The use of ultrasound imaging of the abdominal drawing-in maneuver in subjects with low back pain

Co-contractive activation of the superficial multifidus during volitional preemptive abdominal contraction

OBJECTIVE

To investigate whether the superficial multifidus (MF) muscle at the lower lumbar spine displayed co-contraction during volitional preemptive abdominal contraction (VPAC) through the abdominal drawing-in maneuver (ADIM) or the abdominal bracing maneuver (ABM) in 3 different postural positions.

DESIGN

A within-subject cohort design.

SETTING

A clinical laboratory.

PARTICIPANTS

A healthy convenience sample of 21 women and 13 men; mean age (SD), 25.5 ± 6.5 years.

METHODS

We collected surface electromyographic measurements for the superficial MF at the L5 vertebral level and abdominal wall muscles. Ultrasound imaging was used during screening and testing sessions for confirming transverse abdominis muscle activation while subjects maintained a relaxed state without volitional abdominal contraction (no-VPAC) and performed ADIM and ABM in 3 postural positions: supine, 4-point kneeling, and upright standing.

MAIN OUTCOME MEASUREMENT

The frequency of superficial MF co-contraction occurrences (percentage of the total number of conditions) was measured during ADIM and ABM in 3 different postural positions.

DATA ANALYSES

A Cochran Q test for k-related samples (α = 0.05) was used for data analysis.

RESULTS

Activation of the abdominal wall by using either VPAC strategy resulted in a significantly greater MF co-contraction occurrence when compared with no-VPAC in each position. The ABM produced a significantly higher MF co-contractive occurrence versus the ADIM in the supine position.

CONCLUSION

Both VPAC strategies produced a co-contractive MF response, which appears to be important for lumbar segmental stabilization and control. Analysis of the results suggests that VPAC strategies are appropriate for coactivating the MF, which can enhance spinal protection and rehabilitation responses.

What is a Suitable Pressure for the Abdominal Drawing-in Maneuver in the Supine Position Using a Pressure Biofeedback Unit?

[Purpose] The aim of this study was to determine the appropriate pressure variation for performing a successful abdominal drawing-in maneuver (ADIM). The abdominal muscle thickness variations and contraction ratios were examined in relation to pressure variations using a Pressure Biofeedback Unit (PBU) during an ADIM in the supine position. [Methods] The PBU was placed identically between the lumbar lordosis of 20 healthy subjects (12 males and 8 females) and the pressure of the PBU was maintained at 40 mmHg. Then, while the subjects performed ADIM at four random pressure variations (0, 2, 4, or 6 mmHg), the thicknesses of the transversus abdominis (TrA), the internal oblique abdominal muscle (IO), and the external oblique abdominal muscle (EO) were measured using ultrasonography. [Results] Pressure increases of 0-2 mmHg resulted in significant decreases in IO and EO thicknesses compared to pressure increases of 6 mmHg. Increases of 0-2 mmHg also resulted in significant decreases in IO+EO and EO contraction ratios compared to pressure increases of 6 mmHg, while the preferential activation ratio of the TrA was significantly increased. [Conclusion] Compared to the other pressure increases, an increase of 0-2 mmHg effectively regulated the thicknesses and contraction ratios of superficial muscles such as IO and EO, rather than the thickness and contraction ratio of the TrA, showing high and indirect preferential activation ratios for TrA. Therefore, for successful ADIM, rather than using large PBU pressure increases, exercises that promote slight increases of around 0-2 mmHg from a baseline of 40 mmHg are desirable.

Biofeedback in rehabilitation

This paper reviews the literature relating to the biofeedback used in physical rehabilitation. The biofeedback methods used in rehabilitation are based on biomechanical measurements and measurements of the physiological systems of the body. The physiological systems of the body which can be measured to provide biofeedback are the neuromuscular system, the respiratory system and the cardiovascular system. Neuromuscular biofeedback methods include electromyography (EMG) biofeedback and real-time ultrasound imaging (RTUS) biofeedback. EMG biofeedback is the most widely investigated method of biofeedback and appears to be effective in the treatment of many musculoskeletal conditions and in post cardiovascular accident (CVA) rehabilitation. RTUS biofeedback has been demonstrated effective in the treatment of low back pain (LBP) and pelvic floor muscle dysfunction. Cardiovascular biofeedback methods have been shown to be effective in the treatment of a number of health conditions such as hypertension, heart failure, asthma, fibromyalgia and even psychological disorders however a systematic review in this field has yet to be conducted. Similarly, the number of large scale studies examining the use of respiratory biofeedback in rehabilitation is limited. Measurements of movement, postural control and force output can be made using a number of different devices and used to deliver biomechanical biofeedback. Inertial based sensing biofeedback is the most widely researched biomechanical biofeedback method, with a number of studies showing it to be effective in improving measures of balance in a number of populations. Other types of biomechanical biofeedback include force plate systems, electrogoniometry, pressure biofeedback and camera based systems however the evidence for these is limited. Biofeedback is generally delivered using visual displays, acoustic or haptic signals, however more recently virtual reality (VR) or exergaming technology have been used as biofeedback signals. VR and exergaming technology have been primarily investigated in post-CVA rehabilitation, however, more recent work has shown this type of biofeedback to be effective in improving exercise technique in musculoskeletal populations. While a number of studies in this area have been conducted, further large scale studies and reviews investigating different biofeedback applications in different clinical populations are required.

A literature review reveals that trials evaluating treatment of non-specific low back pain use inconsistent criteria to identify serious pathologies and nerve root involvement

OBJECTIVES

The broad aim of this study was to assess the homogeneity of patients included in trials of non-specific low back pain (NSLBP). To do this, we investigated the consistency and clarity of criteria used to identify and exclude participants with serious pathologies and nerve root compromise in randomized controlled trials, investigating interventions for NSLBP.

METHODS

We searched Medline database for randomized controlled trials of low back pain (LBP). published between 2000 and 2009. We then randomly selected and screened trials for inclusion until we had 50 eligible trials. Data were extracted on the criteria used to identify cases of serious conditions (e.g. cancer, fracture) and nerve root involvement.

RESULTS

The majority of papers (35/50) explicitly excluded patients with serious pathology. However, the terminology used and examples given were highly variable. Nerve root involvement was an exclusion criterion in the majority but not all studies. The criteria used for excluding patients with nerve root involvement varied greatly between studies. The most common criteria were 'motor, sensory or reflex changes' (nine studies), followed by 'pain radiating below the knee' (five studies) and 'reduced straight leg raise which reproduces leg pain' (five studies). In half of the included studies, the criteria used, while alluding to nerve root involvement, were not explained adequately for us to determine the types of patients included or excluded.

DISCUSSION

The inconsistent and unclear criteria used to identify cases of serious pathology and nerve root compromise means that published trials of LBP likely include heterogeneous patient populations. This trait limits our ability to make comparisons across trials or pool studies. Standardization and consensus is important for future research.

The effects of abdominal draw-in maneuver and core exercise on abdominal muscle thickness and Oswestry disability index in subjects with chronic low back pain

The purpose of this study was to effects of abdominal draw-in maneuver and core exercise with 4 weeks using the musculoskeletal ultrasonography on muscle thickness and disability in subjects with low back pain. Twenty patients with nonspecific back pain (abdominal draw-in maneuver group: n= 10, core exercise group: n= 10) were recruited in the study. Both group received exercise intervention 3 times a week for 4weeks. The test were based on muscle thickness (transversus abdominis; Tra, internal oblique; IO and external oblique; EO), disability (Oswestry disability index; ODI) measured immediately before and after intervention. The data was measured by SPSS program 12.0 version and analyzed by Paired t-test and Independent t-test. The following results were obtained. The thickness of IO, EO for both group significantly improved except for muscle thickness of Tra. The ODI were significant difference for both groups. As the results of this study, we suggest that it may be effective method to apply to increase for the thickness of Tra, EO using abdominal draw-in maneuver and thickness of IO using core exercise.

Gender differences on ultrasound imaging of lateral abdominal muscle thickness in asymptomatic adults: a pilot study

OBJECTIVE

To describe gender and side-to-side differences in lateral abdominal wall muscle thickness at rest and during contraction in asymptomatic adults.

DESIGN

Cross-sectional observational study.

SETTING

Tertiary university outpatient musculoskeletal clinic.

PATIENTS

Asymptomatic, healthy adults.

METHODS

A single examiner with training in ultrasound (US) assessment evaluated all subjects and used a different hand to guide the US transducer on each side. Bilateral anteroposterior measurements of transversus abdominis (TrA) and internal oblique (IO) thickness were assessed at rest and during maximal contraction with the use of an abdominal draw-in maneuver (ADM). Three sets of data points were obtained on 12 subjects to determine intrarater reliability within a single session.

MAIN OUTCOME MEASUREMENTS

Anteroposterior thickness of TrA and IO muscles (cm).

RESULTS

A total of 20 subjects (mean age, 29.3 years; range, 23-46 years; 8 men and 12 women; mean body mass index, 24.4 kg/m(2); range, 18.9-34.9 kg/m(2)) were examined. At rest, men had greater TrA and IO thickness compared with women (men, 0.55, and women, 0.35, P = .01; and men, 0.95, and women, 0.77, P = .04, respectively). At rest, there were no side-to-side differences of TrA or IO muscles for both genders. With an ADM, women demonstrated a significant percent change in thickness of their TrA muscle compared with men (women, 0.77, and men, 0.29, P = .001). No significant difference was found between men and women in the percent change of IO thickness with ADM (women, 0.20, and men, 0.12, P = .24). There was excellent intrarater reliability for measurements of the right abdominal muscles (intraclass correlation coefficient = 0.92-0.95) and moderate-to-good intrarater reliability for measurements of the left abdominal muscles (intraclass correlation coefficient = 0.62-0.92).

CONCLUSIONS

Asymptomatic men have greater TrA and IO thickness at rest compared with asymptomatic women; however, women demonstrated a greater percent change in TrA thickness with an ADM compared with men.

Clinimetric analysis of pressure biofeedback and transversus abdominis function in individuals with stabilization classification low back pain

STUDY DESIGN

Descriptive laboratory study.

OBJECTIVE

To determine if a proposed clinical test (pressure biofeedback) could detect changes in transversus abdominis (TrA) muscle thickness during an abdominal drawing-in maneuver.

BACKGROUND

Pressure biofeedback may be used to assess abdominal muscle function and TrA activation during an abdominal drawing-in maneuver but has not been validated.

METHODS

Forty-nine individuals (18 men, 31 women) with low back pain who met stabilization classification criteria underwent ultrasound imaging to quantify changes in TrA muscle thickness while a pressure transducer was used to measure pelvic and spine position during an abdominal drawing-in maneuver. A paired t test was used to compare differences in TrA activation ratios between groups (able or unable to maintain pressure of 40 ± 5 mmHg). The groups were further dichotomized based on TrA activation ratio (high, greater than 1.5; low, less than 1.5). Sensitivity, specificity, and likelihood ratios were calculated.

RESULTS

There was not a significant difference (P = .57) in TrA activation ratios (able to maintain pressure, 1.59 ± 0.28; unable to maintain pressure, 1.54 ± 0.24) between groups. The pressure biofeedback test had low sensitivity of 0.22 (95% confidence interval [CI]: 0.10, 0.42) but moderate specificity of 0.77 (95% CI: 0.58, 0.89), a positive likelihood ratio of 0.94 (95% CI: 0.33, 2.68), and a negative likelihood ratio of 1.02 (95% CI: 0.75, 1.38).

CONCLUSION

Successful completion on pressure biofeedback does not indicate high TrA activation. Unsuccessful completion on pressure biofeedback may be more indicative of low TrA activation, but the correlation and likelihood coefficients indicate that the pressure test is likely of minimal value to detect TrA activation. This study was registered with ClinicalTrials.gov (NCT01015846).J Orthop Sports Phys Ther 2013;43(3):184-193. Epub 16 November 2012. doi:10.2519/jospt.2013.4397.

Quantitative sensory testing changes in the successful management of chronic low back pain

Individuals with chronic low back pain (LBP) represent a significant percentage of patients in physical therapy practice. The clinical pattern often includes diffuse pain and a variety of sensory complaints, making categorization difficult and leading to diagnoses such as non-specific LBP. Objective measures of sensory changes through quantitative sensory testing may help identify central sensitization of nociceptive pathways in this population. Identification of these somatosensory changes may contribute to clinical decision making and patient management. The purpose of this case report is to present objective evaluation findings, including altered somatosensation, in a patient with a 2-year history of LBP, and to describe changes in function and quantitative sensory testing with successful management.

Comparison of the sonographic features of the abdominal wall muscles and connective tissues in individuals with and without lumbopelvic pain

STUDY DESIGN

Cross-sectional, case-control study.

OBJECTIVES

To measure and compare the resting thickness of the 4 abdominal wall muscles, their associated perimuscular connective tissue (PMCT), and interrecti distance (IRD) in persons with and without lumbopelvic pain (LPP), using ultrasound imaging.

BACKGROUND

The muscles and PMCT of the abdominal wall assist in controlling the spine. Functional deficits of the abdominal wall muscles have been detected in populations with LPP. Investigations of the abdominal wall in those with LPP are primarily concerned with muscle, most commonly the transversus abdominis (TrA) and internal oblique (IO). Because the abdominal wall functions as a unit, all 4 abdominal muscles and their associated connective tissues should be considered concurrently.

METHODS

B-mode ultrasound imaging was used to measure the resting thickness of the rectus abdominis (RA), external oblique, IO, and TrA muscles; the PMCT planes; and IRD in 50 male and female subjects, 25 with and 25 without LPP (mean ± SD age, 36.3 ± 9.4 and 46.6 ± 8.0 years, respectively). Univariate correlation analysis was used to identify covariates. Analyses of covariance (ANCOVAs) and the Kruskal-Wallis test (IRD) were used to compare cohorts (α = .05).

RESULTS

The LPP cohort had less total abdominal muscle thickness (LPP mean ± SD, 18.9 ± 3.0 mm; control, 20.3 ± 3.0 mm; ANCOVA adjusted for body mass index, P = .03), thicker PMCT (LPP, 5.5 ± 0.2 mm; control, 4.3 ± 0.2 mm; ANCOVA adjusted for body mass index, P = .007), and wider IRD (LPP, 11.5 ± 2.0 mm; control, 8.4 ± 1.8 mm; Kruskal-Wallis, P = .005). Analysis of individual muscle thickness revealed no difference in the external oblique, IO, and TrA, but a thinner RA in the LPP cohort (LPP mean ± SD, 7.8 ± 1.5 mm; control, 9.1 ± 1.2 mm; ANCOVA adjusted for body mass index, P<.001).

CONCLUSION

To our knowledge, this is the first study to investigate the morphological characteristics of all 4 abdominal muscles and PMCT in individuals with LPP. The results suggest that there may be altered loading of the PMCT and linea alba secondary to an altered motor control strategy involving a reduced contribution of the RA. Further, the change in RA and connective tissue morphology may be more evident than changes in external oblique, IO, and TrA thickness in persons with LPP. The causes and functional implications of these changes warrant further investigation, as does the role of the RA muscle in the development and persistence of LPP.

Test-retest and intrarater reliability of 2-dimensional ultrasound measurements of distance between rectus abdominis in women

STUDY DESIGN

Single-group test-retest reliability study.

OBJECTIVES

To evaluate the test-retest intraobserver reliability of 2-dimensional ultrasound measurement of the distance between the rectus abdominis muscles, the interrectus distance (IRD).

BACKGROUND

Diastasis recti is defined as the separation of the 2 rectus abdominis muscles, with a reported prevalence of between 30% and 70% in women during pregnancy and in the postpartum period. The condition is difficult to measure, and ultrasound imaging has been suggested as a useful method to quantify the diastasis. However, to date, no studies have investigated intratester or intertester reliability of ultrasound to measure the distance between the rectus abdominis muscles during rest and contraction.

METHODS

Ultrasound images from the rectus abdominis were recorded in 24 healthy female volunteers at rest and under 2 conditions of abdominal contraction: abdominal crunch and drawing-in exercises. The probe was positioned at 2 locations: below and above the umbilicus. A blinded investigator measured the IRD offline from 2 different ultrasound images collected on 2 different days (test-retest). Additionally, reanalyses of the same ultrasound images were done on 2 separate occasions (intra-image).

RESULTS

Test-retest measurements of IRD demonstrated good to very good reliability, with intraclass correlation coefficient values between 0.74 and 0.90. The only exception was for IRD measured 2 cm below the umbilicus during the abdominal crunch exercise, which had an intraclass correlation coefficient of 0.50. For intratester reliability of the same images, the intraclass correlation coefficient values were all above 0.90.

CONCLUSION

Ultrasound imaging is a reliable method for measuring the IRD at rest and during abdominal crunch and drawing-in exercises.

Effects of muscular stretching and segmental stabilization on functional disability and pain in patients with chronic low back pain: a randomized, controlled trial

OBJECTIVE

The purpose of this study was to compare the effects of 2 exercise programs, segmental stabilization exercises (SSEs) and stretching of trunk and hamstrings muscles, on functional disability, pain, and activation of the transversus abdominis muscle (TrA), in individuals with chronic low back pain.

METHODS

A total of 30 participants were enrolled in this study and randomly assigned to 1 of 2 groups as a function of intervention. In the segmental stabilization group (SS), exercises focused on the TrA and lumbar multifidus muscles, whereas in the stretching group (ST), exercises focused on stretching the erector spinae, hamstrings, and triceps surae. Severity of pain (visual analog scale and McGill pain questionnaire) and functional disability (Oswestry disability questionnaire) and TrA muscle activation capacity (Pressure Biofeedback Unit, or PBU) were compared as a function of intervention. Interventions lasted 6 weeks, and sessions happened twice a week (30 minutes each). Analysis of variance was used for intergroup and intragroup comparisons.

RESULTS

As compared with baseline, both treatments were effective in relieving pain and improving disability (P < .001). Those in the SS group had significantly higher gains for all variables. The stretching group did not effectively activate the TrA (P = .94).

CONCLUSION

Both techniques improved pain and reduced disability. In this study, SS was superior to muscular stretching for the measured variables associated with chronic low back pain.

Cocontraction of ankle dorsiflexors and transversus abdominis function in patients with low back pain

CONTEXT

The abdominal draw-in maneuver (ADIM) with cocontraction has been shown to be a more effective method of activating the transversus abdominis (TrA) in healthy adults than the ADIM alone. Whether such an augmented core stabilization exercise is effective in managing low back pain (LBP) remains uncertain.

OBJECTIVE

To determine the effect of 2 weeks of ADIM and cocontraction training on abdominal muscle thickness and activation timing and to monitor pain and function in patients with LBP.

DESIGN

Case-control study.

SETTING

Local orthopaedic clinic and research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty patients with mechanical LBP (age = 27.20 ± 6.46 years, height = 166.25 ± 8.70 cm, mass = 58.10 ± 11.81 kg) and 20 healthy, age-matched people (age = 24.25 ± 1.59 years, height = 168.00 ± 8.89 cm, mass = 60.65 ± 11.99 kg) volunteered for the study.

INTERVENTION(S)

Both the LBP and control groups received ten 30-minute sessions of ADIM and cocontraction training of the tibialis anterior (TA) and rectus femoris (RF) muscles over a 2-week period.

MAIN OUTCOME MEASURE(S)

A separate, mixed-model analysis of variance was computed for the thicknesses of the TrA, internal oblique (IO), and external oblique muscles. The differences in mean and peak electromyographic (EMG) amplitudes, onset time, and latency were compared between the groups. The visual analog pain scale, Pain Disability Index, and LBP rating scale were used to assess pain in the LBP group before and after the intervention.

RESULTS

We found an interaction between the LBP and control groups and a main effect from pretest to posttest for only TrA muscle thickness change (F₁,₃₈ = 6.57, P = .01). Reductions in all pain measures were observed after training (P < .05). Group differences in peak and mean EMG amplitudes and onset time values for TrA/IO and TA were achieved (P < .05). The RF peak (t₃₈ = 3.12, P = .003) and mean (t₃₈ = 4.12, P = .001) EMG amplitudes were different, but no group difference was observed in RF onset time (t₃₈ = 1.63, P = .11) or the cocontracted TrA/IO peak (t₃₈ = 1.90, P = .07) and mean (t₃₈ = 1.81, P = .08). The test-retest reliability for the muscle thickness measure revealed excellent correlations (intraclass correlation coefficient range, 0.95-0.99).

CONCLUSIONS

We are the first to demonstrate that a cocontraction of the ankle dorsiflexors with ADIM training might result in a thickness change in the TrA muscle and associated pain management in patients with chronic LBP.

Low impact weight-bearing exercise in an upright posture increases the activation of two key local muscles of the lumbo-pelvic region

To date, a range of exercises have been used to improve the function of the lumbar multifidus (LM) and transversus abdominis (TrA) muscles in people with low back pain, but uncertainty remains as to what exactly constitutes meaningful LM and TrA training. We examined the effects of exercising with a new device which combines weight-bearing, an unstable base of support (BOS) (feet), an upright posture with a relatively stable lumbo-pelvic area, and functional lower limb movement, with the aim of exploring which of these elements may be effective, in increasing LM and TrA muscle activity. Twelve non-symptomatic participants had ultrasound images taken of their LM and TrA during a range of conditions, including rest, traditional exercise approaches to LM and TrA recruitment, and exercising on the new device. Our results indicate that an unstable BOS on its own is not enough to increase LM and TrA activity, and that a combination of weight-bearing, an unstable BOS (feet), an upright posture with a relatively stable lumbo-pelvic area, and functional lower limb movement is most effective at increasing LM and TrA activity. This way of exercising appears to recruit LM more effectively than the widely used "swelling" of LM, and to cause automatic TrA and LM recruitment. Importantly, our findings also indicate LM and TrA may have slightly different roles during trunk stabilisation.

Spine stabilisation exercises in the treatment of chronic low back pain: a good clinical outcome is not associated with improved abdominal muscle function

INTRODUCTION

Various studies have shown that spine stabilisation exercise therapy elicits improvements in symptoms/disability in patients with chronic non-specific low back pain (cLBP). However, few have corroborated the intended mechanism of action by examining whether clinical improvements (1) are greater in patients with functional deficits of the targeted muscles and (2) correlate with post-treatment improvements in abdominal muscle function.

METHODS

Pre and directly after 9 weeks' therapy, 32 cLBP patients (44.0 ± 12.3 years) rated their LBP intensity (0-10) and disability (0-24, Roland-Morris; RM) and completed psychological questionnaires. At the same timepoints, the voluntary activation of transversus abdominis (TrA), obliquus internus and obliquus externus during "abdominal-hollowing" and the anticipatory ("feedforward") activation of these muscles during rapid arm movements were measured using M-mode ultrasound with tissue Doppler imaging.

RESULTS

Pre-therapy to post-therapy, RM decreased from 8.9 ± 4.7 to 6.7 ± 4.3, and average pain, from 4.7 ± 1.7 to 3.5 ± 2.3 (each P < 0.01). The ability to voluntarily activate TrA increased by 4.5% (P = 0.045) whilst the anticipatory activation of the lateral abdominal muscles showed no significant change (P > 0.05). There was no significant correlation between the change in RM scores after therapy and either baseline values for voluntary (r = 0.24, P = 0.20) or anticipatory activation (r = 0.04, P = 0.84), or their changes after therapy (voluntary, r = 0.08, P = 0.66; anticipatory, r = 0.16, P = 0.40). In multiple regression, only a reduction in catastrophising (P = 0.0003) and in fingertip-floor distance (P = 0.0006) made unique contributions to explaining the variance in the reduction in RM scores.

CONCLUSION

Neither baseline lateral abdominal muscle function nor its improvement after a programme of stabilisation exercises was a statistical predictor of a good clinical outcome. It is hence difficult to attribute the therapeutic result to any specific effects of the exercises on these trunk muscles. The association between changes in catastrophising and outcome serves to encourage further investigation on larger groups of patients to clarify whether stabilisation exercises have some sort of "central" effect, unrelated to abdominal muscle function per se.

Abdominal and lumbar multifidus muscle size and symmetry at rest and during contracted States. Normative reference ranges

OBJECTIVES

The purpose of this study was to establish reference values for abdominal and lumbar multifidus muscles at rest and while contracted in a sample of active healthy adults.

METHODS

Three hundred forty participants (mean age ± SD, 21.8 ± 3.9 years; 96 females and 244 males) completed the study. Ultrasound imaging was used to assess the thickness of the transversus abdominis, internal and external oblique, rectus abdominis, and lumbar multifidus muscles. Additionally, the cross-sectional area of the rectus abdominis was assessed.

RESULTS

Although males had significantly thicker muscles than females (P < .05), the relative change in thickness during specified tasks was equivalent. Overall, relative muscle thickness and symmetry were similar to previous studies using smaller sample sizes.

CONCLUSIONS

These findings provide a robust data set of muscle thickness values measured by ultrasound imaging and can be used for comparison to those with pain, abnormal function, and pathologic conditions.

Continued recovery in an adult with cerebellar ataxia

BACKGROUND AND PURPOSE

The authors previously reported on the functional recovery of an adult with chronic, severe ataxia secondary to traumatic brain injury (TBI) after 28 sessions of trunk stabilization and locomotor training (LT). The purpose of this case report is to describe this individual's functional abilities 3.5 years after the intervention.

CASE DESCRIPTION

Thirteen months post-TBI and not expected to be a functional ambulator, an adult male participated in a trunk stabilization and LT intervention. After the intervention, he continued to exercise in a hospital-based fitness program and received additional physical therapy. Evaluation of balance, gait, trunk performance, self-reported function, and quality of life was performed at 6 weeks (baseline), 1 year, and 3.5 years after completing the intervention.

OUTCOMES

Balance, gait, and function improved. Resting left transverse abdominis thickness, measured using ultrasound imaging, increased as did left-side bridge and trunk flexion endurance. He increased community participation and expressed general satisfaction with his overall quality of life.

DISCUSSION AND CONCLUSION

In the 3.5 years after participation in an intervention of trunk stabilization and LT this adult became an independent limited community ambulator. Persons with severe ataxia secondary to TBI may continue to improve many years after injury.

Strengthening transversus abdominis in pregnancy related pelvic pain: the pressure biofeedback stabilization training

Pregnancy related pelvic pain (PRPP) refers to musculoskeletal type of persistent posterior pelvic pain during and after pregnancy with feature of reduced endurance capacity for standing, walking and sitting which leads to severe discomfort and considerable impairment of daily activities.

Changes in lateral abdominal muscle thickness during an abdominal drawing-in maneuver in individuals with and without low back pain

The purpose of this study was to compare lateral abdominal muscle thickness changes in individuals with and without low back pain (LBP) during an abdominal drawing-in maneuver (ADIM) using ultrasound imaging. Twenty individuals (13 females and 7 males, average age 40.1 ± 13.4) with stabilization classification LBP and 19 controls (10 females and 9 males, average age 30.3 ± 8.7) participated in this study. Bilateral measurements were made using ultrasound imaging to determine changes in thickness of the transversus abdominus (TrA) and external and internal oblique (EO+IO) muscles during an ADIM. There were no significant differences in relaxed muscle thickness values or contraction ratios for the TrA or EO+IO between groups or side. Individuals with stabilization classification LBP demonstrated no difference in lateral abdominal muscle thickness during an ADIM when compared with controls without LBP when using a pressure biofeedback device to monitor stability.

Reliability of real-time ultrasound measurement of transversus abdominis thickness in healthy trained subjects

PURPOSE

To investigate intra- and inter-rater reliability of the ultrasound measurement of transversus abdominis (TrA) thickness and thickness change (difference between thickness at rest and during contraction) in asymptomatic, trained subjects. To define the number of repeated measurements that provide acceptable level of reliability. To investigate variability of the measurements over time of 5 days and the reliability of duplicate analysis of images.

METHODS

A single-group repeated-measures design was used to assess reliability. Healthy volunteers (n = 10) were subjected to 1-week training in voluntary activation of TrA. Real-time ultrasound imaging and subsequent measurement of the TrA thickness at rest and during voluntary contraction were repeated on Monday, Wednesday and Friday of the next week.

RESULTS

Using a single repeated measurement, intraclass correlation coefficients (ICCs) for TrA thickness were: 0.86-0.95 (intra-rater), 0.86-0.92 (inter-rater); and for TrA thickness change: 0.34-0.56 (intra-rater), 0.47-0.61 (inter-rater). Using the mean of three repeated measurements respective values were: 0.97, 0.96-0.98; and 0.81-0.84, 0.80-0.90. No significant differences were found between mean values of TrA thickness as well as thickness change obtained on three consecutive measurement days. Duplicate analysis of the images was highly reliable with ICCs of 0.89-0.99.

CONCLUSIONS

Two repeated measurements for TrA thickness and at least three measurements for TrA thickness change are needed to achieve acceptable levels of intra- and inter-rater reliability. In healthy trained volunteers TrA thickness and thickness change are relatively stable parameters over a 5-day period. Duplicate analysis of the same images by two blinded observers is reliable.

Investigation of abdominal muscle thickness changes after spinal manipulation in patients who meet a clinical prediction rule for lumbar stabilization

STUDY DESIGN

Prospective case series.

OBJECTIVES

To investigate changes in abdominal muscle thickness with ultrasound imaging, after spinal manipulative therapy (SMT), in a subgroup of patients with low back pain (LBP) who meet a proposed clinical prediction rule for lumbar stabilization exercise (LSE).

BACKGROUND

The characteristics of a subgroup of patients with LBP who respond clinically to LSE has been proposed. Although the pathoanatomical characteristics of this subgroup have not been determined, clinicians often assume that this type of LBP is related, in part, to neuromuscular deficits of the lateral abdominal muscles. Recent evidence suggests that SMT may facilitate abdominal muscle activity and, therefore, enhance exercises targeting these deficits.

METHODS

Nineteen patients (mean age ± SD, 32.5 ± 7.8 years; 11 female) with LBP, who met the criteria for LSE, underwent ultrasound imaging of the transversus abdominis (TrA) and internal oblique (IO) muscles before, immediately after, and 3 to 4 days after lumbopelvic SMT. Measurements of resting thickness, contracted thickness during the abdominal drawing-in maneuver, and percent thickness change from rest to contraction of the TrA and IO muscles were analyzed with repeated-measures analysis of variance. Numeric pain rating scale and Oswestry Disability Index data were also collected.

RESULTS

No significant differences in resting, contracted, or percent thickness change in the TrA or IO were found over the 3 time periods. There were statistically significant reductions in numeric pain rating scale and Oswestry Disability Index scores, but mean differences failed to meet the minimal clinically important difference.

CONCLUSION

The results provide preliminary evidence that TrA and IO muscle resting and contracted thicknesses do not change post-SMT in patients with LBP in the LSE subgroup. In addition, while reductions in pain and disability were noted, they were not clinically meaningful.

Effects of the abdominal drawing-in maneuver on muscle activity, pelvic motions, and knee flexion during active prone knee flexion in patients with lumbar extension rotation syndrome

OBJECTIVE

To investigate the effects of performing an abdominal drawing-in maneuver (ADIM) during active prone knee flexion on the hamstrings and erector spinae muscle activity, the amounts of pelvic motion and knee flexion, and onset of pelvic movements.

DESIGN

Comparative, repeated-measures study.

SETTING

University research laboratory.

PARTICIPANTS

Men patients (N=18) with lumbar extension rotation syndrome.

INTERVENTION

Subjects performed prone knee flexion in 2 conditions.

MAIN OUTCOME MEASURES

To measure muscle activity, surface electromyogram (EMG) of both erector spinae and the medial and lateral hamstrings was performed. Kinematic data on the pelvic motion and knee flexion were measured using a 3-dimensional motion analysis system. Repeated 1-way analysis of variance was used for the statistical analysis.

RESULTS

Significantly decreased electromyographic activity in the right and left erector spinae and significantly increased electromyographic activity in the medial and lateral hamstrings activity were shown during prone knee flexion in ADIM condition using the pressure biofeedback unit. In addition, the amounts of anterior pelvic tilt, pelvic rotation, knee flexion, and perceived pain decreased significantly during prone knee flexion in the ADIM condition compared with the same maneuver in the non-ADIM condition. The onset of anterior pelvic tilt and pelvic rotation occurred significantly earlier in the non-ADIM condition, compared with the ADIM condition.

CONCLUSIONS

ADIM effectively increased activation of knee flexors, decreased activation of back extensors, and reduced the pelvic motions and low back pain during prone knee flexion in patients with lumbar extension rotation syndrome.

A mechano-acoustic indentor system for in vivo measurement of nonlinear elastic properties of soft tissue

OBJECTIVES

Soft tissue exhibits nonlinear stress-strain behavior under compression. Characterizing its nonlinear elasticity may aid detection, diagnosis, and treatment of soft tissue abnormality. The purposes of this study were to develop a rate-controlled Mechano-Acoustic Indentor System and a corresponding finite element optimization method to extract nonlinear elastic parameters of soft tissue and evaluate its test-retest reliability.

METHODS

An indentor system using a linear actuator to drive a force-sensitive probe with a tip-mounted ultrasound transducer was developed. Twenty independent sites at the upper lateral quadrant of the buttock from 11 asymptomatic subjects (7 men and 4 women from a chiropractic college) were indented at 6% per second for 3 sessions, each consisting of 5 trials. Tissue thickness, force at 25% deformation, and area under the load-deformation curve from 0% to 25% deformation were calculated. Optimized hyperelastic parameters of the soft tissue were calculated with a finite element model using a first-order Ogden material model. Load-deformation response on a standardized block was then simulated, and the corresponding area and force parameters were calculated. Between-trials repeatability and test-retest reliability of each parameter were evaluated using coefficients of variation and intraclass correlation coefficients, respectively.

RESULTS

Load-deformation responses were highly reproducible under repeated measurements. Coefficients of variation of tissue thickness, area under the load-deformation curve from 0% to 25% deformation, and force at 25% deformation averaged 0.51%, 2.31%, and 2.23%, respectively. Intraclass correlation coefficients ranged between 0.959 and 0.999, indicating excellent test-retest reliability.

CONCLUSIONS

The automated Mechano-Acoustic Indentor System and its corresponding optimization technique offers a viable technology to make in vivo measurement of the nonlinear elastic properties of soft tissue. This technology showed excellent between-trials repeatability and test-retest reliability with potential to quantify the effects of a wide variety of manual therapy techniques on the soft tissue elastic properties.

The relationship of transversus abdominis and lumbar multifidus clinical muscle tests in patients with chronic low back pain

INTRODUCTION

Previous research of transversus abdominis (TrA) and multifidus muscle function in the presence of chronic low back pain (LBP) has investigated these muscles in isolation. In clinical practice, it is assumed that a relationship exists between these muscles and so they are often assessed and rehabilitated together. However, no studies have tested or documented this association. This study aimed to examine the relationships between clinical muscle testing and other measures taken in the course of a clinical assessment at a back clinic.

METHODS

This retrospective chart audit examined the files of 82 patients (40 Males, 42 Females) for results of clinical tests of TrA and multifidus muscle contraction, multifidus muscle size measurements and other clinical measures such as distribution of pain and pain on manual examination.

RESULTS

The ability to contract multifidus was related to the ability to contract TrA with the odds of a good contraction of multifidus being 4.5 times higher for patients who had a good contraction of TrA. A poor ability to contract multifidus was related to poor TrA contraction. Patients with unilateral LBP had more multifidus muscle asymmetry (11.6%) than those with bilateral/central pain (0.01%) and had a poor multifidus contraction on the affected side (p < 0.01). No other significant relationships were found.

DISCUSSION & CONCLUSION

Current clinical practice of assessment and rehabilitation of both TrA and multifidus muscles in patients with chronic LBP is supported by the findings of this study. Future studies may investigate if a neurophysiological relationship exists between these muscles.

Association between changes in abdominal and lumbar multifidus muscle thickness and clinical improvement after spinal manipulation

STUDY DESIGN

Prospective case series.

OBJECTIVE

To examine the relation between improved disability and changes in abdominal and lumbar multifidus (LM) thickness using ultrasound imaging following spinal manipulative therapy (SMT) in patients with low back pain (LBP).

BACKGROUND

Although there is a growing body of literature demonstrating physiologic effects following the application of SMT, few studies have attempted to correlate these changes with clinically relevant outcomes.

METHODS

Eighty-one participants with LBP underwent 2 thrust SMT treatments and 3 assessment sessions within 1 week. Transversus abdominis (TrA), internal oblique (IO), and LM muscle thickness was assessed during each session, using ultrasound imaging of the muscles at rest and during submaximal contractions. The Modified Oswestry Disability Index was used to quantify participants' improvement in LBP-related disability. Stepwise hierarchical multiple linear regression and repeated-measures analysis of variance were performed to examine the multivariate relationship between change in muscle thickness and clinical improvement over time.

RESULTS

After controlling for the effects of age, sex, and body mass index, change in contracted LM muscle thickness was predictive of improved disability at 1 week (P = .02). As expected, larger increases in contracted LM muscle thickness at 1 week were associated with larger improvements in LBP-related disability. Contrary to our hypothesis, significant decreases in both contracted TrA and IO muscle thickness were observed immediately following SMT; but these changes were transient and unrelated to whether participants experienced clinical improvements.

CONCLUSION

These findings provide evidence that clinical improvement following SMT is associated with increased thickening of the LM muscle during a submaximal task.

LEVEL OF EVIDENCE

Prognosis, level 4.

Ultrasound assessment of transversus abdominis muscle contraction ratio during abdominal hollowing: a useful tool to distinguish between patients with chronic low back pain and healthy controls?

Spine stabilisation exercises, in which patients are taught to preferentially activate the transversus abdominus (TrA) during "abdominal hollowing" (AH), are a popular treatment for chronic low back pain (cLBP). The present study investigated whether performance during AH differed between cLBP patients and controls to an extent that would render it useful diagnostic tool. 50 patients with cLBP (46.3 ± 12.5 years) and 50 healthy controls (43.6 ± 12.7 years) participated in this case-control study. They performed AH in hook-lying. Using M-mode ultrasound, thicknesses of TrA, and obliquus internus and externus were determined at rest and during 5 s AH (5 measures each body side). The TrA contraction-ratio (TrA-CR) (TrA contracted/rest) and the ability to sustain the contraction [standard deviation (SD) of TrA thickness during the stable phase of the hold] were investigated. There were no significant group differences for the absolute muscle thicknesses at rest or during AH, or for the SD of TrA thickness. There was a small but significant difference between the groups for TrA-CR: cLBP 1.35 ± 0.14, controls 1.44 ± 0.24 (p < 0.05). However, Receiver Operator Characteristics (ROC) analysis revealed a poor and non-significant ability of TrA-CR to discriminate between cLBP patients and controls on an individual basis (ROC area under the curve, 0.60 [95% CI 0.495; 0.695], p = 0.08). In the patient group, TrA-CR showed a low but significant correlation with Roland Morris score (Spearman Rho = 0.328; p = 0.02). In conclusion, the difference in group mean values for TrA-CR was small and of uncertain clinical relevance. Moreover, TrA-CR showed a poor ability to discriminate between control and cLBP subjects on an individual basis. We conclude that the TrA-CR during abdominal hollowing does not distinguish well between patients with chronic low back pain and healthy controls.

Discriminative and reliability analyses of ultrasound measurement of abdominal muscles recruitment

Rehabilitative ultrasound imaging has a great potential to be used as a tool in the assessment of trunk muscle function in patients with low back pain (LBP). However, a further investigation of the discriminative ability of this tool as well as the effect of operators' levels of training on reliability is warranted. Discriminative analysis of ultrasound and electromyography (EMG) measurements of transversus abdominus (TrA), obliquus internus (OI), and obliquus externus (OE) muscles function between people with and without LBP and the effect of operator's training on reliability of TrA muscle function of chronic LBP patients were conducted. For the discriminative study, measurements were collected from 10 subjects with LBP and 10 matched controls during isometric low load tasks with their limbs suspended. For the reliability study, in stage 1 the reliability of single ultrasonographic static images involved 4 operators (1 trained and 3 non-trained), whereas, in stage 2, two operators (1 trained and 1 non-trained) were used to determine the reliability of TrA thickness change. Methods used in the statistical analysis were pearson correlation and receiver operating characteristic curve for the discriminative study and intraclass correlation coefficient (ICC) for the reliability study. While ultrasound measures of OE muscle function showed poor association with EMG (r = 0.28, p = 0.22), TrA and OI function showed moderate to excellent association (TrA: r = 0.74, p < 0.000; OI: r = 0.85, p < 0.000). Ultrasound and EMG measures of TrA and OI function discriminated LBP patients from controls. Reliability of the assessment of TrA function with a trained operator (ICC = 0.92; 95% CI: 0.81-0.97) was substantially higher than a non-trained one (ICC = 0.44; 95% CI: -0.41-0.78). In conclusion, ultrasound measures of deep trunk function is a valid discriminative tool in LBP but highly dependent on operator's level of training.

Inter-rater reliability of ultrasound imaging of the trunk musculature among novice raters

OBJECTIVE

The purpose of this study was to determine the inter-rater reliability of ultrasound imaging for assessing trunk muscle morphologic characteristics at rest and while contracted among different pairs of novice raters. The secondary purpose was to compare 3 different measurement techniques for assessing lateral abdominal muscle thickness.

METHODS

A single-group repeated measures reliability study was conducted on 21 healthy participants (mean ± SD, 21.5 ± 4.4 years; 5 female and 16 male) without low back pain. Ultrasound images of the transversus abdominis, internal oblique, rectus abdominis, and lumbar multifidus muscles were obtained by different pairs of novice raters in a counterbalanced order. All raters received a standardized training program before obtaining measurements.

RESULTS

The intraclass correlation coefficient (1, 3) point estimates ranged from 0.86 to 0.94; the standard error of the measurement ranged from 0.04 to 0.16 cm for the thickness values and 0.67 cm(2) for the cross-sectional area of the rectus abdominis muscle. There was no meaningful difference between the different measurement techniques used to analyze the lateral abdominal muscles.

CONCLUSIONS

Good to excellent reliability was obtained for all measures by novice raters. Minimal differences in reliability were noted between the different measurement techniques to assess lateral abdominal muscle thickness.

A rationale for the provision of extrinsic feedback towards management of low back pain

Low back pain (LBP) is associated with dysfunction of global and local muscle systems, feedback and feedforward postural control mechanisms. Physiotherapists include the use of feedback as part of treatment protocols. Such feedback can focus on a variety of neuromuscular impairments, although the literature related to feedback on the management of LBP has focused mainly on local muscle system impairments. Furthermore, there are various characteristics of feedback that can lead to motor control enhancement or deterioration. The aim of this manuscript is to present a rationale for feedback provision as a rehabilitation tool on the management of LBP. Feedback provision should focus on the main neuromuscular impairment presented by the patient. The suggested rationale describes decision-making stages for the use and progress of feedback interventions. Local muscle system impairment might benefit more from parameter feedback provision, while global muscle system and feedback mechanism impairments may benefit better from program feedback. The described rationale has the potential to help clinicians select the appropriate feedback for the treatment of their patients. Additionally, the presented rationale could be used by researchers to assess how different forms of feedback provision impact on clinical outcomes.

The effect of food consumption on the thickness of abdominal muscles, employing ultrasound measurements

Recently, the roles of transabdominal muscles particularly TrA (transverse abdominis) muscle in spinal stability leading to treatment of low back pain have been suggested. Both in clinical setting and follow up studies, abdominal muscle thickness measurements need to be repeated at a later point in time to demonstrate efficacy of a therapeutic intervention. Different issues have been suggested as source of error in the repeated measurements of abdominal muscle thickness in different days such as patient position and stability of probe location. The level of stomach fullness has not been investigated as a source of error in ultrasonic measurements of transabdominal muscles thickness. This study was performed to evaluate the effect of food consumption on thickness of lateral abdominal muscles. Lateral abdominal muscles thicknesses of 63 healthy volunteer men were measured before and after food consumption. All the measurements were performed in two transducer positions and both sides. Waist circumference and body weight of participants were also measured before and post-food consumption. The thickness measures of all three muscles layers of lateral abdominal muscles (external oblique, internal oblique and transversus abdominis) in both sides and measured positions were significantly reduced after food consumption. We found no correlation between the increase of waist circumference and reduction of muscle layer thicknesses after food consumption. In case of comparison between the values of transabdominal muscle thicknesses over the time, the effect of food consumption on muscle thickness might be assumed as a potential source of error.

Extrinsic feedback and management of low back pain: A critical review of the literature

Effective intervention for low back pain (LBP) can include feedback in one form or other. Although extrinsic feedback (EF) can be provided in a number of ways, most research has not considered how different EF characteristics (e.g. timing and content) influence treatment outcomes. A systematic search related to feedback and LBP was performed on relevant electronic databases. This narrative review aims to describe the forms of feedback provision in the literature regarding management of LBP, and to discuss these in light of previously recommended principles for the use of extrinsic feedback. The present review found support for the provision of EF that focuses on content characteristics including program feedback, summary results feedback, and external focus of attention. Temporal characteristics should enhance the use of intermittent or self-selected feedback. The literature does not support the provision of concurrent or constant EF. As much of the literature related to EF in the management of LBP has not considered content and timing characteristics we have identified future research directions that will clarify the use of content and timing characteristics of EF relative to the management of LBP.

Immediate effects of lumbar spine manipulation on the resting and contraction thickness of transversus abdominis in asymptomatic individuals

STUDY DESIGN

Randomized, blinded, controlled crossover trial.

OBJECTIVE

To determine if thrust joint manipulation (TJM) to the lumbar spine would result in changes to the resting and contraction thickness of transversus abdominis (TrA) in healthy individuals.

BACKGROUND

Recent studies have demonstrated an immediate decrease in resting thickness and an increase in contraction thickness in TrA following lumbar TJM in patients with low back pain (LBP) who met a clinical prediction rule (CPR) for spinal manipulation. This observed phenomenon has not been investigated in healthy individuals.

METHODS

Thirty-five healthy participants were randomly assigned to receive a TJM or sham manipulation treatment. All participants received instruction on how to produce an isolated concentric contraction of the TrA that involved visual ultrasound imaging biofeedback. Data were analyzed using ultrasound imaging to measure changes in thickness of the TrA at rest and during contraction, following the administration of each treatment.

RESULTS

There were no interactions observed between treatment and time for TrA muscle thickness at rest (P = .351) and during the contracted state (P = .761).

CONCLUSION

Our results indicate that TJM to the lumbar spine does not appear to affect the resting or contraction thickness of TrA in healthy individuals. These findings are in contrast to previous research in which patients with LBP who met a CPR demonstrated an immediate decrease in resting thickness and an increase in contraction thickness in TrA following lumbar TJM.

Reliability and relationship between 2 measurements of transversus abdominis dimension taken during an abdominal drawing-in maneuver using a novel approach of ultrasound imaging

STUDY DESIGN

Reliability study of clinical measurement.

OBJECTIVES

The primary purpose was to develop a reliable method for measuring muscle length changes of the transversus abdominis (TrA) during contraction. The secondary purpose was to investigate the relationship between changes in thickness and length (as indicated by the lateral sliding of the anterior muscle-fascia junction) of the TrA muscle during an abdominal drawing-in maneuver. We also provide data on between-day reliability of change in thickness (ΔT) of the TrA.

BACKGROUND

Ultrasound imaging measurements of TrA thickness at rest (Thr) and during maximal contraction (Thm) have been shown to be reliable. However, limited data exist on quantifying changes in TrA length (as indicated by the lateral sliding of the muscle-fascia junction [Δx]) and ΔT during contraction.

METHODS

Eighteen healthy adults (mean ± SD age, 22.6 ± 2.5 years) participated in this study. Brightness mode ultrasound images of the TrA were collected at rest and during an abdominal drawing-in maneuver. Subjects were examined by the same examiner twice within a 48-hour period. ΔT, ΔT/Thr, Thr, Thm, and Δx of the TrA were calculated. Medial-lateral movement of the transducer during measurement was corrected through a custom-written program that used an internal marker created by an echo-absorptive thread attached to the skin. Intraclass correlation coefficients (ICC3,1), within-subject coefficient of variance, and standard error of measurement were calculated. The relationship between ΔT and adjusted Δx of the TrA muscle was investigated.

RESULTS

The ICC values for Thr, Thm, and ΔT of the TrA muscle were greater than 0.75, with the exception of the left ΔT (0.62) and left ΔT/Thr (0.49). After adjusting for medial-lateral motion of the transducer, the ICC values of adjusted Δx were above 0.75, and the within-subject coefficient of variance was below 10%. There was no significant correlation between ΔT and adjusted Δx of the TrA.

CONCLUSION

Ultrasound imaging measurements of TrA thickness and length change were shown to be reliable using a novel method to control for medial-lateral transducer motion. Measuring different but unrelated dimensional changes in the TrA might provide further insight as to the function of the TrA.

No Difference in Transverse Abdominis Activation Ratio between Healthy and Asymptomatic Low Back Pain Patients during Therapeutic Exercise

Dysfunction of the transverse abdominis (TrA) has been associated with LBP. Several therapeutic exercises are prescribed to help target the TrA. Rehabilitative ultrasound imaging (RUSI) is used to capture activation of the TrA during exercise. The purpose was to examine TrA activation during the ADIM and quadruped exercises between healthy and nonsymptomatic LBP patients. We instructed the subjects how to perform the exercises and measured muscle thickness of the TrA at rest and during the exercises using RUSI. This allowed us to calculate TrA activation ratio during these exercises. We found no significant differences between activation ratios of the two groups during either exercise; however TrA activation during the ADIM was higher than the quadruped exercise. These exercises were capable of activating the TrA, which may be in part due to the verbal instruction they received. These exercises could be used during prevention or rehabilitation programs, since the TrA is activated.

Ultrasound imaging transducer motion during clinical maneuvers: respiration, active straight leg raise test and abdominal drawing in

Clinical use of ultrasound imaging by physiotherapists is increasing; however, the clinical setting may be problematic due to variability inherent in the environment. As transducer motion interferes with accurate measurement, this study aimed to measure handheld transducer motion, relative to the pelvis, during a clinical simulation involving typical maneuvers employed in a physiotherapy assessment of the lumbopelvic region. Transducer motion about three axes and through one plane was measured (Vicon, Oxford, UK) on 12 participants during three clinical maneuvers at four abdominal imaging sites. Data were grouped and means used to determine discrepancies in transducer and pelvic motion for each imaging site/maneuver combination. None of the conditions produced large transducer motions relative to the pelvis and all findings were within previously established guidelines for acceptable amounts of transducer motion. These findings suggest that an ultrasound transducer can be held relatively stationary in a clinical setting, for the maneuvers tested.

Application of rehabilitative ultrasound in the assessment of low back pain: a literature review

Low back pain (LBP) is one of the most common work-related conditions affecting all populations both in industrialized and non-industrialized countries, with reported high prevalence and incidence rates and huge direct and indirect costs. Among various suggested causes of LBP, dysfunction of back muscles, particularly lumbar multifidus and transverse abdominis, has been the subject of considerable research during last decades. Of the available imaging techniques, ultrasound (US) imaging technique is increasingly used to assess muscle dimensions and function as a valid, reliable and non-invasive approach. The purpose of the present study was to review the previously published studies (1990-2009) concerning the merit of US imaging of lumbar and abdominal muscles with particular attention to its clinical application in patients with LBP. Studies showed wide variation in terms of methodology, sample size, procedure, definition of LBP, heterogeneous sample, method of analyzing US imaging, US imaging parameters, etc. However, a convincing body of evidence was identified that supports US imaging as a reliable and valid tool both to differentiate patients with LBP from normal subjects and to monitor the effect of rehabilitation programs.