Rotation in Sport Flashcards
(33 cards)
Motor control is defined as what?
The study of how movement is controlled.
The ability to regulate or direct the mechanisms essential to movement.
Regulation/maintenance of a function or action.
What 3 aspects of sport science does motor control involve?
Physiology
Biomechanics
Psychology
Reaction time occurs during the processing stages of a reaction. What 3 steps take place during reaction time?
Stimulus identification.
Response selection.
Response programming.
When does a somersault speed up?
When the shape of an individual changes from straight to tucked.
Speed of rotation increases.
What equation is used to work out angular momentum?
Angular momentum = moment of inertia x angular velocity
Define angular momentum.
A measure of the quantity of rotation of a system of matter.
What is the definition of inertia?
The resistance of a body to change its state of angular motion?
Inertia has 3 principle axis: Frontal, Lateral and Longitudinal. Rank them from smallest to largest when referring to the moments about the axis.
- Longitudinal
- Lateral
- Frontal
What is the equation to calculate inertia for a point mass?
Inertia = md^2
What is the equation to calculate the inertia for a body/real mass?
Inertia = Σ(md2) kg/m^2
State the equation used to calculate angular velocity?
Angular Velocity = angular displacement / time
What units is angular velocity measured in?
- Degrees per second
- Revolutions per second
- Radians per second
What is the mechanical principle in operation for a somersault?
Angular momentum is constant in flight.
What two components must balance out, in order for momentum to remain constant?
Inertia and angular velocity.
If an athlete moves into a tucked position, angular velocity increases, what happens to inertia?
Decreases.
State the equation used to show angular momentum is conserved and constant.
Isωs = Itωt (s = straight, t = tucked)
The movement of an individuals arms will do what during a somersault?
Cause the body to move in the opposite direction to the arms.
This ensures angular momentum = 0 as it is conserved.
During a somersault, what movement decreases moments of inertia?
Tucking.
How is a somersault produced during take-off?
Refer to CoM.
- Force acting through CoM doesn’t cause trampolinist to rotate.
- Leaning forward causes the force from the trampoline bed to act just behind the CoM (some horizontal force and trampolinist rotates).
- As the bed recoils, trampolinist flexes at the hip and the force acts behind the CoM - increases angular momentum.
State how Newton’s law and angular momentum relate.
The rate of change of angular momentum of a body is proportional to the torque causing it and takes place only in the direction in which the torque acts.
What two equations can be used to calculate torque?
Torque = moment of inertia x angular acceleration
Torque = force x distance
How do long jumpers cope with forward somersault momentum during flight?
Arms and legs are circled forwards to prevent the body from rotating forwards (conservation of momentum = 0).
Why do high jumpers use a curved approach?
To produce somersault rotation.
The run-up curve tightens as a high jumper gets closer to the bar. Why is this?
Throws the athlete to the side which creates the somersault rotation they need to clear the bar.
