biomechanics 4 2014

Biomechanics 4

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.

Projectile motion

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

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

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

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

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

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.

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.

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

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.

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.

BERNOULLI EFFECT

• ONLY TALK ABOUT THE BERNOULLI

EFFECT IF THE OBJECT IS NOT

ROUND eg a discus, a javelin, a rugby

ball

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

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

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

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.

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

?



• 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.

Other examples

1.Selection of appropriate

club for a shot in golf

2.Cricket bowling –

releasing the ball high in

bowling

?



• 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



• 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

Observation & analysis

observe

analyse

evaluatefeedback

plan

30-50%

remembered

Bio-

mecha

nics

Notatio

n

tests Questi

on-

naires

video

technical

Tactical

Physical

behavioural

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”

Health screening & PAR-Q

• Physical Activity Readiness

Questionnaire

Field testing & Lab testing

• Numbers involved

• Cost

• Accuracy

biomechanics 4 2014

Education