArm
F
|
• FAR
1st
• ARF
2nd
• AFR
3rd

6.  1 st class of lever in human body
 The joint between the skull and the atlas vertebrae of the
spine the spine is the fulcrum across which muscles lift
the head .

7.  The joint between the hummers and radius – ulna .

8.  2 nd class of lever in human body
 The Achilles tendon, pushing or pulling across the heel of the foot.

10.  3 rd class of lever in human body
 The elbow joint: when lifting a book, the elbow joint is the
fulcrum across which the biceps muscle performs the work.

12.  Benefit from lever ?
 Increase power
 Increase distance
 Increase speed
 Transfer power from one place to another
 precision in work safety
 Avoid risks

13.  Reference
www.dynamicscience.com.au/tester/solutions/hydraulicus/simplem
ach ineslevers1.htm
http://www.montgomery.k12.ky.us/camargo/Projects/simplemachin
es/ simplemachines.htm

http://www.dynamicscience.com.au/tester/solutions/hydraulicus/hu
man body.htm