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Muscle structure & Function
Ch’s 3 & 4
HPR 101 Lecture 2
But 1st, Quiz 1(ch’s 1 & 2)
True or False
1. In weight training, you have the opportunity to participate in your
own creation.
2. The objective in bodybuilding is to see who can lift the most total
weight overhead.
3. Women achieve increases in muscular strength when they
participate in a properly planned weight training program.
4. People under the age of 12 or over the age of 65 should not lift
weights.
5. Weight training can contribute to physical, mental, social,
emotional and spiritual development.
6. Muscles developed through weight training will turn to fat when
you stop training.
7. Proper weight training will result in a loss of flexibility.
8. Proper weight training can increase your speed.
9. Heavy lifting can cause a hernia.
10. Weight lifting requires long hours of weekly training
Overview
• Characteristics of muscle tissue
•Types of muscle tissue
•The structure of skeletal muscle
•Muscle contraction and exercise
•Muscle atrophy and hypertrophy
•Principles of muscle development
Characteristics of muscle
• Extensibility
–The ability of muscle tissue to be stretched
• Elasticity
–The ability of muscle tissue to return to its
normal resting length and shape after being
stretched
• Excitability
–The ability of muscle tissue to receive a
stimulus from the nervous system
• Contractability
–Quality that sets the muscle tissue apart
Types of muscle tissue
• Skeletal muscle
– That which attached to the skeleton, and is voluntary
muscle, meaning we can make it contract consciously
• Smooth muscle
– Primarily lines hollow internal structures in the body.
Is involuntary.
• Cardiac muscle
– Is found only in the heart, and is involuntary
The structure of skeletal muscle
•All skeletal muscles has connective
tissue running through and around it.
•Three categories of connective tissue
1) Epimysium
Connective tissue that surrounds the entire muscle
2) Perimysium
Connective tissue that surrounds a bundle of muscle
3) Endomysium
Surrounds a muscle fiber
Muscle contraction and exercise
•Muscle may only pull, not push
•Even pushing exercises require muscles to
pull on bones across a joint.
•This pulling is called contracting.
The types of contracting:
•Isometric
– Muscle maintains an equal length
•Isotonic
– Movement occurs, but muscle tension remains the
same
•Concentric
– A shortening contraction (as in the upward motion of
barbell curls)
•Eccentric
– A lengthening contraction (as in the downward motion
of barbell curls)
•Isokentic
Motor unit
•A motor nerve coming from the brain or
spinal cord causes a muscle top contract or
a gland to secrete.
•A motor unit consists of a single motor
nerve and all the muscle fibers to which it
sends impulses.
•All-or-none principle
– Muscles either contract or they don’t
•Recruitment
– The number of motor units required depends on the
amount of force needed to accomplish a task
Muscle atrophy & Hypertrophy
•Atrophy
– Muscles that are not used will shrink
•Hypertrophy
– Muscles that are forced to work harder will grow
Basic principles of muscle
development
•Specificity
– 1) You must exercise the specific muscles you want to
develop
– 2) You must follow specific exercise guidelines to
produce the specific type of change you desire
(strength, size or endurance)
•Overload
– To develop, the muscle must be overloaded, or forced
to work harder than normal but not so much as to
cause injury.
•Progression
– The workload must be increased progressively as the
muscle adapts to each new demand, but not so much
as to cause injury
Warm-up, flexibility and stretching
–Warm-up
• Do a light set or a quick (2-3 min’s of aerobic ex.)
–Flexibility
• Refers to the range of motion available in a joint
• Correct weight training consists of:
1.Exercise through a full range of motion in a smooth
continuous manner
2.A balanced program of exercises for all opposing
muscle groups
–Stretching
• Static
–Reasons
»Effective way to increase flexibility
»Injury risk is low
»You can stretch alone
»Relieves some types of muscle soreness
END
–HOMEWORK:
• Read chapters 3 & 4
• Study for quiz
• Train!!
• Performance improvement test next class