Transcript Chapter 7 - Academic Resources at Missouri Western

Outline:
1.Benefits of Strength
Training
2.Changes in Body
Composition
3.Assessment of
Muscular Strength &
Endurance
4.Strength-Training
Prescription
5.Strength Gains
6.Strength-Training
Exercises
7.Dietary Guidelines for
Strength Development
8.Core Strength Training
9.Exercise Safety
Guidelines
10.Setting Up Your Own
Strength Training
Program
Chapter 7
Muscular Strength &
Endurance
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Muscular Strength & Endurance
• A well-planned strength-training
program will help to improve and maintain
everyday functional physical capacity
• Strength-training leads to increased
muscle strength and endurance, muscle
tone, tendon and ligament strength, and
bone density
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Benefits of Strength Training
• Increasing strength:
– Increases or maintains muscle and a higher resting
metabolic rate
– Encourages weight loss and maintenance
– Decreases the risk for injury
– Prevents osteoporosis
– Reduces chronic back pain and alleviates arthritic pain
– Aids in childbearing
– Improves cholesterol levels
– Promotes psychological well-being
– May help lower the risk of high blood pressure and
diabetes
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Muscular Strength & Aging
• Muscular strength may be the most
important health-related fitness
component in the older adult population
• Good strength contributes more to
independent living than any other fitness
component
• Older adults with good strength levels can
successfully perform most activities of
daily living
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Muscular Strength & Aging
• A common occurrence in aging is
sarcopenia - the age-related loss of lean
body mass, strength, and function
• Gradual loss of muscle mass and frailty
lead to falls and loss of function
• Strength training helps to slow the agerelated loss of muscle function
• In some older adults, protein deficiency
contributes to loss of lean tissue
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Muscular Strength & Aging
• Data indicates that strength training can
enhance quality of life
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Improves balance and restores mobility
Makes lifting and reaching easier
Decreases the risk for injuries and falls
Stresses the bones and preserves bone
mineral density, decreasing the risk for
osteoporosis
• Increases muscle mass or size, known as
muscle hypertrophy, thereby increasing
metabolism
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Selected Detrimental Effects from
Using Anabolic Steroids
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Changes in Body Composition
• People, especially women, often become
discouraged because they do not see
quick results on the scale
• Regularly determining body composition to
monitor changes in percent body fat can
offset discouragement
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Assessment of Muscular Strength
& Endurance
• Muscular strength: The ability of a
muscle to exert maximum force against
resistance
• Muscular endurance: The ability of a
muscle to exert submaximal force
repeatedly over time
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Assessment of Muscular Strength
& Endurance
• Muscular endurance or “localized muscular
endurance” largely depends on muscular
strength as weak muscles cannot repeat
an action several times or sustain it
• Strength tests and training programs have
been designed to measure and develop
absolute muscular strength, muscular
endurance or both
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Assessment of Muscular Strength
& Endurance
• Muscular strength is often determined by
the maximal amount of resistance
(weight)--one repetition maximum, or
1 RM--an individual is able to lift in a
single effort
• 1 RM is determined through trial and error
• A true 1 RM might be difficult to obtain the
first time an individual is tested as fatigue
becomes a factor
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Assessment of Muscular Strength
& Endurance
• Muscular endurance is often established by the
number of repetitions an individual can perform
against a submaximal resistance or by the length
of time a given contraction can be sustained
• In strength testing, several body sites should be
assessed because muscular strength and
endurance are both highly specific
• A high degree of strength or endurance in one
body part does not necessarily indicate similarity
in other parts, so no single strength test provides
a good assessment of overall strength
• To make valid comparisons, you should use the
same test for pre- and post-assessments
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Strength-Training Prescription
• Muscle cells can exert more or less force
according to the demands placed upon the
muscular system
• If muscle cells are overloaded as in a strengthtraining program, the cells hypertrophy or
increase in size
• If demands on muscle cells decrease as in
sedentary living or required rest because of
illness or injury, the cells atrophy and lose
strength
• Muscular strength is important to develop and
maintain fitness, health, and total well-being
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Factors that Affect Strength
• Physiological factors combine to create
muscle contraction and subsequent
strength gains
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Neural stimulation
Type of muscle fiber
Overload
Specificity of training
• Basic knowledge of these concepts is
important to understand the principles
involved in strength training
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Types of Muscle Fiber
• The body has two basic types of muscle
fibers:
– Slow-twitch or red fibers
– Fast-twitch or white fibers
• Slow-twitch fibers have a greater capacity
for aerobic work
• Fast-twitch fibers have a greater capacity
for anaerobic work, produce more overall
force for quick, powerful movements as in
strength-training activities
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Types of Muscle Fiber
• Genetics determines the ratio of slow- and fasttwitch fibers
• Training increases the functional capacity of both
fiber types
• Strength training increases their ability to exert
force
• During muscular contraction, slow-twitch fibers
are always recruited first
• As force and speed of the contraction increase,
fast-twitch fibers become important
• Intense, powerful activity activates fast-twitch
fibers
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Overload
• Strength gains are achieved in two ways:
– Increased ability of individual muscle fibers to generate
a stronger contraction
– Recruiting a greater proportion of total available fibers
per contraction
• These two factors combine in the overload
principle - demands placed on a system must be
systematically and progressively increased over
time to cause improvement or development
• Strength training is also called progressive
resistance training
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Overload
• Procedures used to overload in strength
training:
– Increasing resistance
– Increasing number of repetitions
– Increasing or decreasing speed of the normal
repetition
– Decreasing the rest interval for endurance
gains or lengthening the rest interval for
strength gains
– Increasing the volume (total reps performed
multiplied by the resistance used)
– Using any combination of the above
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Specificity of Training
• Principle of specificity of training – for a muscle to
increase in strength or endurance, the training program
must be specific to obtain the desired effects
• The principle is commonly referred to as SAID training
(specific adaptation to imposed demands)
• The SAID principle suggests that to improve specific sport
skills, the strength training exercises performed should
closely resemble the movement patterns used in that
specific sport or activity
• Understanding neural stimulation, muscle fiber types,
overload, and specificity is required to effectively design a
strength training program
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Principles Involved in Strength
Training
• Principles necessary to develop a strength
training program:
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Mode
Resistance
Sets
Frequency
Volume of training
• Key factor for success in muscular strength
development is the individualization of the
program according to these principles, the
person’s goals, and the magnitude of the
individual’s effort during training
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Mode of Training
• Two types of training methods are used to
improve strength:
– Isometric (static)
– Dynamic
• Isometric training: muscle contractions
produce little or no movement as in pushing or
pulling against an immovable object
• Dynamic training: muscle contractions produce
movement as in leg extensions
• To increase isometric versus dynamic strength,
static instead of dynamic training must be used
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In isometric training, muscle contraction
produces little or no movement
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Dynamic Training
Most popular mode for strength training
Strength is gained through full range of
motion
• Improvements are measured easily by
the amount lifted
• Dynamic training has two action
phases when an exercise is performed
1. concentric or positive resistance
2. eccentric or negative resistance
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Dynamic Training
• Concentric phase - the muscle shortens as it
contracts to overcome the resistance
• Eccentric phase - the muscle lengthens to
overcome the resistance
• Both motions work the same muscle against the
same resistance
• Eccentric contractions work to lower weights in a
controlled manner
• Eccentric contractions are more effective in
producing muscle hypertrophy but result in
greater muscle soreness
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Free Weights vs. Machines in
Dynamic Training
• Plate-loaded barbells (free weights) were the most popular
weight training devices until the 1970s when strengthtraining machines became more popular
• A debate rose over which of the two training modalities
was better
• Free weights require the lifter balance the resistance
through the entire lifting motion, raising assumptions that
additional stabilizing muscles are required to balance the
resistance as it moves through the range of motion
• Research has not shown any differences in strength
development between the two exercise modalities
• Muscles do not know the source of the resistance
• Strength development is determined by the quality of the
program and the individual’s effort during the program
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Strength training can be done using
free weights
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Advantages of Free Weights
• Cost - free weights are less expensive than most
machines
• Variety - can be used to perform many exercises
to strengthen most muscles in the body
• Portability - can be moved from one area to
another
• Balance - requires the lifter balance the weights
through the entire range of motion
• One size fits all - can be used by most everyone,
whereas not everyone can use machines such as
small women and adolescents
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Advantages of Machines
• Safety - rarely need spotters
• Selection - a few exercises can only be
performed with machines
• Variable resistance - provided by most
machines; free weights provide fixed
resistance
• Isolation - isolates individual muscles
because stabilizing muscles are not
required
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Advantages of Machines
• Time - less time is required because the
resistance can be set quickly
• Flexibility - provide resistance over a greater
range of motion, contributing to more flexibility
in the joints
• Rehabilitation - small loads can be selected easily
through a limited range of motion
• Skill acquisition - learning a new exercise and
performing it correctly are faster because the
machine controls the direction of movement
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Resistance
• Resistance or intensity is the amount of weight
lifted
• General recommendation for strength
development
– Resistance of about 80% of maximum capacity (1 RM);
example, 1 RM is 150 lbs., resistance should be 120 lbs.
(150 x 0.80)
• Repetitions performed at a certain percentage of
the 1 RM - depends on the amount of muscle
mass involved and if it is a single or multi-joint
exercise
• Large muscle mass involvement and multi-joint
exercises allow more repetitions
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Resistance
• Progressive resistance training - a gradual
increase of resistance over a period of time
• Individuals perform between 3 and 12 repetitions
maximum for strength gains
• If a person can not lift the resistance more than
12 times because volitional fatigue is reached
before 12 repetitions, the weight is adequate for
strength development
• When the person can lift the weight more than 12
times, the resistance is increased by 5-10 pounds
and the person again builds to 12 repetitions
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Resistance
• Strength development can occur using less than 80% of 1
RM and working below 3 RM or above 12 RM
• ACSM recommends a range between 3 RM and 20 RM
• The individual may chose the number of repetitions based
on personal preference
• Elite strength athletes work between 1 and 6 RM and vary
number of repetitions
• Bodybuilders use 60%-85% of 1 RM with 8-20 repetitions
• General fitness requires about 10 repetitions to produce
good results in strength, endurance, and hypertrophy
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Sets
• Set is the number of repetitions
performed for a given exercise
• General fitness recommends one to three
sets per exercise
• Some data indicates that increases in
strength, endurance, and hypertrophy
occur between single and multi-set
training, as long as the single set or at
least one of the multi-sets is a heavy set
performed to volitional exhaustion using
an RM zone (8-12)
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Sets
• There is a limited number of sets the exerciser
can do because of muscle fiber characteristics
• Strength gains may be lessened by performing
too many sets
• Single set programs are preferable if time is a
factor
• Multi-sets can be used for multi-joint exercises
and a single RM zone for single-joint exercises
• Beginners should perform 1-2 light warm-up sets
per exercise using about 50% of the 1 RM
followed by 1-3 sets to near fatigue per exercise
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Sets
• Circuit training: Alternating exercises by
performing them in a sequence of three to six or
more exercises
• To maximize strength gains, the program will be
more time-effective if two or three exercises are
alternated that work different muscle groups
• The bench press, leg extension, and abdominal
curl can be combined so that the person can go
almost directly from one exercise set to the next
without resting 2-4 minutes before preceding to a
new set of a different exercise
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Frequency
• A minimum of 8 weeks of consecutive
training is necessary to achieve significant
strength gains
• Once an individual has achieved a
recommended health fitness strength
level, one training session per week is
sufficient to maintain it
• Highly trained athletes must train twice a
week to maintain their strength levels
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Training Volume
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Volume is the sum of all the repetitions performed multiplied by
the resistances used during a strength-training session
It is used to quantify the amount of work performed in a training
session
The total training volume can be obtained by totaling the volume
of all exercises performed
An individual who performs three sets of six repetitions with 150
pounds has performed a training volume of 2,700 (3 x 6 x 150)
for this exercise
Training volume can be modified by changing the total number of
exercises performed by changing the number of sets per exercise
or the number of repetitions performed per set
High training volumes and low intensities achieve muscle
hypertrophy
Low volumes and high intensities increase strength and power
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Training Volume
• Periodization divides the season into cycles using a
systematic variation in intensity and training volume for
athletes to achieve peak fitness and prevent overtraining
• Overtraining: An emotional, behavioral, and physical
condition marked by increased fatigue, decreased
performance, persistent muscle soreness, mood
disturbances, and feelings of staleness or burnout as a
result of excessive physical training
• To avoid overtraining during periodization, the volume
should not increase by more than 5% from one phase to
the next
• Periodization is becoming popular among fitness
participants who want to achieve higher levels of fitness
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Plyometrics
• Plyometric exercise is explosive jump
training incorporating speed and strength
training to enhance explosiveness
• Objective is to generate the greatest
amount of force in the shortest time
• Requires a solid strength base
• Popular in sports that require powerful
movements--basketball, volleyball,
sprinting, jumping, gymnastics
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Core Strength Training
• The trunk (spine) and pelvis are the “core”
of the body
• Core muscles include abdominal muscles,
hip muscles, and spinal muscles
• These muscle groups are responsible for
maintaining the stability of the spine and
pelvis
• Many major muscle groups of legs,
shoulders, and arms attach to the core
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Core Strength Training
• A strong core allows a person to
– Perform activities of daily living with greater
ease
– Improve sports performance through a more
effective energy transfer from large to small
body parts
– Decrease the incidence of low back pain
– Contributes to better posture and balance
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Stability Exercise Balls
• Large, flexible, inflatable ball used for exercises
that combine Pilates with core strength training
• Exercises are designed to develop abdominal,
hip, chest, and spinal muscles by addressing core
stabilization while the exerciser maintains a
balanced position over the ball
• Emphasis is placed on correct movement and
maintenance of proper alignment
• Primary objective is core strength and stability
• Many stability exercises can be performed to
strengthen other body areas
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Elastic-Band Resistive Exercise
• Elastic bands and tubing can be used as
constant-resistance training
• Help increase strength, mobility, functional
ability, aid in rehab in injuries
• Advantages include
– Low-cost
– Versatility - use at almost all angles/directions
of range of motion
– Large number of exercises to work all joints
– Can be packed in a suitcase
– Add variety to routine
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Setting Up Your Own Strength-Training
Program
• Consult a physician if you have concerns
regarding your ability to safely participate
in a program (not advised for people with
advanced heart disease)
• Determine your stage of change
• Choose training program
• Keep a record of your training sessions
• Base the resistance, number of repetitions
and sets on your current strength-fitness
level and available time for your workout
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