Transcript Muscular Strength and Endurance/Flexibility

Muscular Strength and
Endurance/Flexibility
Muscular Strength and Endurance
Muscular Strength – The maximal force that a muscle can
generate for a single maximum effort. It is usually
assessed by measuring strength using a one-repetition
maximum (1-RM) procedure with either free weights or
some form of variable resistance weight machine.
Muscular Endurance – The ability of the muscle to exert a
submaximal force repeatedly or continuously over time.
Usually measured by determining the maximum number of
repetitions that can be performed. (push-ups/curl-ups)
Basic Skeletal Muscle Characteristics
Musculo-tendinious unit – consists of muscle belly and tendons.
When a muscle contracts (shortens), it moves a bone by pulling on
the tendon that attaches the muscle to the bone.
Muscles consist of individual muscle cells or muscle fibers. They are
connected in bundles. A single muscle is made up of many bundles
of muscle fibers covered by layers of connective tissue that hold the
fibers together.
The muscle fibers are made up of smaller units called myofibrils.
When the brain signals the muscle to contract, protein filaments
within the myofibrils slide across one another causing the muscle
fiber to shorten. (actin and myosin - Sliding Filament Theory)
Muscle Unit
Types of Muscle Fibers
Muscle fibers vary in their structural and
functional characteristics. Color of muscle fiber
is one difference.
CHICKEN vs DUCK
Types of Fibers
Slow Twitch (Red) Type I – High capacity for
aerobic energy supply. Very efficient in
producing ATP. Fatigue resistant. Speed of
contraction of slow twitch fibers is much
slower than fast-twitch. They are adapted
for low intensity, long duration activities.
They utilize aerobic energy system for fuel.
Fast Twitch (White) Type II – High capacity
for rapid force development. Rely on
anaerobic metabolism for fuel. They are
explosive and powerful, but fatigue quickly.
Muscles
Weight training causes the SIZE of the
individual muscle fibers to increase by
increasing the number of myofibrils.
HYPERTROPHY– the development of large
muscle fibers.
Most muscles contain a mixture of slow
and fast twitch fibers.
Inactivity reverses the process
called ATROPHY.
Motor Units
To exert force, the body will recruit one or more motor units
(nerves connected to fibers) to contract. There can be
anywhere from 2 to 100’s of fibers in each unit. The number
of motor units recruited depends on the amount of strength
required.
Small weight → Few motor units
Large weight → More motor units
Strength training improves the body’s ability to recruit
motor units. (Muscle Learning), thus increasing
strength even before muscle size increases.
Motor Units
Motor units (nerves connected to muscle
fibers) are recruited to exert force
BENEFITS OF RESISTIVE TRAINING
Increased muscular strength, endurance
Increased muscle size (hypertrophy)
Increased flexibility or range of motion
Decreased body fat
Increased lean body mass
Increased metabolism
Improved physical appearance
Increased performance in activities
Assists in prevention of osteoporosis
Assessing Muscular
Strength and Endurance
Muscular strength assessed by determining
repetition maximum (1 RM), the maximum
resistance that can be lifted once
Muscular endurance assessed by counting the
maximum number of repetitions of a muscular
contraction
Training Principles
Overload – A gradual increase in the frequency, duration, or
intensity of the activity must occur is any physiological adaptation is
going to occur. For resistive training, this principle specifically
suggests that for greater gains in strength, endurance or power to
occur there must be a manipulation of these factors.
For endurance, increase the number of repetitions in a set, reduce
the recovery time between sets or a combination of the two.
For strength, increase the resistance or load, while restricting the
number of repetitions in a set to 10 or lower.
In each case, over time the muscle will adapt to the changes and
alter its structure and/or function, leading to greater gains.
Training Principles
Specificity – The human body adapts to how it is being trained.
The systems
of the body will physiologically adapt, specifically to the type and nature of
exercise training. How the body adapts, and how much it improves, is directly
related to how hard, and in what manner, it is trained.
Example – If you want a stronger upper body, you must train the chest, back,
shoulders, and arms.
If you want bigger quadriceps, you must train them!
If you want to increase muscular strength, you need to follow the guidelines for
strength development – more weight, less reps. For endurance, less weight,
more reps.
Training Principles
Reversibility – Periods of interrupted training will cause, in
time, a reduction in strength/endurance. Muscle tissue will
not retain, for any length of time, any gains in strength or
endurance associated with resistive training if training is
discontinued or drastically reduced.
Atrophy – A reduction of muscle size. This is a result of
reduced cross sectional area of individual muscle cells (size),
from lack of training or a decrease in the number of cells,
which is more associated with aging.
Rate of atrophy due to detraining is approximately 1% per
week, dependent on the nature and extent of detraining. For
example, total bed rest could be more damaging than just
quitting your resistive training program.
Types of Muscular Contractions
Isometric (Static) – Contractions that generate muscle
tension, but no change in the length of the muscle or movement of a
joint.
Example – tighten the abdominal muscles while sitting still.
Isometric exercises develop strength only at or near the joint angle
where they are performed, not through the entire joint ROM.
Used to strengthen muscles after injury or surgery when movement
of a joint could delay healing.
For maximum gains hold the isometric contraction for 6 seconds and
repeat 5-10 times.
Types of Muscular Contractions
Isotonic (Dynamic) – Involves applying force with
movement. Muscle contractions occur while muscles change
length.
Most popular type of exercises for increasing strength.
Can be performed with free weights, machines, or your own
body weight.
Concentric – Contractions that occur when a muscle
shortens a “positive” contraction.
Eccentric – Contractions that occur when a muscle
lengthens – a “negative” contraction.
Factors Affecting MS&E Training
Muscle size
Strength training does not increase the strength of contraction of
the muscle cells, but rather increases in strength result from a
proportional increase in the diameter or size of the muscle cell.
Gender
Women will not experience as much hypertrophy as men will. This
is due to lower levels of testosterone.
Age
Loss of skeletal muscle tissue is associated with aging, however
the greatest losses are related more to physical inactivity and
sedentary lifestyle and may be preventable and/or reversible.
FITT PRINCIPLES
Frequency – Training with weights should be 2-3 nonconsecutive
days/week. Muscles require a 24-48 hour rest between workouts.
Intensity – The amount of weight (resistance) lifted. This determines
how your body will adapt to weight training and how quickly changes
will occur.
For strength, may use 80% of 1RM for 1-8 repetitions.
Higher amount of weight → Less Repetitions
For endurance, use 40-60% of 1RM for 15-20 repetitions.
Lower amount of weight → More Repetitions
For general fitness, use 70% of 1 RM for 8-12 repetitions.
FITT Principle for Strength
Training
FITT PRINCIPLES
“Time” of Exercise (Repetitions and Sets)- to improve
fitness, you must do enough repetitions of each exercise to
FATIGUE your muscles. The number of repetitions needed to
cause fatigue depends on the amount of weight lifted.
For a general fitness program for both strength and
endurance, complete 8-12 repetitions of 8-10 different
exercises, balancing the muscle groups. (Ab and calf
exercises may require more repetitions.)
Set – Refers to the number of repetitions of an exercise.
Start with 1-2 sets, and build up to increase strength. Allow
enough rest time between sets for the muscles to work at a
high enough intensity. Can work a different muscle group
during the rest period to save time.
Type or Mode of Exercise – For overall fitness
include exercises for your neck, upper back, shoulders,
arms, chest, abdomen, lower back, thighs, buttocks, and
calves – about 8-10 exercises in all.
Balance between agonist (the muscle contracting) and
antagonist (the opposing muscle which must relax and
stretch) muscle groups.
Example – If you do leg extensions (quadriceps), also do leg
curls (hamstrings).
Work the large muscle groups or multiple joints before
working small muscle groups. Example – A chest press
(chest, arms) should be performed before a lateral raise
(deltoids).
See back of chapter for exercises.
Systems of Training
SET SYSTEM – Most popular type of training. Person does an exercise for a
given number of repetitions, or a set, then rests before performing another
set.
SUPERSETS – An exercise set for a particular muscle group is followed by an
exercise for the opposing muscle group. (biceps/triceps)
SUPER MULTIPLE SET – Same concept as supersets, but the lifter completes
all of the sets for a given muscle group, then completes the same number of
sets for the opposing muscle group.
SPLIT ROUTINE – Requires a great amount of time and work. Lifter alternates
muscle groups worked each day, and works out more days/week.
Example – M, W, F work arms, legs and abs; T, Th, Sa, work chest, shoulders
and back.
Systems of Training
PYRAMID SYSTEM – Adding weight until the lifter can complete only
one repetition.
Example – Bench press with a set of 10 reps, then add weight,
complete 8-9 reps, add weight, complete 6-7 reps continuing until
the final set is 1 repetition. (Light to Heavy) Can also pyramid down
from heavy to light weights, increasing the repetitions as weight is
removed.
NEGATIVES – Emphasis is placed on the eccentric part of the
exercise. Slower repetitions are suggested. (Muscle soreness is
usually a result.)
SUPER SLOW – Both concentric and eccentric movements are
slowed down to achieve maximum contractions.
To start: Choose a weight with which you can do
8–12 repetitions with good form
To progress, use the “two-for-two” rule: If your
goal is 8-12 repetitions, add resistance when you
do more than 14 repetitions at your previous two
workouts
Maintain good form at all times
Track your progress
Safety Considerations
1. WARM up prior to the workout.
2. Breathe properly. Breathe out
with strenuous position, and in with
less strenuous position. DON’T
HOLD BREATH.
3. Use spotters with free weights in
any exercise where you could lose
control of the weight.
4. Always use lock-collars on bar
ends so plates don’t fall off.
5. Use proper lifting techniques
Machines
Free Weights
~Safe
~Requires more balance,
coordination
~Convenient
~Allow for a free range of
motion
~Easy to Use
~Don’t need spotter
~Rapid, effortless change
of resistance
~Controlled range of
motion
~Provide both positive and
negative resistance
~Expensive
~Require a lot of space
~Versatile
~Provide positive and
negative resistance
~Require a number of muscle
groups to work together when
lifting
~May require a spotter
~Require time and effort to
adjust resistance.
Muscular System
Muscular System
A Caution About
Supplements and Drugs
A Caution About
Supplements and Drugs
Supplements taken to increase muscle
growth
Anabolic steroids
Human chorionic gonadotrophin (HCG)
Growth hormone
Dehydroepiandrosterone (DHEA) and androstenedione
Insulin and insulin-like growth factor (IGF-1)
Beta-agonists
Protein, amino acid, and polypeptide supplements and socalled metabolic optimizing meals
Side Effects of Anabolic
Steroids
Liver damage and tumors
Reduced HDL
High blood pressure, heart disease,
cancer
Depressed immune function
Psychological disturbances
Depressed sperm and testosterone
production; breast development in males
Masculinization in women and children
Premature closure of bone growth centers
A Caution About
Supplements and Drugs
Supplements taken to speed recovery
from training
Creatine monohydrate
Chromium picolinate
Substances taken to increase training
intensity and overcome fatigue
Amphetamines
Caffeine
A Caution About
Supplements and Drugs
Substances taken to increase endurance
Erythropoietin
Darbepoetien
Substances taken to aid weight control
Diethylpropion, phentermine
Caffeine, PPA, ephedra
Dinitrophenol
Diuretics
Evaluating Dietary
Supplements
Do you need a supplement at all?
Is the product safe and effective?
What studies have been done?
What has the research shown?
Can you be sure that the specific product is of
high quality?
FLEXIBILITY
AND LOW BACK
HEALTH
FLEXIBILITY
Flexibility – Defined as the range of motion (ROM) of a
single joint or a group of joints. It is specific to each joint.
The amount of movement is largely determined by the
tightness of muscles, tendons, and ligaments that are
attached to the joint.
Benefits:
Reduce muscle soreness
Reduce muscle tension
Reduce risk of low back pain
Improve muscle performance
Improve posture
Improve muscle coordination
Reduce the risk of injury
Types of Flexibility
Active (Dynamic) Flexibility – “The degree to which the force of a
muscle contraction can move a joint.” A muscle is stretched by a
contraction of the opposing muscle. Involves movement. Dynamic
shoulder flexibility would affect your ability to swing a golf club.
Important for daily activities and sports.
Passive (Static) Flexibility – Refers to the ability to assume and
maintain an extended position at one end or point in a joint’s range
of motion. It involves no muscle contraction. An outside force or
resistance provided by yourself, a partner, gravity or a weight helps
the joints move through their ROM. Easier to measure than dynamic
flexibility and is usually how we refer to flexibility.
What Determines
Flexibility?
Joint structure—joints vary in direction
and range of movement
Joint capsules = semielastic structures that give
joints strength and stability but limit movement
Muscle elasticity and length
Collagen = white fibers that provide structure and
support
Elastin = yellow fibers that are elastic and flexible
Titin = muscle filament with elastic properties
Muscle Elasticity and
Length
Factors That Affect
Flexibility
Joint Structure and related connective tissue – One cannot change
the joint structure and the range of motion of each joint will vary. But,
the length of the resting muscle fibers can be developed.
Soft Tissue – Muscle tissue, connective tissue, skin, scar tissue, fat
tissue can all affect flexibility.
Age – Aging decreases the natural elasticity of the muscles, tendons
and joints resulting in stiffness. Sedentary lifestyles, common with
aging, also affect flexibility.
Gender – The differences tend to be joint specific and do not always
favor women, which is a common perception.
Muscle temperature – Warmed muscles stretch better than cold
muscles and are less prone to injury.
Pregnancy – Due to release of relaxin, there is a change in the elastic
properties which improves muscle and joint flexibility.
FITT PRINCIPLES
FREQUENCY – minimum of 2-3 days/week; 5-7
days/week may be better.
INTENSITY – Slowly stretch warm muscles to the
point of slight tension or mild discomfort.
TIME – Hold the stretch for 10-30 seconds; repeating
3- 5 times. Relax and breath.
TYPE – Stretch the major muscle groups exercised.
Refer to the end of the chapter for exercises.
Proprioceptive Neuromuscular
Facilitation (PNF)
Most popular PNF stretching is the contract-relax stretching method,
in which a muscle is contracted before it is stretched.
The muscle being stretched is held in an isometric contraction first,
then passively stretched. This also works when the opposing muscle
is contacted prior to the passive stretch.
Example – Stretching the hamstring – Contract the hamstrings, relax
the hamstrings, contract the quadriceps, stretch the hamstrings.
PNF is an effective way to increase flexibility. Usually requires a
partner. PNF protocol should include 4 repetitions of each stretch,
3-5 days/week.
Static vs Ballistic
Stretching
Static stretching is the preferred method of
stretching. A stretch is held to the point of
slight tension or mild discomfort, but not pain.
This allows for the development and retention of
muscular flexibility.
Ballistic (Bouncing) Stretching is the most
dangerous of the stretching procedures. It may
lead to muscle soreness or injury.
Stretching Techniques
A Flexibility Workout
The Lower Back
Low Back Pain has a direct relationship to lifestyle and
wellness behaviors. Proper lifestyle choices can help
prevent LBP. Sedentary lifestyles contribute to loss of
muscular strength, endurance, and a limited ROM.
Low Back Pain is the number one physical complaint by
individuals ages 25-60 in the U.S. Second most common
ailment for job absenteeism for ages 30-60. It contributes
for 25% of days lost for the entire work force.
LBP will affect 60-80% of the American and European
population at some point.
$50 billion will be spent each year by government and
industry for LBP (job absenteeism, disability payments,
worker’s compensations, disability insurance, medical and
legal fees)
Most pain occurs in the lumbar (lower) and sacral region
because it bears the majority of your weight.
Low-Back Health
Function of the spine
Provides structural support for the body
Surrounds and protects the spinal cord
Supports body weight
Serves as attachment site for muscles, tendons,
ligaments
Allows movement of neck and back in all
directions
Skeletal
System
Structure of the Spine
7 cervical vertebrae in the neck
12 thoracic vertebrae in the upper back
5 lumbar vertebrae in the lower back
9 vertebrae at the base of the spine fused into
the sacrum and the coccyx (tailbone)
Structure of the Spine
Vertebrae
Vertebrae consist of a body, an arch, and
several bony processes
Intervertebral disks = elastic disks located
between adjoining vertebrae; consist of a
gel- and water-filled nucleus surrounded by
fibrous rings; serve as shock absorbers
Nerve roots = base of pairs of spinal nerves
that branch off the spinal cord
Vertebrae and
Intervertebral Disk
Core Muscle Fitness
Core muscles include those in the abdomen,
pelvic floor, sides of the trunk, back,
buttocks, hip, and pelvis
Core muscles stabilize the spine and help
transfer force between the upper body and
lower body
Lack of core muscle fitness can create an
unstable spine and stress muscles and joints
Whole body exercises and exercises using
free weights or stability balls all build core
muscle fitness
Causes of LBP
The most common cause of LBP
is physical inactivity!
Poor posture
Faulty body mechanics
Stressful living and working habits
Weak musculature – especially
the abs
Poor flexibility in the lower back
and hamstrings
Smoking
Prevention of LBP
Exercise regularly to
strengthen your back and
abdominal muscles.
Lose weight, if necessary, to
lessen strain on your back.
Avoid smoking (which
increases degenerative
changes in the spine).
Lift by bending at your knees,
rather than the waist, using
leg muscles to do most of the
work.
Receive objects from others or
platforms near to your body,
and avoid twisting or bending
at the waist while handling or
transferring it.
Avoid sitting, standing, or working in any one position
for too long
Maintain a correct posture (sit with your shoulders back and feet
flat on the floor, or on a footstool or chair rung. Stand with head
and chest high, neck straight, stomach and buttocks held in, and
pelvis forward).
Use a comfortable, supportive seat while driving.
Use a firm mattress, and sleep on your side with knees drawn up
or on your back with a pillow under bent knees.
Try to reduce emotional stress that causes muscle tension.
Be thoroughly warmed-up before engaging in vigorous exercise
or sports.
Undergo a gradual progression when attempting to improve
strength or athletic ability.
Treatment of Low Back
Pain
Physical Activity – Only 1% of all back patients
need surgery. Most rehabilitation and prevention
is lifestyle related.
Maintain a normal weight. Excess abdominal
weight can lead to lordosis and poor posture.
Participate in regular aerobic exercise.
Participate in regular muscular strength and
endurance activities, especially for the
abdominal and back regions.
Incorporate lower back and hamstring flexibility
exercises. Work all the planes of motion.
Managing Acute Back Pain
Sudden back pain usually involves
tissue injury
Symptoms: Pain, muscle spasms,
stiffness, inflammation
Treatment:
Ice, then heat
OTC medication (ibuprofen or
naproxen)
Moderate exercise
Managing Chronic Back
Pain
Considered chronic if lasts longer
than 3 months
Symptoms: Stabbing or shooting pain,
steady ache accompanied by
stiffness, pain that is localized or that
radiates to other parts of the body
Treatment: Many options, including
medication, exercise, physical
therapy, massage, acupuncture,
education, and surgery
Tip of the Day
Results in training occur with
consistency and effort – a
lifestyle habit!