Eccentric Training
Encyclopedia
Eccentric training is the lowering phase of an exercise. For example, in a biceps curl
the action of lowering the dumbbell
back down from the lift is the eccentric phase of that exercise — as long as the dumbbell is lowered slowly rather than letting it drop.
There are three distinct phases in the movement of muscle
s and tendon
s: isometric
(no movement), concentric (contracting) and eccentric (Extracting). All three of these stages in muscles movements have an effect on muscle tissues and tendons (tendons are what attach the muscle to the bone).
Eccentric training focuses on slowing down the elongation of the muscle process in order to challenge the muscles, which can lead to stronger muscles, faster muscle repair and increasing metabolic rate.
Eccentric movement provides a braking mechanism for muscle and tendon groups that are experiencing concentric movement to protect joint
s from damage as the contraction is released.
Eccentric training is particularly good for casual and high performance athletes or the elderly and patients looking to rehabilitate certain muscles and tendons.
.
When weight exceeds the force developed by the muscle, as in an eccentric muscle action, the exercise is referred to as negative work because the muscle is absorbing energy in this loaded position.
It goes on to state that eccentric contractions use less energy
, even though they create more force than concentric actions.
Erling Asmussen first introduced eccentric training in 1953 as “excentric,” with ex meaning “away from” and centric meaning “center.” Hence, the term was coined to mean a muscle contraction
that moves away from the center of the muscle.
But the first revelation of the functional significance of these properties occurred by way of a clever demonstration devised by Bud Abbott
, Brenda Bigland, and Murdoch Ritchie. They connected two stationary cycle ergometers
back-to-back with a single chain, such that one cyclist pedaled forward and the other resisted this forward motion by braking the backward-moving pedals. Because the internal resistance
of the device was low, the same force was being applied by both individuals, yet the task was much easier for the individual braking. This demonstration cleverly revealed that a tiny female resisting the movement of the pedals could easily exert more force than, and hence control the power output of, a large burly male pedaling forward.
”.
This mechanical energy is dissipated or converted into one or a combination of two energies.
”. This leads to increase in body temperature.
For example, kinetic energy
is absorbed in running every time your foot strikes the ground and continues as your mass overtakes the foot. At this moment, elastic recoil energy is at its maximum and a large amount of this energy is absorbed and is added to the next stride.
This movement is similar to the action of springs
, where the muscle is continually shortened and stretched resulting in enhanced effectiveness and force. It can lead to the perception of “less effort” even though dealing with higher force.
But time matters in elastic recoil. If this energy is not used quickly it is dissipated as heat
. The role of eccentric training is to use these principles of energy conversion
to strengthen muscle and tendon groups.
s” that each contain a “thick (myosin
) and thin (actin
) myofilament
(muscle filaments or proteins) that overlaps to format a cross-bridge bond (attachment)”.
When in a concentric exercise, shortening of a muscle occurs as the myosin cross bridges continually attach to actin and draw the actin across the myosin — creating force. Each cross-bridge attachment and detachment cycle is powered by the splitting of one molecule of adenosine triphosphate
(ATP). Examples of these type of exercises are kicking a ball or lifting up a weight.
In response to this motion, the eccentric movement stretches the muscle with opposing force
that is stronger than muscle force production. When myofilaments of the muscle fiber are stretched while doing eccentric contracting there may be a less cross bridge attachments of myosin and actin detaching. With more cross bridges attached there are greater force productions produced in the muscle. Examples of activities in which eccentric muscle contractions occur include walking down a hill or resisting the force of gravity while lowering a weight or object.
“Eccentric actions place a stretch on the sacomeres to the point where the myofilaments may experience strain, otherwise known as exercise induced delayed onset muscle soreness
(DOMS)” (Aaron Bubbico & Len Kravitz, 2010). One area of research that has much promise in relation to DOMS and eccentric exercise is the repeated-bout effect (RBE). To help prevent or lessen DOMS from eccentric exercise, or to hasten recovery from it, eccentrically stimulate the muscle then repeat in a week to build up resistance, and the strain will reduce over time.
Their experiment set out to determine the “metabolic cost of exercise on a novel piece of equipment called the Quadmill”. The Quadmill requires the subject to stand in a stationary position on a platform that “oscillates in the vertical and horizontal planes”. The rate of oscillation directly determines the intensity of the exercise, and therefore translates to a stronger workout on the lower body extremities.
During the study, it was hypothesized that the overall metabolic response would be “directly proportional to both body mass and rate of oscillation”. By increasing the rate of oscillation, it was believed, total cost would increase proportionately. However, contrary to the hypothesis, testing found that “there was no apparent relationship between body mass and the total oxidative cost at any of the three intensities (tested)”. Consequently, the conclusions were that “the oxidative response to the exercise occurred during both the exercise and recovery periods” leading to the conclusion that “the device induces a significant anaerobic response that is rate dependent and independent of body mass”. .
and optimal-performance training. For athletes and sports enthusiasts, this eccentric model can help with explosive force.
training in order to prevent injuries or recurring injuries, and trains the body to use the kinetic force driven by eccentric training more efficiently.
According to tests, increases in both strength and muscle fiber are higher in eccentric training than in traditional concentric training.
The rehabilitative nature, low energy costs, high magnitudes of force, and low uptake of oxygen
all align eccentric exercise for both the elderly and rehabilitative functions.
In old age, loss of strength and muscle mass is commonplace. Add to these factors disease
and cardiac and respiratory illness. Eccentric training enables the elderly, and those with the same problems, the ability to train muscle groups and increase strength and resiliency with low-energy exercise.
Eccentric training has also been found to be very beneficial to those with different physical ailments.
in the knee causes serious damage that can last several years and often requires surgery. The ACL is one of the four main stabilizing ligament
s of the knee. During the post-operative rehabilitation of patients, eccentric training can be used as a cornerstone of developing muscle size and strength. According to tests conducted J. Parry Gerber in 2007, structural changes in the muscles greatly exceeded those achieved with standard concentric rehabilitation. The success of the involvement of gradual progressive exposure to negative work ultimately led to the production of high muscle force.
is the progressive loss of muscle mass due to aging. Muscle mass begins to deteriorate as early as the age of 25, and consistently deteriorates into old age. By the age of 80 “one half of the skeletal muscle has been lost” (Lastayo, Woolf, Lewek, Snyder-Mackler, Reich & Lindstedt, 2003). With this great decrease in mass, strength is also decreased. Eccentric training has the ability to counteract sarcopenia through sustained training. The unique trait of greater overloads to the muscle with less strenuous impact on the body, as well as cardiac and respiratory systems, offers a unique case for the elderly. The high-force and low-cost set of attributes in eccentric exercise makes it ideal for the actively impaired.
movement. The close relationship between the muscle and tendons help to dissipate heat or temporarily store kinetic energy. If the forces needed to slow down a limb exceed the capacity of the muscle-tendon system injury is likely to occur.
Athletes with recurring hamstring
and abductor muscle injuries have greater impairment of eccentric strength, suggesting that improvements in eccentric training may minimize the risks of injury by strengthening the muscle-tendon groupings in high-stress areas of the body.
Eccentric training is of huge benefit to those that wish to avert injuries by improving the muscles abilities to absorb more energy before deteriorating. According to one article, “Increased stiffness in tendons, greater force at failure, and an improved ability to absorb energy at the musculotendonous junction result following eccentric exercise training”.
, Osteopenia
is when bone density
is lower than normal levels. Bone mass is affected by muscles forces and their loads to the bone structure. The strength and density of the bone is directly influenced by local strain. Due to the high strain on muscles during eccentric training, coupled with low energy output, eccentric training becomes a cornerstone of the rehabilitative process.
, where the tendons become injured, inflamed or ruptured. While typically these disorders are directly related to eccentric muscle movements, the ability for a muscle to strengthen and prevent injury through eccentric training is great. Controlled rehabilitative regimes will actually strengthen and repair tendons. Ample evidence supports the notion that the tendon, like the muscle, can adapt favorably to physical stress and eccentric loads.
It has been deduced that high muscle tendon forces delivered in a controlled environment are needed for optimal tendon adaptation. While eccentric stress is related to the injury, high force eccentric exercises are needed to maximize recovery.
Athletic", The Open Sports Sciences Journal, 2010, Volume 3, pp. 52–55.
Biceps curl
The biceps curl is any of a number of weight training exercises that target the biceps brachii muscle in order to develop one or more of the following attributes:*size*definition*strength*endurance*power...
the action of lowering the dumbbell
Dumbbell
The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs .-History:...
back down from the lift is the eccentric phase of that exercise — as long as the dumbbell is lowered slowly rather than letting it drop.
There are three distinct phases in the movement of muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s and tendon
Tendon
A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...
s: isometric
Isometric exercise
Isometric exercise or isometrics are a type of strength training in which the joint angle and muscle length do not change during contraction...
(no movement), concentric (contracting) and eccentric (Extracting). All three of these stages in muscles movements have an effect on muscle tissues and tendons (tendons are what attach the muscle to the bone).
Eccentric training focuses on slowing down the elongation of the muscle process in order to challenge the muscles, which can lead to stronger muscles, faster muscle repair and increasing metabolic rate.
Eccentric movement provides a braking mechanism for muscle and tendon groups that are experiencing concentric movement to protect joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
s from damage as the contraction is released.
Eccentric training is particularly good for casual and high performance athletes or the elderly and patients looking to rehabilitate certain muscles and tendons.
Negative movement
This movement has also been described as negative training. This “negative” movement is necessary to reverse the muscle from its initial trajectoryTrajectory
A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbit—the path of a planet, an asteroid or a comet as it travels around a central mass...
.
When weight exceeds the force developed by the muscle, as in an eccentric muscle action, the exercise is referred to as negative work because the muscle is absorbing energy in this loaded position.
It goes on to state that eccentric contractions use less energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
, even though they create more force than concentric actions.
History
Adolf Fick originally discovered in 1882 that “contracting muscle under stretch could produce greater force than a shortening muscle contraction” like in concentric movements. Fifty years later, A.V. Hill determined that “the body had lower energy demand during an eccentric muscle contraction than during a concentric muscle action”.Erling Asmussen first introduced eccentric training in 1953 as “excentric,” with ex meaning “away from” and centric meaning “center.” Hence, the term was coined to mean a muscle contraction
Muscle contraction
Muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same...
that moves away from the center of the muscle.
But the first revelation of the functional significance of these properties occurred by way of a clever demonstration devised by Bud Abbott
Bud Abbott
William Alexander "Bud" Abbott was an American actor, producer and comedian. He is best remembered as the straight man of the comedy team of Abbott and Costello, with Lou Costello.-Early life:...
, Brenda Bigland, and Murdoch Ritchie. They connected two stationary cycle ergometers
Exercise machine
An exercise machine is any machine used for physical exercise. These range from simple spring-like devices to computerized electromechanical rides to recirculating-stream swimming pools...
back-to-back with a single chain, such that one cyclist pedaled forward and the other resisted this forward motion by braking the backward-moving pedals. Because the internal resistance
Internal resistance
A practical electrical power source which is a linear electric circuit may, according to Thévenin's theorem, be represented as an ideal voltage source in series with an impedance. This resistance is termed the internal resistance of the source. When the power source delivers current, the measured...
of the device was low, the same force was being applied by both individuals, yet the task was much easier for the individual braking. This demonstration cleverly revealed that a tiny female resisting the movement of the pedals could easily exert more force than, and hence control the power output of, a large burly male pedaling forward.
Energy
During the eccentric phase of movement, the muscle absorbs energy. This work is done “by stretching the muscle and in this process the muscle absorbs mechanical energyMechanical energy
In physics, mechanical energy is the sum of potential energy and kinetic energy present in the components of a mechanical system. It is the energy associated with the motion and position of an object. The law of conservation of energy states that in an isolated system that is only subject to...
”.
This mechanical energy is dissipated or converted into one or a combination of two energies.
- 1. Heat
- 2. Elastic Recoil
Heat
The energy that is absorbed by the muscle will be dissipated as heat if the muscle is being used as a “damper or shock absorberShock absorber
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. It is a type of dashpot.-Nomenclature:...
”. This leads to increase in body temperature.
Elastic Recoil
The energy that is absorbed by the muscle can be converted into elastic recoil energy, and can be recovered and reused by the body. This creates more efficiency because the body is able to use the energy for the next movement, decreasing the initial impact or shock of the movement.For example, kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
is absorbed in running every time your foot strikes the ground and continues as your mass overtakes the foot. At this moment, elastic recoil energy is at its maximum and a large amount of this energy is absorbed and is added to the next stride.
This movement is similar to the action of springs
Spring (device)
A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...
, where the muscle is continually shortened and stretched resulting in enhanced effectiveness and force. It can lead to the perception of “less effort” even though dealing with higher force.
But time matters in elastic recoil. If this energy is not used quickly it is dissipated as heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
. The role of eccentric training is to use these principles of energy conversion
Energy conversion
Transforming energy is when the energy changes into another form.In physics, the term energy describes the capacity to produce changes within a system, without regard to limitations in transformation imposed by entropy...
to strengthen muscle and tendon groups.
Physiological mechanisms
The muscle has “tension producing tissue comprising small contractile units referred to as sarcomereSarcomere
A sarcomere is the basic unit of a muscle. Muscles are composed of tubular muscle cells . Muscle cells are composed of tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as dark and light bands...
s” that each contain a “thick (myosin
Myosin
Myosins comprise a family of ATP-dependent motor proteins and are best known for their role in muscle contraction and their involvement in a wide range of other eukaryotic motility processes. They are responsible for actin-based motility. The term was originally used to describe a group of similar...
) and thin (actin
Actin
Actin is a globular, roughly 42-kDa moonlighting protein found in all eukaryotic cells where it may be present at concentrations of over 100 μM. It is also one of the most highly-conserved proteins, differing by no more than 20% in species as diverse as algae and humans...
) myofilament
Myofilament
Myofilaments, the filaments of myofibrils constructed from proteins,. The principal types of muscle are striated muscle, obliquely striated muscle and smooth muscle. Various arrangements of myofilaments create different muscles. Striated muscle has transverse bands of filaments...
(muscle filaments or proteins) that overlaps to format a cross-bridge bond (attachment)”.
When in a concentric exercise, shortening of a muscle occurs as the myosin cross bridges continually attach to actin and draw the actin across the myosin — creating force. Each cross-bridge attachment and detachment cycle is powered by the splitting of one molecule of adenosine triphosphate
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
(ATP). Examples of these type of exercises are kicking a ball or lifting up a weight.
In response to this motion, the eccentric movement stretches the muscle with opposing force
Opposing force
An opposing force or enemy force is a military unit tasked with representing an enemy, usually for training purposes in war game scenarios...
that is stronger than muscle force production. When myofilaments of the muscle fiber are stretched while doing eccentric contracting there may be a less cross bridge attachments of myosin and actin detaching. With more cross bridges attached there are greater force productions produced in the muscle. Examples of activities in which eccentric muscle contractions occur include walking down a hill or resisting the force of gravity while lowering a weight or object.
“Eccentric actions place a stretch on the sacomeres to the point where the myofilaments may experience strain, otherwise known as exercise induced delayed onset muscle soreness
Delayed onset muscle soreness
Delayed onset muscle soreness , also called muscle fever, is the pain and stiffness felt in muscles several hours to days after unaccustomed or strenuous exercise. The soreness is felt most strongly 24 to 72 hours after the exercise. It is caused by eccentric exercise...
(DOMS)” (Aaron Bubbico & Len Kravitz, 2010). One area of research that has much promise in relation to DOMS and eccentric exercise is the repeated-bout effect (RBE). To help prevent or lessen DOMS from eccentric exercise, or to hasten recovery from it, eccentrically stimulate the muscle then repeat in a week to build up resistance, and the strain will reduce over time.
Scientific Research
Several different studies have been conducted testing the hypothesis of eccentric training and its benefits. The first commercial eccentric trainer, the Quadmill, is the machine that has been used to test the benefits of eccentric training in the article named AN INITIAL ASSESSMENT OF THE METABOLIC COST OF USING THE QUADMILL by Howlett K., T. Keniston, A. Grassl, A. Olsson, C. Eidem, and D.J. McCann from Department of Exercise Science, Gonzaga University, Spokane, WA.Their experiment set out to determine the “metabolic cost of exercise on a novel piece of equipment called the Quadmill”. The Quadmill requires the subject to stand in a stationary position on a platform that “oscillates in the vertical and horizontal planes”. The rate of oscillation directly determines the intensity of the exercise, and therefore translates to a stronger workout on the lower body extremities.
During the study, it was hypothesized that the overall metabolic response would be “directly proportional to both body mass and rate of oscillation”. By increasing the rate of oscillation, it was believed, total cost would increase proportionately. However, contrary to the hypothesis, testing found that “there was no apparent relationship between body mass and the total oxidative cost at any of the three intensities (tested)”. Consequently, the conclusions were that “the oxidative response to the exercise occurred during both the exercise and recovery periods” leading to the conclusion that “the device induces a significant anaerobic response that is rate dependent and independent of body mass”. .
Findings
Several key findings have been researched regarding the benefits of eccentric training:- Eccentric training creates greater force owing to the “decreased rate of cross-bridge muscle detachments.” PatientPatientA patient is any recipient of healthcare services. The patient is most often ill or injured and in need of treatment by a physician, advanced practice registered nurse, veterinarian, or other health care provider....
s and athletes will have more muscle force for bigger weights when eccentric training. - Eccentric contractions use less energy and actually absorb energy that will be used as heat or elastic recoil for the next movement.
- Increased DOMS leads to more tenderness in eccentric, rather than pure painPainPain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
or tendon swellingSwelling (medical)In medical parlance, swelling is the transient enlargement or protuberance in the body and may include tumors. According to cause, it may be congenital, traumatic, inflammatory, neoplastic or miscellaneous....
amongst patients. - Repeated-bout Effect markedly reduces DOMS. “Completing bouts of eccentric training and then repeating the workout 1 week (or more) later will result in less DOMS after the second workout.”
- Older individuals are less vulnerable to injuryInjury-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...
from eccentric exercise, primarily because of the reduced strain on muscle-tendon groupings as compared to traditional concentric exercise. - Stretching of the muscles and eccentric training provides protection from injury or re-injury.
- Eccentric training has proven to be an excellent post rehabilitationPhysical therapyPhysical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
intervention for lower-body injuries. - Subjects report less weariness from eccentric training than from concentric training.
- Total body eccentric training can raise resting metabolic rate by about 9 per cent, with the greatest magnitude in the first two hours.
- While energy costs remain low, the degree of force is very high. This leads to muscles that respond with significant increases in muscle strength, size and power.
Sports and rehabilitation
With eccentric training, muscles are able to create more for less work, which has special meaning in the realms of high performance sports — both for injury preventionInjury prevention
Injury prevention are efforts to prevent or reduce the severity of bodily injuries caused by external mechanisms, such as accidents, before they occur. Injury prevention is a component of safety and public health, and its goal is to improve the health of the population by preventing injuries and...
and optimal-performance training. For athletes and sports enthusiasts, this eccentric model can help with explosive force.
training in order to prevent injuries or recurring injuries, and trains the body to use the kinetic force driven by eccentric training more efficiently.
According to tests, increases in both strength and muscle fiber are higher in eccentric training than in traditional concentric training.
The rehabilitative nature, low energy costs, high magnitudes of force, and low uptake of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
all align eccentric exercise for both the elderly and rehabilitative functions.
In old age, loss of strength and muscle mass is commonplace. Add to these factors disease
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
and cardiac and respiratory illness. Eccentric training enables the elderly, and those with the same problems, the ability to train muscle groups and increase strength and resiliency with low-energy exercise.
Eccentric training has also been found to be very beneficial to those with different physical ailments.
Anterior Cruciate Ligament (ACL) damage
Tearing an ACLAnterior cruciate ligament
The anterior cruciate ligament is a cruciate ligament which is one of the four major ligaments of the human knee. In the quadruped stifle , based on its anatomical position, it is referred to as the cranial cruciate ligament.The ACL originates from deep within the notch of the distal femur...
in the knee causes serious damage that can last several years and often requires surgery. The ACL is one of the four main stabilizing ligament
Ligament
In anatomy, the term ligament is used to denote any of three types of structures. Most commonly, it refers to fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua, fibrous ligament, or true ligament.Ligament can also refer to:* Peritoneal...
s of the knee. During the post-operative rehabilitation of patients, eccentric training can be used as a cornerstone of developing muscle size and strength. According to tests conducted J. Parry Gerber in 2007, structural changes in the muscles greatly exceeded those achieved with standard concentric rehabilitation. The success of the involvement of gradual progressive exposure to negative work ultimately led to the production of high muscle force.
Sarcopenia
SarcopeniaSarcopenia
Sarcopenia is the degenerative loss of skeletal muscle mass and strength associated with aging...
is the progressive loss of muscle mass due to aging. Muscle mass begins to deteriorate as early as the age of 25, and consistently deteriorates into old age. By the age of 80 “one half of the skeletal muscle has been lost” (Lastayo, Woolf, Lewek, Snyder-Mackler, Reich & Lindstedt, 2003). With this great decrease in mass, strength is also decreased. Eccentric training has the ability to counteract sarcopenia through sustained training. The unique trait of greater overloads to the muscle with less strenuous impact on the body, as well as cardiac and respiratory systems, offers a unique case for the elderly. The high-force and low-cost set of attributes in eccentric exercise makes it ideal for the actively impaired.
Muscle tendon injuries
The entire muscle-tendon system works cohesively to slow down limbLimb (anatomy)
A limb is a jointed, or prehensile , appendage of the human or other animal body....
movement. The close relationship between the muscle and tendons help to dissipate heat or temporarily store kinetic energy. If the forces needed to slow down a limb exceed the capacity of the muscle-tendon system injury is likely to occur.
Athletes with recurring hamstring
Hamstring
In human anatomy, the hamstring refers to any one of the three posterior thigh muscles, or to the tendons that make up the borders of the space behind the knee. In modern anatomical contexts, however, they usually refer to the posterior thigh muscles, or the tendons of the semitendinosus, the...
and abductor muscle injuries have greater impairment of eccentric strength, suggesting that improvements in eccentric training may minimize the risks of injury by strengthening the muscle-tendon groupings in high-stress areas of the body.
Eccentric training is of huge benefit to those that wish to avert injuries by improving the muscles abilities to absorb more energy before deteriorating. According to one article, “Increased stiffness in tendons, greater force at failure, and an improved ability to absorb energy at the musculotendonous junction result following eccentric exercise training”.
Osteopenia
Usually viewed as a precursor to osteoporosisOsteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
, Osteopenia
Osteopenia
Osteopenia is a condition where bone mineral density is lower than normal. It is considered by many doctors to be a precursor to osteoporosis. However, not every person diagnosed with osteopenia will develop osteoporosis...
is when bone density
Bone density
Bone density is a medical term normally referring to the amount of mineral matter per square centimeter of bones. Bone density is used in clinical medicine as an indirect indicator of osteoporosis and fracture risk.This medical bone density is not the true physical "density" of the bone, which...
is lower than normal levels. Bone mass is affected by muscles forces and their loads to the bone structure. The strength and density of the bone is directly influenced by local strain. Due to the high strain on muscles during eccentric training, coupled with low energy output, eccentric training becomes a cornerstone of the rehabilitative process.
Tendinoses
Intense repetitive activities tend to create chronic tendon disordersTendinosis
Tendinosis, sometimes called chronic tendinitis, tendinosus, chronic tendinopathy or chronic tendon injury, is damage to a tendon at a cellular level . It is thought to be caused by microtears in the connective tissue in and around the tendon, leading to an increase in tendon repair cells...
, where the tendons become injured, inflamed or ruptured. While typically these disorders are directly related to eccentric muscle movements, the ability for a muscle to strengthen and prevent injury through eccentric training is great. Controlled rehabilitative regimes will actually strengthen and repair tendons. Ample evidence supports the notion that the tendon, like the muscle, can adapt favorably to physical stress and eccentric loads.
It has been deduced that high muscle tendon forces delivered in a controlled environment are needed for optimal tendon adaptation. While eccentric stress is related to the injury, high force eccentric exercises are needed to maximize recovery.
Chronic Patellar Tendonitis
A condition that arises when the tendon and the tissues that surround it, become inflamed and irritated. This is usually due to overuse, especially from jumping activities. This is the reason chronic patellar tendonitis is often called “jumper’s knee.” A study done by Roald Bahr and colleagues looked at which method of tendon rehabilitation exercise — the “eccentric squat” exercise or the universal gym “leg extension/leg curl” — produced more recovery results in terms of recovery in the treatment of chronic patellar tendonitis. On the twelve week exercise program, participates were tested for thigh circumference and quadricep and hamstring moment of force. There was no significant difference between the groups in either quadricep or hamstring moment of force and hamstring moment of force significantly increased in both groups, but the eccentric squat saw significantly lower pain ratings and produced twice as many “pain free” subjects at the end of the program than the other group.Sources
- Aagaard, Per, "The Use of Eccentric Strength Training to Enhance Maximal Muscle Strength, Explosive Force (RDF) and Muscular Power - Consequences for
Athletic", The Open Sports Sciences Journal, 2010, Volume 3, pp. 52–55.
- Bahr, Roald, Fossan, Bjorn, Loken, Sverre, and Engebretsen, Lars, August 2006, "Surgical Treatment Compared with Eccentric Training for Patellar Tendinopathy (Jumpers Knee) A Randomized Controlled Trial", The Journal of Bone and Joint Surgery, Volume 88A, Number 8, pp. 1689–1698.
- Bubbico, Aaron and Kravitz, Len, Ph.D, October 2010 "Eccentric Training", Idea Fitness Journal, Volume 7, Number 10.
- Gerber, J. Parry, Marcus, Robin L., Dibble, Leland E., Greis, Patrick E., Burks, Robert T. and LaStayo, Paul C., March 2007, "After Anterior Cruciate Ligament Reconstruction Effects of Early Progressive Eccentric Exercise on Muscle Structure", The Journal of Bone and Joint Surgery, Volume 89, pp. 559–57.
- LaStayo, Paul C., Ewy, Gordon A., Pierotti, David D., Johns, Richard K., Lindstedt, Stan, May 2003, "The positive effects of negative work: increased muscle strength and decreased fall risk in a frail elderly population", Journal of Gerontology, Volume 58A, Number 5, pp. 419–424.
- LaStayo, Paul C. Ph.D, Woolf, John M., Lewek, Michael D., Snyder-Mackler, Lynn, Trude-Reich, Lindstedt, Stan L. Ph.D, October 2003, "Eccentric Muscle Contractions: Their Contribution to Injury, Prevention, Rehabilitation, and Sport", Journal of Orthopaedic & Sports Physical Therapy, Volume 33, Number 10, pp. 557–571.
- Lindstedt, S. L., LaStayo, P.C., and Reich, T.E., December 2001, "When Active Muscles Lengthen: Properties and Consequences of Eccentric Contractions", New Physiol. Sci , Volume 16, pp. 256–261.
- Roig, M., O’Brien, K., Kirk, G., Murray, R., McKinnon, P., Shadgan, B., Reid, W.D., 2009, "The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis", British Journal of Sports Medicine, Volume 43, pp. 556–568.
- Howlett K., T. Keniston, A. Grassl, A. Olsson, C. Eidem, and D.J. McCann, January 2011 [AN INITIAL ASSESSMENT OF THE METABOLIC COST OF USING THE QUADMILL ] Department of Exercise Science, Gonzaga University, Spokane, WA. Category:Resistance training