Transcript Skeletal Muscle Properties

Neuromuscular Training
Foundations
And Assessment
Foundations
• Objectives of Resistance Training
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Weight & Power Lifting
Bodybuilding
General Muscular Fitness
Rehabilitation
Sport Specific
Muscle physiology
• Definitions of Muscular Function
Muscle Endurance
Muscle Endurance is the
ability of a muscle or
muscle group to
contract repeatedly or
constantly against a
resistance
Muscle Strength
Muscle Strength is
ability of a muscle or
muscle group to exert
maximal force against
a resistance in a single
repetition.
Muscular Power
Muscular Power is the
ability to exert force
quickly; refers to the
rate at which muscular
force is applied.
Power = Force x
Velocity
Muscular Flexibility
Flexibility refers to a
joint’s range of motion
(ROM).
Range of motion is
dependent upon bony
structure and
“permissiveness” of
muscle and tendons
surrounding the joint
Types of Contraction
Type of
Contraction
Isotonic
(DCER)
Type of Muscle Action
Function
Dynamic concentric
Acceleration
Dynamic eccentric
Deceleration
Isokinetic
Dynamic isokinematic
Acceleration or
Deceleration
Isometric
Static
Fixation
Types of Muscle Contraction
• Isometric: static muscle contraction in
which muscle tension develops but there is
no change in joint angle.
• Isokinetic: dynamic muscle contraction in
which limb displacement or joint rotation
has a constant velocity.
• Isotonic: dynamic muscle contraction
moving a constant external resistance.
Isotonic Contractions
Assessing Muscular Function
Assessing
Muscular
Strength/
Endurance
Laboratory
Methods
Laboratory
and Field Methods
Field
Tests
Assessing Muscular Function
• Laboratory Methods
– Electromyography: measurement of neural or
electrical activity that brings about muscle
contraction
– Isokinetic machines: measurement of torque
throughout range of motion at controlled velocity
– Force transducer: measure static strength and
endurance
Assessing Muscular Function
• Laboratory and Field
Methods
– Dynamometer: use a
spring device
– Constant Resistance
Equipment: use 1
repetition maximum
(1-RM) trial and error
or 5-RM and 10-RM
submaximal methods.
Assessing Muscular Function
• Field Tests
– Callisthenic Activities: relative strength or
endurance
– Vertical Jump/Standing Broad Jump: explosive
leg power
Force: Velocity Relationship
• Muscle’s force
generating capacity
declines with
increasing shortening
velocity.
• Conversely, as load
increases, maximum
shortening velocity
decreases.
• Greatest force (MVC)
achieved @ zero
velocity.
Power: Velocity Relationship
• Peak power rapidly
increases with
increasing velocity up to
peak velocity region.
• Thereafter, maximal
power decreases due to
reduction in max force
at faster speeds.
• At any given velocity,
greater power occurs in
FT fibers than ST fibers.
Torque: ROM Relationship
• Strongest biceps brachii angle seems to be 90°-130°.
• Amount of tension directly related to degree of
overlap of thick and thin filaments in sarcomere.
• When muscle stretched, contact between actin &
myosin crossbridge is poor, contraction weak.
• Inverse relationship
between load that can
be lifted and number
of repetitions that can
be performed.
• Relationship for
strength training zone
60 to 100% of 1 RM
range.
% 1RM
Load: Repetition Relationship
100
95
90
85
80
75
70
65
60
55
50
1 2 3 4 6 8 10 12 14 15
Repetitions
Gender Differences
• Women 50% less
than men in
absolute upper
body strength.
• Women 25-30%
less than men in
absolute lower
body strength.
Gender Differences
• Women 5% to 15%
weaker than men
when expressed
relative to body
weight.
• No difference in
strength when
expressed in muscle
cross-sectional area.
Children Weightlifting
• Lifting weights in
children has not been
shown to prevent full
growth of bones.
• Children who lift
weights in
supervised programs
do not suffer more
injuries than adults.
Giuliano
Illustration References
• McArdle, William D., Frank I. Katch, and Victor
L. Katch. 2011. Essentials of Exercise
Physiology 4th ed. Image Collection. Lippincott
Williams & Wilkins.
• Plowman, Sharon A. and Denise L. Smith. 1998.
Digital Image Archive for Exercise Physiology.
Allyn & Bacon.
• Robergs, Robert A. and Steven J. Keteyian. 2000.
Fundamental Principles of Exercise Physiology.
McGraw Hill.