What is Resisted isometric movements?

Working with the patients in the clinic and assessing their structural affection has always been a mind scratching job. Multiple tests are performed but there remains a doubt that which structure/ tissue is involved – contractile or non- contractile/ inert tissue. Contractile tissue refers to Muscle, Tendon, Musculo – Tendinous junction, Teno – Periosteal junction, Nerves, etc.  

Contractile tissue assessment involves voluntary contraction of muscles. These contractions include strong isometric contraction, multiple angle isometrics or concentric/ eccentric contraction. During this testing, it is checked if there is any pain or not and if it is then what is the intensity and quality of pain. Along with the pain it is also assessed what is the strength of contraction and which type of contraction is painful as well as weak.

For solving the above queries, the testing is done by Resisted Isometric Movements. However these movements are always tested last in the examination of the joints. This type of movement consists of a strong, isometric voluntary contraction of muscles and primarily detects muscles as well as nerves supplying the tested muscles.

  • If the muscle, its tendon or the bone into which they insert is at fault, pain & weakness result; the severity of pain and weakness helps to judge the degree of injury and patient’s pain threshold.

Some of the important points to be taken care of while assessing:

  1. There should not be any movement while performing the test because if movement occurs then inert tissue will also move and it will be difficult to find out which is the offending structure- contractile or inert.
  2. The test joint should be put in neutral or resting position in order to minimize tension on inert tissue.
  3. The movements should be done in resting position of the joint as in this position muscle is in its optimal length so that maximum force can be elicited.
  4. Moreover this position can be modified if required when assessing for tight or lengthened structures as well performing multiple angle isometric testing.
  5. This test involves isometric hold so it is essential to have the muscle strength of grade 3 to 5 on the muscle test grading scale.
  6. If there is difficulty in differentiating between grades 4 and 5, eccentric break test can be used. The test starts as an isometric contraction, but then assessor applies sufficient force to cause eccentric contraction or break in the isometric contraction.
  7. Post testing isometrics, other types of contraction can also be checked for according to patient’s complain.

Steps to perform Resisted Isometric Movements:

  1. The joint is placed in neutral or resting position. Every joint has a specific resting position.
  2. The patient is asked to perform strong isometric contraction, not to move the part and the assessor will resist with almost equal amount of force to prevent any movement from occurring and also to ensure that patient exerts maximum effort.
  3. However movement cannot be completely eliminated, but this will minimize it.

After these movements are performed, the assessor determines the contractile tissue affected by judging the degree of pain & strength of contraction. Along with these movements, functional testing, myotomes assessment, manual muscle testing, palpation and special tests are also equally important.

Active movements as well as passive movements can also be performed. And it has been observed that if contractile tissue is injured, active movement is painful in one direction (contraction) and passive movement is painful in opposite direction (stretch). Resisted isometric movement is painful in the direction of active movement.

There are 4 classic Patterns of contractile tissue lesions, according to pain & strength. They are as follows:

  • Strong & Pain free: – There is no lesion of the contractile tissue (muscles as well as nerves supplying) which is being tested regardless of being tender on touch.

 

  • Strong & Painful – In this there is local lesion of muscle or tendon. 1st or 2nd degree muscle strain. 2nd degree strain produces more muscle weakness and pain than 1st degree strain.

There can be tendinitis, tendinosis, paratenonitis or paratenonitis with tendinosis or partial avulsion fracture, but in this contraction will be strong (not as good side) and painful, pain will be around the tendon and not the muscle.

 

  • Weak & Painful: – This is seen in cases of severe lesion around of joint such as fracture. Weakness is usually caused by reflex inhibition of muscles around the joint secondary to pain.

 

  • Weak & Pain free: – This indicates complete rupture of muscle or tendon (3rd degree) or involvement of peripheral nerve or nerve root supplying that muscle. With neurological involvement, assessor must differentiate between affection of (a) peripheral nerve by checking muscles & (b) nerve root by checking myotomes and dermatomes. Differentiate between UMN & LMN lesions.

3rd degree strains usually are painless, but many a times along with this there is 1st or 2nd degree strain of surrounding muscles resulting into pain. To find out 3rd degree strain, one must check for presence of hole or gap in muscle by palpation or check the muscle bulk when contraction is attempted and how it gives appearance of obvious deformity.

 

Reference

  • Magee DJ. “Orthopaedic Physical Assessment.” 5th Philadelphia: WB Saunders. 2012.
  • Image : http://www.ptonthenet.com

 

Soft endfeel

How to check End feel during examination?

Soft endfeel

It has always been a query regarding the end feel for a particular joint and its movement. In order to solve this query here is a bit of overview on it. Hope it clarifies the doubts and solves the issue with better ease for judging the particular type of end feel.

Defining the End Feel in easier terms is the feel that is perceived by the assessor at the end of any movement. The movement that the patient performs actively is repeated passively and when the end of the available range is reached over pressure is applied to get a feel of resistance of tissue. This feel of barrier at the end of a passive range of motion is called end feel.

Steps to be noted while assessing End Feel

  1. Movement & end pressure should be done slowly and carefully
  2. Detect the end of available range of motion
  3. Distinguish between normal & abnormal end feel
  4. Caution to be taken not to be too forceful and injure the tissue
  5. Always compare it with the contra lateral side

Significance of taking End feel

  • It helps the assessor to differentiate between limiting structures
  • It guides in measuring range of motion and compare with the contra lateral side and thereby detect the pathology
  • It determines if the limitation is due to articular or peri-articular problem
  • Proper evaluations of end feel help determine a prognosis for the condition & learn severity or stage of problem.
  • The quality of resistance at end range
  • Each joint has a normal end feel at a normal point in Range of Motion (ROM)
  • Incorrect end feel, or correct end feel at incorrect ROM indicate pathology

 

 

 

 

 

NORMAL OR PHYSIOLOGICAL END FEEL

1. Soft tissue approximation Subcutaneous tissues (muscle bulk, fat) are pushing against each other

e.g.- Knee Flexion, Elbow Flexion

2. Tissue stretch (Muscle stretch) Passive elastic stretch (Tension)

Feels like stretching a bicycle tire inner tube

e.g.- Hip Flexion with Knee Extension

 

3. Tissue stretch (Capsular stretch) Tension in joint capsule

Feels like stretching a leather belt; more resistance than ligament

e.g.- Extension of MCP Joint of Fingers

4. Tissue stretch (Ligamentous stretch) Tension in ligaments surrounding the joint

Feels like stretching a leather belt

e.g.- Forearm Supination

5. Hard (Bony) Bone contacting bone (painless)

Feels like pushing 2 wooden surfaces together

e.g.- Elbow Extension

 

 

ABNORMAL OR PATHOLOGICAL END FEEL

1. Soft Capsular Related to compressing & stretching of soft tissues

Similar to Normal but with restricted ROM. Is often found in acute conditions with stiffness occurring early in range & increases until end of range

Soft boggy end feel

e.g.- Synovitis, Soft Tissue Oedema

2. Hard Capsular Similar limitation comes abruptly after smooth, friction free movement

e.g.- Frozen Shoulder, Chronic Conditions

3. Early Muscle Spasm Invoked with movement, with a sudden arrest of movement often accompanied by pain

End feel is sudden

e.g.– Acute protective spasm associated with Inflammation

4. Late Muscle Spasm Restriction occurs at or near end of ROM

Caused by instability & the resulting irritability caused by movement

e.g.- Chronic condition, spasm caused by instability

5. Springy When passive movement performed rebound phenomenon occurs

e.g.- Meniscal Tear or spasm

6. Empty Sensation is painful at certain limit.

Range is not restricted but patient is not willing to allow motion to end of range because of anticipated pain and so assessor did not reach end feel

Feels like the joint has more range available, but patient is purposefully preventing movement through full ROM.

e.g.- Acute Joint Inflammation, Bursitis, Abscess, Fractures, Psychogenic disorders

7. Bone to Bone Similar to normal end feel but range is not complete

e.g.- Osteophyte formation, Myositis Ossificans

 

 

References

  • Magee DJ. “Orthopaedic Physical Assessment.” 5th Philadelphia: WB Saunders. 2012.
  • Image courtsey : bostonbodyworker.com

 

Overhead squat assessment

The over head squat is one of the most valuable assessment you can do with your patient. Before starting assessment one should check rang of motion of all joints.

Rationale:

This test for bilateral symmetrical mobility and stability of hip, knee and ankle joint .In addition to check shoulder as well as thoracic mobility.

Red flag must be address before assessment.

How to perform?

  • Instruct the patient for 5 repetitions of squat as per his comforts zone.
  • Heel should not off the ground while performing task.
  • You must address in your document regarding pain or discomfort during squatting.
  • Do not let the patient know what you are looking for otherwise patient might adjust him self and we may get false result.
  • We should consider different view motion from different angles.

Courtsey:prezi

Observation check list:

1). Feet pronate and externally rotate:

This may indicate tightness in the soleus, gastrocnemius, peroneals, hamstring and piriformis and/or weakness in the gluteus medius. There may also be a restriction in ankle joint dorsiflexion, since the body will pronate the foot to gain more motion in the ankle mortise. If dorsiflexion is limited, there is a posterior chain extensibility dysfunction or ankle joint extensibility problem, or both.

2). Knees buckle / hip internal rotation:

May indicate weak/inhibited gluteus maximus/medius, tight adductor complex and iliotibial band. May be an inability to control hip movements, pointing to an underlying motor control stability problem.

3). Low back arches:

There might be tight iliopsoas and/or other hip flexors and latissimus dorsi,
compensating for a weak core.

4). Low back rounds:
It may reflects the overactive external obliques, compensating for a weak core. Observe if there is a rotational component to the movement when the low back rounds due to the fascial attachment of the spiral line of myofascial from the external oblique to the opposite shoulder.
5). Arms fall forward:
It may indicate tight latissimus dorsi and /or pectoralis major/minor and weak lower trapezius, rhomboids, teres minor and infraspinatus.
6). Lateral shift:
A shift to either the right or left side during any part of the movement may indicate a motor control stability problem or an underlying self-protective mechanism to deviate away from pain.
  1. Sahrmann SA. Diagnosis and Treatment of Movement Impairment Syndromes. St. Louis, MO: Mosby; 2002.
  2. Liebenson C. Integrated Rehabilitation Into Chiropractic Practice (blending active and passive care). In: Liebenson C, ed. Rehabilitation of the Spine. Baltimore, MD: Williams & Wilkins; 1996:13–43.
  3. Comerford MJ, Mottram SL. Movement and stability dysfunction—contemporary developments. Man Ther 2001;6(1):15–26.
  4. Janda V. Evaluation of Muscle Imbalances. In: Liebenson C, ed. Rehabilitation of the Spine.
  5. Baltimore, MD: Williams & Wilkins; 1996:97–112.
  6. Sahrmann SA. Posture and muscle imbalance. Faulty lumbar pelvic alignments. Phys Ther 1987;67:1840–4.
  7. Janda V. Muscles and Motor Control in Low Back Pain: Assessment and Management. In: Twomey LT, ed. Physical Therapy of the Low Back. Edinburgh: Churchill Livingstone; 1987:253–78

Lower Back Pain When You Bend Forward? Here’s how you should manage.

Lower Back Pain When You Bend Forward? Here’s how you should manage.

Lumbar pain during flexion movement  is one of the commonest symptoms that we all face in our routine practice. There are a number of clinical reasoning processes, which need to be considered.

Much of the literature focuses on the changes in intra-discal pressure associated with spinal flexion. Which indicate that spinal flexion pain is associated with increased disc strain.  In order to strengthen the hypothesis of disc related flexion pain the clinician needs to establish other components of discogenic characteristics to support the hypothesis.

Here are some few things to remember when patient come with lower back pain.

  1. Observe everything, from entering into our examination room, starting with the client rising from a chair.
  2. History – link injury mechanisms, pain mechanisms with specific activities and past exercise regimens. Is there any “red flags” appear or not .
  3. Perform provocative tests – what loads, postures and motions exacerbate, what are relieving factors and what are aggravating factors? This needs to be address.
  4. Perform functional screens and tests – Are there perturbed postural, motion and motor patterns?
  5. If the clinical picture is complex and beyond your comfort zone, develop a referral relationship with a competent corrective exercise specialist.

It is not a matter of client performing an exercise – it is a matter of the client performing the exercise with perfection.

Observation Point:

  • Look for a dysfunctional movement pattern
  • Not able to hip hinge properly.
  • Allow the lower lumbar spine to flex forward.
  • Look for the patient get up from their seat
  • Do they difficulty to maintain neutral spine or bend forward into flexion as they arise?
  • Do they have pain while getting up from chair?
  • In the treatment room, watch them take off their shoes.
  • Ask patient to pick object from floor and observe behavior pattern of movement.
  • Look for fear or uncertainty at the prospect of bending forward.

Physical examination :

This is the main part one should find out what exact pathology it is.

  • Positive straight leg raise. Often you’ll see more subtle findings than in classic sciatica. They may experience more tightness in the back of the leg on one side or the other. They may experience buttock pain. I prefer the sitting straight leg raise. If needed, add foot dorsiflexion, have the patient bend forward, and/or add a Valsalva maneuver.
  • One of Comerford’s tests for flexion control is called the waiter’s bow. Briefly teach the patient to bend forward while maintaining the spine in neutral. Stand to the side and watch them do this. Do they do it well or do they lose neutral? For tactile feedback, place your index finger horizontally on the sacrum, and the other hand’s index finger just above, across the L5 spinous process. Now have the patient bend forward using the waiter’s bow. Do your fingers separate? Recheck between L5 and L4. If your fingers are separating, the patient’s lumbar spine in moving into flexion. It means that even when they are trying to, they cannot control flexion. See pictures below.

  • Palpate the interspace for tenderness. Place the patient prone with a pillow under their abdomen, so the lumbar spine is in slight flexion. Apply deep digital pressure to the interspinous spaces and the inferior spinous process, pushing simultaneously posterior to anterior and inferior to superior. I start with L5-S1 and work upward to at least L3-4. Is the interspace tender? Ask them to rate the tenderness on a 1-3 scale: 1-mild, 2-moderate or 3-severe. (I used to think this was the ideal test, but it is not always positive, even in those I know have flexion intolerance. Maybe it represents increased inflammation in those with flexion intolerance.)
  • Repeated end-range loading of extension This can be done prone or standing. Does this relieve or centralize their pain?
  • If they are not in acute pain, you can do repeated end-range loading of flexion, either from standing or in a long sit posture. Ask them to slump forward. Does this aggravate their pain; does this elicit increased buttock or leg pain, or sensory changes?
  • Palpate the lower lumbar paraspinal muscles. In disc-related pain, a discrete area will often feel atrophied, often unilaterally. There is often a divot, a hole, a small area of atrophy, at the level of the disc injury. As chiropractors, we are much more used to getting information on the restricted side, rather than the side that is moving too much.

 Unlock the mystery of pain

  • Treatment of flexion-intolerant pain is primarily self-care. Yes, your soft-tissue work and mobilizations can help, but self-care is primary and essential. There is no magic you can do that will override what the patient is doing 24/7. You have to teach them to move differently to solve flexion-intolerant pain. According toStuart McGill, “The first step in any exercise progression is to remove the cause of the pain, namely the perturbed motion and motor patterns.”9
  • There are two components of self-care. First, have them quit doing stupid stuff that is reinjuring them over and over. Totally stop the sit-ups and crunches. They cannot do yoga-style prolonged flexion. Pilates is not much effective as it often uses too much uncontrolled flexion. Don’t assume the patient knows this; they likely don’t. If they are sitting too much and for too long, help them figure out how to change that habit via frequent breaks and/or by utilizing a standing workstation.
  • Second, train them to move differently.
  • Yes, they need to strengthen their inhibited core muscles, but they need start with these simple movements, done precisely.

References

  1. Yin-gang Zhang, Tuan-mao Guo, Xiong Guo, Shi-xun Wu. Clinical diagnosis for discogenic low back pain.Int J Biol Sci, 2009;5(7):647-658.
  2. Hides JA, Richardson CA, Jull GA. Multifidus muscle recovery is not automatic after resolution of acute, first-episode of low back pain.Spine, 1996;21(23):2763-2769.
  3. Hides JA, Stokes MJ, Saide M, Jull GA, Cooper DH. Evidence of lumbar multifidus muscle wasting ipsilateral to symptoms in patients with acute/subacute low back pain.Spine, 1993;19(2):165-172.
  4. O’Sullivan P, Twomey L, Allison G, et al. Altered patterns of abdominal muscle activation in patients with chronic low back pain.Aust J Physio, 1997;43:91-98.
  5. MacDonald D, Moseley GL, Hodges PW. People with recurrent low back pain respond differently to trunk loading despite remission from symptoms.Spine, 2010 Apr 1;35(7):818-24.
  6. Gibbons SGT, Comerford MJ. Strength versus stability. Part 1: Concept and terms.Orthopaedic Division Review. March / April: 2001:21-27.
  7. Liebenson C. “Flexion Intolerant Back” (10-minute video). Toronto, Ontario, 2011; filmed and edited by Phillip Snell.
  8. McGill S. “Designing Back Exercise: From Rehabilitation to Enhancing Performance.” (Guide to training the flexion-intolerant back.)

 

Courtsey : http://www.dynamicchiropractic.com/mpacms/dc/article.php?id=56837

Strong, Functional arch acts like suction cup

The arch is important structure in foot. Good arch provide support and prevent overuse injuries. When we talked about overpronated foot it is more chances of repetitive strain injury to the medial side structure of foot.

The human foot plays major role in allowing us to walk properly on surfaces and keep upright. While maintaining balance and stability with such a small base of support , it is important that your feet are doing their job.

Think foot acts like a tripod with 3 point of contact:

1) Base of big toe

2) Base of fifth metatarsal head

3)Heel

When human body requires additional stability in stance phase, hour foot should have equal pressure applied through these points into the ground. When we walk pressure applied on these points and you will activate a group of intrinsic muscles that act to root your foot and maintain stability.

When all these points acts in synchronize manner , foot acts as suction cup. It allows your foot quickly grip to the ground when stability is needed, whether you do dead lift, squat or any other lower limb exercises. Mostly psychometric exercise foot is major role plying.

We mainly concentrate on foot tripod activation during rehabilitation phase. We do assessment accurately and find the cause and working on missing link. Do not forget  to  rehabilitate tripod. That’s how we approach things in our clinic and we get results.

 

Drilling through upper limb

 

Shoulder is a complex joint. For  shoulder flexion to get the arm overhead – 12 ribs and their vertebral attachments and 10 with sternal attachments, scapular motion through 3 dimensions (frontal plane, saggital plane, and transverse plane rotations), humeral rotation and alignment within the glenoid fossa, AC and SC joint motions or limitations, vertebral motion of at least the 12 thoracic vertebral segments, and  finally local muscular issues – means to get your arms in the air to wave them like you just don’t care can take motion from 38 joints through 3 planes of action and muscular actions from at least 24 muscles that attach through the thoracic spine, scapula and humerus.

It’s tough for the scapulae to retract and depress if the person has rounded shoulder (i.e.rib cage is stuck in flexion.)

In terms of scapular motion, the shoulder blades have the ability to move through 3 planes due to their floating attachment to the body.

For rotation, the scapula rely on triangulation force application from 3 different muscle groups to create upward rotation and 3 different groups to produce downward rotation.

During upward rotation movements, sufficient scapulohumeral rhythm should be 1:2, where the humerus moves 2 degrees for every degree that the scapula rotates. For reference, when the arm is overhead at 180 degrees of flexion, the scapula should be rotated to 60 degrees (180-60 = 120, maintaining the 2:1 ratio).

When that scapular rotation doesn’t happen and they wind up shrugging the shoulder to get it into place, essentially substituting torso side bending for scapular motion. There could also be adhesive changes in the shoulder joint itself, a condition commonly known as frozen shoulder, and in this instance the rhythm goes from 2:1 down to 1:1, where pretty much all of the movement comes from the shoulder blade and none comes from the humerus itself.

A side from upward and downward rotation, there is  also forward tilting and backward tilting of scapula . Forward tilt is also commonly called winging scapula.(when there is under active of serratus anterior)

 

By itself, a winged scapula isn’t a problem, but it is a graphic example of a shoulder that may not have positional strength or stability to get the blade flat to the spine(Poor motor control of scapula). In order to find stability, the shoulder blade winds up peeling off the torso and angling forward, making it difficult to adequately retract or rotate.

 

Typically working to improve winging involves directly training the serratus anterior to help promote protraction, however in my experience the serratus isn’t weak but constantly on, and you can barely palpate the lower traps and rhomboids because they’re fairly atrophied. In many ways, a winging scapula isn’t a single muscle problem, but a systemic  compensation. Pretty much all of the muscles attaching to the scapula need to be strengthened .

 

Again, This just illustrates the rotational capability of the shoulder blade outside of upward or downward rotation. This type of tilting works through the transverse plane in relation to the torso, but there’s also saggital tilting.

 

This is common with people who have significant thoracic rounding into kyphosis, as well as a forward head posture. It’s challenging to do anything with the shoulder blades other than elevate and protract in this position without addressing thoracic motion first, hence breathing mechanics to try to pull them away from the flexion bias towards more extension positional aptitude.

 

A lot of these motions can be helped or hindered through common muscle training and posture work, but some is affected through degenerative or injurious tendencies through the AC joint and SC joint.

 

Many people with degenerative issues such as arthritis tend to also develop some significant reductions in movement capability through the SC joint, which should be able to rotate, elevate and protract relatively easily. If it’s stuck, the shoulder blade won’t move.

 

So in terms of getting the shoulder blade to move, there’s a bunch of different ways. Principally, just make it move through the basic patterns of protraction, retraction, elevation, depression, upward and downward rotation and you’ll have your bases covered. Just make sure the movement is in the direction you want .

You could do any of these exercises, or different ones if you want. As long as the movements work that’s all that matters. If you can’t get a specific movement to work, spend some more time on correct inhibited structure.Especially if that movement is important to any activity you want to do. For example, if you can not get your movement  easily , you should  locked up for thoracic spine or poor positioning to accommodate the movement, spend some time trying to adjust your thoracic positioning and mobility to allow an easier time to access those movements.

 

Drilling ROW Movement:

 

Prior to starting any of the scapular movements, look at the thoracic spine, as we discussed earlier. A rounded thoracic spine will make retraction and rotation difficult. A hyper extended spine will make elevation and protraction difficult.

 

The lattismus  muscle causes the humerus to extend and externally rotate, and pulls the scapula into retraction and depression. If you’re doing a row and your shoulder blade winds up in your ear with the hand on your chest and elbow out in the boonies away from your body, you’re not using your lat. Do you want to use your lat? Yes, you do, especially when doing a row, so therefore you need to adjust how those shoulders move .

 

Next, look at glenohumeral motion. The basic stuff to check are external rotation and internal rotation, as well as both rotations through specific positions like with the arm abducted, addicted, or where ever you’re going to need to have rotational control. If you want to do muscle testing on the muscles controlling these motions, have at it.

 

I can see in my practice that many people complains about shoulder or back pain after joining gym. What I observe is there is lack of understanding of joint position performing exercise. There is also lack of flexibility issue.

 

To press a bar overhead requires a fair amount of GH internal rotation (biceps wind up pointing towards ears = IR). To bench press requires similar internal rotation. To squat, do lat pull downs behind the head, or thumbs up rear delt raises all take more external rotation, so understanding what movements you have control over and available can make difference in your exercise selection and relative risk of injury with each exercise.

 

                   Take home message

There are  bunch of contributing factors that can affect shoulder motion. From the above discussion always start with  thoracic positioning, scapular motion, and finally look at glenohumeral motion when dealing with tricky shoulder movements that just aren’t giving you what you want.

Bibiliography:

 1)  Functional anatomy of the shoulder : . 2000 Jul-Sep; 35(3): 248–255.

 

Cervicogenic Headache : What’s the Evidencebase treatment?

How many of your patients with neck pain suffer from headaches as well, or vice-versa? Cervicogenic headaches are characterized by unilateral headache radiating from the posterior to anterior head, unilateral upper cervical pain and facet “locking,” which is often aggravated by sustained neck positions. 

For cervicogenic headache patients, modalities such as TENS, cryotherapy, or low-level laser therapy can be helpful. Spinal manipulative therapy has been shown effective for cervicogenic headache patients in several studies. Other manual therapies such as instrument-assisted soft tissue mobilization and kinesiological taping can be helpful adjuncts.

Therapeutic exercise including muscle stretching and specific strengthening exercises can help address muscle imbalances seen in cervicogenic headaches. Several studies have shown that cervical strengthening exercises with  elastic resistance can help reduce headache and neck pain symptom.

In summary, management of cervicogenic headaches begins with an accurate diagnosis.  A multi-modal approach including Thera-Band exercises, modalities and manual therapies can help to reduce  symptoms of cervicogenic  headache.

Cervicogenic headaches: An evidence-led approach to clinical management.  

  2011 Int J Sports Phys Ther. 6(3):254-266.