WJEC Biomechanics

1. Biomechanics 4

2. Learning Outcomes
Be able to:
• Name 3 things that effect how far a projectile
travels horizontally
• Explain what effects the optimal angel of release
• Explain what a parabola flight path is and what
causes deviations from parabola flight path.

3. Projectile motion

4. Projectiles e.g.
• Athlete who propels themselves in to the
air such as high jumper or long jumper in
athletics
• Object hit, thrown or kicked in to the air
such as shot put, badminton shuttle,
football
• When an athlete breaks contact with the
ground or objects are released, they
become projectiles

5. Release of projectiles
Three factors effect the horizontal distance a
projectile travels:
• The angle of release
• The velocity at release
• The height at which released

6. Optimal angle of release
Depends on - release height & landing height
RH = LH
Optimal angle = 45 degrees
E.g. Lofted pass in football
RH>LH
Optimal angle<45degrees
E.g. Shot put RH<LH
Optimal angle> 45degrees
E.g. Bunker shot in golf

7. Task 1
With a partner decide whether the
optimum angle of release is equal to,
less than or greater than 45 degrees.
•Racing dive in swimming
•High jump
•Underarm serve in volleyball
•Long jump
•Tennis serve

8. Velocity of release
Increase release velocity to
increase horizontal distance
travelled
E.g.
•Speed at run up for Long
Jump
•Speed of rotation on hammer
throw

9. Height of release
Consider two shot putters
Providing angle and velocity
of release the same for both,
the taller shot putter will
achieve a greater distance
because of height of release.

10. Projectiles and forces in flight
Projectiles that have a large weight force and small air resistance force e.g.
shot puts, follow paths close to a true parabola.

11. Deviations from parabolic flight path
• Objects travelling at high speeds e.g. golf balls
• Objects that have large cross sectional area e.g. footballs
• Objects that do not have a smooth surface e.g. badminton shuttle
………all these incidents have distorted parabola.
……….the golf ball will follow a flight path closer to a true parabola than a table
tennis ball because it is heavier

12. Task 2
• Using the text books and iPads
investigate how the “Bernoulli
Principle” and the “Magnus Effect”
affect the flight path of an object
• And produce a short presentation
using Explain Everything.

13. Projectiles and lift
If projectile can gain some lift during flight, it will stay in the air longer and
achieve a greater horizontal distance.
Best way to introduce this is to think of an aeroplane wing and how this works.
Fast flow – pressure low
Slow flow- pressure high
Bernoulli Principle
Rounded shape pushes air over it and
makes it travel further than air
underneath the wing.

14. BERNOULLI EFFECT
• ONLY TALK ABOUT THE BERNOULLI
EFFECT IF THE OBJECT IS NOT
ROUND eg a discus, a javelin, a rugby
ball

15. Magnus Effect – types of spin
Top Spin
View from side
Ball Dips
Decreases distances travelled
Slice
View from top
Ball deviates right
Hook
View from top
Ball deviates left
Back Spin
View from side
Ball floats
Increases distances travelled

16. Magnus effect
Direction of travelDirection of travel
Direction of spin
Faster moving air creates low pressure
underneath the ball
Slower moving air creates high
pressure above the ball
Pressure
always
moves
from high
to low –
this
causes
the ball to
dip as it
travels

18. Question: Explain the flight path of each projectile (10)

20. How have you applied your knowledge of
biomechanics to improve performance in your sport?
• I know what planes of movement are involved and I
have done a movement analysis & worked out which
muscles are required. I have mimicked the movements in
my training. Eg a football throw-in is an example of
movement in the saggital plane – the agonist muscle is
the triceps and the latissimus dorsi. I have used an
appropriate weight training activity for the triceps which is
the triceps press in the gym. For the latissimus dorsi I
have used the Lat pull-down machine.

21. Other ideas:
1.Making use of training
equipment eg perform centre
that involves movement in all
direction – not just one plane
of movement
2.Analysis of a golf swing – abduction of
the lead shoulder / adduction of the
trailing shoulder – an eg of movement
in the frontal plane – muscles used
deltoids, latissimus dorsi & pectorals
?

22. How have you applied your knowledge of
biomechanics to improve performance in your sport?
• Using my knowledge of levers - I have made the
best use of levers when I serve in tennis. I know
that more power can be generated when I use a
longer lever.I toss the ball high and make contact
with the ball when it is as high as possible. This
has improved the speed of my serve.

23. Other examples
1.Selection of appropriate
club for a shot in golf
2.Cricket bowling –
releasing the ball high in
bowling
?

24. How have you applied your knowledge of
biomechanics to improve performance in your sport?
• Newton’s Laws –
1. Inertia -
2. Acceleration – as a footballer - the larger the
force applied – the further the football will
travel into the opponents half.
3. Reaction – as a cricketer – the bat applies a
force in the opposite direction to the ball

25. How have you applied your knowledge of
biomechanics to improve performance in your sport?
• I have used my knowledge of fluid mechanics.
• As a footballer / cricketer / golfer I know that I can
use the Magnus force to change the flight of the
ball………………..example in a practical
situation: curve a free kick past defence, apply
back spin to a cricket ball, apply top spin to a
tennis serve, make a golf shot curve around a
tree

26. Observation & analysis
observe
analyse
evaluatefeedback
plan
30-50%
remembered

27. Bio-
mecha
nics
Notatio
n
tests Questi
on-
naires
video
technical
Tactical
Physical
behavioural

28. Possible question:
• The question might ask you to focus on
only one area………..”What methods
could you use / could the coach use to
analyse the technical aspects of a
performance?”
• For technical – talk about “the perfect
model”

29. Health screening & PAR-Q
• Physical Activity Readiness
Questionnaire

30. Field testing & Lab testing
• Numbers involved
• Cost
• Accuracy