1. Muscular System

2. Facts Myology: study of muscles
Kinesiology: study of voluntary muscles and their actions
Human body has more than 600 muscles
Most abundant tissue in the human body
Can only pull not push

3. Facts cont. Makes up 40-50% of body weight
Long excitable cells capable of contraction
All muscle cells are muscle fibers
Larger the fibers the greater the force
Muscles attach to bones by tendons

4. Functions Responsible for movement “MACHINES OF THE BODY”
Maintains posture
Stabilizes joints
Generates heat

5. Characteristics EXCITABILTIY- reacts to stimuli
CONTRACTIBILITY- can become shorter and thicker when work is done
EXTENSIBILITY- can become longer and thinner
ELASTICITY- ability to return to its normal length after the force applied has been removed

6. Muscle Groups AGONISTS- ANTAGONISTIC Prime movers
Cause particular movement
Several muscles contract at same time causing a movement
ANTAGONISTIC
Usually arranged in pairs – one contracts and one extends

7. Types of Contractions ISOMETRIC ISOTONIC Muscles do not change shape
Tension produced never exceeds the resistance
Examples
Pushing against a locked door
Trying to pick up a car
ISOTONIC
Muscles change shape
Tension rises and exceeds the resistance
Two types
Concentric contractions
Eccentric contractions

8. Isotonic contractions
Concentric
Shortening
Positive work is done
Energy is released to exert force or lift a weight

9. Isotonic contractions cont…
Eccentric
Lengthening
Peak tension is less than the resisitance
Requires less energy to accomplish task
Examples: walking down stairs & weight

10. Muscle Groups Antagonistic Relaxes Opposite or reversed
Prime mover is active then antagonistic
Change automatically
Example: hold your arm out in front of you then bend the elbow while feeling the biceps in the front & the tricep in the back with the other hand

11. Types of Antagonistic Muscles
Flexion
Decreases angle of the joint & brings 2 bones together
Extension
Increases the angle or distance between 2 bones
Extend greater than 180o is hyperextension

12. Types of Antagonistic Muscles
Abduction
Move a limb away from the midline
Fanning movement of fingers and toes
Adduction
move a limb toward the midline

13. Types of Antagonistic Muscles
Circumduction
Combination of flexion, extension, abduction, & adduction
Rotation
Movement of bone around its longitudinal axis

14. Types of Antagonistic Muscles
Supination
Moving the palm from a posterior position to an anterior position
Pronation
Move the palm from an anterior position to a posterior position

15. Types of Antagonistic Muscles
Eversion
Turn the sole of the foot laterally
Inversion
Turn the sole of the foot so it faces medially

16. Types of Antagonistic Muscles
Plantar Flexion
Straightens the ankle joint
Toes point downward
Standing on your toes
Dorsiflexion
Moves instep of foot up and dorsally toward the shin
Standing on your heels

17. Types of Antagonistic Muscles
Elevation
Raising the scapula
Depression
Pulling the scapula to an inferior position