Biomechanics Flashcards
What is Biomechanics?
The science of studying living things from a mechanical perspective.
It allows coaches to analyse athlete movement, improve technique and reduce injury risk
3 Examples of equipment used by Biomechanists
- Computer and digital analysis
- Cinematography
- Resistance pools pr swimming flumes
What are the benefits of biomechanics?
- Optimisation of sports performance (developing most efficient and effective technique)
- Prevention and reduction of injuries (understanding injury causes and development +application of proper technique)
- The design and development of improved equipment + materials to maximise sports performance
What is a force?
A push or pull upon an object resulting from the object’s interaction with another object- Measured in Newtons (N)
What is Gravity?
A force of attraction that pulls together all matter (Newtons, N)
- the more matter something has, the greater the force of its gravity
- the bigger the object, the stronger the gravitational pull
What is Mass?
A measurement of how much matter is in an object (Kg)
- mass is a combination of the total number of atoms, the density of the atoms, and the type of atoms in an object
What is Weight?
the measure of the force of gravity on an object (Newtons, N)
-the mass of an object will never change, but the weight of an item can change based on its location
- e.g. you may wieght 100 kg on Earth, but in outer space you would be weightless
What is Newton’s 1st 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.
e.g. a soccer ball won’t move from it’s position unless a force acts upon it, such as the player kicking it
What is Newton’s 2nd law (ACCELERATION)
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
e.g. a netball will accelerate much faster than a medicine ball when thrown with the same amount of force
What is Newton’s 3rd law (ACTION & REACTION)
For every action there is an equal and opposite reaction
e.g. when a tennis player hits a ball the racket exerts a force on the ball (action force) and the ball exerts an equal and opposite force on the racket (reaction force)
What is Linear Motion?
Motion along a line that may be straight (straight line motion) or curved (curvilinear motion), with all part of the body moving in the same direction at the same speed.
e.g. an 100m sprint
What is Angular Motion
Also known as rotary motion, evident when the body or an object turns about an axis of rotation.
e.g. a somersault in gymnastics
What is General Motion?
A combination of angular motion and linear motion
e.g. a cyclist, his arms are involved in linear motion and his legs are involved in angular motion through the turning of the wheels. Together they are involved in general motion.
Calculate speed (the rate of motion, without taking into consideration of change in direction)
Speed (m/s) = Distance (m)/ Time (s)
e.g. a sprinter runs a 200m run (in a straight line) and completes this in 21 seconds
speed= 200/21
speed= 9.52 m/s
Calculate Velocity (the rate of change in location)
Velocity (m/s)= Displacement (m)/ Time (s)
e.g. a sprinter runs a 200m run (in a straight line) and completes this in 21 seconds
Velocity= 200/21
Velocity= 9.52 m/s
Acceleration
the rate of change of velocity or speed in a given time
Force/mass
e.g. an 100m sprint
Deceleration (+Example)
Reduction in speed or rate, negative acceleration
e.g needing to come to a sudden stop in netball
Example of angular motion through the vertical axis
Vertical axis= from head to toe
e.g. an ice skater spinning
Example of angular motion through the transverse (horizontal) axis
transverse axis= from hip to hip
e.g. a diver performing a somersault
Example of angular motion through the medial axis
medial axis= belly button to lower back
e.g. a gymnast performing a cartwheel
Example of Newtons 1st law (inertia) applying to angular motion
e.g. a drop punt in football spins through the air only after it has been kicked
Example of Newtons 2nd law (acceleration) applying to angular motion
e.g. a diver spins rapidly in a tuck position only after they have pushed hard into the diving board
Example of Newtons 3rd law (equal action and reaction) applying to angular motion
e.g. a spinning ball hits the ground and its amount of spin is reduced by the opposite action applied by the ground
Explain how changes in moment of inertia effect Angular Velocity
When moment of inertia (resistance of a rotating body to change) is high then the angular velocity is low, however when the moment of inertia is decreased then the angular velocity increases (causing a faster spin)
What are the three main elements of a lever?
- A force arm
- An axis
- A resistance arm
- the arrangement of these three elements determines the type of lever
What is the 1st class lever?
axis is between resistance arm and point of force application
e.g. oar in rowing
force (effort 💪), axis, resistance (load 🧱)
What is the 2nd class lever?
resistance between axis and force, force arm longer than resistance arm
e.g. calf raises
force, resistance, axis
What is the 3rd class lever?
Force applied between resistance and axis, short force arm and long resistance arm
e.g. bicep curl
axis, force, resistance
How are levers used in sport?
-athletes will generally combine the use of short and long levers to maximise performance
-a short lever during the acceleration phase (joints will be bent or flexed)
-a long lever is used during the striking phase (joints will be straight or extended)
What is force?
Any pulling or pushing activity that alters the motion of a body (object)
What is isometric force? +Example
When a force is created but no movement is created (e.g. calf stretch against a wall)
What is isotonic force? +Example
A force large enough to change the state of motion of an object
e.g. kicking a ball
What is sub-maximal force?
When a performer does not use all the force available to complete a task
e.g. throwing a tennis ball to someone 1m away
What is maximal force?
Achieved by a combination of perfect timing, maximal muscle contraction and excellent technique
e.g. throwing a ball from the outfield
What is force summation?
Production of the optimally desired amount of force by successfully activating a number of body segments
What are the two ways force summation can be achieved?
Simultaneously- when an explosive action of all body parts occurs at the same time e.g. block start in athletics
Sequentially- Where body parts are moved in sequence to generate great force e.g. bowling in cricket
What is momentum?
momentum is a measure of the amount of motion a body has
Momentum (M)= Mass (m) x Velocity (v)
-to increase momentum an object must increase its mass or its velocity
-the greater an objects momentum the further it will travel before it stops
What is impulse?
Impulse is a measure of the force applied for a specific time
e.g. a run up in shot put
Impulse= force x time
What actions increase impulse?
Impluse can be increased by allowing for force to be applied over a longer period. For example having a full backswing when throwing a ball or turn in shot put or discus
What is force reception?
For reception refers to absorbing the momentum of a moving object
e.g. taking a mark in football
What is projectile motion?
the motion of an object that is moving through the air unassisted with only gravity and air resistance acting upon it (moves along a curved path)
What affects projectile motion of an object? (3 factors)
- Angle of release
- Height of release
- Speed of release
(As well as gravity and air resistance)
Air Resistance effect on an objects projectile motion
- Air resistance effects the horizontal component of a projectile
- it can either accelerate or decelerate a projectile depending on direction of the air resistance
(tailwind vs headwind)
What is air resistance?
Resistance to motion of a projectile created by the air through which the projectile must travel
What is drag force?
Disturbed air that creates a resistance force opposing the movement of a projectile through the air
What is static balance?
Is when a person remains over a relatively fixed base
What is dynamic balance?
Is when a performer is in motion
Four factors affecting balance and stability
- MASS (the heaver the object the more stable than the lighter object )
-Base of support (the greater the base of support the greater the balance)
-The lower the centre of gravity above the base of support the greater the balance
-the further the line of the centre of gravity from the edge of the base of support the greater the balance
State the four rules of summation (Number, Order, Timing, Stability)
Number- use as many body parts as possible
Order- Use the largest body parts with the greatest mass first (e.g. the legs and quads)
Timing- Sequentially accelerate each body part so its momentum optimally passes onto the next body part
Stability- sequentially stabilise each body part so that the next body part accelerates arou
What is the 1st Lever used for?
Generate great speed + great strength
e.g. oar in rowing
What is the 2nd lever used for?
Used to increase strength that humans apply to objects (least common)
e.g. calf raises
What is the 3rd lever used for?
Helps to generate great speed (most common)
e.g. using your arm to throw
