the contraction of muscles

1. mr. s. sakala

2. MUSCLE CONTRACTIONS
• Through the process of muscle contraction,
tension is developed within muscle tissue, which
may or may not lead to movement of a part of the
body.
• The term contraction often means to shorten;
however, during a muscle contraction the tension
may cause muscle to stay the same, get longer or
become shorter.

3. TYPES OF CONTRACTIONS
There are two main types of muscle contractions
which are ;
ISOTONIC CONTRACTION
CONCENTRIC
CONTRACTION
ECCENTRIC
CONTRACTION
ISOMETRIC
CONTRACTION

4. • Isotonic means same tension.
• Tension developed is constant and muscle
changes its length.
• Isotonic contraction is noted in movement of
limbs.
– E.g a man attempting to lift 25kg requires the use
of biceps.
– Before the muscle can shorten and move the 25kg
load, it must first develop slightly more than 25kg
of tension or it must overcome the 25kg weight

5. • In the isotonic system the muscle shortens
against the fixed load.

6. TWO TYPES OF ISOTONIC CONTRACTIONS
• Concentric contraction occurs when the muscles
shortens
• In the act of curling, the muscle shortens when the arm
flexes at the elbow and this is known as concentric
contraction

7. • Eccentric contraction occurs when the muscles
lengthens
• Eccentric contraction helps in the control of
the rate of movement.

8. ISOMETRIC CONTRACTION
• Isometric means ‘same length’ and in this case
it refers to the same length of muscles
• During isometric contractions, the contraction
does not create any movement. Although the
muscle may increase in size(bulge)
• This is what happens when we attempt to lift
more than we can.

10. CONCLUSION
• muscle contraction is defined by the changes in
length during muscle contraction
• Isotonic contractions generate force by
changing the length of the muscle and can
either be concentric or eccentric contraction
• A concentric contraction causes the muscle to
shorten thereby, generating force which
amounts to positive work.

11. • Eccentric contraction causes muscle to elongate
in response to a greater opposing force. this can
cause loss of muscle tone (injuries) if load is
abnormal.
• Isometric contraction the generate force without
changing the length of the muscle e.g. when
pushing a car.
• In an isometric contraction, there is continuous
minimal contractions which are not sufficient
enough to elicit a response hence there is no
work done.