The Muscular System (2)
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Transcript The Muscular System (2)
The Muscular System (2)
Structure of muscle
Muscles are made up
of many muscle
fibres, each of which
contain many
myofibrils.
These can either be
slow twitch or fast
twitch.
Types of Muscle Fibre
Slow twitch (Oxidative) Fibres
Deep red in colour
Have a good Oxygen supply
They contract slowly, but can work for long periods
of time without tiring.
Fast twitch (Glycolytic) Fibres
White in colour
A more forceful contraction, but fatigue relatively
quickly.
Muscle Tone
Muscle cells are never all resting at the same time.
Some are muscles are always ready for action – this
is known as muscle tone.
One of the functions of muscle tone is that it keeps
the body primed and ready for instant action.
Also keeps the body in an upright position
This is called POSTURE
Our joints are held firm by the flexor and extensor
muscles both working at the same time
Exercise & the Muscular
system
What are the immediate effects of exercise
on the muscular system?
Exercise increases the body’s demand for Oxygen
and glycogen as the muscles need more fuel to
function.
Extra waste products are created, and extra blood
needs to be pumped around the body to take these
away.
Aerobic exercise can continue for a sustained period
of time as the intensity is relatively low.
High intensity exercise will result in the production of
lactic acid, if this builds up then exercise will cease
as muscles begin to ache and possibly cramp
What are the long term effects
of exercise?
Increased muscle size: Hypertrophy
Training using the principle of progressive
overload, applies stress to the skeletal muscles.
This results in them being damaged as the
muscle fibres are pulled apart causing trauma.
The body rebuilds bridges between muscle
fibres, and actually makes them slightly
stronger
This requires up to 48 hours.
Anabolic Steroids
Most common drugs used to enhance sports performance.
Testosterone, stanozonal, nandrolone and bodlenone.
Anabolic steroids
Mimic the male hormone testosterone
Increase muscle mass and develop
bone growth.
Therefore increase strength
Also allow you to train harder.
Increases aggression
Side effects
Deepen the voice & cause the
growth of facial hair.
Mood swings and aggression
Increased risk of CHD’s.
Bad Posture
It is important that our bodies remain
balanced.
However we often allow our bodies to
stoop or sag
This causes weight to be unevenly
distributed and some muscles are required
to carry extra weight.
If
they are weak they will soon become tired.
Continual bad posture can lead to long
term deformity of the spinal column.
Factors contributing to bad
posture
Working long hours slouching over a
desk
Poorly fitting shoes/high heels
Poor muscle tone
Poor flexibility
Weak muscles in the lower back, legs
and the abdominal muscles.
Overweight.
Curvature of the spine
Lordosis
Causes lower back
problems, leading to
pain.
Weak abdominals
and gluteus maximus
muscles can add to
these problems.
Curvature of the spine
Kyfosis
Sometimes described as ‘hump
back’
This is an excessive outwards
curvature or flexion in the upper
back.
This is often due to weak adductor
muscles in the shoulder region
Curvature of the spine
Scoliosis
This is a condition in which there
is lateral curvature of the spine,
which can be observed with an
x-ray
Good vs Bad posture
Improving or maintaining good
posture
Strength work
Strength exercises
Weight training
Heavy weights are not needed
Correct lifting technique helps achieve and
maintain good posture
Flexibility
Will help to produce an athlete or individual
with improved body shape
Potential injuries
Atrophy
Loss of muscle mass & strength due to stopping
training.
Soft tissue injuries
Include tears, pulls & strains
Small muscle fibres may be torn from their attachment to a
tendon
During intense competition muscle
fibres contract & relax very
quickly, & this can cause
connective tissue & the blood
vessels which run inside them to
be torn.
Task
Why do we warm up & cool down?
What should be included in a warm up?
Design an appropriate warm up for one
of your chosen sports.