Chapter 12 - Rotation Flashcards Preview

Kin 150 - Gymnastics foundations > Chapter 12 - Rotation > Flashcards

Flashcards in Chapter 12 - Rotation Deck (26):
1

What are the names of the three rotational axes (give examples)?

Longitudinal (spins, turns)
Transverse (rolls, bar circles)
Anterior/posterior axis (cartwheels)

2

What are rotations caused by?

Rotations are caused by off-centre forces. Off-centre forces do not pass through the centre of mass.

3

What is displacement?

Displacement is when something is moved (pushed perhaps) and a force is passing through the centre of mass directly, linear motion occurs.

4

What is a force couple?

When two off-centre forces work together and help to rotate the body in different ways.

5

Where is the longitudinal axis?

head to toe (imagine a pole through head to toe)

6

What is the Transverse axis?

hip to hip

7

What is the Anterior/ Posterior axis?

front to back

8

"for every action there is an _____"?

equal and opposite reaction

9

The further off centre the more ___, less ___

more rotation and less displacement

10

What is altering rotation?

distribution around the centre of mass

11

What is inertia?

object at rest

12

How do you mechanically generate all rotations?

- swinging the body along the axis
- stationary with offcentre force ( the further away the more rotation)
- force couple

13

Which axis do we swing about?

external axis

14

In the descending part of a swing, is gravity good or bad?

it is good because it increases rotation

15

where is the COM in the descending part of a swing?

the com is farther from the bar, do shoulder elevation

16

Where do you want the COM in the ascending part of a swing?

as close to the bar as possible

17

What muscle state is in the descending part of a swing?

eccentric (straight arms and legs)

18

What muscle state is in the ascending part of a swing?

concentric (bent arms and legs)

19

How do you go higher in the ascending part of a swing?

distribute body mass closer to the axis its working on

20

Is gravity good or bad in the ascending part of a swing?

it is bad, negative off center force

21

What will friction cause during rotation? How do you stop it?

less rotation and sore hands therefore hook not squeeze.

22

What is the difference between hook and squeeze in a swing?

hook: less surface therefore less friction, cant swing as far, not as slow
squeeze: more surface area, more friction, swing longer, hang on longer, slow

23

when do you regrasp in a swing?

on the backswing

24

what is a key fundamental for swinging?

hangs

25

what is torque?

force times lever arm

26

how do you get a shorter radius for a closer COM

bend at shoulders