Biomechanical principles and levers 5.1 Flashcards
What is linear motion
Motion in a straight or curved line, all body parts moving in the same distance and speed in the same direction
What’s an example of linear motion in a curved line
200M sprint
What’s an example of linear motion in a straight line
100M sprint
What is inertia
The resistance an object has to a change in its state of motion
What causes an object to change velocity
Another force exerted on the original velocity
If the mass is larger will the inertia be greater or smaller
Larger the inertia
What does having a larger inertia mean
More force is needed to change it’s state of motion
2 players weighting in at 120KG and 75KG which one would stop faster
75KG player
What does newtons first law state
Everyone continues in its state of rest or motion in a straight line, unless compelled to change that state by external forces exerted upon it
What is a sporting example of newtons first law
high jump, they change their state of motion when taking off
What does newtons 2nd law state
The rate of momentum of a body is proportional to the force causing it and the change that takes place in the direction in which the force acts
In newtons 2nd law what is acceleration directly proportional to
the force causing the change
What is the equation of force (newtons 2nd Law)
Force= Mass X acceleration
What does newtons third law state
To every action, there is an equal and opposite reaction
Give an example of newtons 3rd law
sprinter pushes off the black (action) and the block pushes back on sprinter (reaction)
What is ground reaction force (GRF) in newtons third law
the force exerted on the ground by the body in contact with it
What force does an individual have on the ground
contact force
What is linear motion measured in
Scalar quantities
What are examples of linear motion
- Speed
- Distance
What does scalar quantities not take into account
Direction
How do you calculate speed
Distance/Time
What is centre of mass
Point of balance
What can raise the centre of mass in the human body
Raising your arms
In general where is the centre of mass
Around the hip area
What can cause the general centre of mass to differ
Gender
What are the reasons that gender can cause the centre of mass to change
Males: more weight around the shoulders
Females more weight around the hips
What must be considered to increase your stability
- Height of the centre of mass
- Position of the line of gravity
- Area of the support base
- Mass of the performer
In a lower or higher centre of mass better for stability
Lower
Sporting example of sports that use a lower centre of mass
Rugby, Judo, wrestling
What happens if the sprinters mass is over the edge of the area of support
you’ll start to over balance
What’s a sporting example when the centre of mass is over the edge of the area of support
sprinter in a set position
how does having the centre of mass over the edge of the area of support aid the performers performance
Allows athlete to fall forward and will create momentum for speed to leave the block ASAP
Why is the Fosbury flop in high jump a good technique to use
performer doesn’t have to lift their centre of mass a great distance
Why is the scissor kick less beneficial to the performer
their centre of mass will remain in the body and therefore has to be lifted over the bar
What are the 3 parts of a lever
Pivot (fulcrum)
Load (resistance)
effort (source of energy)
What does the skeleton form
System of levers
What do joints form
Fulcrums
What do muscles form
Effort
What is the resistance or load
The weight of the body part being moved
How many types of levers are there
3 types
What is the layout of the first class lever
effort (arrow pointing down)
fulcrum in the middle
resistance (Arrow pointing down)
What is the layout of the second class lever
- fulcrum on the left
- Resistance on the middle (arrow pointing down)
- effort on the right (arrow pointing up)
What is the layout of the third class lever
Fulcrum on the left
effort in the middle (arrow pointing up)
resistance on the right (arrow pointing down)
What is an example of a first class lever
flexion and extension
What is an example of a second class lever
plantar flexion of the ankle
What is an example of a third class lever
hip, knee and elbow flexion
What is mechanical advantage
Where the force arm is longer than the resistance arm
What is mechanical disadvantage
where the resistance arm is longer than the force arm
What are the mechanical advantages of a 2nd class lever
generate larger forces
has to lift the whole body weight
What are the mechanical disadvantages of a 2nd class lever
slow with a limited range of movement
What are the mechanical advantages of a first and third class lever
large range of movement and any resistance can be moved quickly
What are the mechanical disadvantages of a first and third class lever
cannot apply much force to move an object
