Isometric Stretching
Muscle without tonus (tension) has essentially no restriction to movement. Muscle is comprised of lengths of fibres all aligned in a particular direction but with no actual connection between them. The contractile mechanism is initiated by impulses from the brain which alters the calcium ion flow to the interfilament parts and starts a process by which the fibres "stick" to each other. Without any nervous trigger to begin contractions between the two major proteins actin and myosin there is no contraction. There is no tension. Relaxed muscle with much reduced tonus is relatively easy to lengthen. Muscle under tension is difficult to lengthen because of this interaction. Certainly beyond the current untrained length. The difference between sliding out the top plank of wood from a pile or trying to pull off the plank if it is nailed to the one beneath. These could not be separated. However, muscle is wrapped up in connective tissue - the outer covering of muscle fibres. The component to lengthen is this connective tissue. It has no ability to contract itself but offers considerable resistance. It is like comparing elastic and string. Elastic can be deformed by lengthening but will return to its original length. String will simply get to a particular length and not get any longer without snapping.
The connective tissue will be stretched if the range of movement of a limb is increased. An alternative way of approaching this is to keep the limb at a particular angle (and so muscle length) and then aHempt to shorten the muscle and hence the surrounding connective tissue. The muscle can shorten a liHle by a powerful contraction. The tension generated can be enormous. But since the limb cannot move the connective tissue has to lengthen a liHle as the distance between the ends of the limb remains constant but the muscle length is expected to shorten by the same amount. The result is that the connective tissue itself is put under stretch.
So this isometric stretching process lengthens the connective tissue which is a very limiting factor to muscle elongation. However relaxed the muscle may be, the connective tissue - which cannot be relaxed as there is no possibility of contraction within it - will restrict muscle length. If the connective tissue is lengthened AND the mental control adjusted to overcome physiological damage protection mechanisms then potential is increased dramatically.
Isometric stretching is the most effective stretches of them all. Isometric stretching is actually the reverse of static stretching. Static stretching requires a relaxed muscle lengthened but kept under continuous stretch at the limit of range movement. This keeps the connective tissue under tension but allows the brain to register the new length for future reference. Isometric stretching can modify the muscle connective tissue length from just about any position. The limb does not have to be at its maximum range - any position will do. The nature of muscle is that thousands of strands of fibres are all aligned in roughly the same direction. A stretch of long duration will allow many of them - if not all - to be placed under tension or a new length. A likely problem is a stretch of short duration does not allow so many to be registered so an unequal data set is learned and the imbalance causes some discomfort. This should be offset by the more controlled long duration static stretch.
Dynamic stretching allows speed adjustments to be made. Developing static passive flexibility, which usually exceeds static active or dynamic flexibility for the same joint, can reduce the incidence of injury. The reserve tensility (flexibility reserve) is greater if the difference between them is greater. Active movements can also be increased in amplitude but the difference between active and passive diminishes as active flexibility improves. Static active or passive stretching performed alone will not necessarily be matched with increases in dynamic flexibility proportional to the increase in the static flexibility. Speed conditioning is dependent on the dynamic exercises to reset the nervous control of muscle spindles. Static flexibility may increase when muscles are fatigued and is the reason for doing them at the end of a workout. Isometric stretching is similar to static stretching but using strong contractions of the fully stretched muscles. This causes reflexive relaxation and a subsequent increase in the length of the muscle because of the involvement the Golgi organs in the tendons and muscle spindle stretch receptors (see full version).
When the maximum length for the muscle has been achieved, at the current stage of training, the position is held for up to 15-30 seconds or more. In a poorly stretched leg a contraction is not necessary in some cases since body weight ensures the muscle is under load, for example in the side splits. In a well stretched leg further gains of length and strength can still be achieved by this additional forced contraction at full length. This method of stretching should be used in a similar way to any strength training - the muscles must be given time to recover. Isometric means one length. The muscle is stretched to its maximum length then a tension is applied. An example of this is the front split where the body is lowered but at the lowest point the muscles are initially relaxed.
This is a static passive stretch. Tension is then gradually applied in the forward leg to contract the hamstrings. The effect of this contraction is to flex the knee which cannot move because of contact of the heel of the foot of this leg with the floor.
This stretch is isometric. The strength of a muscle can also be increased at different positions of flexion by using isometric contractions. Instead of at full length intermediate positions are held under an isometric stretch. This will produce gains in the strength of the muscle at this position. In the front kick position with the heel of your foot placed over a stationary object to raise the leg to its maximum height, the hamstrings are stretched to the maximum length (static passive) if the knee is kept locked out. If the toes and foot pulled back towards the shin the stretch is emphasised and the calf muscles are also involved. However, this becomes an isometric stretch if tension is now applied in an effort to push the leg downwards and flex the knee. It is effectively the same as the front split for short hamstrings using the body weight under the influence of gravity. This also works the hip extensors with more emphasis if the knee is bent but raised as far upwards as possible.
Isometric stretching is the fastest method to achieve static passive flexibility. At full length muscle fibres contract and connective tissue attached to them is stretched. This is the derivation of tension. Strength gains can be made depending on the force of contraction. Such gains are at the full length of the muscle where it is normally at its most disadvantaged. Stretched muscle is weakened by virtue of the increased length of the sarcomere. The overlap between the protein filaments is reduced resulting in a loss of contractile force. Isometric stretching helps to restore this loss. Review the Section 2 on muscle contraction. When a muscle normally contracts and moves two bones together the connective tissue tension is reduced - the muscle shortens. In the isometric stretch at the full length of the muscle, the connective tissue is placed under greater than normal tension as the muscle is slightly longer than at rest. A forceful contraction but without moving the limbs the muscle will attempt to shorten but is not allowed to so that the tension will build up. Remember that isometric stretching is very demanding on muscle and sufficient rest time, at least one full day (24-36 hrs), should be allowed between sessions for the muscle to recover completely.
Perform isometric stretches by gradually stretching the muscles and allow them to "creep" to the normal full length without using contractions. After a few seconds, from this position increase the stretch. Maintain the position then increase the distance further. When at the maximum limit of stretch, apply the short strong tensions built up over 2-3 seconds and hold for another 2-3 seconds at the maximum tension. Do the isometric tensioning 3-5 times but on the final one hold for 30 seconds at the maximum. A similar method is to use tension at each position of the stretch as it is increased each time holding for several seconds as before. The final tension is done just once but for 30 seconds at the maximum muscle length. A more severe method of isometric stretching involves reaching the maximum muscle length and tensioning. Hold this tensed stretched position until the muscle spasms then relax the stretch. After a brief pause repeat at full length and maximum tension until the muscle spasms again. Do this for 3-5 times holding the last tension for as long as possible - maybe several minutes. This will make you want to scream! Whichever method you use strength gains will be achieved at that muscle length.
To counter the loss of tension by lengthening a muscle the ideal position to improve the strength is at full length to restore this loss. Concentrate on harder and longer contractions at full muscle length. Use weight if necessary but in any case attempt to modify the style by increasing the difficulty - for example do not use hands in splits. To stretch isometrically too often and too powerfully will not allow the muscle time to recover. The only way to increase the frequency of isometric stretching sessions would be to reduce the maximum tension considerably but little in the way of strength gains would be achieved. However, it may be sensible to train in this way to begin with while the muscle develops conditioning. It depends on what you want from stretching but remember that the stronger the muscle is then the more stability it offers joints and protection from injuries.
Strength gains through isometric stretching will reach a plateau after a few weeks since the same load is placed on the muscle, no further muscle fibre recruitment occurs. Further gains will need weight resistance training to place a greater load on the muscle. The combination of isometric stretching and use of weight (either isotonically or isometrically applied) is ideal. The weight of the body can be utilised also by, for example, sliding up or walking up from a splits position. A strong and flexible muscle will result. Remember that at the full range of motion for a muscle, and stretching by definition means at its longest, the muscle will remain flexible as the strength improves. The contractile elements of muscle have almost no friction when under no tension and properly stretched connective tissue reduces the build up of tension as the muscle is lengthened. If muscle soreness is experienced then either reduce the intensity of stretches or leave off the isometric stretching completely until this soreness has disappeared - usually only a day or so extra. Passive relaxed stretching can replace the isometric stretching during such times to maintain good muscle condition. Ensure that isometric exercises are preceded by dynamic exercises but can be followed by relaxed passive stretching to finish. Reintroduce the isometric stretches when discomfort has cleared. There is nothing to be gained by stretching an injured muscle.
The soreness is as a result of overloading the tendon and connective tissue and is the same as for a negative isotonic contraction. The entire muscle structure has done greater work than it is prepared for so the loading on these tissues will be damaging. Until the connective tissue has itself lengthened through stretching then the damage to this collagen material will occur. Reduce the intensity of isometric contractions at full muscle length until the connective tissues have progressively adjusted. If the muscle strength increases and muscle fibre recruitment continues through stimulation either by isometric stretching or weight resistance work then the problem can worsen and lead to long term (chronic) injury. The connective tissue must be given time to lengthen and thus reduce the excess tension build up within the tendon. To some extent the Golgi organs will protect the tendon and connective tissue by not allowing too powerful contractions (discuss Renshaw cells) but pain is a sign to stop. Already alluded to is the danger of anabolic steroid abuse and the potential serious damage to tendons by artificially promoting muscle mass gains which outstrip the changes to connective tissue. This imbalance of growth leads to the destruction of muscle integrity and torn muscles and tendons.
Stretched (and weakened) muscle is fine for the increase in the range of motion and may allow more control of limbs by avoiding prestretching muscle - winding them up by throwing up a limb rather than controlled lifting. Prestretching involves the elastic nature of connective tissue and pulling it to greater length. No change in the structure of connective tissue occurs just its temporary length increase under load. A powerful muscle is also fine and allows greater control over limbs by increasing the ability to lift, raise and decelerate as opposed to the use of momentum by "throwing" a limb. In the absence of stretching, prestretching is still a problem. A more powerful muscle will allow a greater prestretch of the connective tissue to occur and create more force but which is harder to control. Golgi organs will reduce the likelihood of an overload injury if the prestretching is too great by relaxing the muscle but such injuries can occur. In power gains without stretching, the range of motion instead of being increased will actually be decreased. The reason the muscle shortens if not stretched is that the muscle enlarges and in effect swells out in size with little modification to the connective tissue length. The balance of power can be maintained by training agonist and antagonist but without stretching, the range of movement of the limb they control will be compromised. Stretching both muscles will make them more efficient and improve this range of motion. To compensate for the increase in size of muscle fibres but not the length of the connective tissue, the tension regulation mechanisms (Golgi organs and gamma-motorneurons in the muscle spindles) will restore the normal resting tonus (internal tension) by shortening the muscle. To maintain or increase the range of motion the whole muscle, including the connective tissues, must be lengthened.
This is not the same as the lowered tonus during sleep causing the muscle length to be shortened to counter the decrease in the nerve impulses from the stretch receptors of "super relaxed" muscle. A loss of tension allows an increase in these contraction impulses which also inhibit contractions of the antagonist muscle (reciprocal inhibition). Under these conditions the agonist muscle can shorten quite easily with little resistance from the antagonist. In the reverse sense, increases in tension are countered by the tendency to inhibit alpha-motorneurons, which cause contraction, facilitating antagonist contraction. Under normal conscious conditions the increased general tonus restores the normal range of motion by this antagonist contraction to pull out the agonist muscle to a slightly greater length (the waking stretch response). Tension arises from connective tissue in resting muscle. The elastic nature of this tissue allows it to take up the slack if tonus is lost. The whole point about permanent stretching is resetting the normal nervous resting tension.
The connective tissue will be stretched if the range of movement of a limb is increased. An alternative way of approaching this is to keep the limb at a particular angle (and so muscle length) and then aHempt to shorten the muscle and hence the surrounding connective tissue. The muscle can shorten a liHle by a powerful contraction. The tension generated can be enormous. But since the limb cannot move the connective tissue has to lengthen a liHle as the distance between the ends of the limb remains constant but the muscle length is expected to shorten by the same amount. The result is that the connective tissue itself is put under stretch.
So this isometric stretching process lengthens the connective tissue which is a very limiting factor to muscle elongation. However relaxed the muscle may be, the connective tissue - which cannot be relaxed as there is no possibility of contraction within it - will restrict muscle length. If the connective tissue is lengthened AND the mental control adjusted to overcome physiological damage protection mechanisms then potential is increased dramatically.
Isometric stretching is the most effective stretches of them all. Isometric stretching is actually the reverse of static stretching. Static stretching requires a relaxed muscle lengthened but kept under continuous stretch at the limit of range movement. This keeps the connective tissue under tension but allows the brain to register the new length for future reference. Isometric stretching can modify the muscle connective tissue length from just about any position. The limb does not have to be at its maximum range - any position will do. The nature of muscle is that thousands of strands of fibres are all aligned in roughly the same direction. A stretch of long duration will allow many of them - if not all - to be placed under tension or a new length. A likely problem is a stretch of short duration does not allow so many to be registered so an unequal data set is learned and the imbalance causes some discomfort. This should be offset by the more controlled long duration static stretch.
Dynamic stretching allows speed adjustments to be made. Developing static passive flexibility, which usually exceeds static active or dynamic flexibility for the same joint, can reduce the incidence of injury. The reserve tensility (flexibility reserve) is greater if the difference between them is greater. Active movements can also be increased in amplitude but the difference between active and passive diminishes as active flexibility improves. Static active or passive stretching performed alone will not necessarily be matched with increases in dynamic flexibility proportional to the increase in the static flexibility. Speed conditioning is dependent on the dynamic exercises to reset the nervous control of muscle spindles. Static flexibility may increase when muscles are fatigued and is the reason for doing them at the end of a workout. Isometric stretching is similar to static stretching but using strong contractions of the fully stretched muscles. This causes reflexive relaxation and a subsequent increase in the length of the muscle because of the involvement the Golgi organs in the tendons and muscle spindle stretch receptors (see full version).
When the maximum length for the muscle has been achieved, at the current stage of training, the position is held for up to 15-30 seconds or more. In a poorly stretched leg a contraction is not necessary in some cases since body weight ensures the muscle is under load, for example in the side splits. In a well stretched leg further gains of length and strength can still be achieved by this additional forced contraction at full length. This method of stretching should be used in a similar way to any strength training - the muscles must be given time to recover. Isometric means one length. The muscle is stretched to its maximum length then a tension is applied. An example of this is the front split where the body is lowered but at the lowest point the muscles are initially relaxed.
This is a static passive stretch. Tension is then gradually applied in the forward leg to contract the hamstrings. The effect of this contraction is to flex the knee which cannot move because of contact of the heel of the foot of this leg with the floor.
This stretch is isometric. The strength of a muscle can also be increased at different positions of flexion by using isometric contractions. Instead of at full length intermediate positions are held under an isometric stretch. This will produce gains in the strength of the muscle at this position. In the front kick position with the heel of your foot placed over a stationary object to raise the leg to its maximum height, the hamstrings are stretched to the maximum length (static passive) if the knee is kept locked out. If the toes and foot pulled back towards the shin the stretch is emphasised and the calf muscles are also involved. However, this becomes an isometric stretch if tension is now applied in an effort to push the leg downwards and flex the knee. It is effectively the same as the front split for short hamstrings using the body weight under the influence of gravity. This also works the hip extensors with more emphasis if the knee is bent but raised as far upwards as possible.
Isometric stretching is the fastest method to achieve static passive flexibility. At full length muscle fibres contract and connective tissue attached to them is stretched. This is the derivation of tension. Strength gains can be made depending on the force of contraction. Such gains are at the full length of the muscle where it is normally at its most disadvantaged. Stretched muscle is weakened by virtue of the increased length of the sarcomere. The overlap between the protein filaments is reduced resulting in a loss of contractile force. Isometric stretching helps to restore this loss. Review the Section 2 on muscle contraction. When a muscle normally contracts and moves two bones together the connective tissue tension is reduced - the muscle shortens. In the isometric stretch at the full length of the muscle, the connective tissue is placed under greater than normal tension as the muscle is slightly longer than at rest. A forceful contraction but without moving the limbs the muscle will attempt to shorten but is not allowed to so that the tension will build up. Remember that isometric stretching is very demanding on muscle and sufficient rest time, at least one full day (24-36 hrs), should be allowed between sessions for the muscle to recover completely.
Perform isometric stretches by gradually stretching the muscles and allow them to "creep" to the normal full length without using contractions. After a few seconds, from this position increase the stretch. Maintain the position then increase the distance further. When at the maximum limit of stretch, apply the short strong tensions built up over 2-3 seconds and hold for another 2-3 seconds at the maximum tension. Do the isometric tensioning 3-5 times but on the final one hold for 30 seconds at the maximum. A similar method is to use tension at each position of the stretch as it is increased each time holding for several seconds as before. The final tension is done just once but for 30 seconds at the maximum muscle length. A more severe method of isometric stretching involves reaching the maximum muscle length and tensioning. Hold this tensed stretched position until the muscle spasms then relax the stretch. After a brief pause repeat at full length and maximum tension until the muscle spasms again. Do this for 3-5 times holding the last tension for as long as possible - maybe several minutes. This will make you want to scream! Whichever method you use strength gains will be achieved at that muscle length.
To counter the loss of tension by lengthening a muscle the ideal position to improve the strength is at full length to restore this loss. Concentrate on harder and longer contractions at full muscle length. Use weight if necessary but in any case attempt to modify the style by increasing the difficulty - for example do not use hands in splits. To stretch isometrically too often and too powerfully will not allow the muscle time to recover. The only way to increase the frequency of isometric stretching sessions would be to reduce the maximum tension considerably but little in the way of strength gains would be achieved. However, it may be sensible to train in this way to begin with while the muscle develops conditioning. It depends on what you want from stretching but remember that the stronger the muscle is then the more stability it offers joints and protection from injuries.
Strength gains through isometric stretching will reach a plateau after a few weeks since the same load is placed on the muscle, no further muscle fibre recruitment occurs. Further gains will need weight resistance training to place a greater load on the muscle. The combination of isometric stretching and use of weight (either isotonically or isometrically applied) is ideal. The weight of the body can be utilised also by, for example, sliding up or walking up from a splits position. A strong and flexible muscle will result. Remember that at the full range of motion for a muscle, and stretching by definition means at its longest, the muscle will remain flexible as the strength improves. The contractile elements of muscle have almost no friction when under no tension and properly stretched connective tissue reduces the build up of tension as the muscle is lengthened. If muscle soreness is experienced then either reduce the intensity of stretches or leave off the isometric stretching completely until this soreness has disappeared - usually only a day or so extra. Passive relaxed stretching can replace the isometric stretching during such times to maintain good muscle condition. Ensure that isometric exercises are preceded by dynamic exercises but can be followed by relaxed passive stretching to finish. Reintroduce the isometric stretches when discomfort has cleared. There is nothing to be gained by stretching an injured muscle.
The soreness is as a result of overloading the tendon and connective tissue and is the same as for a negative isotonic contraction. The entire muscle structure has done greater work than it is prepared for so the loading on these tissues will be damaging. Until the connective tissue has itself lengthened through stretching then the damage to this collagen material will occur. Reduce the intensity of isometric contractions at full muscle length until the connective tissues have progressively adjusted. If the muscle strength increases and muscle fibre recruitment continues through stimulation either by isometric stretching or weight resistance work then the problem can worsen and lead to long term (chronic) injury. The connective tissue must be given time to lengthen and thus reduce the excess tension build up within the tendon. To some extent the Golgi organs will protect the tendon and connective tissue by not allowing too powerful contractions (discuss Renshaw cells) but pain is a sign to stop. Already alluded to is the danger of anabolic steroid abuse and the potential serious damage to tendons by artificially promoting muscle mass gains which outstrip the changes to connective tissue. This imbalance of growth leads to the destruction of muscle integrity and torn muscles and tendons.
Stretched (and weakened) muscle is fine for the increase in the range of motion and may allow more control of limbs by avoiding prestretching muscle - winding them up by throwing up a limb rather than controlled lifting. Prestretching involves the elastic nature of connective tissue and pulling it to greater length. No change in the structure of connective tissue occurs just its temporary length increase under load. A powerful muscle is also fine and allows greater control over limbs by increasing the ability to lift, raise and decelerate as opposed to the use of momentum by "throwing" a limb. In the absence of stretching, prestretching is still a problem. A more powerful muscle will allow a greater prestretch of the connective tissue to occur and create more force but which is harder to control. Golgi organs will reduce the likelihood of an overload injury if the prestretching is too great by relaxing the muscle but such injuries can occur. In power gains without stretching, the range of motion instead of being increased will actually be decreased. The reason the muscle shortens if not stretched is that the muscle enlarges and in effect swells out in size with little modification to the connective tissue length. The balance of power can be maintained by training agonist and antagonist but without stretching, the range of movement of the limb they control will be compromised. Stretching both muscles will make them more efficient and improve this range of motion. To compensate for the increase in size of muscle fibres but not the length of the connective tissue, the tension regulation mechanisms (Golgi organs and gamma-motorneurons in the muscle spindles) will restore the normal resting tonus (internal tension) by shortening the muscle. To maintain or increase the range of motion the whole muscle, including the connective tissues, must be lengthened.
This is not the same as the lowered tonus during sleep causing the muscle length to be shortened to counter the decrease in the nerve impulses from the stretch receptors of "super relaxed" muscle. A loss of tension allows an increase in these contraction impulses which also inhibit contractions of the antagonist muscle (reciprocal inhibition). Under these conditions the agonist muscle can shorten quite easily with little resistance from the antagonist. In the reverse sense, increases in tension are countered by the tendency to inhibit alpha-motorneurons, which cause contraction, facilitating antagonist contraction. Under normal conscious conditions the increased general tonus restores the normal range of motion by this antagonist contraction to pull out the agonist muscle to a slightly greater length (the waking stretch response). Tension arises from connective tissue in resting muscle. The elastic nature of this tissue allows it to take up the slack if tonus is lost. The whole point about permanent stretching is resetting the normal nervous resting tension.
posted by Louis Brothnias @ 12:31 PM
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