1. Y12 Physical Education AS90433
Bio mechanics
Biomechanics studies what makes a body
move. It studies internal and external
forces (remember a force is a push or a
pull) that act on the body and other
objects. It is possible to work out how
your body should move in order to
perform a task more efficiently. So for
example we can use biomechanics to
make you a better player!

2. Y12 Physical Education AS90433
Biomechanics Summary
Balance and Stability
Newton's Laws
Force Summation
Projectile Motion
Levers

3. Y12 Physical Education AS90433
Balance and Stability
This is defined as the ability to
hold or maintain a position in
space
Stability generally depends on:
The location of the centre of
gravity (COG) with respect to the
base of support.
The direction of forces involved

4. Y12 Physical Education AS90433
Balance and Stability
Centre of Gravity is the point in the body
at which all body parts are in balance.
In the anatomical position males
generally have a higher COG than
woman.
The body rotates around the COG

5. Y12 Physical Education AS90433
Four Main Principles of Stability
1. The closer the line of gravity is to the
centre of the base of support, the greater
the probability of maintaining balance
2. The broader the base of support, the
greater the probability of maintaining
balance.

6. Y12 Physical Education AS90433
Four Main Principles of Stability
3. Our balance is improved when we lower
our Centre of Gravity in relation to the
base of support. eg:
4. The further one part of the body moves
away from the line of gravity, the
probability of maintaining balance
decreases unless another body part
moves to compensate for it. eg.

7. Y12 Physical Education AS90433
Balance and Stability
We can further increase stability:
Increase Friction eg________
Lean into an incoming Force eg______
Increase Rotation eg________
Increase Mass eg________

8. Y12 Physical Education AS90433
Newton’s Laws of Motion
Newton’s First Law: Law of Inertia
An object at rest tends to remain at rest
unless it is acted on by an external force.
An object in motion tends to remain in
motion and to travel in a straight line with
uniform velocity unless acted on by an
external force.

9. Y12 Physical Education AS90433
Newton’s Laws of Motion
Newton’s Second Law: Law of
Acceleration
When a force acts on a body, it’s resulting
change in momentum is proportional to
the force causing it and inversely
proportional to the mass
Force = Mass x Acceleration

10. Y12 Physical Education AS90433
Newton’s Laws of Motion
Newton’s Third Law: Law of
Action/Reaction
For every action there is an equal and
opposite reaction

11. Y12 Physical Education AS90433
Force Summation
To give an object momentum eg throwing,
kicking, hitting, the amount of
momentum given to the object is
determined by the ‘sum of all forces
generated by each body part’.

12. Y12 Physical Education AS90433
Force Summation
Five Basic Guidelines to generate optimal
force:
Use of body segments
Stretch out
Sequencing of Body segments – larger
first
Timing of Body Segments
Full Range of Motion
See Handout

13. Y12 Physical Education AS90433
Force Summation
Note importance of:
Stabilisation
Timing

14. Y12 Physical Education AS90433
Force Summation
Consider force summation in relation to drawing and driving.

15. Y12 Physical Education AS90433
Projectile Motion
Any object released into the air is a projectile.
eg?
Six Factors Affect a Projectile’s Path
Gravity
Air resistance
Speed of Release
Angle of Release
Height of Release
Spin

16. Y12 Physical Education AS90433
Projectile Motion
Of the six, the most important factors are
Gravity which acts to decrease the
height a projectile will travel and Air
Resistance which acts to decrease
distance.
Note a projectile will travel in a parabolic
curve unless acted on by another
influence

17. Y12 Physical Education AS90433
Gravity and Air Resistance
Gravity
Effects an object at a constant of 10N
Gravity is a weak attractive force but we
cannot escape it!
Air Resistance
Effects the path of a projectile depending
on its mass, speed and/or surface area.
Eg Graph the path of a petanque ball vs a shuttlecock

18. Y12 Physical Education AS90433
The greater the speed of release, the greater
the distance traveled.
Two Parts:
Initial Vertical Speed
Initial Horizontal Speed
The greater the vertical speed: the higher and
longer (time) the projectile will fly.
The greater the horizontal speed: the further it
will fly.
Speed of Release

19. Y12 Physical Education AS90433
Speed of Release
Force = Mass x Acceleration
To increase force can increase one or both. How?
This may create problems such as …
Remember Newton’s Second Law:

20. Y12 Physical Education AS90433
Angle of Release
You need an optimum angle to maximise
the benefits of vertical and horizontal
velocity.
If the angle is too high:
If the angle is too low:

21. Y12 Physical Education AS90433
Angle of Release
•Angling of the release of the bowl
allows for what to occur?

22. Y12 Physical Education AS90433
Height of Release
As the Height of Release increases, so
does the distance that will be gained.
Not really relevant in bowls but definitely in
Petanque – How?

23. Y12 Physical Education AS90433
Spin
In order to cause rotation a force has to be
applied to one side of the COG.
Topspin Causes:
Backspin Causes:

24. Y12 Physical Education AS90433
Levers
Levers consist of 3 parts
1. Resistance
2. Effort
3. Fulcrum or Pivot
1
2
3

25. Y12 Physical Education AS90433
Levers
Two main functions:
To increase the resistance that can be
moved eg__________
To increase the velocity at which an
object will move with a given force. eg
_______
There are 3 types of levers. See handout.