Rotation in Sport and Motor control

Question 1

Define motor control

Answer 1

The study of how movement is controlled
The ability to regulate or direct the mechanisms essential to movement

Question 2

When does a somersault speed up and what mechanical principle is in play?

Answer 2

When the body moves from straight to tucked
Angular momentum stays constant throughout the movement

Question 3

What is angular momentum?

Answer 3

The measure of the quantity of rotation of a system of matter
Moment of inertia x angular velocity

Question 4

Was is the moment of inertia?

Answer 4

Resistance of a body to change its state of angular motion
Measurement of the distribution of mass about an axis
Lower = faster rotation
Greatest in the frontal axis then lateral then longitudinal
sum of mass x d squared
Kg.m2

Question 5

Can a somersault be initiated after takeoff?

Answer 5

Yes but not a lot
Angular momentum is constant

Question 6

How is a somersault produced during takeoff?

Answer 6

Leaning forwards moves the CoM forward so the vertical reaction force passes slightly behind the CoM and acts outside of it = torque

Question 7

Equation for conservation of angular momentum

Answer 7

IsWs = ItWt

Question 8

What is rotational torque?

Answer 8

Moment of inertia x angular acceleration
Torque = force x distance

Question 9

How do long jumpers cope with forward somersault momentum during flight?

Answer 9

By rotating their arms and legs forward

Question 10

Newton’s 1st law in relation to angular momentum

Answer 10

A body will remain at rest or continue in
a state of constant angular motion unless it is acted upon by an external torque

Question 11

Newton’s 2nd law in relation to angular momentum

Answer 11

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