1. KEY KNOWLEDGEKEY SKILLS  The different parts that make up levers including the axis, force and resistance arms and how they relate to movements  How do centre of gravity, base of support, line of gravity and mass affect the balance and stability of objects and sportspeople?  Explain the application of key biomechanical principles to a range of sporting movements by using correct terms  Investigate and interpret graphs of biomechanical principles pertaining to movements in sports and activities  Participate in, analyse and report on a range of practical activities that consider biomechanical principles  Use biomechanical principles to critique the effectiveness of different movements  Analyse different sporting actions to identify similarities and differences as well as the correct application of biomechanical principles to improve performance. © Cengage Learning Australia 2011

3. The lever arm is the perpendicular distance from the axis of rotation to the force’s line of action Torque is the rotary effect caused by the application of an eccentric force. © Cengage Learning Australia 2011

4. Sometimes more than one force acts on a body When forces acting on a body are equal but applied in opposite directions they create a force couple Force couples produce torque and the object will rotate about its axis of rotation. Force couples © Cengage Learning Australia 2011

5. An object that is motionless = static equilibrium An object moving with constant velocity = dynamic equilibrium Stability is the resistance to change of equilibrium, affected by : Body mass Friction between the body and contact surface Base of support Location of centre of gravity Equilibrium exists when there are no unbalanced forces or torques acting on an object. © Cengage Learning Australia 2011

6. Levers have three main parts: An axis (fulcrum or pivot point) A resistance (weight or load to be moved) A force (effort) Muscles pulling on bones act as levers. © Cengage Learning Australia 2011

7. Lever classification © Cengage Learning Australia 2011

8. First-class levers – resistance and force are on either side of the axis © Cengage Learning Australia 2011

9. Second-class levers – resistance occurs between the force and the axis © Cengage Learning Australia 2011

10. Third-class levers – force between the resistance and the axis © Cengage Learning Australia 2011

11. Levers are used to provide a mechanical advantage. Mechanical advantage = force arm ÷ resistance arm Most levers in the human body are third-class levers and have a mechanical advantage less than 1, which suits them to increased ranges of motion and speed. © Cengage Learning Australia 2011