Introduction to Biomechanics - 2
Lorna McAvoy - AJHS PE Dept
STATIC
DYNAMIC
Men's
Rings
B-Boys
Balance is a desirable attribute in the performance of skills.
A body is most stable when the principles of balance are applied.
1. Anything can be balanced if its centre of gravity is directly
over its base of support
2. The wider the base of support the more balanced or stable the
object or body is.
3. The lower the centre of gravity the more balanced or stable
the object is.
4. As one body part moves another must move to compensate
that movement
Maintaining balance and stability during sporting
performance has a number of benefits:
It allows a person to put more force into a
movement and complete that movement
accurately and with control.
Lorna McAvoy - AJHS PE Dept
In pairs, one person acts as the pushing force and the other person
acts as the object being pushed. The person acting as the pushing
force now attempts to push their partner off balance with the
person acting as the object, positioning their body in such a way
as to resist being pushed over.
1. Describe the things the person being pushed did to resist being
pushed off balance. Explain these in terms of centre of gravity,
line of gravity and base of support.
2. Describe in detail the implications of these results when
engaged in contact sports such as rugby or judo.
Lorna McAvoy - AJHS PE Dept
Force Summation
Maximum force is produced when a person is able to use:
• As many body parts as possible.
•In the correct sequence (use large muscles first & then
the smallest muscles last but fastest).
•With the correct timing.
•Through the greatest range of motion.
in order to perform a movement.
Force Summation
This is known as the principle of force summation.
The more body segments involved, the greater the
force or speed generated.
The speed of the last body part during the release
of an object will determine the velocity of the
object as it leaves the hand or foot.
McAvoy - Jump Serve
Practical Lab
The Medicine Ball Experiment
Collect an experiment sheet from
Miss McAvoy
To gain maximum momentum, the force needs
to be generated by:
•Using as many body parts as possible.
•In the correct sequence (use large muscles first &
then the smallest muscles last but fastest).
•With the correct timing.
•Through the greatest range of motion.
Lorna McAvoy - AJHS PE Dept
Homework Task
Collect a
worksheet
from Miss
McAvoy
Stick this in
your book
and complete
Adductors
Quadriceps
Quadriceps
Deltoid
Hip Flexors
Hamstring
Obliques
Pectoral
Quads
Gastrocnemious
Abdominal Rectus
Triceps
Deltoid
Pectoral
Triceps
Wrist Flexors