CHAPTER IX RESEARCH QUESTION 5 CORE STABILITY AND LUMBO-PELVIC DYSFUNCTION

CORE STABILITY: ANATOMICAL, BIOMECHANICAL AND PHYSIOLOGICAL EVIDENCE Christopher McLean

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

Many researchers and authors agree that the key aim of core stability programmes is to optimise the performance of muscle activity around the lumbar spine to prevent harmful movement (Lawrence, 2003; Norris, 2001; Richardson et al., 1999; Westlake, 2003). Thomson (2002) concluded following an evidence based review of the literature on chronic low back pain that individuals with greater ranges of spinal motion have increased risk of future troubles and that endurance and not strength related to reduced symptoms. The developing core stability concept recommends that the spine must be in a stable neutral position before developing forces to enhance performance (Stott, 2002; McGill et al., 2003; Panjabi, 1992a). The neutral position of the lumbar spine is described as a position of lordosis where the pelvis is positioned somewhere inbetween a full anterior and posterior pelvic tilt (Stott, 2002). In this position there is minimal stress through the facet joints, intervertebral discs, ligaments and joint capsules (Panjabi, 1992a). The deep stabilising muscles which are believed to be tonically active, are minimally active in the neutral position therefore minimising the potential for muscular fatigue (Cholewicki et al., 1997; Hodges et al., 2000). It has been hypothesised that fatigue of the stabilising muscles is a major contributing factor to lumbo-pelvic dysfunction (Thomson, 2002). Lack of muscular control at a motion segment could adversely effect spinal mechanics as the muscular system has a major role in spinal stability as discussed in Chapter V.

Cholewicki et al. (1997) demonstrated that modest levels of coactivation of the paraspinal and abdominal wall muscles were necessary to maintain a stable spine in a neutral position. Continuous, low grade muscle activation of these muscles should maintain stability with all activities of daily living. Studies by Luoto et al (1995) suggested that it is not absolute strength of the local stabilising muscles that prevents injury or lumbo-pelvic dysfunction but endurance capacity or muscle control.

A number of researchers have observed alterations of the motor control system following injury (Burnett et al., 2004; O’Sullivan et al, 1997; Richardson et al, 1997). It would appear that these motor disturbances such as multifidus inhibition following back pain, compromise spinal segmental stability (Hides et al., 1996). McGill et al. (2003) summarised spinal stability as coming from active and passive stiffness. Passive stability can be lost through tissue damage and active stiffness may be compromised by disturbed motor patterns following injury (McGill et al., 2003). © Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

It has been suggested that pain and dysfunction are related (Richardson et al., 1999). A number of studies have demonstrated that a decrease in the cross sectional area of local stabilising muscles on the ipsilateral side to the symptoms existed in back pain subjects (Hides et al, 1994 and 1996). There has been evidence of specific loss of cross sectional area of the lumbar multifidus (Hides et al, 1994) and psoas major (Gibbons et al., 2002) that corresponded with specific vertebral levels. Hides et al (1996) found that on resolution of pain there was still dysfunction present with the multifidus muscle in terms of decreased cross sectional area and muscle activation patterns. To optimise this situation it would be necessary to improve the muscle activation patterns of multifidus as well as rebalance the muscle mass in terms of cross sectional area. The literature on low threshold training for the local stabilising muscles places an emphasis on the need for muscle contractions to be performed at low percentages of a maximal voluntary contraction (Richardson and Jull, 1995; Richardson et el., 1999 and 2002). These levels are below those of strength training that result in hypertrophy. While it has been hypothesised that neuromuscular pathways appear to be enhanced with low threshold training (Cholewicki et al., 1997; Hubley Kozey and Vezina, 2002a), herein the question lies, what mechamisms can be employed to return deep stabilising muscles such as multifidus to normal physiological proportions? A similar phenomena of muscle wasting and decreased activation through reflexive inhibition has been observed at the patellofemoral joint (Arvidsson et al., 1986). Dysfunction at the patellofemoral joint results in inhibition of the vastus medialis obliques (VMO) muscle (McConnell, 2002). Patellofemoral joint rehabilitation programmes generally encourage isolated VMO activity first in controlled ranges then progress to more dynamic and functional tasks (McConnell, 2002). The work of McConnel (2002) has further parallels with lumbopelvic stabilisation programmes in that they both acknowledge the principal of placing the osseous structures in neutral positions. The McConnel (2002) programme can involve taping techniques to keep the patella from maltracking whilst performing isolated VMO contractions (McConnell, 2002) compared with lumbopelvic programmes that concentrate initially on achieving a neutral pelvic position (Stott, 2002). The apparent reflexive inhibition of these muscles has been shown to be reversed through specific active exercises (Cowan et al., 2002; Crossley et al., 2002; Hides et al, 1996; McConnel, 2002). Hides et al., (1996) found that multifidus CSA returned to normal levels following stabilisation exercises. It could be postulated that the return of multifidus CSA is related to the normalisation of tonic neural activity. This is an area of research that warrants further investigation. © Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

Overload training is a method used to increase power, strength and hypertrophy of global mobilising muscles (Astrand and Rodahl, 1986; Campos et al., 2002). This review did not find any studies comparing overload training principles of the local or global stabilising muscles with low threshold training strategies. Whilst there is reported success of low threshold segmental stabilising programmes (Hubley-Kozey and Vezina, 2002a; Richardson et al., 1999; Sung, 2003) there is still considerable scope for further research to determine if current low threshold strategies are the most efficient form of rehabilitation. Determining whether principles of overload training are appropriate or even beneficial during lumbo-pelvic rehabilitation or injury prevention programmes was not clear from this investigation. No investgative studies were identified that considered the progression from low threshold training to overload strength training. This remains a significant gap in the core stability concept.

The application of research into general muscle strength suggests that the muscle with the largest cross sectional area (CSA) is capable of the greatest force production (Astrand and Rodahl, 1986). If the neural pathway to each muscle is the same then the potential benefit for the muscle with the largest CSA is that it could potentially prevent large excursions of movement beyond the neutral zone due to its capacity to generate an antagonistic force that threatened the neutral alignment of the spine or trunk structures. Another possible benefit could be that the extra muscle bulk simply provides more cushioning and therefore has a dampening effect on direct blows to the body. This review did not find any studies that investigated or addressed these issues.

Muscle function can have an enormous effect on the lumbo-pelvic region (Gibbons and Comerford, 2001a). By either being overactive or tight (shortened) muscles can cause asymmetry around an axis of movement (Comerford and Mottram, 2000). Norris (2000) commented that, “stabiliser muscles tend to ‘weaken’ (sag), whereas mobilisers tend to ‘shorten’ (tighten). Kendall et al. (1983) coined the term ‘stretch weakness’ for stabiliser muscles that maintain their overall normal length however are elongated in their normal resting position. This hypothesis fits in with Panjabi’s (1992b) views on the importance of the deep stabilising muscles maintaining the neutral zone. Studies investigating muscle activation patterns during loading of the thoraco-lumbar region and the preactivation of the local stabilisation muscles of the trunk during upper limb movement support the aforementioned theories (Hodges et al., 2000). The above © Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

views are given further substance by the findings of Hodges and Richardson (1996) that transverse abdominus activation enhances efficient muscular stabilisation of the lumbar spine. In contrast, this well constructed case-control study also found poor transverse abdominus muscle activation patterns in back pain subjects.

While there has been significant interest in the importance of the neutral position for the lumbar spine to minimise or prevent back pain (Stott, 2002) less evidence has been purported on the possible influence of asymmetry of the lower limb and the impact of this on the lumbopelvic region. A case study by Cibulka (1999) appeared to indicate that by improving the symmetry at the hip through a programme of stretching and strengthening low back pain was reduced. This study reportedly aimed to decrease lower limb external rotation during the gait cycle and thereby optimise biomechanical forces. This study can only be considered as weak evidence for the benefits of symmetry about the pelvis due to limitations in the study design including sample size and inadequate objective measures.

This review of the evidence found a number of studies that reported positive findings in relation to exercise and back pain (Dolan et al., 2000; Hides et al., 2001; Hodges and Richardson, 1996; Linton and Van Tulder, 2001; Nelson et al., 1999; O’Sullivan et al., 1997; Van Der Velde and Mierau, 2000). There was difficulty in extrapolating meaningful results from some of these studies as they considered a number of variables concurrently that could influence back pain. Dolan et al. (2000) considered a combined programme of aerobic, stretching and strengthening exercises on subjects following a microdiscectomy. The strengthening component described followed core stability training principles however this study design did not make it possible to determine to what extent each of the variables contributed to the improved outcome that was measured by pain and disability. Other limitations of this study were the lack of description in the methodology concerning the specific details of the exercise programme such as frequency, sets and repetitions of exercise. In the study by Hides et al. (2001) the role of specific stabilising exercises for transverse abdominus and multifidus was considered combined with normal medical management and the resumption of normal daily activity. This study provided better evidence for the role of stabilising exercises as the effects of medical management and normal daily activity could be removed from the equation by the control group. Subjects receiving stabilising exercises had better outcomes as measured by recurrence rates. © Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

A number of studies reported no benefit or minimal effect from exercise in improving back pain or posture (Dumas et al., 1995a and 1995b). There were a number of significant limitations from this study including the type of exercise prescribed to the population of pregnant women. The intervention was a general exercise programme based on Canadian guidelines that included aerobic, abdominal strengthening, flexibility and endurance exercises. Specific details of the exercises were not reported in this study however the universal prescription of the same exercises to all pregnant women may have resulted in some receiving inappropriate exercises for their individual states. There was an indication that the lumbar lordotic curve slightly decreased in the exercise group and that with greater lordotic angles higher pain levels were reported.

Systematic reviews on the effects of back pain and exercise provide an indication of general trends however the strength of their evidence is reduced due to their methodology as they are often comparing many different forms of interventions and variables, for example, type of exercise, frequency, duration, intensity and populations. The review by Linton and Van Tulder (2001) suggested that exercise had a mild preventative effect on back pain however was unable to conclude what type of exercise was best. To gain more useful contributions from systematic reviews there would be significant benefit from limiting searches to compare the results from studies that used similar intervention strategies. The term exercise is too generic and limits the opportunity to make specific conclusions and recommendations. An example of a more beneficial study design would be to compare subjects suffering from chronic back pain that have been exposed to the same form of intervention such as low threshold stabilising exercises.

Table 12 highlights the intervention studies used in this guideline. The evidence table associated with the guideline development for Key Question 5 can be seen in Table 18, Appendix G. Checklists associated with the analysis of 3 systematic reviews can be seen following these tables.

Table 12. Intervention studies for Question 5: Does core stability training decrease the recurrence or extent of lumbo-pelvic dysfunction?

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

Bibliographic citation CIBULKA, M. T. (1999) Low back pain and its relation to the hip and foot. Journal of Orthopaedic and Sports Physical Therapy, 29, 595-601.

Study type

Case study

Ev. Lev. 3

General comments

This paper presented data suggestive of a relationship between lower extremity mechanics and back pain. While there appeared to be a successful outcome with the treatment provided the reported assessment technique appeared to be biased and neglected testing significant muscle groups. While iliopsoas muscle length was tested there was no report of strength or function of other core stability muscles. Hip extensor strength was reported however not flexor strength. The treatment plan was aimed at regaining biomechanical symmetry at the hip by stretching the right hip medial rotators and also strengthening them. This was hypothesised by the author to have decreased the degree of forefoot pronation by decreasing the extent of ‘toed-out’ gait. This study provided weak evidence on the benefits of symmetry about the pelvis and the effect this has on low back pain. A more robust and thorough study design would be necessary to draw significant conclusions on the effect of pelvic stability on low back pain. Of interest was the intensity of recommended muscle training of 5 sets of 12 repetitions for the combined hip abduction and medial rotation strengthening. This was an example of isolationist muscle training techniques. There was no mention of dynamic neuromuscular or functional training.

DOLAN, P., GREENFIELD, K., NELSON, R. J. & NELSON, I. W. (2000) Can exercise therapy improve the outcome of microdiscecto my? Spine, 25(12), 15231532.

Prospecti ve RCT

1+

Results demonstrated that a 4 week postoperative exercise programme significantly improved pain, disability and spinal function. In this study the exercise group included aerobic, stretching and strengthening exercises. While trunk muscle strengthening and classic core stability exercises were the dominant form of exercise included they were not the only form of exercise intervention the group was exposed to. An alteration to the study design that would allow comparison of the 3 individual forms of exercise would be necessary to derive conclusions on the effect of core stability like exercises on the outcome of this patient group. The combined effect of these 3 forms of exercise were positive in improving spinal function most notably pain and disability. The results of this high quality study, with good control for bias, are suggestive of a positive role for core strengthening exercises however no absolute conclusions on their efficacy can be drawn. This study does not outline a specific exercise programme detailing intensity and frequency of specific sets and repetitions for exercises. Preferring to allow subjects to work ‘at their own pace.’ This feature would be considered a significant limitation of this study.

DUMAS, G. A., REID, J. G.,

Case control

2-

Study found that exercise according to Canadian guidelines had no detectable effect on posture and postural

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

WOLFE, L. A., GRIFFIN, M. P. & MCGRATH, M. J. (1995a) Exercise, posture, and back pain during pregnancy. Part 1. Exercise and Posture. Clinical Biomechanics, 10(2), 98-103.

adjustments. While cited in the title there was no report on back pain in this study. The parameters of the exercise programme were outlined however no comprehensive description of specific details were given regarding frequency of exercise, intensity or pre and post exercise objective data for core stability parameters such as abdominal or extensor muscle function. Little evidence can be derived from this study to support or negate core stability efficacy.

DUMAS, G. A., REID, J. G., WOLFE, L. A., GRIFFIN, M. P. & MCGRATH, M. J. (1995b) Exercise, posture, and back pain during pregnancy. Part 2. Exercise and back pain. Clinical Biomechanics, 10(2), 104-109.

CaseControl

2+

Fitness classes according to Canadian guidelines did not prevent or reduce back pain during pregnancy. Pain increased in the second half of pregnancy in the exercise group and not the control group. The greatest limitation of this study was the type of exercise performed, not explained. Perhaps inappropriate for a population of pregnant women. Little to be gained from the findings of this study.

HIDES, J. A., JULL, G. A. & RICHARDSON , C. A. (2001) Long-term effects of specific stabilizing exercises for first-episode low back pain. Spine, 26, E243-E248.

RCT

1+

This study suggested that specific exercise therapy in addition to medical management and resumption of normal activity may be more effective in reducing low back pain recurrences than medical management and normal activity alone. As both multifidus and transverse abdominis muscles are considered local stabilising muscles that provide the key to core stability training theories and systems it would appear that enhanced function improves lumbo-pelvic function.

HODGES, P. & GANDEVIA, S. C. (2000a)

Cohort

2-

This study demonstrated that EMG activity of the diaphragm was present throughout expiration with repeated upper limb movement in both sitting and standing

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

Activation of the human diaphragm during a repetitive postural task. Journal of Physiology, 165-175.

postures. When subjects moved with increasing frequency, the peak upper limb acceleration correlated with diaphragm EMG amplitude and thus diaphragm contraction was related to trunk control. It was concluded that the diaphragm contributes to both posture and respiration during a task that repetitively challenges trunk posture.The tonic diaphragmatic activity whilst undertaking a task that challenges trunk posture may control segmental motion indirectly by increasing intra-abdominal pressure, extending the lumbar spine and therefore assisting spinal orientation. The results suggest that core stability training involving activation of the diaphragm could aid in decreasing recurrence and extent of lumbo-pelvic dysfunction. The results of this study must be extrapolated with caution. A small sample size displayed a considerable variance in results. No strict inclusion criteria ensured homogeneity of subjects.

HODGES, P. & RICHARDSON , C. A. (1996) Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of Transversus Abdominis. Spine, 21, 2640-2650.

Case control

2+

Results of this study indicate that the central nervous system initiates activation of the trunk muscles and in particular transverse abdominus prior to limb movement. Contraction of the transverse abdominus was not influenced by the direction of reactive forces. The activation of transverse abdominus was delayed in the low back pain group. The results suggest that core stability training focusing on strengthening transverse abdominus can decrease the recurrence and extent of lumbo-pelvic dysunction and low back pain. More studies with larger population sizes are required to strengthen these conclusions.

HODGES, P., CRESSWELL, A., DAGGFELDT, K. & THORSTENSS ON, A. (2000) Three dimensional preparatory trunk motion precedes asymmetrical upper limb movement. Gait and Posture, 11, 92-101.

Cohort

2-

This study shows that 3D trunk motion precedes unilateral upper limb movements. The results suggest that anticipatory postural adjustments result in movements and simple rigidification of the trunk. The study also found that TrA was active and IAP increased prior to movement of the UL irrespective of movement direction and thus plays a role in preparatory limb movement. Training of TrA therefore could enhance lumbo-pelvic function. Care must be taken to extrapolate these results as only a small sample was measured and results were poorly reported.

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

LINTON, S. J. & Van TULDER, M. W. (2001) Preventative interventions for back and neck pain problems. What is the evidence? Spine, 26(7), 778-787.

See checklist for systematic review in Appendix G

McNEELY, M. L., TORRANCE, G. & MAGEE, D. J. (2003) A systematic review of physiotherapy for spondylolysis and spondylolisthes is. Manual Therapy, 8(2), 80-91.

See checklist for systematic review in Appendix G

1-

The review of the literature suggested that exercise demonstrates a moderate preventative effect. The studies did not conclude which type of exercise and in particular if core stability training can be used to decrease the recurrence or extent of lumbo-pelvic dysfunction and thus back and neck pain. This review was limited in that it may not have identified all relevant articles on the subject. The search may have been expanded by the finer definition of prevention eg disability levels or reduced sick leave. The review also did not assess methodological quality of the included studies. Many of the studies included had a poor level of methodological quality. Most studies chosen used small sample sizes and thus lacked power to determine the extent of positive effects. Subjects chosen represented a variety of occupations. The majority of studies also had a relatively short followup period and may not have yet seen a full preventative effect. Interventions varied considerably in terms of content, frequency and duration. Control interventions varied and the definition of outcome differed from sick leave to pain. There was a lack of studies found evaluating a multimodal approach to preventing back and neck pain.

1-

There were very few studies found examining the efficacy of physiotherapy for the treatment of spondylolysis and sponylolisthesis. The two studies chosen for this review were both initially rated as ‘weak’. The study that was re-rated as ‘strong’ gave evidence to suggest that specific trunk stabilizing exercises have a positive effect on low back pain related to spondylolysis and spondylolisthesis. This suggested that there is a role to play clinically, in strengthening the core stabilisers to improve lumbo-pelvic dysfunction. The other study evaluated gave evidence to suggest that a combination of extension exercises, an extension brace and education are beneficial in the treatment of spondylolisis and sponylolisthesis. This review only included studies written in English and therefore the studies chosen were only a representative sample of the existing research. It was predicted that few acceptable studies would be found and therefore the review was open to the inclusion of any prospective study. As a result, the Critical Appraisal focused on methodological criteria and not on criteria to discriminate between biased and unbiased RCTs. In the two studies identified intervention and control group activities were not clearly outlined and outcome measures not clearly described in terms of validity and reliability. Both studies also consisted of a small sample size which may have underestimated the effect of the interventions.

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

NELSON, B. W., CARPENTER, D. M., DREISINGER, T. E., MITCHELL, M., KELLY, C. E. & WEGNER, J. A. (1999) Can spinal surgery be prevented by aggressive strengthening exercises? A prospective study of cervical and lumbar patients. Archives of Physical Medicine and Rehabilitation, 80, 20-25.

Case series

3

Although there were many methodological flaws in this study, results showed only 3/38 patients initially indicated for spinal surgery required surgery during a 16 month followup period which included maintenance training, after an approxiamate 10 week intensive and specific exercise program. These results indicate that spinal surgery may be prevented in at least the short term by aggressive strength training. More information is required from this study to ascertain exactly what exercises were included in the exercise and maintenance program. There were many methodological limitations. Patients were not randomized, there was no control group, clinical results of the program (excellent, good, fair or poor) were not determined by a blind observer and are subjective, but argueably it is a simple and accurate measure of short term outcome in the clinical setting, not all patients completed the strength program and not all patients were available to be followed up.

O'SULLIVAN, P. B., TWOMEY, L. T. & ALLISON, G. T. (1997) Evaluation of specific stabilizing exercise in the treatment of chronic low back pain with radiologic diagnosis of spondylosis or spondylolisthes is. Spine, 22, 2959-2967.

RCT Testretest

1+

Results of this study support the hypothesis that specific exercise training of transverse abdominus and multifidus (the ‘stabilisers’) can help to reduce levels of pain and functional disability in LBP patients with spondylolisis and sponylolisthesis where the basic morphology of the spine has been compromised. This proved to be more effective than a general exercise program undertaken by most of the control group. The findings indicate an alternative intervention approach in patients with pathology that is normally treated with spinal fusion. That is to train the core stabilisers and improve lumbo-pelvic function. It may also be a treatment of choice in patients diagnosed with ‘instability’.

RICHARDSON , C. A., SNIJDERS, C.

Cohort

2-

Results of this study indicate that the transverse abdominus muscle can significantly decrease laxity of the SIJ (increase stiffness). Although results must be

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

A., HIDES, J. A., DAMEN, L., PAS, M. S. & STORM, J. (2002) The relationship between transversus abdominis muscles, sacroiliac joint mechanics, and low back pain. Spine, 27, 399-405.

extrapolated with caution due to the small sample size and lack of control group, results suggest that training of the TrA (core stabiliser) could enhance lumbo-pelvic function by increasing SIJ stiffness.

Van TULDER, M. W., MALMIVAARA , A., ESMAIL, R. & KOES, B. W. (2000) Exercise therapy for low back pain. A systematic review within the framework of the cochrane collaboration back review group. Spine, 25, 2784-2796.

See checklist for systematic review in Appendix G

Van Der VELDE, G. & MIERAU, A. (2000) The effect of exercise on percentile rank aerobic capacity, pain, and self-rated disability in patients with chronic lowback pain. Archives of Physical Medicine and Rehabilitation,

Retrospe ctive chart survey

1+

The results of this systematic review suggested that exercise therapy is not more effective for treating acute low back pain than other active/inactive methods. Results also suggest that exercise therapy is more effective than usual care by a general practitioner although just as effective as conventional physiotherapy for chronic low back pain.

Although only RCTs were included in this review, care must be taken to extrapolate these findings into clinical practice as there are many limitations to the review. Studies chosen consisted largely of heterogeneous populations and differed in interventions (type, duration, frequency and intensity of exercise program) and outcome measures employed. More RCTs using specific exercise interventions are required to make better conclusions about the effect of specific exercise on lumbo-pelvic dysfunction and low back pain

Case control

2-

The results of this study support those of previous studies that an active approach to chronic low back pain (CLBP) in conjunction with other forms of treatment may decrease pain and disability. Further investigation is required to determine exactly which exercise interventions are appropriate.This study is limited by the retrospective design as many factors could not be controlled. The same diagnostic criteria was not used by all referring health professionals, some patients reported pain outside the lumbar region which may have affected testing performance and the effect of concurrent therapies eg medicine and manipulative therapies could not be determined. Thus it is uncertain whether exercise alone would have resulted in the same decreases in pain and disability. Only results of the 137 CLBP subjects who completed the exercise program were included. Results may not have been so favourable if non-compliers and compliers to the 6 week program were included. Those

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX

81, 1457-1463.

BURNETT, A. F., CORNELIUS, M. W., DANKAERTS, W. & O'SULLIVAN, P. B. (2004) Spinal kinematics and trunk muscle activity in cyclists: a comparison between healthy controls and non-specific chronic low back pain subjects-a pilot investigation. Manual Therapy, 9, 211-219.

who completed the exercise program probably have a more positive attitude toward the program and this may partially explain the decrease in perceived pain and disability. Improvement in aerobic capacity and decrease in pain and disability may also be attributable to learning effects, desensitization and psychological benefits associated with exercise. Aerobic capacity was measured by the step test. It is difficult to ascertain whether performance in the step test reflected lower levels of fitness or if pain may have hindered performance in CLBP subjects and thus underestimated the level of aerobic capacity. Aerobic capacity was the only measure of physical fitness included in the study. If Other components of physical fitness were measured, results could be used more widely. Pilot Casecontrol

2+

This study demonstrates that altered spinal kinematics and trunk muscle activity are related to low back pain in cyclists. The group with pain associated with cycling demonstrated loss of cocontraction of multifidus in this study. The lumbar multifidus is one of the main stabilisers of the lumbar spine. There was also an increase in lower lumbar flexion and rotation demonstrated. This study suggested there is a role to strengthen multifidus in cyclists to stabilise the lumbar spine and control the movements of lubar flexion and rotation. Limitations of the study to be considered include the cyclists being able to adopt 2 different riding positions (tri bars and drop bars) which created a large SD in spinal kinematics data and hence decreased the effect size between pain and non pain groups, and the small sample size (however this allowed greater homogeneity of the non-specific low back pain group. Also to be considered are other physical activities/amount of training subjects are involved in as this could contribute to results.

See Appendix and References

© Christopher McLean 2006 ‘Core Stability: Anatomical, Biological and Psychological Evidence’ Chapter IX