BiomechanicsBiomechanics

Newton’s Laws of MotionNewton’s Laws of Motion

• There are three laws that you need There are three laws that you need to be able to apply to volleyball.to be able to apply to volleyball.

Newton’s 1Newton’s 1stst Law – The Law Law – The Law of Inertiaof Inertia

• “ “ A body continues in its state of rest or A body continues in its state of rest or uniform motion unless an unbalanced force uniform motion unless an unbalanced force acts upon it”acts upon it”

• Basically once something is at rest or Basically once something is at rest or begins moving it will keep doing so until begins moving it will keep doing so until acted upon by another force.acted upon by another force.

• Inertia – is a Inertia – is a body’s tendency to remain body’s tendency to remain at rest or in motionat rest or in motion. The more mass an . The more mass an object has the larger its inertia. object has the larger its inertia.

ExampleExample• When performing a When performing a

chest pass, unless a chest pass, unless a player applies a force player applies a force through the hands to through the hands to pass the ball, the ball pass the ball, the ball will sit in the players’ will sit in the players’ hand, remaining at rest. hand, remaining at rest.

Your turnYour turn• Write below/alongside how you could Write below/alongside how you could

apply Newton’s 1apply Newton’s 1stst Law to a Volleyball Law to a Volleyball Skill. SETSkill. SET

Newton’s 2Newton’s 2ndnd Law – The Law Law – The Law of Accelerationof Acceleration

• ““the acceleration of an object is the acceleration of an object is directly proportional to the force directly proportional to the force causing it, is in the same direction as causing it, is in the same direction as that force, and is inversely that force, and is inversely proportional to the mass of the proportional to the mass of the object.”object.”

• Bigger force = bigger acceleration.Bigger force = bigger acceleration.• Smaller mass = bigger acceleration.Smaller mass = bigger acceleration.• Force = mass X accelerationForce = mass X acceleration

ExampleExample

• If a person hit a golf If a person hit a golf ball and a cricket ball ball and a cricket ball with a cricket bat, the with a cricket bat, the golf ball will accelerate golf ball will accelerate quicker because it has quicker because it has less mass.less mass.

• The ball will accelerate The ball will accelerate quicker when hit with a quicker when hit with a large amount of force large amount of force (front foot drive) than (front foot drive) than with a less forceful with a less forceful stroke (forward stroke (forward defensive)defensive)

Your turnYour turn• Write below/alongside how you could Write below/alongside how you could

apply Newton’s 2apply Newton’s 2ndnd Law to a Volleyball Law to a Volleyball Skill. SERVESkill. SERVE

Newton’s 3Newton’s 3rdrd Law – The law Law – The law of reactionof reaction

• ““For every action there is an equal For every action there is an equal and opposite reaction”and opposite reaction”

• Whenever a force is applied to Whenever a force is applied to something there will be an something there will be an equal and equal and oppositeopposite force going in the other force going in the other direction.direction.

• Medicine ball throw sitting on a Swiss Medicine ball throw sitting on a Swiss ballball

ExampleExample

• When a sprinter pushes When a sprinter pushes off the blocks, he applies off the blocks, he applies a force by driving his foot a force by driving his foot into the block – there is into the block – there is an equal and opposite an equal and opposite reaction of his body being reaction of his body being propelled away from the propelled away from the blocks.blocks.

• By driving his foot into By driving his foot into the blocks the sprinter is the blocks the sprinter is using ground reaction using ground reaction forces to propel his body.forces to propel his body.

Your turnYour turn• Write below how you could apply Write below how you could apply

Newton’s 3Newton’s 3rdrd Law to a Volleyball Skill. Law to a Volleyball Skill. BLOCKBLOCK

LEVERSLEVERS - First Class - First Class LeverLever

• E.g Head on E.g Head on VertebraeVertebrae

• Fulcrum in MiddleFulcrum in Middle

Resistance

FulcrumEffort

Second Class LeverSecond Class Lever

• E.g Rising on to E.g Rising on to toes / calf raisetoes / calf raise

• Resistance in the Resistance in the MiddleMiddle

Resistance

Fulcrum

Effort

Third Class LeverThird Class Lever

• E.g Bicep CurlE.g Bicep Curl

• Effort in the MiddleEffort in the Middle

•Most frequently Most frequently occurring lever in occurring lever in the bodythe body

Resistance

Fulcrum

Effort

Maximising lever length to Maximising lever length to improve performance.improve performance.

• Shortening the lever arm (by bending Shortening the lever arm (by bending the joint) allows the lever arm to the joint) allows the lever arm to generate force and to be rotated with generate force and to be rotated with more speed.more speed.

• Once this is has been achieved the Once this is has been achieved the lever arm can be lengthened (by lever arm can be lengthened (by straightening the joint to maximise straightening the joint to maximise the speed at the end of the lever.the speed at the end of the lever.

• This can be used to strike and propel This can be used to strike and propel objects more effectively. objects more effectively.

ExampleExample• The player reduces the lever arm length by flexing their The player reduces the lever arm length by flexing their

elbow, allowing force to be generated and the racket elbow, allowing force to be generated and the racket swung with more speed. As the ball is hit, the elbow swung with more speed. As the ball is hit, the elbow extends to increase the length of the lever and allow the extends to increase the length of the lever and allow the racket head to travel at full speed. This allows the ball racket head to travel at full speed. This allows the ball to leave the racket head with more speed. to leave the racket head with more speed.

• Fulcrum = shoulder, Force = anterior deltoid, Fulcrum = shoulder, Force = anterior deltoid, Resistance = racket headResistance = racket head

Your turnYour turn• Write below how you could maximise Write below how you could maximise

lever length to improve a Volleyball Skill. lever length to improve a Volleyball Skill. SPIKESPIKE

MomentumMomentum

• The amount of motion an object has. The amount of motion an object has. It is a combination of mass and It is a combination of mass and velocity.velocity.

• Momentum = Mass X VelocityMomentum = Mass X Velocity

• Transfer of momentum can occur Transfer of momentum can occur internally or externallyinternally or externally

ExampleExample

• Forearm pass in Forearm pass in volleyballvolleyball

• Small downward Small downward momentum applied by momentum applied by the ball. the ball.

• Large upward Large upward momentum applied by momentum applied by the forearm.the forearm.

• Resulting momentum Resulting momentum applied to the ball – in applied to the ball – in the direction of the the direction of the largest force. largest force.

Force SummationForce Summation

• Allows maximum forces to be Allows maximum forces to be produced by the muscles and then produced by the muscles and then transferred into the physical activity. transferred into the physical activity.

• Achieved by adding forces of each Achieved by adding forces of each body segment together. Therefore body segment together. Therefore producing a larger force than one producing a larger force than one force alone. force alone.

Relationship between number of body parts used Relationship between number of body parts used and force producedand force produced

force

time

Shoulder/arm

Hand

Hip/thigh

Trunk

Shoulder/arm

Hand

SMALL FORCE

LARGE FORCE

Maximising force Maximising force summationsummation

• Begin movements with the larger muscles of Begin movements with the larger muscles of the body.the body.

• Once the larger muscles have been recruited, Once the larger muscles have been recruited, force can be transferred through to the force can be transferred through to the smaller muscles of the extremities (hand and smaller muscles of the extremities (hand and feet) feet)

• Correct timing allows maximum transfer of Correct timing allows maximum transfer of force between body parts. If a certain body force between body parts. If a certain body segment begins to accelerate before or after segment begins to accelerate before or after the previous segment has reached peak force, the previous segment has reached peak force, less force will be transferred.less force will be transferred.

Your turnYour turn• Write below how you maximise force Write below how you maximise force

summation to improve a volleyball skill. summation to improve a volleyball skill. SERVESERVE

Projectile MotionProjectile Motion

• Any object released into the air is Any object released into the air is termed a termed a projectileprojectile..

• The flight of a projectile consists of a The flight of a projectile consists of a horizontalhorizontal and and verticalvertical component. component.

Vertical

component

Horizontal component

Factors affecting the flight Factors affecting the flight of a projectile:of a projectile:

1.1. GravityGravity

2.2. Air resistanceAir resistance

3.3. Speed of releaseSpeed of release

4.4. Angle of releaseAngle of release

5.5. Height of releaseHeight of release

6.6. SpinSpin

GravityGravity

• Gravity acts upon a body to give it mass. Gravity acts upon a body to give it mass.

• The greater the weight of an object the The greater the weight of an object the greater the influence of gravity upon it.greater the influence of gravity upon it.

• Gravity limits the height that a projectile Gravity limits the height that a projectile can attain. (acts on the vertical can attain. (acts on the vertical component of flight)component of flight)

Air resistanceAir resistance

• In many sporting activities, the effect of air In many sporting activities, the effect of air resistance is very small, but several factors resistance is very small, but several factors influence it:influence it:

1.1. The larger the surface to volume ratio the The larger the surface to volume ratio the more air resistance. Shuttlecock – golf ball.more air resistance. Shuttlecock – golf ball.

2.2. The surface of the object. If it is rough then The surface of the object. If it is rough then air resistance will be greater.air resistance will be greater.

3.3. Speed – as speed increases so does air Speed – as speed increases so does air resistance.resistance.

4.4. Mass – the lighter the object the more air Mass – the lighter the object the more air resistance will affect it. resistance will affect it.

Speed of releaseSpeed of release

• Generally the greater the speed of release the Generally the greater the speed of release the greater the distance gained.greater the distance gained.

• Speed of release is divided into two components: Speed of release is divided into two components: • a) initial vertical velocitya) initial vertical velocity• b) initial horizontal velocityb) initial horizontal velocity

Vertical component

Horizontal component

Direction of flight

Angle of releaseAngle of release

• For any given speed of release, the For any given speed of release, the optimum angle of release is 45optimum angle of release is 45°. This °. This assumes that there is no air resistance, assumes that there is no air resistance, and that the landing point and take off and that the landing point and take off point are at the same height.point are at the same height.

• IN most sporting situations the angle of IN most sporting situations the angle of release is usually around 35° to 45°. This release is usually around 35° to 45°. This is due to air resistance and the take off is due to air resistance and the take off point is normally higher than the landing point is normally higher than the landing point. point.

Height of releaseHeight of release

• For a given speed and angle of For a given speed and angle of release, the greater the height of release, the greater the height of release the greater the distance release the greater the distance gained.gained.

• This is due to having more time in the This is due to having more time in the air.air.

• Eg. A golfer hitting a ball off the top Eg. A golfer hitting a ball off the top of a hill would hit it further than a of a hill would hit it further than a golfer at the bottom of the hill.golfer at the bottom of the hill.

SpinSpin

• Two basic principles are:Two basic principles are:

1.1. Range is decreased with topspinRange is decreased with topspin

2.2. Range in increased with back spinRange in increased with back spin

TOPSPINBACKSPIN

Direction of ball

Direction of ball

high

low

low

high

SpinSpin

• The reason a ball with topspin dips The reason a ball with topspin dips suddenly and a backspin shot will suddenly and a backspin shot will travel further is due to air pressure. travel further is due to air pressure.

• Topspin high pressure on top of the Topspin high pressure on top of the ball forcing it downball forcing it down

• Backspin high pressure under the Backspin high pressure under the ball forcing it up. ball forcing it up.

Your turnYour turn• How could use of projectile motion be used to improve a How could use of projectile motion be used to improve a

volleyball serve that goes into the net all the time?volleyball serve that goes into the net all the time?