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CHAPTER 7
Muscle Strength and Endurance
I.
II.
Muscle structure and function
A. Structure
1. Macrostructure of muscle (figure 7.1)
2. Motor unit (figure 7.2)
3. Sarcomere
4. Filament arrangements (figures 7.3 and 7.4)
B. Motor unit function
1. Sliding-filament theory
a. Biochemical process
2.
3. One motor unit can
4. Result of asynchronous firing of a single motor unit
a.
Neuromuscular physiology
A. Neural pathways:
1. sensory
2. motor
B. All-or-none principle
C.
D.
Resting potential and action potential
Physiological properties of skeletal muscle
1. Irritability a.
b.
2. Contractility 3. Viscosity 4. Extensibility and elasticity 5. Contracture
6. Fatigue
a.
7. Summation
a.
III.
Fast- and slow-twitch fibers
A. Slow-twitch muscle fiber
1.
2.
3.
4.
5.
6.
7.
B. Fast-twitch muscle fiber
1.
2.
3.
4.
5.
6.
7.
8.
IV.
Muscle strength, power, and endurance
A. Definitions
1. Muscle strength 2. Muscle power 3. Muscle endurance B. Relationship between muscle strength and muscle endurance
1. Continuum:
2.
Reps and % repetition maximum (RM)
3.
C.
4. Training volume
Recovery after fatigue
1. Initial recovery
a.
2. Middle recovery
a.
3.
4.
V.
Force production
A. Joint angle
1.
B. Length-tension
1.
2.
C.
Muscle size and fiber arrangement
1.
2.
D.
Speed of contraction
E.
VI.
Later recovery
Implications for therapeutic exercise
a. Muscle hypertrophy of fast-twitch fibers usually occurs
from
Number and type of muscle fibers
1.
Types of muscle activity
A. Static
1. Also called
2. Tension is produced in the muscle without
3.
4.
Advantages
a.
b.
c.
Disadvantages
a.
b.
5.
Fatigue factor:
6.
For optimal strength gains to occur, the muscle's effort must
be
B.
VII.
Dynamic
1. Implies that a change in
2. Isotonic: a change in the muscle's
a. Concentric:
b. Eccentric:
3. Isokinetic:
a. Concept of accommodating resistance
Open and closed kinetic chain activity
A. Definitions
1. Kinetic chain –
2.
Open kinetic chain –
3.
Closed kinetic chain –
B.
VIII.
Distinctions
1. Open kinetic chain activities produce high-velocity motions
2. Closed kinetic chain activities place less shear stress on the
joints, so they are safer to use earlier in a therapeutic
exercise program
3. Functional activities include a combination of open and
closed kinetic chain movements
4. Other joints within the chain must be included in the
therapeutic exercise program
5. The function of one joint affects the function of other joints
within the closed kinetic chain
Evaluating muscle strength
A. Evaluation methods
1. Manual muscle test
2. Cable tensiometers
3. Isokinetic equipment
4. Free weights or weight machines (1 RM)—
5.
Grip or pinch dynamometers
B. Manual muscle test
1. Assessment of the muscle's ability to
2.
3.
Grades of muscle strength: 5 to 0 (see table 7.3)
Protocols
IX.
X.
XI.
Gradations of muscle activity
A. PROM
B. AAROM
C.
AROM
D.
RROM
Strength equipment
A. Manual resistance
B. Body weight
C.
Rubber tubing and bands
D.
Free weights
E. Isotonic machines
F.
Isokinetic machines
G.
Other equipment: Nautilus, other machines
Proprioceptive neuromuscular facilitation
A. Facilitation
1.
2.
3.
4.
B.
Patterns of movement
1. Central nervous system stimulation produces
2.
C.
These mass movement patterns incorporate
a. Flexion and extension
b. Adduction and abduction
c.
Rotation
Principles of application
1.
2.
3.
4.
5.
D.
6. The motions are performed
7. The clinician must
PNF techniques
1. For flexibility:
2.
XII.
A quick stretch applied immediately before the beginning of
the movement pattern utilizes the stretch reflex to
For strengthening:
Strengthening principles
A. Basic principles
1. Strength exercises should
2.
B.
C.
3.
Using many exercises that accomplish the same thing
4.
The strengthening program should
5.
Progression of a strengthening program is
SNAP principle
1.
2.
3.
4.
a.
SAID principle:
1. A muscle will
2. If high loads with low reps are used,
3. If low loads with high reps are used,
4. Exercises should
D.
XIII.
Rate of strength gains
1.
2.
3.
Exercise progression
A. Different systems
1. DeLorme system
2. Oxford technique
3. DAPRE (Daily Adjusted Progressive Resistive Exercise)
4. Houglum progression
B. These systems all
C.
Strength must be
D.
An overload should always be applied with