Unit 11 - Biomechanical Theory

Question 1

Biomechanics Definition

Answer 1

concerned with understanding the behaviour and function of the living human body when it is acted upon by forces

Question 2

Newton’s First Law

Answer 2

A body or object either remains in a stationary position or continues to move at a constant velocity, unless an external force is exerted upon it.
Inertia is the property of matter that causes an object to resist any changes in motion.

Question 3

Newton’s Second Law

Answer 3

Newton’s formula (F = ma) describes the relationship between the force acting on an object (F), its mass (m), and its acceleration (a).

Question 4

Newton’s Third Law

Answer 4

A reaction force arises whenever one body exerts a force on another. The reaction force is equal and opposite in magnitude and direction to the applied force.

Question 5

Levers

Answer 5

simple machines

Question 6

Machine

Answer 6

device, consisting of fixed yet interrelated parts, that is capable of altering the direction and magnitude of a force

Question 7

Functions of Levers

Answer 7

• Balance two or more forces
• Provide a force advantage, whereby less effort force is required to overcome a greater resistance force
• Provide an advantage in speed of movement, whereby the load to be moved moves farther and faster than the effort force

Question 8

Linear (or Translational) Motion

Answer 8

This type of motion is also commonly known as rectilinear or straightline motion.
Linear motion takes place when a body or its collective parts moves the same distance, in the same direction, in the same amount of time

Question 9

Angular (or Rotational) Motion

Answer 9

movement of a body about an axis
- the force does not act through the centre of an object or body but rather is “off-centre,” and this results in rotation

Question 10

Centric Force

Answer 10

force applied directly through the centre of an object or body and it results in linear motion only: the object or body will move linearly in the direction of the applied force.

Question 11

Eccentric Force (Off-Centre)

Answer 11

force is a force directed through a point other than the centre of the object or body and it always results in rotational motion (and sometimes linear motion, too)

Question 12

Torque

Answer 12

turning (or twisting) effect produced when a force is applied to a body at some distance from an axis of rotation

Question 13

Class 1 Lever

Answer 13

the fulcrum (the axis of rotation) is located between the point of application of the force (the effort) and the resistance (the load) being moved.
Everyday examples of first class levers include:
See-saws, Crowbars, Pliers, Scissors (two first-class levers joined together), A hammer pulling out a nail
An example in our bodies is - neck as it shifts from a position of flexion to a position of extension

Question 14

Class 2 Lever

Answer 14

the resistance, (the load) is positioned between the point of application of the force (the effort) and the axis of rotation (the fulcrum).
Everyday examples of second class levers include:
Wheelbarrows, Staplers, Doors, Can openers
An example in our bodies is - the ankle joint

Question 15

Class 3 Lever

Answer 15

the point of application of the force (the effort) is located between the fulcrum (the axis of rotation) and the resistance (the load).
Everyday examples of third class levers include:
Brooms, Rakes, Fishing rods, Baseball bats
An example in our bodies is - a person performing a biceps curl
- The biceps muscle (effort) inserts on the radius (at the end of which is the load itself) in combination with the elbow joint (fulcrum)