What is muscular contraction?
Muscle contraction is the activation of tension-generating sites within muscle fibers. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length such as holding a heavy book or a dumbbell at the same position.
What are the three types of muscle contractions?
Of the three types of contractions--shortening (concentric), isometric, and lengthening (eccentric)--injury is most likely to occur and the severity of the injury is greatest during lengthening contractions. Th … Contraction-induced injury results in the degeneration and regeneration of muscle fibers.
What is the pathophysiology of contraction-induced muscle injury?
Contraction-induced injury results in the degeneration and regeneration of muscle fibers. Of the three types of contractions--shortening (concentric), isometric, and lengthening (eccentric)--injury is most likely to occur and the severity of the injury is greatest during lengthening contractions. Th …
What happens to the length of a muscle when it contracts?
In concentric contraction, muscle tension is sufficient to overcome the load, and the muscle shortens as it contracts. This occurs when the force generated by the muscle exceeds the load opposing its contraction.
What causes the most muscle damage?
low-force muscle contractions and a greater number of contractions most likely causes greater damage to contractile proteins and the ECM, resulting in more severe exercise-induced muscle damage (78).
Does eccentric cause more muscle damage?
Indeed, eccentric exercise induces greater muscle damage and negative functional consequences in an healthy naïve muscle than other types of exercise (Friden and Lieber, 1992).
What type of contraction is most likely to cause soreness?
Any exercise can cause DOMS when you start a new routine or increase the intensity, but exercises that require eccentric muscle contraction, in particular, are more likely to cause DOMS. Eccentric contraction is the muscle's contraction to bear load against gravity while being lengthened.
What type of contraction causes more muscle fatigue?
It is known that concentric contractions produce muscle fatigue without any accompanying damage (Newham et al. 1983a,b).
What is stronger concentric or eccentric?
Muscles are stronger in eccentric contractions than in isometric and concentric contractions. Following eccentric action, muscle force is increased—a phenomenon referred to as residual force enhancement (RFE).
Which builds more muscle eccentric or concentric?
Most studies favor the eccentric movement to produce a higher increase in muscle hypertrophy compared with concentric training, however, the difference in effect is very small – on average 3.2% more muscle growth from eccentric movements, without statistical significance (1–2).
Does eccentric contraction cause muscle soreness?
In contrast to isometric and concentric exercises, eccentric muscle activity is much more effective mechanically; however, it may expose the muscle to soreness (2, 3). Eccentric contraction either provides a reinforcement stimulus to the skeleton muscles or causes damage to the muscle and produces pain.
What is eccentric vs concentric contraction?
There are 2 types of isotonic contractions: concentric and eccentric. In a concentric contraction, the muscle tension rises to meet the resistance then remains stable as the muscle shortens. During eccentric contraction, the muscle lengthens as the resistance becomes greater than the force the muscle is producing.
Why is eccentric contraction important?
Eccentric contractions play an important role in everyday human movements, including mobility, stability, and muscle strength. Shortly after the sliding filament theory of muscle contraction was introduced, there was a reluctant recognition that muscle behaved as if it contained an “elastic” filament.
What causes more fatigue concentric or eccentric?
Thus, despite having developed a lower force, concentric contractions produced a greater long-lasting fatigue.
Why are eccentric contractions stronger?
Theories as to why strength increases occur following eccentric loading include enhanced neural stimulation to and within muscle, higher stored elastic energy in muscle, and increases in muscle hypertrophy. Neural stimulation within muscle from eccentric exercise causes a greater muscle spindle stretch.
What is tetanic contraction?
In tetanic contractions, the force increases within several (fast motor units) or even several tens (slow units) of initial stimuli, and then stabilizes at a certain level. From: Muscle and Exercise Physiology, 2019.
Why is it important to know the types of muscle contractions?
It is not only important for the mere fact of knowing what they consist of, but because it is relevant to know what the body is subjected to when performing physical ...
Which type of muscle contraction is the first to be present?
Auxotonic contraction. To culminate with the main types of muscle contraction, it is necessary to mention the auxotonic. This type is the combination of isotonic and isometric contraction. In this they converge as a whole; the isotonic is the first to be present and the isometric is the one that culminates in the auxotonic contraction.
What is isometric contraction?
Isometric contraction refers to the static position of the muscle in conjunction with great tension. In this, there is no evidence of lengthening or shortening of the involved muscle, therefore, it maintains its length.
What is the difference between eccentric and concentric contraction?
It is evident when extending the arm, for example, but with a constant tension in it. Concentric contraction: it occurs in the opposite way to the eccentric one.
What is the most used contraction in the day to day?
Isotonic contraction. Within the types of muscle contraction, the isotonic is considered the antithesis of the isometric. In this, there is muscle movement and, therefore, the length of each muscle involved is constantly modified. In addition, it is the most used contraction in the day to day, thanks to the movements of the body in general.
What is spinal cord contraction?
For its part, the spinal cord focuses on reflex arches or involuntary movements. Within the movements of the muscles, different types of muscle contraction stand out, which can be classified according to their stimulus or movement. Some are even classified as contraction only with exerting tension without movement.
Is isokinetic contraction the same as isotonic contraction?
Isokinetic contraction is quite similar to isotonic, due to the characteristics they share. They are even often confused on a regular basis. This type of contraction refers to the shortening and lengthening of the muscle fibers, but in a uniform and constant way.
Types of muscle contractures
Depending on the moment in which they appear and the reason, muscle contractures can be divided into two different types:
Causes of muscle contracture
In most cases, contractures appear when performing an activity or effort inappropriately. Executing a bad gesture and maintaining it over time or taking excessive weight can overload an area and cause contracture. Despite being a fairly common muscle damage, there are factors that contribute to making it more frequent.
Treatment of muscle contracture
Before telling how to treat it, it is important to talk about preventing it. To avoid a muscle injury, we recommend that you ensure correct posture when performing daily activities, warm up well before exercising , avoid gestures or repetitive movements, and do physical activity progressively, without forcing yourself excessively.
What is the injury to skeletal muscle fibers during contractions?
Injury to skeletal muscle fibers during contractions: conditions of occurrence and prevention. Contraction-induced injury results in the degeneration and regeneration of muscle fibers. Of the three types of contractions--shortening (concentric), isometric, and lengthening (eccentric)--injury is most likely to occur and the severity ...
How long does it take for a muscle to recover from a contraction?
The recovery from contraction-induced injury is usually complete within 30 days.
Overview
Vertebrate
In vertebrate animals, there are three types of muscle tissues: skeletal, smooth, and cardiac. Skeletal muscle constitutes the majority of muscle mass in the body and is responsible for locomotor activity. Smooth muscle forms blood vessels, gastrointestinal tract, and other areas in the body that produce sustained contractions. Cardiac muscle make up the heart, which pumps blood. Skeletal and cardiac muscles are called striated muscle because of their striped appearan…
Types
Muscle contractions can be described based on two variables: force and length. Force itself can be differentiated as either tension or load. Muscle tension is the force exerted by the muscle on an object whereas a load is the force exerted by an object on the muscle. When muscle tension changes without any corresponding changes in muscle length, the muscle contraction is described as isometric. If the muscle length changes while muscle tension remains the same, th…
Invertebrate
In annelids such as earthworms and leeches, circular and longitudinal muscles cells form the body wall of these animals and are responsible for their movement. In an earthworm that is moving through a soil, for example, contractions of circular and longitudinal muscles occur reciprocally while the coelomic fluid serves as a hydroskeleton by maintaining turgidity of the earthworm. When the circular muscles in the anterior segments contract, the anterior portion of animal's body begi…
History
In 1780, Luigi Galvani discovered that the muscles of dead frogs' legs twitched when struck by an electrical spark. This was one of the first forays into the study of bioelectricity, a field that still studies the electrical patterns and signals in tissues such as nerves and muscles.
In 1952, the term excitation–contraction coupling was coined to describe the physiological process of converting an electrical stimulus to a mechanical response. This process is fundame…
See also
• Anatomical terms of motion
• calcium-induced calcium release
• Cardiac action potential
• Cramp
• Dystonia
Further reading
• Saladin, Kenneth S., Stephen J. Sullivan, and Christina A. Gan. (2015). Anatomy & Physiology: The Unity of Form and Function. 7th ed. New York: McGraw-Hill Education.
• Krans, J. L. (2010) The Sliding Filament Theory of Muscle Contraction. Nature Education 3(9):66
External links
• Sliding Filament Model of Muscle Contraction
• Animation: Myofilament Contraction Archived 2013-05-21 at the Wayback Machine