Eccentric muscle contractions on the discussion

 Eccentric muscle contractions on the discussion (reproduced Lilac Garden Forum)
This is a site in the Lilac Garden on the discussion of muscle eccentric way, I benefit from reserved to the muscles the way concerned friends to share blog, thanks forum Notes of speech of you friends. next thank you again! some point we should all be careful to judge.
eccentric muscle contraction is defined as:
stretch muscles in a controlled manner, resulting in the gradual elongation of muscle fibers in the muscle contraction tension at the same time as the contraction of elongated eccentric contraction,
purpose of eccentric contraction is often control body movements, contraction is relatively slow, more complex neural control, in the fine more involved in sports

a muscle contraction, the contraction of skeletal muscle contraction
form, can be expressed as myofilament sliding induced sarcomere shortening can also be expressed as no sarcomere shortening to increase muscle tone. According to the muscle contraction changes in the length and tension, muscle contraction can be divided into 4 types: isotonic (concentric) contraction, isometric, eccentric, isokinetic contraction.
(a) isotonic (concentric) contraction
1. Concept: the first contraction of the muscle tension increased after the shorter length, starting and finishing points close to each other, causing body movement.
2. Features: Tension increases in front, shortening the length of the post; shortened after the start, no increase in tension until the contraction ends. is the driving force of the movement's main form of contraction.
example: barbell was lifted; run; lifting heavy loads, etc..
(b) isometric
1. concepts: muscle contraction increase the length of the constant tension. that static contraction, then do not do mechanical work.
(do not move something, do not bring objects)
2. Features: overload exercise; and other joints and muscles eccentric contractions simultaneous contraction of the heart to maintain a certain position, as to create conditions for the movement of other joints.
example: squat, squat (strap, trunk; legs, buttocks); gymnastics Cross support, angle support; Martial Arts Zhan Zhuang other.
(c) of the eccentric contraction
1. concepts: muscle tension, while generating stretched.
2. Features: Control effect of gravity on the human body work concessions mm; brake mm to prevent sports injuries.
example: squat mm quadriceps; carrying heavy loads mm down the upper arm, forearm muscle; high jump mm quadriceps, gluteus maximus
(d), and other dynamic contraction
1. Concept: In the context of the whole muscle activity, muscle at a constant speed, is always equal to the strength of contraction and resistance.
2. Features: contraction velocity constant during contraction; muscles in the entire range of motion can be generated within maximum tension; as an effective means to improve muscle strength.
example: freestyle stroke (note that the controversial point of view !!!!!)< br> (e) contraction of skeletal muscle in different forms of comparison
1. Strength: Eccentric most powerful.
2. Metabolism: eccentric low energy consumption, physiological reaction than concentric contraction
3. muscle soreness: eccentric> isometric> concentric contraction
II , the mechanical performance of skeletal muscle contraction (slightly)
three motor unit mobilization
1. The concept of motor unit
1 个 a-motor neurons and their domination of the muscle fibers a motor unit. Sports unit is the basic unit of muscle contraction.
2.
mobilize the concept of motor units: the number of motor units involved in activities and nerve impulse frequency of the high and low payment, and formed the mobilization of motor units.
performance: the maximum contraction characteristics of motor unit mobilization.
Training: purports to maintain a certain contraction of the muscle force for a long time to be an inferior race, based on maximum power.
2f8c1 brother's point of view:
eccentric contraction eccentric contraction easily activate motor units, increased The discharge rate, the smaller will be able to raise rates have a greater muscle strength; the same time, when accompanied by eccentric stretch of viscoelastic tissues, inhibit the reconstruction of viscoelastic tissues, and promote functional recovery
eccentric high state of muscle tension is a characteristic feature of the injury loss of eccentric contraction of muscle cramps is to prevent the eccentric training increased muscle tone and reduce muscle tension in one of the ways we currently think
eccentric important than the concentric contraction, the intensity performance to be based on the patient, tired, replaced an action, or for 10 to 20 times
important obstacle is the eccentric muscle training, as long as the eccentric contraction of any muscle can be done at random, it will not spasm .
concentric contraction and eccentric strengthening of the deficiency. spasticity performance under certain conditions, the difficulties for the eccentric exercise, if the completion of the muscle to eccentric exercise freely, certainly there is no spasm, but the patient's spontaneous movement, the universal application of clinical The range of motion training techniques, strength training and technology are strengthening to the heart contraction, this is spasm of the important environmental factors. We are opposed to a simple range of motion training, promoting the use of gravity, muscles do not strengthen the advantages of joint activities degree of training, emphasizing the importance of eccentric
rest, rest breaks pull
gray0110 wrote:
a question: a significant problem!
we discuss the concentric contraction and eccentric When spoken contraction of contraction, the resistance is greater than the contraction, but not necessarily that the muscle can not produce a force greater than the resistance, but the muscles to adapt to environmental characteristics and the purpose of a performance sport that is less than the resistance force of the muscle may be muscle can not fight the resistance, the output may be do not need more muscle power; 2. Since it is inevitable contraction of the electrical activity associated with end plate and muscle actin and myosin in relative motion, but this movement is not to shorten the sarcomere , but to make the shortened sarcomere controlled variable length. such as when he bends over the buckling - relaxation, if the erector spinae electrical activity at a time but not really being stretched, then we can not say erector spinae doing the eccentric contraction, but also, for example, shoulder abduction process is slow and the abductors of gravity movement of mutual antagonism, although this time adductors are stretched, but if there is no electrical activity, not accompanied by the The eccentric adductor; 3. eccentric contractions of human active or passive adaptation to the environment's performance, but not necessarily under conscious control, that is in motion the process of which our consciousness is not concerned about which muscle shortening and muscle specific variable-length arrangements, awareness and safety campaign aims simply, so there is not proper to use active and passive, but an automatic with the (adapted). If we put a heavy object in his hand gently down, then brachial two eccentric muscle contractions do take the initiative; when we throw a heavy object quickly, the heart contraction of triceps movements call the shots, while being passively stretched biceps, biceps shortening in the position of being the passive tension out into the rest position or neutral position when we can say that doing eccentric biceps? (of course, is pulled to a certain length of the biceps during the contraction of protection is certainly eccentric contraction). If someone to straighten me the elbow, I do not force, to pull him enjoy it, then there is no biceps as eccentric, if he and I fight, then, to be eccentric biceps contraction. In addition, the composition of muscle contraction no shrinkage, rather than shrink the passive components of the tension generated tension, then we can say that in the eccentric muscle contraction it? eccentric contraction is the essence of myosin filaments pull the actin filaments so that the controlled sarcomere longer, rather than being pulled muscle.
My view is that the heart contraction and eccentric contraction to the beginning of the isometric contraction are not necessarily, for example, when elbow extension Duanwan, for isometric biceps , but certainly can not be converted to eccentric contraction. If the position of the muscles do not shorten the isometric contraction, then there is no way to do eccentric contractions, at least in the position to be reducing the distance to the neutral position there is no way to complete the eccentric contraction . eccentric contraction of the relationship between muscle strength and resistance, there are two cases, one maximum strength is greater than the resistance, but in order to adapt to the environment intentionally less than the output resistance, one less than the maximum strength resistance, but struggled to adapt to the environment for, such as the strength of the disparity in two pairs of tug of war, a team for another team to pull over at once, but can not say there is no force in this team.
2f8c1: agree liu_alex analysis: strict isotonic contraction hard to find, the natural environment, there can be a constant velocity. and think that if we set out those neurophysiological therapy rules, and with neurological rehabilitation biomechanics to guide it, isokinetic exercise is a valuable training method.
Since the isotonic contraction and isokinetic contraction is not found in the natural environment, something we can ignore this in motion analysis in two ways, to a better understanding of the muscles during exercise purpose of the work, analysis and environmental correction br> can be used for dynamic muscle work and static work. dynamic changes in muscle length work is work, work is static isometric muscle work for.
dynamic work can be divided into concentric and eccentric work work. to the heart work is shorter in length contraction of the muscle form of working, then the resistance is less than muscle contraction; centrifuge work is the contraction of muscles to be elongated form of the work, when the resistance is greater than muscle contraction.
work can be divided into static To support the work of strengthening work, permanent job.
muscle tension to balance the resistance of a certain moment, thus to maintain the static position of the work, said the support work. muscles support the work done in two forms, one is a long muscle shorten the time to maintain the state to balance the resistance torque, the other is a long time to maintain the elongation of the muscle state to balance the resistance moment.
muscles around the joint is stretched by gravity trends, and to a certain degree of tension to prevent the joint out under the action of gravity, said strengthening the work of this kind of work.
against each other together to complete contraction of the muscles at the same time support the sexual tension to a fixed part, said the permanent job.
gray brother's problem is actually related to the eccentric contraction deeper problem, we neuromuscular control mechanisms under different eccentric contractions can be classified again: active and passive eccentric eccentric contractions. the value of active eccentric contractions is no doubt, but for passive eccentric contraction specific control mechanisms and value-related research I have not seen (or even above classification is also my brother under the gray invented temporary post). the face of severe paralysis, the use of passive eccentric eccentric active off than more than likely, so to conduct basic research related to it is very meaningful. liu_alex on this issue a brief introduction, I think the problem with this complex do not match, so please liu_alex and other relevant information the heroes detail, with on the sources of evidence. Thank you and look forward to!
thank liu_alex 2f8c1 corrections brother, my classification is confusing
liu_alex wrote:
only three kinds of muscle contraction in the form: isotonic, isometric, isokinetic ( such action). to the heart and the eccentric contraction is in the form of isotonic contraction.
form of muscle contraction only 3 species: isotonic, isometric, isokinetic. The standard itself is different. Isokinetic Concentric Contraction can also be / eccentric contraction eccentric muscle contraction
the power generated is greater than the concentric contraction, the eccentric contraction with low energy consumption, physiological reaction than to the heart muscle contraction strength when the hour is easier to do when the performance of eccentric contractions the active movement. This is not one of the causes of exercise-induced paralysis? personal experience: relative to the eccentric flaccid paralysis spastic paralysis for better results,
ask you how eccentric early hemiplegia flaccid paralysis as the services I do strap from / around the waist and hip muscles begin, if not easy
extremities to the heart contraction and eccentric contraction of the standard is the direction, one is shrink one is relaxed, eccentric contraction of the muscle of Changes in the microstructure to the heart contraction is not, after eccentric contractions in the movement quickly produced an acute inflammatory response, mainly related myalgia, gray brother eccentric contraction of the problems talked about when the is active or passive, is not what we want to think too much, active or passive, eccentric contraction of the muscle ultrastructure that is the same as the individual. there is no documentary evidence to support, welcome Fu Zheng
gray0110 wrote:
My view is concentric contraction and eccentric contractions of the isometric contraction begins, gray brother I got a little problem this big can not be reduced if the location of the muscles do isometric contraction, then there is no way to do eccentric contractions, and do not agree, eccentric low energy consumption, the question is how do we at least be reduced to verify the location of the distance to the neutral position there is no way to complete the eccentric contraction.,
wrote:
freestyle program the movement of water is definitely not a constant velocity. the natural state of human body can do that a constant velocity.
arms alternating with the water movement speed of resistance change with changes in arm along with the fact that change
on most of our sports are not the standard isotonic, isometric exercise. freestyle strokes alternating arms action should be very similar to constant velocity, liu_alex can, for example
First thing is clear: there can be no natural environment isokinetic! upstairs said water skiing is definitely not a constant velocity. isokinetic exercise may only provide resistance by the computer can do.
contractile function of muscle cells: muscle joint nerve m excited to pass, br> mechanism for skeletal muscle contraction, sliding filament theory of muscle, skeletal muscle contraction coupling m excited, calcium's role in the coupling process,
factors affect the performance of striated muscle contraction, one contraction, contraction of the compound, not complete rigidity and full tonic contraction, isometric and isotonic contraction, muscle contraction, after loading on the impact of initial length before loading or muscle contraction of the muscle, muscle contraction ability to change the influence of muscle contraction muscle contraction performance
performance of contraction as follows: The tension generated by the contraction force and / or the degree of muscle shortening shortening; and generate tension or reduce the rate of velocity.
performance of striated muscle contraction is a contraction under the pre-load / rear load, self- combined effect of the contraction ability and decision factors such as muscle contraction
and load capacity is independent of contractility, the decision to the inherent performance characteristics of muscle contraction
on skeletal muscle, the muscle contraction efficiency performance of contraction is mainly exogenous of: the nervous system involved in regulation of muscle contraction in the number of motor units and muscle contraction frequency
2f8c1 brother so I can understand your eccentric resistance training: the use of pre-load / rear load
I felt eccentric contraction should not be limited to the understanding of the macro, there should be something more and more in-depth, first served for the taste of the two to find.
* When the muscle for isometric and concentric contraction, Ⅰ-type fiber is first raised, with the raising ratio increased, Ⅱ a fiber to be raised, Ⅱ b fiber excitation threshold, the larger, high-intensity exercise has been raised, but in the eccentric contractions, the recruitment order are subject to change, and even fast muscle fibers first raised the opposite phenomenon. for details, see annex. This suggests that eccentric training can increase the excitability of fast muscle fibers.
* Yang and other molecular biological techniques found that after stretching and other sports can generate a stimulus in the muscle tissue alone secreted growth factor. This suggests that eccentric training effect on the endocrine specific. Some studies found that: blood pressure, heart contraction to the rapid rise and decline in eccentric contraction; isokinetic exercise also found that the cardiovascular response to contraction of the heart stronger than the eccentric contraction. These all indicate different effects on the body movement pattern may be a difference.
mei6791 wrote:
isokinetic contraction
1. Concept: In the context of the whole muscle activity, muscle at a constant speed, always equal to the strength of contraction and resistance.
2. Features: contraction velocity constant during contraction; muscles in the entire range of motion can be generated within the maximum tension; as an effective means to improve muscle strength.
Example: I remember the freestyle stroke
Samuel David Stone, impact, although not resulting in water movement and the relationship between isokinetic exercise, but only in the upward movement in the water when the buoyancy, resistance both before and after the three directions under the environment is attractive, so the way the water should cause movement attention.
in microfilament sliding hypothesis. and the interaction of myosin best be explained. It is also induced contraction of the heart of the theoretical basis of the optimal initial length. The second, stretching and relaxation of muscle under passive tension of the extension with a significant increase in muscle because the tension in the connective tissue sheath and the muscle fiber itself internally generated tension. visco elastic tissue that is the result of distraction storage. in the eccentric muscle contraction, active and passive during the process can be combined together and produce far maximum active tension is much larger than the peak power. If the muscle lengthening, the muscle strength is particularly high. that is proportional to the stress and deformation rate, which is the rate of eccentric contraction tension dependence.
mei6791 wrote:
Although eccentric contraction from physiological point of view, more effective than concentric contraction, eccentric muscle contraction, but can lead to the disorder of the sarcomere and significant muscle pain. eccentric contraction-induced muscle pain and mechanical pain due to compression and stretch There is a difference. eccentric muscle can cause significant changes in muscle ultrastructure
repeatedly referred to the landlord are concerned about this issue the same, but did not find a more suitable long explanation, recently learning mechanics repair and hypertrophy. The damage caused by muscle activity is a change in sarcoplasmic reticulum, cell membrane rupture and normal sarcomere disorder characterized. sarcoplasmic reticulum damage can affect calcium homeostasis, leading to muscle cell excitability reduced, so a few days later, muscle strength is reduced. muscle rupture the cell membrane proteins such as creatine kinase and histamine gradually leak into the stroma, which can stimulate nociceptors, causing 24 to 72 hours after training delayed soreness and swelling. muscle damage can be within 1 hour after training, and detected by biopsy, but in the next few days will be worse. not sure, but the muscle fibers than type Ⅱ Type Ⅰ of this muscle fiber damage more sensitive.
visible, eccentric contractions cause muscle pain is conditional, that is carrying the load must be large, the general is not caused by eccentric contractions delayed onset muscle soreness, which also our life experience is the same For example, gait analysis tips: walk more during the eccentric muscle to control the center of gravity forward, but we did not walk a result of delayed onset muscle soreness, if a few people running, and occasionally a run but it is easier cause muscle soreness.
and with the exercise intensity and duration of change .****** DMS has the characteristics of sensory changes after exercise, the muscles appear first few hours feeling uncomfortable, and reached a peak 1 to 3 days. Clinically, patients often show hard for the reduced activity and muscle swelling. swelling occurred in the peak period on or after 1 day after exercise. These phenomena indicate that muscle adequate pressure to increase. the loss of muscle strength is also common ****** force could be detected down to ****** for 10 days after it confirmed the first 2 days after eccentric exercise, muscle pain, edema, mainly by muscle fibers and the water pressure is increased in muscle tissue structural abnormalities in .****** 2 to 3 days after exercise, the most severe and occurs mainly in fast muscle fibers (Ⅱ B-type fiber ).****** recent studies have shown that after eccentric damage the organizational structure is repairable. and strengthen muscles after injury and repair the anti-damage caused by eccentric contraction ability.
shows the repair of damage caused by eccentric contractions is a positive performance to adapt to the environment.