A lever is a mechanical device which produces turning action about an axis

1. LEVER
ACTION
BY
CHANDRAKANT BARIK
NIS COACH
KALINGA STADIUM COMPLEX IN-CHARGE

2. Definition
•A lever is a mechanical device which producesturning action
about an axis
The skeletal and muscularsystems work together to move your
body parts.
•Some of these body parts can be thought of as simple
machines or lever. Human moves through a system of
levers.
•Levers cannot be changed, but they can be utilized more
efficiently.

3. Parts of lever

4. Parts of lever
1.A rigid bar which turns around a fixed point called fulcrum / Axis .
•In human body rigid bar is bone and fulcrum / Axis is joint.
2.The main force for operating the lever is provided by muscles
(Power / Force / Effort
3. The action of operating the lever is resisted by weight (Resistance /
weight / Load).
4. The distance from force to axis is called Force arm(FA)
5. The distance from resistance to axis is called Resistance arm(RA)

6. Axis
Force Resistance
ForceArm
Resistance Arm

7. Axis
Force Resistance
ForceArm Resistance Arm

8. TYPE OF LEVER
1. 1st order lever / 1st class lever / Type1 lever
2. 2nd order lever / 2nd class lever / Type2 lever
3. 3rd order lever / 3rd class lever / Type3 lever
1 lever
In the first order lever, the axis is in between the force and the resistance.
• Example:
• Sea-Saw
• Balance
• Scissors
• Plantarflexion • Plantarflexion
• Hyperextension of neck
• Extensionof the forearm

14. 2nd order lever / 2nd Class lever / Type 2 lever
In a lever of the second order, the resistance point lies in
between the fulcrum and the point of application of force.
• Examples:
• The opening of a door
• Handcart
• Lemon squeezer
• Nut cracker
• The push-up
• Heel raise
• Push-up
• heel raise
•Type 2 lever always favors force (because FA is bigger than RA)

18. 3rd Order lever / 3rd Class lever / Type 3 lever
• In this class of lever, the point of application of force lies in
between the fulcrum and the resistance.
Examples:
• Fire tong
• Forceps
• Elbow flexion
• Dorsiflexion
• Hitting a hockey ball
• Kicking a football
• Elbow extension
• Dorsiflexion
• •Type 3 lever always favors Speed (because RA is bigger than
FA)

23. Advantagesof lever
1. A lever increases the speed, range or power of muscular contraction.
2. 2. To gain mechanical advantage (MA).

24. THANK YOU