momentum 2017 - st leonard's college · momentum 2017 session 2: examining the biomechanical...

Momentum 2017

S E S S I O N 2 :

E X A M I N I N G T H E B I O M E C H A N I C A L P R I N C I P L E S T H AT C A N B E A P P L I E D W H E N A N A LY S I N G A N D I M P R OV I N G M OV E M E N T S K I L L S U S E D I N P H Y S I C A L A C T I V I T Y A N D S P O R T

R A C H A E L W H I T T L E

Session overviewIntroduction

Curriculum overview

Key knowledge and Key skills

Biomechanical principles:◦ Kinematic concepts of human movement

◦ Kinetic concepts of human movement

◦ Equilibrium

©RWHITTLE 2017 2

Curriculum overview

©RWHITTLE 2017 3

Unit 3: Movement skills and energy for physical activity

This unit introduces students to the biomechanical and skill acquisition principles used to analyse human movement skills and energy production from a physiological perspective. Students use a variety of tools and techniques to analyse movement skills and apply biomechanical and skill acquisition principles to improve and refine movement in physical activity, sport and exercise. They use practical activities to demonstrate how correct application of these principles can lead to improved performance in physical activity and sport.

http://www.vcaa.vic.edu.au/Documents/vce/physicaledu/PhysicalEducationSD_2017.pdf

Curriculum overview

©RWHITTLE 2017 4

Area of Study 1

How are movement skills improved?

This area of study examines the biomechanical and skill acquisition principles that can be used to analyse and improve movement skills used in physical activity and sport. Through coaching and involvement in practical activities, students investigate and analyse movements in a variety of activities to develop an understanding of how the correct application of biomechanical and skill acquisition principles leads to greater efficiency and accuracy in movement skills.

Outcome 1

On completion of this unit the student should be able to collect and analyse information from, and participate in, a variety of physical activities to develop and refine movement skills from a coaching perspective, through the application of biomechanical and skill acquisition principles.


Key knowledge and key skills

©RWHITTLE 2017 5

Key

knowledge

perform

interpret

discuss

explain

reportapply

participate

observe

analyse

KEY KNOWLEDGE

biomechanical principles for analysis of human movement including:

◦ angular and linear kinetic concepts of human movement: Newton’s three laws of motion, inertia, mass, force, momentum and impulse

◦ angular and linear kinematic concepts of human movement: distance, displacement, speed, velocity, acceleration and projectile motion (height, angle and speed of release)

◦ equilibrium and human movement: levers (force, axis, resistance and the mechanical advantage of anatomical levers), stability and balance (centre of gravity, base of support and line of gravity)

KEY SKILLS

◦ perform a qualitative analysis of a movement skill using video and systematic observation to analyse and to analyse and improve a variety of movement skills

◦ analyse, interpret and apply graphical, visual and physical representations of biomechanical principles to improve movement skills in a coaching context

©RWHITTLE 2017 6


Biomechanics

Kinematic ConceptsLINEAR

◦ Distance

◦ Displacement

◦ Speed

◦ Velocity

◦ Acceleration

◦ Projectile motion

ANGULAR

◦ Angular distance

◦ Angular displacement

◦ Angular speed

◦ Angular velocity

◦ Angular acceleration

©RWHITTLE 2017 7

Angular speed and velocity

◦ Angular speed - the angular distance travelled divided by the time taken to cover the distance

◦ Angular velocity - the rate of change of angular displacement over time

◦ Speed of rotation is important in sports such as diving, gymnastics and dancing, where athletes need to complete rotations during limited flight time.

◦ Angular velocities increase with the difficulty of the skill being performed. The angular velocity required to complete a single rotation is not as great as the angular velocity required to complete a triple rotation.

©RWHITTLE 2017 8

Projectile motion◦ Angle of release

◦ Height of release

◦ Velocity of release

What is the desired outcome of the movement skill?

What impact does varying one factor have on the flight path of the projectile?

What is the relationship between each of the factors?

©RWHITTLE 2017 9

Kinetic conceptsLINEAR

◦ Newton’s three laws of motion

◦ Inertia

◦ Mass

◦ Force

◦ Momentum

◦ Impulse

ANGULAR

◦ Newton’s laws of angular motion

◦ Moment of inertia

◦ Torque

◦ Angular momentum

©RWHITTLE 2017 10

Summation of momentum

o To kick or throw or hit powerfully you need to be able to generate a large force or great acceleration.

o Sequential summation of momentum results in maximal force production:

©RWHITTLE 2017 11

Large body parts initiate the movement and provide a base of support

Smaller, faster body parts, area all involved in the movement

o Use the large muscles of the thighs and trunk first. These body parts have a large mass but move slower.

o Each body part is then sequentially accelerated, transferring momentum from the large and slow body parts to the lighter faster moving body parts.

o Each body part is stabilised before the momentum is transferred.

o By using as many body parts as possible, the time over which the force is applied is maximized.

o Follow through is important so that the last body part doesn’t slow down before the ball is released, kicked or hit.

Impulse – momentum relationship

Momentum = mass x velocity◦ p = mv

How is momentum different to inertia?◦ A stationary object has inertia but not momentum

How can you change an objects momentum?◦ Apply a force – the larger the force the greater the change in momentum.

Impulse = force x time◦ I = Ft

Change in momentum = change in impulse◦ △Ft = △mv

The greater the impulse the greater the change momentum.

Think catching, shot put, swimming, rowing.....others?

©RWHITTLE 2017 12

Equilibrium◦ Levers (force, axis, resistance and mechanical advantage)

◦ Stability and balance (centre of gravity, base of support and line of gravity)

©RWHITTLE 2017 13

First class lever

Second class lever

Third class lever

The role of levers

©RWHITTLE 2017 14

What is the purpose of the lever?◦ Increase force?

◦ Increase speed?

◦ Increase range of motion?

Mechanical advantage◦ A mechanical advantage greater than 1

means that the force required to move the load is less than the force of the resistance.

◦ In simple terms this means that in this type of lever system, a greater weight can be moved with less effort.

◦ All second-class levers have a mechanical advantage greater than 1.

©RWHITTLE 2017 15

Mechanical advantage ◦ Most lever systems in the human body are third class.

◦ This means that anatomical levers will have a mechanical advantage of less than one.

◦ Levers in the body are designed to increase the speed and range of motion of the lever, the arm or leg for example.

©RWHITTLE 2017 16

Balance and stability

Factors affecting balance:◦ Base of support

◦ Centre of gravity

◦ Line of gravity

◦ Mass of the body

©RWHITTLE 2017 17