Mechanical Principles
Learning Outcomes
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What is balance, are there different types of balance?
Centre of gravity
Body tension
Transfer of Weight and benefits to performance if completed
effectively
• Force and the application of force.
• Friction
• Follow through
Balance
Balance is the ability to retain the centre of
gravity over your base of support. There are
two types of balances:
1) Static balances
2) Dynamic balances
Centre of Gravity
Centre of gravity is to do with stability.
i. The heavier you are, the more stable you will
be
ii. To be balanced your centre of gravity should be
inside your base
iii.A low position with a wide base is more
balanced
Centre of Gravity
Balance Homework 5
Body Tension
For technique to be effective it is helpful if the
major muscles involved in balances have good
body tension.
In gymnastics explain how good body tension
helped to improve the quality of your balances?
Transfer Of Weight
The transfer of weight allows you to move your body from
one place to another. How well you transfer your weight
involves considering how well balanced you are when
performing.
To transfer your weight in any direction, you must apply a
force in the opposite direction. The force is created when
you contract your muscles.
At times, this can be single actions such as throwing the
javelin. At other times, for example when running, simple
actions are repeated.
Name 2 activities, describe one technique which requires
a single transference of weight and describe another
technique which requires repeated transference of weight
Application of Force
When performing different skills and techniques
different forces are applied and resisted.
For every action there is an equal and
opposite reaction (Newton’s third law)
Application of Force
If speed is required then the greater force applied
the better. Differences in the mass of the body
will affect performance.
If the force applied to the sprinting block (100m
sprint) is the same the athlete with a smaller
mass will accelerate at a quicker rate.
Application of Force
If speed is required then the greater force applied
the better. Differences in the mass of the body
will affect performance.
If the force applied to the sprinting block (100m
sprint) is the same the athlete with a smaller
mass will accelerate at a quicker rate.
Force
You must apply force in one direction to move in the
opposite direction.
Look at the following examples. Explain where force is
applied and what direction the person or equipment
moves.
B
A.
C
Friction
This is when contact between two surfaces cause a
slowing down or gripping effect.
This can be an advantage or disadvantage depending on
the activity and the skill or technique you are trying to
complete.
Adv.
Football boots getting a good grip on the
ground to stop the player slipping and allow
them to change direction quickly
DisAdv.
In cycling when the wind slows you down
Choose four activities explain how friction affects your
performance.
Rotation
In different activities you rotate (turn) in order to carry
out skills and techniques.
When throwing the discus in athletics you turn around in
a spinning back-to-front movement to generate power.
This is a complex technique. You build up speed before
throwing by quickly turning until you have regained
balance.
You can also rotate by performing a forward roll.
Name two skills in which you turn head over heals.
Resistance
When you apply force there will be resistance. Like friction,
resistance can either be an advantage or disadvantage.
Adv. When sprinting in athletics the starting blocks are an
advantage. They provide resistance.
DisAdv.
If you are running into a headwind this
slows you down.
Resistance can be reduced or increased depending on your
technique. In swimming if you keep your head out of the
water when doing the front crawl this creates a greater
resistance with the water and slows you down. Reduce
resistance by putting head level with the water (streamlined)
Follow through
When completing different skills and techniques it is
important to have a good follow through. A good follow
through is part of effective performance and follows on
from the preparation and action phases in different skills
and techniques.
An example would be kicking a ball in football, the follow
through is in the direction of the shot.
In other actions the follow through involves body rotation.
The ball and socket joints in the hips
and shoulder help rotation in this
striking action.
Mechanical Principles
A. What is the importance of transfer of weight when completing
an ‘overhead clear’?
B. When completing a ‘headstand’ what affect would having a
small base have your performance?
C. Why is body tension important when completing static
balances?
D. Where must your centre of gravity be maintained to hold a
balance?
E. Give an example of a dynamic balance?
F. Name two activities where equipment is used to reduce
friction?
G. In swimming, how did improving your technique, reduce your
resistance in the water?
H. Describe one technique in three different activities where follow
through is important (use kicking, striking and throwing)?