Term
| what is the isometric muscle contraction? |
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Definition
| muscle contraction produces no gross change in the joint angle-often call static, or holding contractions to stabilize joints |
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Term
| What is the example of isometric muscle contraction? |
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Definition
| The scapula must be stabilized against the thorax then the hand reach forward or upward |
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Term
| What is the Isokinetic Muscle contraciton? |
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Definition
| occurs when the rate of movement (angular or linear velocity) is constant. |
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Term
| WHat is the example of the isokinetic muscle contraciton? |
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Definition
| an electromechanical device (isokinetic dynamometer) is used to limit the rate of movement of a preset angular velocity crank arm regardless of the force exerted by the contracting muscle. |
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Term
| WHat is the example of the isokinetic muscle contraciton? |
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Definition
| During isokinetic exercise the resistance accommodates the external force at the skeletal lever so that the muscle maintains maximum output throughout the full range of motion |
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Term
| What is the isotonic Muscle contraction? |
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Definition
| refer to a muscle contraction lifting a load vertically against gravity. THe idea is that shortening of the muscle occurs at a constant rate throughout the full excursion. |
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Term
| What is the isotonic Muscle contraction? |
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Definition
| the tension is not exactly identical due to length-tension and mechanical advantage variablility |
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Term
| What is eccentric muscle contraction? |
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Definition
| muscle lengthens during active contraction |
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Term
| What is the example of the eccentric muscle contraction? |
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Definition
| quadriceps muscle group assisting in lowering the body to sit or decending a step. |
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Term
| What is the example of the eccentric muscle contraction? |
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Definition
The elbow flexors lowering a glass of water to the table.
The anterior tibialis from heel contact to foot flat. |
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Term
| What is the characteristic of the eccentric muscle contraction? |
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Definition
| decelerate body segments and provide shock absorption such as when landing from a jump |
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Term
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Definition
| a contracting muscle or group of muscle always contract actively to produce a concentric, isometric, or eccentric contraction |
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Term
| What is antagonist muscle? |
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Definition
| that possesses the opposite anatomic action of the agonist |
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Term
| What is the character of antagonist muscle? |
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Definition
| the antagonist is a non-contracting muscle that neither assist nor resist the motion but that passively elongates or shortens to permit the motion to occur |
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Term
| What are the example of antagonist muscle? |
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Definition
| wrist extension when the palm is facing the table top, the wrist extensors are the agonist and the wrist flexors are the antagonists |
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Term
| What are the example of antagonist muscle? |
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Definition
| when the dorsum of the hand is facing the table and the wrist is flexed against gravity. The wrist flexors are the agonists, and the wrist extensors are the antagonists. |
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Term
| What is synergist muscle contraction? |
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Definition
it contracts at the same time as the agonist.
The action of a synergist may be identical, supportive or complementary to that of the agonist.
commonly act isometrically at the joints far removed from the primary motion to fixate, or stabilize, proximal joints so that motion may occur at distal joints. |
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Term
When the seated subject flexes the elbow to lift a load in the hand, the flexors contract concentrically and are classified as the agonists.
As the elbow is then extended to lower the load, the flexors perform an eccentric contraction and are still classified as agonists. |
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Definition
The antagonistic extensors are relatively relaxed and elongate to permit the motion of elbow flexion.
The extensors remain inactive and are still the antagonists, |
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Term
| In the situation when the subject is placed in the supine position with the shoulder in 90 degrees of flexion and performs the same motions of elbow flexion and extension, the agonist-antagonist relationships are reversed Here: |
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Definition
| the elbow extensors are the agonists for elbow extension (isotonic contraction) and for elbow flexion (eccentric contrction), while the flexors are the antagonist for both motions. |
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Term
What do you learn about length-tension relationship:
before the muscle fibers could produce tension the myofascial slack needs to be taken up by muscle contraction |
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Definition
| SHort of resting length the fibers are not tensed enough and therefore not yet ready to produce osteokinetic motion |
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Term
Length-Tension Relationships
Following the uptake of the slack in the muscle there is a rapid rise in tensile capacity peaking at about 110% of resting length. Further lengthening of the muscle results in reduction of the overlap of Actin and Myosin filaments, thereby preventing coupling of the full number of cross-bridges. |
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Definition
| The upswing of the tension curve beyond 170% of resting length is caused by the rise in passive tension of the fibers The tearing point of the fiber occured at about 200% of resting length. |
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Term
WHat do you know about passive insufficiency?
Shortness of a multi-joint muscle where the length of the muscle is not sufficient to permit normal elongated across two or more joints simultaneously, they may reach state of passive insufficiency and not allow further motion by the agonistl. |
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Definition
| For example: The hip can be flexed from 115degree to 125 degree with a flexed knee, but when the knee is kept in extension, hip flesion (SLR) is usually limited to about 70 degree because of passive insufficiency of the hamstrings muscle which are now stretched over the hip and the knee. |
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Term
Passive Insufficiency
Certain pathologies may cause muscles and tendons to lose their normal excursion/range of motion. These conditions include muscle tightness, spasticity, shortening from trauma or surgery. |
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Definition
| Thus, even though the agonist contact strongly, motion may be severly limited by the deficient excursion of the antagonist |
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Term
What do you learn about active insufficiency?
Active insufficiency refers to the relative weak contractile force of the muscle when its attachment are approximated and the muscle is attempting to contract on the lower portion of its length-tension curve |
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Definition
| Example: maximum isometric grip strength is greatest when the wrist is in slight extension. When the wrist is flexed the grip strength is markedly reduced. The ineffectual grip produced when the wrist is held in full flexion due to the combination of active insufficiency of the long finger flexors (flexors digitorum superficialis and profundus) and passive insufficiency of the antagonistic long finger extensor (extensor digitorum) |
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Term
What do you know about Leverage and Length-Tension Interactions:
Another unique manner in which the body avoids the weakness of active insufficiency is by changes in the mechanical leverage or the tangential component. |
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Definition
| Example of the biceps brachii muscle the length-tension factor is most favorable when the elbow is in full extension. The maximum tension that can be produced during contraction of the muscle decreases as the elbow approaches and passes 90 degrees of flexion. |
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Term
What do you know about Leverage and Length-Tension Interactions cont:
To compensate for the loss in active muscle tension, the leverage of the muscle (distance from fulcrum to line of pull) increases to a maximum at 90 degrees, where the musculotendinous unit assumes a most ideal line of pull. |
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Definition
| The patella serves a similar purpose in the Quadriceps muscle group. The patella increase the force arm distance and consequently torque production. It does so most significantly as the length-tension factor becomes less favorable (as the knee extends). |
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Term
What do you know about age and gender?
It is recognized that males are generally stronger than females. In both genders, however, muscle strength is gained from birth through adolescence, peaking between the ages of 20-30 years, and gradually declining with advancing age. |
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Definition
| The muscle strength of young boys is approximately the same as that of young girls up to the age of puberty. Thereafter males exhibit a significantly greater grip strength than females, with the greatest differences occurring between ages of 30 and 50. |
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Term
What do you know about age and gender?
The greater strength of males appears to be related primarily to the greater muscle mass they develop after puberty. The ratio of lean body mass to whole body mass is similar in males and females up to about age 16. After puberty the muscle mass of males becomes as much as 50 percent greater than that of females, and the ration of lean body mass to whole body mass also favors males. |
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Definition
| On the other hand, muscle strength per cross-sectional area of muscle appears to be similar in males and females, as does the proportion of fast-twitch and slow-twitch muscle fibers. |
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Term
What do you know about skeletal muscle architecture?
There is a strong correlation between that physiologic cross-sectional area of a muscle and the maximal force that the muscle can produce when stimulated. |
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Definition
| The physiologic cross-section transects each fasciculus at a right angle and therefore includes all of fibers in pennate muscles. Most muscle fibers and fasciculi attach to the central tendon at acute angles. |
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Term
What do you know about fiber architecture cont?
Most of the muscle in the body are of pennate structure (interossei, deltoid, and hamstrings), designed for more force at the expenseof less shortening distance. The parallel structure of fibers (lumbricals and sartorius) provides greater shortening distance but less force for an equivalent muscle mass. |
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Definition
| Muscle fiber architecture determines the range of muscle shortening, number of fibers that may contribute to Power generation and may affect the speed of shortening. |
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Term
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Definition
| Muscle belly>fascicullus>endomytrium>sarcolemma> myofibri |
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Term
| What is Pennate muscles Uni-pennate? |
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Definition
| when all the fascicles are on the same side of the central tendon |
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Term
| What is the bi-pennate muscle? |
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Definition
| when the fascicles are on both sides of the central tendon, the pennate. THe rectus femoris of the quadriceps, is a good example |
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Term
| What is the multi-pennate muscle? |
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Definition
| If the central tendon branches within a pennate muscle, as seen in the deltoid muscle in the shoulder. |
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Term
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Definition
| extends leg at knee and flexes thigh at hip; part of the quadriceps group |
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Term
| What is the angle of pennation? |
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Definition
The angle between the longitudinal axes (central tendon) of the whole muscle and its fibers in a pennate muscle.
Pennation is not the most mechanically ideal mechanism range is reduced in order to gain more power. The most range efficient arrangement for the muscle's line of action to be parallel to the muscle fibers. Any angular deviation away from the central long axis means that energy is wasted or more poorly converted along the muscle line of pull. |
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Term
| What do you know about angle of pennation? |
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Definition
The physical layout of the skeleton is such that we often need high cumulative power rather than contraction distance and pennation is the best suited mechanism for this.
The larger the angle of pennation the stronger (and shorter) the contraction is, since more fibers are engaged in the production of the muscle contraction over a larger cross sectional area (CSA). |
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Term
| What is the Physiological CSA? |
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Definition
| represents the maximal number of actin-mosin cross-bridges that can be activated in parallel during contraction, the maximal force-generating capacity of a given muscle is propotional to its total physiological cross sectional area. |
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Term
| What do you know about the motor unit? |
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Definition
| Large motor neurons that constitute the link to the pathway of motor response are located either in the brainstem (for the muscle of the face and head) or in the spinal cord (for the muscle of the neck, trunk and extremities). The motor neurons in the spinal cord are located in the gray matter of the ventral horns. The motor neuron along with its axon and all of the muscle fibers that are innervated by this motor neuron, comprise the motor unit. |
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Term
| What do you know about the motor unit? |
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Definition
| The majority of the neurons that innervate skeletal muscles are the Alpha type sometimes called alpha motor neuron. Motor commands are carried from the neuronal cell bodies over peripheral nerve fibers for transmission across the neuromuscular junciton that synapses between the nerve and the muscle. |
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Term
| What do you know about the motor unit? |
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Definition
| The number of muscle fibers innervated by asingle motor nerve fiber varies from as feww as 5 (in some eyemuscles requiring fine control) to as many as 1000 or more (in large muscle such as the gastronemius. |
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Term
| What do you know about innervatin ratio? |
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Definition
is used to describe the average number of muscle fibers per motor unit in a given muscle.
The innervation ratio is determined by dividing the number of muscle fibers by the number of large motor axons innervating that particular muscles. |
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Term
| What do you know about the motor unit? |
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Definition
ALl muscle fibers within a given motor unit contract or relax almost simultaneously. It is not possible for some muscle fibers of amotor unit to contract while other fibers in the same motor unit are relaxed.
The principle described is know as the all-or-non law. |
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Term
| What do you know about the motor fiber type? |
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Definition
| are distinguished mainly by the metabolic pathways by which they can generate ATP and the rate at which its energy is made available to the contractile system of the sarcomers, which determines the speed and quality of muscle contraction. |
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Term
| What are motor fiber type? |
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Definition
| The three fiber types are termed type I, slow-twitch oxidative (SO) fibers; type IIA-fast-twitch oxidative-glycolytic (FOG) fibers and type IIB-fast-twitch glycolytic (FG) fibers |
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Term
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Definition
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Term
What do you know about fiber type 1?
Typer I (SO) |
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Definition
are characterized by a low activity of Myosin ATPase and therefore, a relatively slow contraction time. The glycolytic (anaerobic) activity is low in this fiber type, but a high content of mitochondria produces a high potential for oxidative (aerobic) activity.
This fiber are difficult to fatigue because the high rate of blood flow to these fibers delivers oxygen and nutrients at a sufficient rate to keep up with the relatively slow rate of ATP breakdown by myosin ATPase. Thus, the fibers are well suited for prolonged, low intensity work. These fibers are relatively small in diameter and produce relatively little tension. The high myoglobin content of type I fibers gives the muscle a red color |
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Term
| What do you know about fiber type IIA? |
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Definition
| are considered interemediate between type I and type IIB because their fast contraction time is combined with a moderately well-developed capacity for both aerobic (oxidative) and anaerobic glycolytic activity |
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Term
| What do you know about fiber type IIA? |
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Definition
well-developed blood supply. They can maintain their contractile activity for relatively long periods.
However, at high rates of activity, the high rate of ATP splitting exceeds the capacity of both ocidative phosphorylation and glycolysis to sypply ATP, and these fibers thus eventually fatique. Because the myoglobin content of this muscle type is high, the muscle is often categorized as red muscle. |
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Term
| What do you know about fiber type IIB? |
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Definition
rely primarily on glycolytic (anearobic) activity for ATP production. Few capillaries and little myoglobin are found in these fibers referred to as white muscle.
Although, this fibers are able to produce ATP rapidly, they fatigue easily because therir high rate of ATP splitting quickly depletes the glycogen needed for glycolysis. These fibers generally are of large diameter and are thus able to produce great tension, but only for short periods before they fatigue. |
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Term
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Definition
THe fiber compositionof a given muscle depends on the function of that muscle. Some muscles perform predominantly one form of contractile activity and are often composed mostly of one muscle fiber type.
An example is the soleus muscle in the calf. which primarily maintains posture and is composed of a high percentage of type I fibers |
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Term
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Definition
more commonly muscles are required to perform endurance-type activity under some circumstances and high-intensity strength activity under others. These muscles generally contain a mixture of the three muscle fibers typers.
In a typical mixed muscle exerting low tension, some of the small motor untes, composed of type I fibers, contract. As the muscle force increases, more motor units are recruited and their frequency of stimulation increases. As the demands peaks, greater and more sustained muscle power is achieved by recruitment of larger motor units composed of type IIA (FOG) givers and eventually type IIB (FG) fibers |
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