Introduction to biomechanics


Bio-mechanics

When our body is in the standingLet's have a look at some of the more
position it is in a state of unsteadycommon biomechanical problems:
equilibrium because the base is smallProblem 1.
and the centre of gravity is a long wayIt's the fashion not to tie trainers and
above it. That is why it has to beshoes up but this prevents the shoe from
balanced by keeping the centre ofsupporting the inside of the foot and
gravity over the base, otherwise theallows the foot to roll or 'pronate' too
body would fall over.much in standing and walking.
Equilibrium: The steadiness of the bodyThis means the knee and the hip rolls
depends on the size of its base and theinwards too much which makes the inside
distance of the centre of gravity fromcalf and inside thigh muscle shorter.
that base. An object having a large baseThe iliotibial band can then rub against
and a low centre of gravity is notthe outside knee giving pain.
easily upset.Further up, the bottom muscles become
The first thing necessary in order totoo long and stop working as they should
accomplish good posture is to straightendo which puts added stress on the pelvis
the neck, keep the chin down and back.and low back joints. Before you know it
The second important thing is correctyou have back pain, knee pain and ankle
deep breathing.pain! And all because of fashion!
The line of gravity in the fundamentalProblem 2.
standing position falls in front of theWhether you drive 5 miles or 500 miles a
ears, and in front of the cervical andday your car seat is really important.
dorsal vertebrae, through the lumbarIn many cars the base of the seat slopes
vertebrae, through the hip joint, andbackwards. In fact some of the more
slightly in front of the ankle joint.expensive cars are the worst because
But this probably varies in individualsthey want you to feel 'snug' and safe in
according to their build and height.the seat. However, this position forces
"Biomechanics is that branch of scienceyour pelvis to sit too far backwards.
concerned with the understanding of theOnce this happens your low back and
interrelationships of structure andupper back flex forward too much but
function of living beings with respectthen your neck muscles have to work
to the kinematics and kinetics ofreally hard to stop your head from
motion"flexing too much and allow you to see
Poor Posture associated by thewhere you are going. This position then
following:forces your shoulder blades to stretch
Genetic disorders, Familial association,too far forwards and a large stress is
Irregular/no exercise, Bad habits whenplaced on both the front and the back of
sitting or standing, Carrying excessthe shoulder.
loads, (School/shopping) UnderweightThe result is neck pain and /or upper or
Overweight (Inadequate diet)low back pain. This position can
Mental Attitude towards oneself.exacerbate sciatica as it is a big
Biomechanics is our way of describingstretch for the nerves.
how each bit of your body moves inThe solution is to raise the back of the
relation to another bit.seat so it becomes more horizontal. Some
Our bodies are fantastic at compensatingcars allow you to alter this angle but
when things are not quite perfect butif yours does not then sit on a small
unfortunately when we run out ofcushion or buy a special wedge shape
compensations we usually end up withcushion that fits into the seat.
pain and stiffness.



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