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Advice for the Clinician: The role of the transverse abdominus in promoting spinal stability
SELF- HELP ADVICE FOR THE CLINICIAN
Introduction
Craig Liebenson DC 10474 Santa Monica Blvd., 202 Los Angeles, CA 90025, USA Correspondence to: C. Liebenson Tel: +1 310 470 2909; Fax: +1 310 470 3286; E-mail: cldc@¯ash.net Received January 2000 Revised January 2000 Accepted February 2000
........................................... Journal of Bodywork and Movement Therapies (2000) 4(2),109^112 2000 Harcourt Publishers Ltd This paper may be photocopied for educational use
One of the ®rst steps in training muscles to provide necessary protection to joints is in re-educating the kinaesthetic awareness to achieve and maintain a co-contraction of agonist and antagonist muscles around a joint. One of the key muscles responsible for stiening the lumbar spine in a `neutral range' so that harmful endrange loading strategies can be avoided is the transverse abdominus. The purpose of therapeutic exercise is to promote recovery from injury and prevent further instability. Whereas a ®t individual, especially an athelete may bene®t from exercises in a full range of motion (ROM) sedentary individuals or those with pain or dysfunction may need to restrict their ROM during exercise in order to reduce potentially harmful loading. Therapeutic exercise is prescribed for the purpose of reconditioning a `weak link' or stressing damaged tissue to facilitate tissue repair and remodelling. Avoiding excessive loading is crucial to clinical success. However, if load or stress is not sucient a conditioning eect will not be achieved. The central question is how can we isolate and challenge the
key stabilization muscles without overloading the passive osteoligamentous restraints.
Motor control errors and spinal instability According to Cholewicki and McGill stabilization is greatly enhanced by co-contraction of antagonistic trunk muscles (Cholewicki & McGill 1996). In fact, muscular co-contraction has been demonstrated to contribute to joint stiness independent of the muscle torque producing ability (Carter et al. 1993). Even though energetically costly, such co-contraction has been shown to occur during most daily activities (Marras & Mirka 1990). In particular, these co-contractions are most obvious during reactions to unexpected or sudden loading (Marras et al. 1987, Lavender et al. 1989). Recent studies have pointed out how important the motor control system is for preventing spinal injury. Inappropriate muscle activation sequences during seemingly trivial tasks such as bending over to pick up a pencil can compromise spinal stability and potentiate buckling of the passive ligamentous restraints (McGill SM et al. 1995). Co-contractions of
109
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
The role of the transverse abdominus in promoting spinal stability
The role of the transverse abdominus in promoting spinal stability
The role of the transverse abdominus in promoting spinal stability
Liebenson agonist and antagonist muscles of the spine sucient to maintain a `neutral spine' posture appear to be a major factor in maintaining spinal stability (Cholewicki J et al. 1997). This motor control skill is compromised under challenging aerobic circumstances (McGill et al. 1995). When a spinal stabilization and respiratory challenge is simultaneously encountered the nervous system will select maintainance of respiration over spinal stability. An example of this is during repetitive bending or lifting activities the back will become vulnerable due to poor aerobic ®tness even if the motor control system is well trained. Therefore, aerobic conditioning is an important component of a spinal rehabilitation program. One study examined the theory that antagonistic trunk muscle coactivation is necessary to provide mechanical stability to the lumbar spine around a neutral posture. The authors found that antagonistic muscle coactivation increased in response to increased axial load on the spine. EMG measurements were gathered from three ¯exors Ð external oblique, internal oblique, and rectus abdominus; and three extensors Ð multi®dus, lumbar erector spinae, and thoracic erector spinae. The subjects were asked to perform slow trunk ¯exion and extension movements in a semiseated position with hip motion restricted, but trunk motion free. Weights were then added to the torso. One conclusion was that `increased levels of muscle coactivation may constitute an objective indicator of the dysfunction in the passive stabilizing system of the lumbar spine' (Cholewicki et al. 1997). Richardson et al. showed that cocontraction of transverse abdominus and multi®di is maximised during isometric resisted rotation of the trunk (Richardson et al. 1990). In
another study is was shown that lower abdominal hollowing or abdominal bracing procedures are preferable to the posterior pelvic tilt because they achieve a better co-contraction of the transverse abdominus and multi®dus (Richardson et al. 1992). EMG studies have shown that the transverse abdominus was recruited prior to any other abdominal muscle when the trunk was subjected to sudden perturbations (Cresswell 1994). In a study looking at abdominal activity during upper limb movements, the transverse abdominus was the only muscle active prior to initiation of arm motions (Hodges & Richardson 1997a). The same was found to be true during lower limb movements (Hodges & Richardson 1997b). Hodges and Richardson reported that a slow speed of contraction of the transverse abdominus during arm or leg movements was well correlated with LBP (Hodges & Richardson 1998, 1999). O'Sullivan et al. found that synergist substitution of the rectus abdominus for the agonist transverse abdominus during an abdominal `drawing in' manouvre strongly correlated with chronic back pain and that speci®c rehabilitation which improved this dysfunction was superior to a more general exercise approach (O'Sullivan P et al. 1997).
`Neutral spine' coordination test Jull has described a test to assess the patient's ability `to hold the lumbar spine steady under increasing levels of load' (Richardson & Jull in Grieve 1994). The patient is placed in the supine hooklying position, with the lumbar spine placed upon a `pressure feedback device', an in¯atable cushion attached to a standard pressure gauge to allow accurate monitoring of lumbar spine
Fig. 1 `Neural spine' coordination test.
positional changes. The patient is instructed to perform an active trunk prepositioning technique of either abdominal `hollowing' (in which the patient is instructed to `make your lower abdomen cave in') or abdominal `bracing' (in which the patient is instructed to `contract the abdominals by actively ¯aring out laterally in the region of the waist just above the iliac crests', Fig.1). Once the patient is able to `preactivate and maintain the cocontraction pattern' outlined above, the individual is then asked to hold the position while `load [is] added via the weight of the lower limbs' being moved passively into a (progressively more, Fig. 2) loaded position.
Training The ®rst level of stabilization training is to learn the kinaesthetic awareness to produce and maintain the `neutral range' of the spine. The patient's `functional-neutral range' is the painless range which is appropriate (i.e. coordinated) for the task at hand (Morgan 1988). Typically it involves a co-contraction of deep abdominal and back muscles which stabilize the lumbar posture in a slight lordosis. This should be customized for each patient. Obviously a patient with spinal stenosis may be `biased' more towards ¯exion, whereas a younger disc patient may be `biased' more towards extension. However, systematic testing of the patients symptomatic response to various loading strategies must be performed to customize the
110
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
Advice for the Clinician
Fig. 2 Neutral spine coordination test with added load.
Table 1 Safe back workout progressions Level one Ð kinaesthetic awareness of how to actively achieve a `neutral spine' Level two Ð isometric stabilization by adding distal loading via the extremities Level three Ð dynamic stabilization by performing trunk motions w/neutral spine
abdominal hollowing techniques which teach how to activate the pelvic ¯oor muscles are facilitory (Lewit 1999). Once a patient has learned the kinaesthetic awareness of producing co-contraction of agonist-antagonist trunk muscles then they are ready to advance to higher levels of motor control by training endurance of all trunk muscles and challenging their coordination (Table 1). In the second level of safe back training, the individual is taught to maintain the `neutral joint position' of the spine/pelvis while load is added distally through the arms and/or legs. This motor control is called isometric stabilization. Exercises are trained with endurance not strength as the goal. Therefore, submaximal load is used with prolonged hold times of between 5 and 8 seconds. These longer duration, lower eort exercises will allow reconditioning, repair, and remodelling of the dysfunctional or injured `weak link' to occur with a minimum risk of further re-injury or pain aggravation. To perform level 2 stabilization exercises the patient should be able to demonstrate that they can ¯atten the abdominals without holding their breath, or raising their ribs (see Fig. 2, Patient Advice). They are then asked to hold the position while they move their arms or legs into ¯exion or extension Ð the `deadbug' (Fig. 3).
Fig. 3 `Dead-bug'.
Fig. 4 Trunk curl-up.
In the third safe back training level the individual learns how to control the `neutral joint position' of the spine/pelvis during trunk movements. This is called dynamic stabilization (see trunk curl, Fig. 4). Even more activation of the transverse abdominus and oblique abdominals is possible if the curl-up is performed on a labile gymnastic ball rather than the ¯oor (McGill 1999).
Conclusion The most important thing to remember about safe back training is that in the acute stage the exercises should reduce or centralize the patients pain and in the subacuterecovery stage they should improve motor control. In most instances, a realistic goal is to teach the patient better spinal awareness during activities and to give them a few simple exercises. Only a minority of patients with speci®c functional de®cits will require more challenging exercises. To facilitate the formation of a new motor program labile surfaces (balls, foam, platforms) are utilized as much as possible. These not only spontaneously facilitate aerent pathways in a concentrated
111
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
The role of the transverse abdominus in promoting spinal stability
determination of each patient's `functional-neutral range'. To perform abdominal hollowing the patient is instructed `make your lower abdomen cave in' or to `draw your navel towards your spine'. The `hollowing' technique involves co-contraction of the transverse abdominus and multi®dus. The patient can palpate this just medial to their anterior superior iliac spine. This will increase conscious perception and help the patient to learn how to volitionally activate the muscles (Richardson & Jull in Grieve 1994). This abdominal hollowing can be practiced in a variety of positions Ð supine, quadruped, seated, standing, etc. It will also be used during nearly all exercises to pre-position the lumbar spine into a safe `functional range' or `neutral position'. In the event that the patient has trouble learning to perform
The role of the transverse abdominus in promoting spinal stability
Liebenson way, but are fun for the patient to work with. Training the transverse abdominus muscle can help patients develop the kinaesthetic awareness of their `neutral spine posture' and endurance to maintain this during activities of daily living. Injury prevention depends on the ability to identify a hazardous situation involving end-range loading and to correct it with either passive or active pre-positioning to a more `neutral position'. This skill should be trained so that it is not only possible with conscious control, but as an automatic habit so it can protect the spine against novel situations or even unexpected perturbations. REFERENCES Cholewicki J, Panjabi MM, Khachatryan A 1997 Stabilizing function of the trunk ¯exor-extensor muscles around a neutral spine posture. Spine 19: 2207±2212
Cresswell AG, Oddsson L, Thorstensson A 1994 The in¯uence of sudden perturbations on trunk muscle activity and intra-abdominal pressure while standing. Experimental Brain Research 98: 336±334. Hodges PW, Richardson CA 1997a Feedforward contraction of transversus abdominus is not in¯uenced by the direction of arm movement. Experimental Brain Research 114: 362±70 Hodges PW, Richardson CA 1997b Contraction of the abdominal muscles associated with movement of the lower limb. Physical Therapy 77: 132±144 Hodges PW, Richardson CA 1998 Delayed postural contraction of the transverse abdominus associated with movement of the lower limb in people with low back pain. J Spinal Disord 11: 46±56 Hodges PW, Richardson CA 1999 Altered trunk muscle recruitment in people with low back pain with upper limb movements at dierent speeds. Arch Phys Med Rehabili 80: 1005±1012 Lewit K 1999 Chain reactions in the locomotor system in the light of coactivation patterns based on developmental neurology. J Orthopedic Medicine 21: 52±58
McGill SM 1999. Personal communication of unpublished research. Morgan D 1988 Concepts in functional training and postural stabilization for the low-back-injured. Top Acute Care Truma Rehabil 2: 8. O'Sullivan P, Twomey L, Allison G 1997 Evaluation of speci®c stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolysthesis. Spine 24: 2959±2967 Richardson C, Jull G, Toppenberg R, Comerford M 1992 Techniques for active lumbar stabilisation protection: A pilot study. Australian Journal of Physioth 38: 105±112 Richardson A, Jull GA 1994 Concepts of assessment and rehabilitation for active lumbar stability. In: Boyling JD, Palastanga N, eds. Grieve's modern manual therapy of the vertebral column, 2nd edn. Edinburgh: Churchill Livingstone Richardson CA, Jull GA 1995 Muscle control Ð pain control. What exercises would you prescribe? Manual Therapy 1: 2±10 Richardson C, Toppenberg R, Jull G 1990 An initial evaluation of eight abdominal exercises for their ability to provide stabilisation for the lumbar spine. Australian Journal of Physioth 36: 6±11
112
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
Introduction
Craig Liebenson DC 10474 Santa Monica Blvd., 202 Los Angeles, CA 90025, USA Correspondence to: C. Liebenson Tel: +1 310 470 2909; Fax: +1 310 470 3286; E-mail: cldc@¯ash.net Received January 2000 Revised January 2000 Accepted February 2000
........................................... Journal of Bodywork and Movement Therapies (2000) 4(2),109^112 2000 Harcourt Publishers Ltd This paper may be photocopied for educational use
One of the ®rst steps in training muscles to provide necessary protection to joints is in re-educating the kinaesthetic awareness to achieve and maintain a co-contraction of agonist and antagonist muscles around a joint. One of the key muscles responsible for stiening the lumbar spine in a `neutral range' so that harmful endrange loading strategies can be avoided is the transverse abdominus. The purpose of therapeutic exercise is to promote recovery from injury and prevent further instability. Whereas a ®t individual, especially an athelete may bene®t from exercises in a full range of motion (ROM) sedentary individuals or those with pain or dysfunction may need to restrict their ROM during exercise in order to reduce potentially harmful loading. Therapeutic exercise is prescribed for the purpose of reconditioning a `weak link' or stressing damaged tissue to facilitate tissue repair and remodelling. Avoiding excessive loading is crucial to clinical success. However, if load or stress is not sucient a conditioning eect will not be achieved. The central question is how can we isolate and challenge the
key stabilization muscles without overloading the passive osteoligamentous restraints.
Motor control errors and spinal instability According to Cholewicki and McGill stabilization is greatly enhanced by co-contraction of antagonistic trunk muscles (Cholewicki & McGill 1996). In fact, muscular co-contraction has been demonstrated to contribute to joint stiness independent of the muscle torque producing ability (Carter et al. 1993). Even though energetically costly, such co-contraction has been shown to occur during most daily activities (Marras & Mirka 1990). In particular, these co-contractions are most obvious during reactions to unexpected or sudden loading (Marras et al. 1987, Lavender et al. 1989). Recent studies have pointed out how important the motor control system is for preventing spinal injury. Inappropriate muscle activation sequences during seemingly trivial tasks such as bending over to pick up a pencil can compromise spinal stability and potentiate buckling of the passive ligamentous restraints (McGill SM et al. 1995). Co-contractions of
109
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
The role of the transverse abdominus in promoting spinal stability
The role of the transverse abdominus in promoting spinal stability
The role of the transverse abdominus in promoting spinal stability
Liebenson agonist and antagonist muscles of the spine sucient to maintain a `neutral spine' posture appear to be a major factor in maintaining spinal stability (Cholewicki J et al. 1997). This motor control skill is compromised under challenging aerobic circumstances (McGill et al. 1995). When a spinal stabilization and respiratory challenge is simultaneously encountered the nervous system will select maintainance of respiration over spinal stability. An example of this is during repetitive bending or lifting activities the back will become vulnerable due to poor aerobic ®tness even if the motor control system is well trained. Therefore, aerobic conditioning is an important component of a spinal rehabilitation program. One study examined the theory that antagonistic trunk muscle coactivation is necessary to provide mechanical stability to the lumbar spine around a neutral posture. The authors found that antagonistic muscle coactivation increased in response to increased axial load on the spine. EMG measurements were gathered from three ¯exors Ð external oblique, internal oblique, and rectus abdominus; and three extensors Ð multi®dus, lumbar erector spinae, and thoracic erector spinae. The subjects were asked to perform slow trunk ¯exion and extension movements in a semiseated position with hip motion restricted, but trunk motion free. Weights were then added to the torso. One conclusion was that `increased levels of muscle coactivation may constitute an objective indicator of the dysfunction in the passive stabilizing system of the lumbar spine' (Cholewicki et al. 1997). Richardson et al. showed that cocontraction of transverse abdominus and multi®di is maximised during isometric resisted rotation of the trunk (Richardson et al. 1990). In
another study is was shown that lower abdominal hollowing or abdominal bracing procedures are preferable to the posterior pelvic tilt because they achieve a better co-contraction of the transverse abdominus and multi®dus (Richardson et al. 1992). EMG studies have shown that the transverse abdominus was recruited prior to any other abdominal muscle when the trunk was subjected to sudden perturbations (Cresswell 1994). In a study looking at abdominal activity during upper limb movements, the transverse abdominus was the only muscle active prior to initiation of arm motions (Hodges & Richardson 1997a). The same was found to be true during lower limb movements (Hodges & Richardson 1997b). Hodges and Richardson reported that a slow speed of contraction of the transverse abdominus during arm or leg movements was well correlated with LBP (Hodges & Richardson 1998, 1999). O'Sullivan et al. found that synergist substitution of the rectus abdominus for the agonist transverse abdominus during an abdominal `drawing in' manouvre strongly correlated with chronic back pain and that speci®c rehabilitation which improved this dysfunction was superior to a more general exercise approach (O'Sullivan P et al. 1997).
`Neutral spine' coordination test Jull has described a test to assess the patient's ability `to hold the lumbar spine steady under increasing levels of load' (Richardson & Jull in Grieve 1994). The patient is placed in the supine hooklying position, with the lumbar spine placed upon a `pressure feedback device', an in¯atable cushion attached to a standard pressure gauge to allow accurate monitoring of lumbar spine
Fig. 1 `Neural spine' coordination test.
positional changes. The patient is instructed to perform an active trunk prepositioning technique of either abdominal `hollowing' (in which the patient is instructed to `make your lower abdomen cave in') or abdominal `bracing' (in which the patient is instructed to `contract the abdominals by actively ¯aring out laterally in the region of the waist just above the iliac crests', Fig.1). Once the patient is able to `preactivate and maintain the cocontraction pattern' outlined above, the individual is then asked to hold the position while `load [is] added via the weight of the lower limbs' being moved passively into a (progressively more, Fig. 2) loaded position.
Training The ®rst level of stabilization training is to learn the kinaesthetic awareness to produce and maintain the `neutral range' of the spine. The patient's `functional-neutral range' is the painless range which is appropriate (i.e. coordinated) for the task at hand (Morgan 1988). Typically it involves a co-contraction of deep abdominal and back muscles which stabilize the lumbar posture in a slight lordosis. This should be customized for each patient. Obviously a patient with spinal stenosis may be `biased' more towards ¯exion, whereas a younger disc patient may be `biased' more towards extension. However, systematic testing of the patients symptomatic response to various loading strategies must be performed to customize the
110
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
Advice for the Clinician
Fig. 2 Neutral spine coordination test with added load.
Table 1 Safe back workout progressions Level one Ð kinaesthetic awareness of how to actively achieve a `neutral spine' Level two Ð isometric stabilization by adding distal loading via the extremities Level three Ð dynamic stabilization by performing trunk motions w/neutral spine
abdominal hollowing techniques which teach how to activate the pelvic ¯oor muscles are facilitory (Lewit 1999). Once a patient has learned the kinaesthetic awareness of producing co-contraction of agonist-antagonist trunk muscles then they are ready to advance to higher levels of motor control by training endurance of all trunk muscles and challenging their coordination (Table 1). In the second level of safe back training, the individual is taught to maintain the `neutral joint position' of the spine/pelvis while load is added distally through the arms and/or legs. This motor control is called isometric stabilization. Exercises are trained with endurance not strength as the goal. Therefore, submaximal load is used with prolonged hold times of between 5 and 8 seconds. These longer duration, lower eort exercises will allow reconditioning, repair, and remodelling of the dysfunctional or injured `weak link' to occur with a minimum risk of further re-injury or pain aggravation. To perform level 2 stabilization exercises the patient should be able to demonstrate that they can ¯atten the abdominals without holding their breath, or raising their ribs (see Fig. 2, Patient Advice). They are then asked to hold the position while they move their arms or legs into ¯exion or extension Ð the `deadbug' (Fig. 3).
Fig. 3 `Dead-bug'.
Fig. 4 Trunk curl-up.
In the third safe back training level the individual learns how to control the `neutral joint position' of the spine/pelvis during trunk movements. This is called dynamic stabilization (see trunk curl, Fig. 4). Even more activation of the transverse abdominus and oblique abdominals is possible if the curl-up is performed on a labile gymnastic ball rather than the ¯oor (McGill 1999).
Conclusion The most important thing to remember about safe back training is that in the acute stage the exercises should reduce or centralize the patients pain and in the subacuterecovery stage they should improve motor control. In most instances, a realistic goal is to teach the patient better spinal awareness during activities and to give them a few simple exercises. Only a minority of patients with speci®c functional de®cits will require more challenging exercises. To facilitate the formation of a new motor program labile surfaces (balls, foam, platforms) are utilized as much as possible. These not only spontaneously facilitate aerent pathways in a concentrated
111
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0
The role of the transverse abdominus in promoting spinal stability
determination of each patient's `functional-neutral range'. To perform abdominal hollowing the patient is instructed `make your lower abdomen cave in' or to `draw your navel towards your spine'. The `hollowing' technique involves co-contraction of the transverse abdominus and multi®dus. The patient can palpate this just medial to their anterior superior iliac spine. This will increase conscious perception and help the patient to learn how to volitionally activate the muscles (Richardson & Jull in Grieve 1994). This abdominal hollowing can be practiced in a variety of positions Ð supine, quadruped, seated, standing, etc. It will also be used during nearly all exercises to pre-position the lumbar spine into a safe `functional range' or `neutral position'. In the event that the patient has trouble learning to perform
The role of the transverse abdominus in promoting spinal stability
Liebenson way, but are fun for the patient to work with. Training the transverse abdominus muscle can help patients develop the kinaesthetic awareness of their `neutral spine posture' and endurance to maintain this during activities of daily living. Injury prevention depends on the ability to identify a hazardous situation involving end-range loading and to correct it with either passive or active pre-positioning to a more `neutral position'. This skill should be trained so that it is not only possible with conscious control, but as an automatic habit so it can protect the spine against novel situations or even unexpected perturbations. REFERENCES Cholewicki J, Panjabi MM, Khachatryan A 1997 Stabilizing function of the trunk ¯exor-extensor muscles around a neutral spine posture. Spine 19: 2207±2212
Cresswell AG, Oddsson L, Thorstensson A 1994 The in¯uence of sudden perturbations on trunk muscle activity and intra-abdominal pressure while standing. Experimental Brain Research 98: 336±334. Hodges PW, Richardson CA 1997a Feedforward contraction of transversus abdominus is not in¯uenced by the direction of arm movement. Experimental Brain Research 114: 362±70 Hodges PW, Richardson CA 1997b Contraction of the abdominal muscles associated with movement of the lower limb. Physical Therapy 77: 132±144 Hodges PW, Richardson CA 1998 Delayed postural contraction of the transverse abdominus associated with movement of the lower limb in people with low back pain. J Spinal Disord 11: 46±56 Hodges PW, Richardson CA 1999 Altered trunk muscle recruitment in people with low back pain with upper limb movements at dierent speeds. Arch Phys Med Rehabili 80: 1005±1012 Lewit K 1999 Chain reactions in the locomotor system in the light of coactivation patterns based on developmental neurology. J Orthopedic Medicine 21: 52±58
McGill SM 1999. Personal communication of unpublished research. Morgan D 1988 Concepts in functional training and postural stabilization for the low-back-injured. Top Acute Care Truma Rehabil 2: 8. O'Sullivan P, Twomey L, Allison G 1997 Evaluation of speci®c stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylolysis or spondylolysthesis. Spine 24: 2959±2967 Richardson C, Jull G, Toppenberg R, Comerford M 1992 Techniques for active lumbar stabilisation protection: A pilot study. Australian Journal of Physioth 38: 105±112 Richardson A, Jull GA 1994 Concepts of assessment and rehabilitation for active lumbar stability. In: Boyling JD, Palastanga N, eds. Grieve's modern manual therapy of the vertebral column, 2nd edn. Edinburgh: Churchill Livingstone Richardson CA, Jull GA 1995 Muscle control Ð pain control. What exercises would you prescribe? Manual Therapy 1: 2±10 Richardson C, Toppenberg R, Jull G 1990 An initial evaluation of eight abdominal exercises for their ability to provide stabilisation for the lumbar spine. Australian Journal of Physioth 36: 6±11
112
J O U R NAL O F B O DY W O R K AN D MOV E M E N T TH E R APIE S APRIL 20 0 0