biomechanical principles

Question 1

explain Centre of Gravity (COG)

Answer 1

The theoretical point through which all weight of an object acts.

Will change position as the body moves

Must be within Base of support to achieve balance

Helps you to successfully turn, lift, balance

Question 2

explain the Line of gravity (LOG)

Answer 2

is a theoretical line drawn from centre of gravity to the floor

Question 3

how do you locate the COG

Answer 3

draw a box around the body touching the outermost part of the body.

connect each diagonal, the point in the middle is the COG

Question 4

explain Base of Support

Answer 4

Area within the boundary of the body parts in contact with the floor.

A larger base of support results in increased stability (stability is the ability to maintain balance).

Question 5

why is holding a retire on demi pointe more challenging than standing in a squat in second

Answer 5

the base of support for a retire is smaller than the plie

Question 6

when is balance achieved

Answer 6

Is achieved when the body is at a state of equilibrium.

Question 7

factors effeting balance (6)

Answer 7

1. Size of base of support
2. Position of centre of gravity
3. Line of gravity
4. Mass of the body
5. If line of gravity falls within the base of support, balance is achieved
6. It is easier if base of support is bigger, and line of gravity is shorter

Question 8

what is a weight transfer

Answer 8

A weight transfer occurs when dancer moves their weight from one body part to another

Question 9

name the 2 types of weight transfer

Answer 9

full weight transfer

partial weight transfer

Question 10

explain a full weight transfer

Answer 10

cog is vertically projected from one body part to another so the original body part can be lifted from the floor

e.g. hand stand from standing

Question 11

explain a partial weight transfer

Answer 11

cog is only partly projected, original body part cant be lifted.

e.g. a downward dog from standing

Question 12

what is motion

Answer 12

The continual change in position of the body relative to a particular point.

Question 13

name the 4 types of motion

Answer 13

• Linear
• Angular
• General
• Projectile

Question 14

what is linear motion

Answer 14

when the whole body moves in a line, all body parts travel the same distance in the same direction at the same time

Question 15

eg of linear motion

Answer 15

a shunt

Question 16

what is angular motion

Answer 16

motion which rotates around a fixed point called the axis of rotation- this can be internal or external

Question 17

eg of angular motion

Answer 17

internal = shoulder

external = gymnast rotating around a bar

Question 18

what is torque

Answer 18

the force applied to a point that doesn’t pass through the axis of rotation.

Because the force is applied off centre it has a turning effect.

Question 19

eg of torque

Answer 19

torque in turns is created by the push of the foot off the floor and drawing of the arms inward to the body.

Question 20

explain General Motion

give an example

Answer 20

Is a combination of both linear and angular- This is what most movement will be classified under. eg chaines turns.

Question 21

what is Projectile Motion

Answer 21

involves the path of the body through the air. All movement in the air creates a parabola. The shape of the parabola is determined by the velocity of release and angle of projection

Question 22

what is a parabola

Answer 22

a curve

Question 23

what is the velocity of release

Answer 23

the speed reached at the moment of elevation. Faster velocity of release increases the height and time in the air

Question 24

what is the desired angle of projection for

• higher jumps
• lower jumps

Answer 24

the ideal angle is approximately 45 degrees or higher if you want to achieve height and longer time in the air.

To achieve jumps with more lateral movement rather than height, lower the angle of projection.

Question 25

what is force production

Answer 25

the three laws of motion which still influence most principles of motion

Question 26

1st law

Answer 26

A body will remain at rest or in uniform motion in a straight line until an external force acts on that body to change its state of motion. -An example of this in dance could be partner counter balances.

Question 27

2nd law

Answer 27

The amount of acceleration produced when an unbalanced force acts on a body is proportional to the size of that force - This may be a travelling movement across the space or the speed and magnitude of a specific movement.

Question 28

3rd law

Answer 28

For every action there is an equal and opposite reaction. - This principle may also be applied with a partner as you pull, push, lift or support them.