| Weight training is a common type
of strength training for developing the strength and
size of skeletal muscles. It uses the force of gravity
(in the form of weighted bars, dumbbells or weight
stacks) to oppose the force generated by muscle through
concentric or eccentric contraction. Weight training
uses a variety of specialized equipment to target
specific muscle groups and types of movement. Weight
training differs from bodybuilding, weightlifting,
powerlifting and strongman, which are sports rather than
forms of exercise. Weight training, however, is often
part of the athlete's training regimen.
Weight training
versus strength training
Strength training is an inclusive term for all types
of exercise devoted toward increasing muscular strength
and size (as opposed to muscular endurance, associated
with aerobic exercise, or flexibility, associated with
stretching exercise like yoga or pilates, though
endurance and flexibility can improve as a byproduct of
training). Weight training is one type of strength
training and the most common, seen by all but
specialists as synonymous with strength training. The
difference between weight training and other types of
strength training is how the opposition to muscular
contraction is generated. Resistance training uses
elastic or hydraulic forces to oppose muscular
contraction, and isometric exercise uses structural or
intramuscular forces (e.g. doorways or the body's own
muscles).
History of weight training
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Main article: History of strength training
Hippocrates explained the principle behind weight
training when he wrote "that which is used develops, and
that which is not used wastes away." Progressive
resistance training dates back at least to Ancient
Greece, when legend has it that wrestler Milo of Croton
trained by carrying a newborn calf on his back every day
until it was fully grown. Another Greek, the physician
Galen, described strength training exercises using the
halteres (an early form of dumbbell) in the 2nd century.
Another early device was the Indian club, which came
from ancient Persia where it was called the "meels." It
subsequently became popular during the 19th century, and
has recently made a comeback in the form of the clubbell.
The dumbbell was joined by the barbell in the latter
half of the 19th century. Early barbells had hollow
globes that could be filled with sand or lead shot, but
by the end of the century these were replaced by the
plate-loading barbell commonly used today.
The 1960s saw the gradual introduction of exercise
machines into the still-rare strength training gyms of
the time. Weight training became increasingly popular in
the 1980s, following the release of the bodybuilding
movie Pumping Iron, and the subsequent popularity
of Arnold Schwarzenegger. Since the late 1990s
increasing numbers of women have taken up weight
training, influenced by programs like Body for Life;
currently nearly one in five U.S. women engages in
weight training on a regular basis.[2]
Basic principles
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Main article: Strength training
The basic principles of weight training are
essentially identical to those of strength training, and
involve a manipulation of the number of repetitions
(reps), sets, tempo, exercise types and weight moved to
cause desired increases in strength, endurance, size or
shape. The specific combinations of reps, sets,
exercises and weight depends upon the aims of the
individual performing the exercise; sets with fewer reps
can be performed with heavier weights.
In addition to the basic principles of strength
training, a further consideration added by weight
training is the equipment used. Types of equipment
include barbells, dumbbells, pulleys and stacks in the
form of weight machines or the body's own weight in the
case of chin-ups and push-ups. Different types of
weights will give different types of resistance, and
often the same absolute weight can have different
relative weights depending on the type of equipment
used. For example, lifting 10 kilograms using a dumbbell
requires significantly more force than moving 10
kilograms on a weight stack due to the use of pulleys.
Weight training also requires the use of 'good form',
performing the movements with the appropriate muscle
group, and not transferring the weight to different body
parts in order to move greater weight (called
'cheating'). Failure to use good form during a training
set can result in injury or a failure to meet training
goals - since the desired muscle group is not challenged
sufficiently, the threshold of overload is never reached
and the muscle does not gain in strength.
Comparison to other types
of strength training
The benefits of weight training overall are
comparable to most other types of strength training -
increased muscle, tendon and ligament strength, bone
density, flexibility, tone, metabolic rate and postural
support. There are benefits and limitations to weight
training as compared to other types of strength
training.
Weight training
versus resistance training
Resistance training involves the use of elastic or
hydraulic resistance to contraction rather than gravity.
Weight training provides the majority of the resistance
at the beginning, initiation joint angle of the
movement, when the muscle must overcome the inertia of
the weight's mass. After this point the overall
resistance alters depending on the angle of the joint.
In comparison, hydraulic resistance provides a fixed
amount of resistance throughout the range of motion,
depending on the speed of the movement. Elastic
resistance provides the greatest resistance at the end
of the motion, when the elastic element is stretched to
the greatest extent.
Weight training
versus isometric training
Isometric exercise provides a fixed amount of
resistance based on the force output of the muscle. This
strengthens the muscle at the specific joint angle at
which the isometric exercise occurs, with some lesser
gains in strength also occurring at proximal joint
angles. In comparison, weight training strengthens the
muscle throughout the range of motion the joint is
trained in, causing an increase in physical strength
from the initiating through to terminating joint angle.
Weight training and
bodybuilding
Although weight training is similar to bodybuilding,
they have different objectives. Bodybuilders compete in
bodybuilding competitions; they train to maximize their
muscular size and develop extremely low levels of body
fat. In contrast, most weight trainers train to improve
their strength and anaerobic endurance while not giving
special attention to reducing body fat below normal.
Weight trainers tend to focus on compound exercises to
build basic strength, whereas bodybuilders often use
isolation exercises to visually separate their muscles
and to improve muscular symmetry.
However, the bodybuilding community has been the
source of many of weight training's principles,
techniques, vocabulary, and customs. Weight training
does allow tremendous flexibility in exercises and
weights which can allow bodybuilders to target specific
muscles and muscle groups, as well as attain specific
goals.
Safety
Weight training can be one of the safest forms of
exercise, especially when the movements are slow,
controlled, and carefully defined. However, as with any
form of exercise, improper execution can result in
injury. When the exercise becomes difficult towards the
end of a set, there is a temptation to cheat, i.e. to
use poor form to recruit other muscle groups to assist
the effort. This may shift the effort to weaker muscles
that cannot handle the weight. For example, the squat
and the deadlift are used to exercise the largest
muscles in the body—the leg and buttock muscles—so they
require substantial weight. Beginners are tempted to
round their back while performing these exercises. This
causes the weaker lower back muscles to support much of
the weight, which can result in serious lower back
injuries. To avoid such problems, weight training
exercises must be performed correctly. Hence the saying:
"train, don't strain".
An exercise should be halted if marked or sudden pain
is felt, to prevent further injury. However, not all
discomfort indicates injury. Weight training exercises
are brief but very intense, and many people are
unaccustomed to this level of effort. The expression "no
pain, no gain" refers to working through the discomfort
expected from such vigorous effort, rather than to
willfully ignore extreme pain, which may indicate
serious soft tissue injuries.
Discomfort can arise from other factors. Individuals
who perform large numbers of repetitions, sets and
exercises for each muscle group may experience a burning
sensation in their muscles, which, contrary to popular
belief, is not caused by lactic acid build-up.[citation
needed] These individuals may also
experience a swelling sensation in their muscles from
increased blood flow (the "pump"). True muscle fatigue
is experienced as a marked and uncontrollable loss of
strength in a muscle, arising from the nervous system
(motor unit) rather than from the muscle fibers
themselves. Extreme neural fatigue can be experienced as
temporary muscle failure. Some weight training programs
actively seek temporary muscle failure; evidence to
support this type of training is mixed at best.
Irrespective of their program, however, most athletes
engaged in high-intensity weight training will
experience muscle failure from time to time.
Beginners are advised to build up slowly to a weight
training programme. Untrained individuals may have some
muscles that are comparatively stronger than others. An
injury can result if, in a particular exercise, the
primary muscle is stronger than its stabilising muscles.
Building up slowly allows muscles time to develop
appropriate strengths relative to each other. This can
also help to minimise delayed onset muscle soreness. A
sudden start to an intense program can cause significant
muscular soreness. Unexercised muscles contain
cross-linkages that are torn during intense exercise.
Weight trainers commonly spend 5 to 20 minutes
warming up their muscles with aerobic exercise before
starting a workout. They also stretch muscles after they
have been exercised. The exercises are performed at a
steady pace, taking at least two to four seconds to lift
and lower the weight, to avoid jerks that can damage
muscles and joints.
Exercises where a barbell is held above the body,
which can result in injury if the weight drops onto the
lifter, are normally performed inside a squat cage or in
the presence of one or more spotters, who can safely
re-rack the barbell if the weight trainer is unable to
do so.
Anyone beginning an intensive physical training
programme is typically advised to consult a physician,
because of possible undetected heart or other conditions
for which such activity is contraindicated.
There have been mixed reviews regarding the use of
weightlifting belts and other devices, such as lifting
straps. Critics claim that they allow the lifter to use
more weight than they should. In addition, the
stabiliser muscles in the lower back and gripping
muscles in the forearms receive less benefit from the
exercises.
Wrist straps (also known as cow ties or lifting
straps) are sometimes used to assist in gripping very
heavy weights. The straps wrap around the wrist and tuck
around the bar or weight being lifted, transferring some
of the weight directly to the wrist instead of through
the fingers. They are particularly useful for the
deadlift. Some lifters avoid using wrist straps in
order to develop their grip strength. Wrist straps can
allow a lifter initially to use more weight than they
might be able to handle safely for an entire set, and
can place potentially harmful stress on the bones of the
wrist.
Types of exercises
Isotonic and
plyometric exercises
These terms combine the prefix "iso" (meaning "same")
with "tonic" (strength) and "plio" (more) with "metric"
(distance). In "isotonic" exercises the force applied to
the muscle does not change (while the length of the
muscle decreases or increases) while in "plyometric"
exercises the length of the muscle stretches and
contracts rapidly to increases the power output of a
muscle.
Weight training is primarily an isotonic form
of exercise, as the force produced by the muscle to push
or pull weighted objects should not change (though in
practice the force produced does decrease as muscles
fatigue). Any object can be used for weight training,
but dumbbells, barbells and other specialised equipment
are normally used because they can be adjusted to
specific weights and are easily gripped. Many exercises
are not strictly isotonic because the force on the
muscle varies as the joint moves through its range of
motion. Movements can become easier or harder depending
on the angle of muscular force relative to gravity - for
example, a standard biceps curl becomes easier as the
hand approaches the shoulder as more of the load is
taken by the structure of the elbow. Certain machines
such as the Nautilus involve special adaptations to keep
resistance constant irrespective of the joint angle.
Plyometric exercises exploits the
stretch-shortening cycle of muscles to enhance the
myotatic (stretch) reflex. This involves rapid
alternation of lengthening and shortening of muscle
fibers against resistance. The resistance involved is
often a weighted object such as a medicine ball, but can
also be the body itself as in jumping exercises.
Plyometrics is used to develop explosive speed, and
focuses on maximal power instead of maximal strength by
compressing the force of muscular contraction into as
short a period as possible, and may be used to improve
the effectiveness of a boxer's punch, or to increase the
vertical jumping ability of a basketball player.
Isolation exercises versus
compound exercises
An isolation exercise is one where the
movement is restricted to one joint and one muscle
group. For example, the leg extension is an
isolation exercise for the quadriceps. Specialized types
of equipment are used to ensure that other muscle groups
are only minimally involved—they just help the
individual maintain a stable posture—and movement occurs
only around the knee joint. Most isolation exercises
involve machines rather than dumbbells and barbells
(free weights), though free weights can be used when
combined with special positions and joint bracing.
Compound exercises work several muscle groups
at once, and include movement around two or more joints.
For example, in the leg press movement occurs
around the hip, knee and ankle joints. This exercise is
primarily used to develop the quadriceps, but it also
involves the hamstrings, glutes and calves. Compound
exercises are generally similar to the ways that people
naturally push, pull and lift objects, whereas isolation
exercises often feel a little unnatural. Compound
exercises generally involve dumbbells and barbells (free
weights), involving more muscles to stabilize the body
and joints as well as move the weight.
Each type of exercise has its uses. Compound exercises
build the basic strength that is needed to perform
everyday pushing, pulling and lifting activities.
Isolation exercises are useful for "rounding out" a
routine, by directly exercising muscle groups that
cannot be fully exercised in the compound exercises.
The type of exercise performed also depends on the
individual's goals. Those who seek to increase their
performance in sports would focus mostly on compound
exercises, with isolation exercises being used to
strengthen just those muscles that are holding the
athlete back. Similarly, a powerlifter would focus on
the specific compound exercises that are performed at
powerlifting competitions. However, those who seek to
improve the look of their body without necessarily
maximising their strength gains (including bodybuilders)
would put more of an emphasis on isolation exercises.
Both types of athletes, however, generally make use of
both compound and isolation exercises.
Free weights versus
weight machines
Free weights are dumbbells, barbells, and
kettlebells. Unlike weight machines, they do not
constrain users to specific, fixed movements, and
therefore require more effort from the individual's
stabilizer muscles. It is often argued that free weight
exercises are superior for precisely this reason. As
weight machines can go some way toward preventing poor
form, they are somewhat safer than free weights for
novice trainees. Moreover, since users need not
concentrate so much on maintaining good form, they can
focus more on the effort they are putting into the
exercise. However, most athletes, bodybuilders and
serious fitness enthusiasts prefer to use compound free
weight exercises to gain functional strength.
Some free weight exercises can be performed while
sitting or lying on a Swiss ball. This makes it more
difficult to maintain good form, which helps to exercise
the deep torso muscles that are important for
maintaining posture. |