Download types of muscle contractions

Muscle & Contraction Types
S3.H9.L1- Understands types of strength exercises (e.g. isometric, isotonic, isokinetic, concentric, eccentric, etc.) and stretching exercises (e.g.
static, dynamic, PNF, etc.) for personal fitness development (e.g. strength, endurance, range of motion)
https://www.youtube.com/watch?v=94Q-fvCAJzQ
Muscles are the “engine” that your body uses to propel itself. They turn energy into motion. It would be
impossible for you to do anything without your muscles. Absolutely everything that you conceive of with
your brain is expressed as muscular motion.



The only ways for you to express an idea are with the muscles of your larynx, mouth and tongue (spoken words)
With the muscles of your fingers (written words or “talking with your hands”)
With the skeletal muscles (body language, dancing, running, building or fighting)
TYPES OF MUSCLES:
1. Skeletal muscle is the type of muscle that we can see and feel.
a. When a body builder works out to increase muscle mass, skeletal muscle is what is being exercised
b. Skeletal muscles attach to the skeleton and come in pairs known as agonist & antagonist—one muscle to
move the bone in one direction (contract) and another to move it back the other way (relax). An example is
the biceps and triceps muscles. These muscles usually contract voluntarily: meaning that you think about
contracting them and your nervous system tells them to do so.
2. Cardiac muscle is found only in your heart, and its big features are endurance and consistency.
a. It can stretch in a limited way and contract with the force of a skeletal muscle but only contracts
involuntarily: You do not control this contraction.
3. Smooth muscle is found in the walls of hollow organs such as the Stomach, Oesophagus, Bronchi and in the walls
of blood vessel and is Involuntary in nature
a. used in controlling internal organs, for example, moving food along the Oesophagus or contricting
blood vessels during Vasoconstriction.
TYPES OF MUSCLE CONTRACTIONS:
1. Isotonic: meaning same tension
2. Isometric: meaning same distance or not moving
3. Isokinetic: meaning same speed
1. Isotonic Contractions
Isotonic contractions are those which cause the muscle to change length as it contracts and causes movement
of a body part. There are two types of isotonic contraction:
a. Concentric
b. Eccentric
A. Concentric Contractions: SHORTENS

Cause the muscle to shorten as it contracts
o An example is bending the elbow from straight to fully flexed, causing a concentric contraction of the
Biceps muscle
o Concentric contractions are the most common type of muscle contraction and occur frequently in daily
and sporting activities.
B. Eccentric: LENGTHENS


Opposite of concentric and occur when the muscle lengthens as it contracts.
This is less common and usually involves the control or deceleration of a movement being initiated by the
eccentric muscles.
o For example, when kicking a football, the Quadriceps muscle contracts concentrically to straighten the
knee and the Hamstrings contract eccentrically to decelerate the motion of the lower limb. This type of
contraction puts a lot of strain through the muscle and is commonly involved in muscle injuries.
2. Isometric Contractions: MUSCLE CONTRACTS BUT NO MOVEMENT OF JOINT



No change in the length of the contracting muscle.
This occurs when carrying an object in front of you as the weight of the object is pulling your arms down
but your muscles are contracting to hold the object at the same level. Another example is when you grip
something, such as a tennis racket.
There is no movement in the joints of the hand, but the muscles are contracting to provide a force
sufficient enough to keep a steady hold on the racket.
o EXAMPLE: Carrying groceries in from the car
3. Isokinetic Contractions: SAME SPEED OF MOVEMENT
Isokinetic contractions are similar to isotonic contractions in that the muscle changes length during the contraction,
but where they differ is that Isokinetic contractions produce movements of a constant speed. To measure this is a
special piece of equipment known as an Isokinetic Dynamometer is required. Examples of using isokinetic
contractions in day-to-day and sporting activities are rare. The best is breast stroke in swimming, where the water
provides a constant, even resistance to the movement of adduction.
INTERESTING MUSCLE FACTS:
1. Muscles make up 40% of your total body weight
2. It takes half as long to gain muscle than it does to lose it
3. To take one step, you use 200 muscles
4. Humans are born with all the muscle fibers they will ever have
5. Your tongue is the strongest muscle in your body
6. When you’re cold, your muscles contract involuntarily
7. The only muscle that never tires is our heart
8. There are 5 different shapes of skeletal muscles
9. Most sources state that there are 640 named skeletal muscles in the human body, although some figures
go up to as many as 840. The reason people say differing numbers is because some people count each
muscle within a complex muscle.
EXAMPLES: IDENTIFY THE TYPE OF MUSCLE CONTRACTION BELOW
For the following examples list whether the picture is demonstrating an isotonic or isometric contractions?
________________Isometric____________________
_____________Isotonic_____________________
_________Isometric__________________________
___________________Isotonic____________________
_____________Isotonic_________________________
______________Isotonic_____________________
________Isometric______________________
__________Isometric_____________________