Biomechanical movement principles
Have you ever wondered why some players are able to regularly make a skill look effortless, producing perfect results every time? what about equipment? Why has the swimsuit evolved to look like something from space? Why do athletes spend so much money on the latest gear?
An understanding of biomechanics will enable you to answer these questions and improve your performance.
An understanding of biomechanics will enable you to answer these questions and improve your performance.
Biomechanics is the field of sports science that applies the laws of mechanics and physics to human performance to gain a greater understanding of performance in physical activity. It is the study of forces and the effects of those forces on and within the human body. As individuals strive to improve performance, they look to biomechanics for guidance on technique, style, development and refinement of equipment, and analysis of performance.
To utilise biomechanics to enhance skill learning and physical performance, it is necessary to have an understanding of the biomechanical principles that underlie human movement and the execution of certain skills. These principles include:
- Newton's laws of motion (which have been around since the 1700's and continue to be central to understanding human movement)
- Motion (including human motion and projectile motion)
- Leverage (we use levers every day to make tasks easier to perform)
- Force Production
- Application of force (including the concepts of inertia, momentum, impulse, accuracy and force reception)
- Transfer of momentum, conservation of momentum and moment of inertia
- Impact, coefficient of restitution, rebound and friction
- Balance and stability (Smyth, D et. al., 2011)
To utilise biomechanics to enhance skill learning and physical performance, it is necessary to have an understanding of the biomechanical principles that underlie human movement and the execution of certain skills. These principles include:
- Newton's laws of motion (which have been around since the 1700's and continue to be central to understanding human movement)
- Motion (including human motion and projectile motion)
- Leverage (we use levers every day to make tasks easier to perform)
- Force Production
- Application of force (including the concepts of inertia, momentum, impulse, accuracy and force reception)
- Transfer of momentum, conservation of momentum and moment of inertia
- Impact, coefficient of restitution, rebound and friction
- Balance and stability (Smyth, D et. al., 2011)
| Linear and Angular Motion Homework sheet |
Newtons Laws of Motion
Why is it easier to throw a tennis ball further than a medicine ball?
Why do swimmer/sprinters use starting blocks?
If landing from a jump, do you keep your knees straight or bend them?
Newtons 3 Laws of motion have been around since the 1700's and are still integral to the understanding of human movement.
Newtons first law of motion: Inertia - ‘An object whether at rest or in motion will continue in that state unless it is acted upon by a force strong enough to change its state of motion or rest.’
Biomechanical principles to which Newton's first law is relevant include:
- straight line or angular motion
- levers
- inertia
- balance and stability
Newton's second law of motion: Acceleration/Momentum - ‘The acceleration of an object is directly proportionate to the amount of force applied and takes place in the direction in which the force is applied.’
Force = mass x acceleration.
Biomechanical principles to which Newton's second law is relevant include:
- acceleration
- momentum
- moment of inertia
Newton's third law of motion: Action and Reaction - ‘For every action, there is an equal and opposite reaction.’
Biomechanical principles to which Newton's third law is relevant include:
- transfer of momentum
- conservation of momentum
- elasticity
- coefficient of restitution
- rebound
- friction
(Smyth et. al., 2011).
Why is it easier to throw a tennis ball further than a medicine ball?
Why do swimmer/sprinters use starting blocks?
If landing from a jump, do you keep your knees straight or bend them?
Newtons 3 Laws of motion have been around since the 1700's and are still integral to the understanding of human movement.
Newtons first law of motion: Inertia - ‘An object whether at rest or in motion will continue in that state unless it is acted upon by a force strong enough to change its state of motion or rest.’
Biomechanical principles to which Newton's first law is relevant include:
- straight line or angular motion
- levers
- inertia
- balance and stability
Newton's second law of motion: Acceleration/Momentum - ‘The acceleration of an object is directly proportionate to the amount of force applied and takes place in the direction in which the force is applied.’
Force = mass x acceleration.
Biomechanical principles to which Newton's second law is relevant include:
- acceleration
- momentum
- moment of inertia
Newton's third law of motion: Action and Reaction - ‘For every action, there is an equal and opposite reaction.’
Biomechanical principles to which Newton's third law is relevant include:
- transfer of momentum
- conservation of momentum
- elasticity
- coefficient of restitution
- rebound
- friction
(Smyth et. al., 2011).
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Levers
Why are door handles on the edge of the door and not in the middle?
Is having long limbs an advantage for tennis players?
If you have two children who want to play on a see-saw but one is bigger than the other, how can you make it work?
We use levers everyday. Objects such as scissors, nut crackers, wheelbarrows and nail clippers all work because of levers. In sport it is important to understand how levers work as it allows athletes to optimise their movement efficiency (Smyth et. al., 2011).
Why are door handles on the edge of the door and not in the middle?
Is having long limbs an advantage for tennis players?
If you have two children who want to play on a see-saw but one is bigger than the other, how can you make it work?
We use levers everyday. Objects such as scissors, nut crackers, wheelbarrows and nail clippers all work because of levers. In sport it is important to understand how levers work as it allows athletes to optimise their movement efficiency (Smyth et. al., 2011).
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Force Summation
To obtain maximum force, it is important to combine, or add up the forces applied by different body parts. This concept is known as summation of force. This is influenced by the:
- number of body parts used
- order and timing of the movement
- force and velocity generated
- way in which the body and body parts are stabilised and balanced (Smyth et. al., 2011)
To obtain maximum force, it is important to combine, or add up the forces applied by different body parts. This concept is known as summation of force. This is influenced by the:
- number of body parts used
- order and timing of the movement
- force and velocity generated
- way in which the body and body parts are stabilised and balanced (Smyth et. al., 2011)
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Projectile Motion
We consider balls that we throw and kick as projectiles; can you think of any example in sport where the human body as a projectile?
Do you think its easier for a taller person to put a shot or a smaller one?
A projectile is any object that is launched, hurled or thrown, such as a bullet shot from a gun or a tennis ball hit by a racquet. The path of a projectile is called its trajectory. The human body can also be a projectile - think of a diver entering the water, or a pole vaulter launching themselves into the air.
The trajectories of objects can be affected by many things including:
- angle of release
- height of release
- speed of release
- external forces of gravity
- air resistance
(Smyth et. al., 2011)
We consider balls that we throw and kick as projectiles; can you think of any example in sport where the human body as a projectile?
Do you think its easier for a taller person to put a shot or a smaller one?
A projectile is any object that is launched, hurled or thrown, such as a bullet shot from a gun or a tennis ball hit by a racquet. The path of a projectile is called its trajectory. The human body can also be a projectile - think of a diver entering the water, or a pole vaulter launching themselves into the air.
The trajectories of objects can be affected by many things including:
- angle of release
- height of release
- speed of release
- external forces of gravity
- air resistance
(Smyth et. al., 2011)
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Spin and magnus effect
What happens when an opponent spins a ball in tennis?
Why do cricket bowlers rub the ball on their pants before bowling?
How and why do you create a drop shot in racquet sports?
How does a soccer player get the ball to go directly into the goal from a corner kick?
Spin is created when a ball or any object is subjected to an external force creating a force couple. The Magnus effect explains the deviation of flight paths of balls with spin. Topspin tends to shorten the flight of the ball, which dips sharply at the end of its flight. Backspin also shortens the flight of the ball, which falls more slowly at the end of the flight. Sidespin makes the ball curve left or right in the direction of the spin (Smyth et. al., 2011).
What happens when an opponent spins a ball in tennis?
Why do cricket bowlers rub the ball on their pants before bowling?
How and why do you create a drop shot in racquet sports?
How does a soccer player get the ball to go directly into the goal from a corner kick?
Spin is created when a ball or any object is subjected to an external force creating a force couple. The Magnus effect explains the deviation of flight paths of balls with spin. Topspin tends to shorten the flight of the ball, which dips sharply at the end of its flight. Backspin also shortens the flight of the ball, which falls more slowly at the end of the flight. Sidespin makes the ball curve left or right in the direction of the spin (Smyth et. al., 2011).
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Coefficient of restitution and elasticity
Why do they get new balls during a tennis match?
Why did players get their tennis rackets restrung during the Australian Open Tennis Championship?
Which would bounce more, a soccer ball or a ten pin bowling ball?
The coefficient of restitution simply refers to how far and in what direction a ball bounces. Many factors can affect a balls coefficient of restitution including:
- temperature of the ball
- the condition of the ball
- the material of the ball
- the piece of equipment the ball was struck with and,
- the speed of the ball
An important factor that determines the way an object reacts upon impact with another object or surface is its elasticity. The greater the elasticity of the object, the faster it will return to its original shape and the farther it will rebound after impact (Smyth et. al., 2011)
Why do they get new balls during a tennis match?
Why did players get their tennis rackets restrung during the Australian Open Tennis Championship?
Which would bounce more, a soccer ball or a ten pin bowling ball?
The coefficient of restitution simply refers to how far and in what direction a ball bounces. Many factors can affect a balls coefficient of restitution including:
- temperature of the ball
- the condition of the ball
- the material of the ball
- the piece of equipment the ball was struck with and,
- the speed of the ball
An important factor that determines the way an object reacts upon impact with another object or surface is its elasticity. The greater the elasticity of the object, the faster it will return to its original shape and the farther it will rebound after impact (Smyth et. al., 2011)
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Balance and Stability
When performing a quadriceps stretch, why do people put their other arm out to the side? Why do wrestlers stand with their feet apart and bend their knees? Do you think men or women have a lower centre of gravity (balance point), why? The ability to maintain control of your body … is often the difference between an excellent and an average performance. There are two types of balance:
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Linear Motion and Speed
Human performance in physical activity almost always involves some sort of motion unless a static balance is being performed. This motion can be recognised as being linear or angular motion, or general motion, which is a combination of both.
Velocity measures the rate of change of distance with time in a given direction (displacement), whereas speed measures the rate of change of distance with time (Smyth et. al., 2011)
Human performance in physical activity almost always involves some sort of motion unless a static balance is being performed. This motion can be recognised as being linear or angular motion, or general motion, which is a combination of both.
Velocity measures the rate of change of distance with time in a given direction (displacement), whereas speed measures the rate of change of distance with time (Smyth et. al., 2011)
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Distance and Displacement
This concept is usually linked closely with velocity and speed. Distance can be described as the length of the path along which a body travels - measured in metres or kilometres. Displacement is the length between the starting and end points.
This concept is usually linked closely with velocity and speed. Distance can be described as the length of the path along which a body travels - measured in metres or kilometres. Displacement is the length between the starting and end points.
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Momentum and Impulse
What would happen if a small and a big rugby player collided?
In billiards, why does the white ball often stop after it hits another ball?
How does an ice skater speed up when spinning on the ice?
Is it easier to do a standing long jump or a run-up and jump?
The summation of forces allows more momentum to be produced. Momentum is the product of an objects mass and velocity. An object can have momentum only if it is moving. The greater its momentum, the further it may travel and the harder it is to stop or slow the object. The concept of impulse and the impulse-momentum relationship is be described by the formula:
Impulse = force x time (where time is the length of time force is applied to the object).
Please note:
Force equals the object's mass multiplied by its acceleration. The longer a force can be applied and the greater the force applied, the greater the object's impulse or change of momentum. (Smyth et. al., 2011).
What would happen if a small and a big rugby player collided?
In billiards, why does the white ball often stop after it hits another ball?
How does an ice skater speed up when spinning on the ice?
Is it easier to do a standing long jump or a run-up and jump?
The summation of forces allows more momentum to be produced. Momentum is the product of an objects mass and velocity. An object can have momentum only if it is moving. The greater its momentum, the further it may travel and the harder it is to stop or slow the object. The concept of impulse and the impulse-momentum relationship is be described by the formula:
Impulse = force x time (where time is the length of time force is applied to the object).
Please note:
Force equals the object's mass multiplied by its acceleration. The longer a force can be applied and the greater the force applied, the greater the object's impulse or change of momentum. (Smyth et. al., 2011).
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Moment of inertia and torque
Torque is the force that produces a rotating or twisting motion. It is sometimes also referred to as rotational force. It depends on the amount of force used and the distance the force is applied from the centre of the object.Inertia describes a body's resistance to a change in its state of motion. It is easiest to understand as an object's resistance to beginning movement. It can also refer to a body's resistance to changing its state of motion (such as a cricket ball bowled towards a batter). The heavier the object, the greater its inertia and therefore the greater the force required to move it or change its state of motion (Smyth et. al., 2011)
Torque is the force that produces a rotating or twisting motion. It is sometimes also referred to as rotational force. It depends on the amount of force used and the distance the force is applied from the centre of the object.
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References:
Arkinstall, M, Dawson, T, Johnson, C, Sinclair, P and Zahra, M 2010 'VCE Physical Education 1', Macmillan Education, Australia.
Smyth, D, Judge, W, O'Keeffe, M, Shephard, F, Flouch, M and O'Rourke, K 2011 'Live it Up 1: VCE Physical Education Units 1 & 2, 3rd edition', Jacaranda, Queensland, Australia.
Telford, A, Seery, P, Whittle, R, Corrie, M and Malpeli, R 2010 'Physical Education: VCE Units 1 & 2', Nelson Cengage :Learning, Australia
Smyth, D, Judge, W, O'Keeffe, M, Shephard, F, Flouch, M and O'Rourke, K 2011 'Live it Up 1: VCE Physical Education Units 1 & 2, 3rd edition', Jacaranda, Queensland, Australia.
Telford, A, Seery, P, Whittle, R, Corrie, M and Malpeli, R 2010 'Physical Education: VCE Units 1 & 2', Nelson Cengage :Learning, Australia
