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國立台灣大學九十一學年度生物力學
Mechanical Property of Biological Materials: Skeletal Muscles
主要參考書：
1. Lorenz T & Campello M: Biomechanics of skeletal muscle. In Nordin, M. & Frankel V.H.,
2001. Basic Biomechanics of the Musculoskeletal System, 3rd ed. Philadelphia, PA, Lea &
Febiger
Basic Concepts
A. Functions of the skeletal muscle
1. to creat motions
2. to provide strength
3. to protect joints by absorbing shock
B. Componenets of the skekeletal muscle
muscle: perimyosium
fasciculus: endomyosium
sacrolemma
muscle fiber (cell): myofibril: myosin
actin
C. Types of muscle contraction
1. static work: no mechanical work performed
-- isometric contraction
2. dynamic work: mechanical work performed
a. concentric contraction
b. eccentric contraction
c. isokinetic contraction: maximum muscle moment produced
Factors Affecting Muscle Strength
A. Length-Tension relationship
1. The tension that a muscle generates varies with its length.
2. obtained under isometric contraction
and only for maximum activation of
tension
the muscle
3. For a single muscle fiber stimulation,
the maximum tension is found at the
resting length.
4. For a whole muscle contraction
a. active tension
b. passive tension
HC\BioMech\muscle03.doc
for a single muscle fiber
resting length
sacromere length
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Mar 10,
2003
國立台灣大學九十一學年度生物力學
Mechanical Property of Biological Materials: Skeletal Muscles
total tension
tension
passive
tension
active
tension
length
B. Load-Velocity relationship
load
eccentric
isometric
concentric
0
contraction velocity
C. Force-Time relationship
isometric force
force
time
D. Other factors
1. temperature
temperature  nerve conduction velocity  frequency of stimulation  muscle force 
temperature  enzyme activity  efficiency of muscle contraction 
temperature  elasticity of collagen  extensibility of muscle  muscle force 
HC\BioMech\muscle03.doc
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Mar 10,
2003
國立台灣大學九十一學年度生物力學
Mechanical Property of Biological Materials: Skeletal Muscles
2. prestretching
streching  muscle contraction more
Muscle Remodeling
A. Muscle atrophy due to disuse or immobilization
1. decrease in the cross-sectional area of muscle fibers
2. decrease in the number of muscle fibers
3. decrease in the aerobic capacity by changing the proportion of muscle fiber types
a. sedentary people: decrease in numbers of type I muscle fibers
b. athletes: decrease in the fiber type affected by that sports
B. Muscle hypertrophy due to physical training
1. increase in the cross-sectional area of muscle fibers
2. increase in the number of muscle fibers
3. change in the proportion of muscle fiber types
C. Muscle hypertrophy due to electric stimulation
HC\BioMech\muscle03.doc
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2003