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Muscle Activity
--Understanding muscle actions--Benefits of Aerobic Exercise--Types of muscle contractions
Types of muscle contractions
Isotonic Contractions Myofilaments slide, muscles shorten, movement occurs
Isometric Contractions Muscles do not shorten*Tension in the muscle increases, but filaments don’t slide
Muscle Tone Continuous, partial contraction*Occurs when some fibers of a relaxed muscle are still contracting
How does exercise affect your muscles?
Inactivity leads to weakness, then atrophy
Regular Exercise increases size, strength and endurance
Aerobic Exercise results in stronger, more flexible muscles
that resist fatigue
A.) muscles blood supply increasesB.) muscle cells form more mitochondria and are able to store more Oxygen
Benefits of Aerobic Exercise
1.) More efficient body metabolism2.) Improves digestion3.) Enhances coordination4.) Strenghtens the skelelton5.) Enlarges the heart :
a.) more blood pumped out
b.) less fat in blood vessels (arteries/veins/capillaries)
c.) better gas exchange of O2 CO2
Resistance Exercise
You may know resistance training as “Lifting Weights”
Resistance ExerciseMuscles are pitted against a semi-immovable object
Increased Muscle Size because of enlargement of each muscle cell and it’s connective tissue
All Skeletal Muscles….“The Golden Rules”
1.) A muscle must cross at least 1 joint
2.) Usually, the muscle bulk lies proximal to the crossed joint
3.) All muscles have at least 2 attachments
4.) Muscles can only pull
5.) During a contraction: Insertion moves toward the origin
Origin attaches to the less movable bone (proximal)
Insertion attaches to the movable bone (distal)
Muscle Movements
Prime Mover Major responsibility of a particular movement
Antagonist opposes or reverses a movement
Synergist Assists a prime mover
Fixators specialized synergist that holds a bone in place to stabilize
Prime Mover Contracts Antagonist Relaxes
Opposing Motions
Think of the actions of:
Biceps Brachii vs. Triceps Brachii
What movements are occuring during those motions?
Opposing Movements
Prime Mover vs. Antagonist
Flexion decreasing the angle at the joint
Extension increasing the angle at the joint
Where do these motions occur?Knees, Elbows, Fingers, Toes
Flexion Extension
Opposing Movements
Prime Mover vs. Antagonist
Abduction Moving a limb away from the body’s midline
Adduction Moving a limb toward the body’s midline
Where do these motions occur?Shoulder, Hip
Abduction Adduction
Opposing Movements
Prime Mover vs. Antagonist
Pronation Turning the palm over to face the palm tothe floor
SupinationTurning the palm up to the the ceiling
Where do these motions occur?Wrist
Opposing Movements
Prime Mover vs. Antagonist
Plantarflexion Pointing the toes away from the shin
Dorsiflexion Bring toes toward the shin to expose
the palmar surface of the foot
Where do these motions occur?Ankle/Foot
Opposing Movements
Prime Mover vs. Antagonist
Inversion point toes toward the other foot
Eversion Point toes away from the other foot
Where do these motions occur?Ankle/Foot
Opposing Movements
Circumduction combining movements to produce a
circular motion (cone-like)Where? Shoulder/Hip
Rotation neck motion allowing on an axis, allowingthe person to look either left or right
Where? Neck, Spine
Deviation movement of the wrist to one side or the
other (to the radius, or to the ulna)Where? Hand/Wrist
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