Biomechanics Flashcards
Define articulating bones
The bones that form a joint
What type of joint is the shoulder?
Ball and socket
What type of joint is the elbow?
Hinge
What type of joint is the hip?
Ball and socket
What type of joint is the knee?
Hinge
What type of joint is the ankle?
Hinge
What type of joint is the neck?
Pivot
How many articulating bones from the neck?
2
Name the articulating bones of the neck
Atlas and axis
How many articulating bones form the shoulder?
2
Name the articulating bones of the shoulder
Humerus and scapula
Name the articulating bones of the elbow
Humerus, ulna and radius
Name the articulating bones of the hip
Pelvis and femur
Name the articulating bones of the knee
Femur and tibia
Name the articulating bones of the ankle
Talus, tibia and fibula
Define the term agonist
Prime mover - the muscles that cause a movement
Define the term antagonist
The muscle that works against the agonist to help produce a co-ordinated movement
Define the term fixator
Muscles that stabilise the origin so that antagonists can work effectively
Define the term synergist
A muscle that works together with another muscles to generate movement
Name 3 types of muscle contraction
- Concentric
- Eccentric
- Isometric
Define concentric contraction
The muscle shortens as it contracts
Define the term eccentric contraction
The muscle lengthens as it contracts
Define the term isometric contraction
The muscle contracts with no movement
Which movements can be used at the elbow?
Flexion and extension
Which movements can be used at the knee?
Flexion and extension
Which movements can be used at the ankle
Plantar flexion and dorsi flexion
What is the agonist at the knee in the eccentric phase of a squat?
Quadriceps
What is the agonist at the knee in the concentric phase of a squat?
Quadriceps
What is the agonist at the elbow in the eccentric phase of a bicep curl?
Biceps
Identify the plane and axis a shot putter moves through when completing their throw
Sagittal plane/transverse axis
Identify the plane and axis of motion at the shoulder in the upwards phase of a press up
Transverse plane/longitudinal axis
Identify the plane and axis of movement at the shoulder as a performer plays a forehand shot in tennis
Transverse plane/longitudinal axis
During sprinting, flexion occurs at the hip.
Identify which plane and about which axis hip flexion occurs.
Sagittal plane/transverse axis
How many lever systems are there
3
During which movement does the 1st class lever system occur?
Elbow extension
At which part of the body do we see a 2nd class level system?
The ankle
How is a fulcrum represented when drawing a lever system?
Traingle
How is a resistance represented when drawing a lever system?
Rectangle
How is effort represented when drawing a lever system?
Arrow
In a first class lever system, what is drawn in the centre?
Triangle (fulcrum)
In a second class lever system, what is drawn in the centre?
Rectangle (resistance)
In a third class lever system, what is drawn in the centre?
Arrow (effort)
Identify two advantages of a second class lever system
- The effort arm is longer than the resistance arm.
- This allows the performer to generate a lot of force with minimal effort.
- Beneficial when jumping as high as possible during a high jump.
Identify 2 disadvantages of a second class lever system
- The resistance arm is shorter than the effort arm.
- This means there is a short range of movement.
Identify two advantages of a third class lever system
- The resistance arm is longer than the effort arm.
- This allows for a large range of movement.
- This also allows movements to occur faster, which helps build momentum.
- This means that a long jumper can lift their legs higher during the flight phase and can also build more momentum within the run up.
Identify two disadvantages of a third class lever system
- The effort arm is shorter than the resistance arm.
- This means it requires a large amount of effort to produce force;
- Which could cause fatigue.
Define displacement and state its unit of measurement
The shortest straight line distance between 2 points
Metres (m)
Define velocity and state its unit of measurement
The rate in change of displacement
Metres per second (m/s)
How is velocity calculated?
Displacement/time
Define acceleration and state its unit of measurement
The rate a body changes from one velocity to another
m/s2
How is acceleration calculated?
Final velocity - initial velocity/time
Define momentum and state its unit of measurement
Mass x velocity
Kilogram metres per second (KGM/S)
Define weight and state its unit of measurement
The amount of force exerted by gravity on an object
Newtons (N)
How is weight calculated?
Mass (kg) x gravity (9.8)
Name Newton’s first law of motion
Law of inertia
Explain Newton’s first law of moition
- The performer will remain stationary until an external force Is applied
- The performer will travel with a constant velocity until another force is applied
- External force is applied by the performer’s muscles
Name Newton’s second law of motion
Law of acceleration
Explain Newton’s second law of motion
The rate of change of momentum of a body is directly proportional to the force causing it and the change takes place in the direction in which forces the act
Name Newton’s third law of motion
The law of action-reaction
Explain Newton’s third law of motion
To every action there is an equal and opposite reaction
Define stability
The ability to maintain a centre of mass over a base of supprot
Name 3 factors that affect stability
- Height of centre of mass
- Size of base of support
- Line of gravity
- Mass
How does height of centre of mass effect stability?
The lower the centre of mass, the more stable a performer
How does the size of base of support effect a performer’s stability?
The wider the base of support, the more stable the performer
How does line of gravity effect a performer’s stability?
The closer the line of gravity to base of support, the grater the stability
How does mass effect a performer’s stability?
The greater the mass of the object/performer, the greater the stability
Define impulse
Force x Time
Explain the forces of an impulse at the start of a 100m race
- Small Negative (Landing)force
- Large Positive (Push off) Force
- Net force is Positive
- Causes performer to accelerate
Explain the forces of an impulse during a 100m race
Both Negative landing force and positive push of force are equal
Net force is 0
Performer will travel at a constant velocity.
Explain the forces of an impulse during the end part of a 100m race
- Large negative landing force.
- Small positive push off force.
- Net force is negative.
- Performer will decelerate.
Define moment of inertia
The spread of mass from the axis of rotation
Define angular velocity
Speed of rotation
If a performer increase moment of inertia, what happens to angular velocity?
Decreases
How can an increase in moment of inertia be achieved?
Spreading limbs away from the body
If a performer decreases moment of inertia, what happens to angular velocity?
Increases
How can a decrease in moment of inertia be achieved?
Bringing limbs towards the body
How can angular momentum be calculated?
Moment of inertia x Angular velocity
Angular momentum always…
remains constant
Identify 3 factors that effect flight path
- Height of release
- Angle of relase
- Force of release
Define drage
A force that happens in the opposite direction to motion
Name 2 forms of drag
- Form drag
- Skin drag
