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

Ultrasound Biofeedback Increases Abdominal Muscle Activation in Golfers With a History of Low Back Pain

OBJECTIVES

To compare activation ratios of the transverse abdominis (TrA) during an abdominal draw-in maneuver (ADIM) and abdominal obliques during a golf swing, with and without ultrasound biofeedback, and to determine intrarater reliability of these ultrasound thickness measures.

DESIGN

Single-session crossover study.

SETTING

Laboratory.

PARTICIPANTS

Sixteen adult golfers with 2 or more episodes of low back pain (LBP) in the past year.

INTERVENTIONS

Verbal cueing alone and verbal cueing with ultrasound biofeedback.

MAIN OUTCOME MEASURES

Bilateral TrA activation ratios were calculated during an ADIM with and without ultrasound biofeedback. Activation ratios of the abdominal obliques were calculated bilaterally during golf swings with and without ultrasound biofeedback. Intraclass correlation coefficients (ICCs) were calculated for average thickness across all muscles and conditions for the nonbiofeedback trials.

RESULTS

Transverse abdominis activation ratios were significantly higher when ultrasound biofeedback was provided bilaterally ( P < 0.001). Abdominal oblique activation ratios during the golf swing were also significantly higher with ultrasound biofeedback for the lead ( P = 0.014) and trail ( P < 0.001) sides. Intraclass correlation coefficient values ranged from 0.92 to 0.97 ( P < 0.001).

CONCLUSIONS

Ultrasound biofeedback can increase activation ratios of the TrA during a supine ADIM in adult golfers with a history of LBP. Postswing ultrasound biofeedback increases activation of the abdominal obliques during a golf swing in golfers with a history of LBP. Ultrasound thickness measures of the TrA and obliques have excellent intrarater reliability.

Contraction assessment of abdominal muscles using automated segmentation designed for wearable ultrasound applications

PURPOSE

Wearable ultrasound devices can be used to continuously monitor muscle activity. One possible application is to provide real-time feedback during physiotherapy, to show a patient whether an exercise is performed correctly. Algorithms which automatically analyze the data can be of importance to overcome the need for manual assessment and annotations and speed up evaluations especially when considering real-time video sequences. They even could be used to present feedback in an understandable manner to patients in a home-use scenario. The following work investigates three deep learning based segmentation approaches for abdominal muscles in ultrasound videos during a segmental stabilizing exercise. The segmentations are used to automatically classify the contraction state of the muscles.

METHODS

The first approach employs a simple 2D network, while the remaining two integrate the time information from the videos either via additional tracking or directly into the network architecture. The contraction state is determined by comparing measures such as muscle thickness and center of mass between rest and exercise. A retrospective analysis is conducted but also a real-time scenario is simulated, where classification is performed during exercise.

RESULTS

Using the proposed segmentation algorithms, 71% of the muscle states are classified correctly in the retrospective analysis in comparison to 90% accuracy with manual reference segmentation. For the real-time approach the majority of given feedback during exercise is correct when the retrospective analysis had come to the correct result, too.

CONCLUSION

Both retrospective and real-time analysis prove to be feasible. While no substantial differences between the algorithms were observed regarding classification, the networks incorporating the time information showed temporally more consistent segmentations. Limitations of the approaches as well as reasons for failing cases in segmentation, classification and real-time assessment are discussed and requirements regarding image quality and hardware design are derived.

A Comparison between Core Stability Exercises and Muscle Thickness Using Two Different Activation Maneuvers

Core stability training is crucial for competitive athletes, individuals who want to improve their health and physical performance, and those undergoing clinical rehabilitation. This study compared the ultrasound (US) muscle thickness of the abdominals and lumbar multifidus (LM) muscles between seven popular trunk stability exercises performed using hollowing and bracing maneuvers. Forty-four healthy young adults, aged between 21 and 32 years, performed a plank, bird dog, beast crawl, dead bug, Pilates tap, bridge, and side planks using the bracing and the hollowing maneuver. The thickness of the transversus abdominis (TrA), internal oblique (IO), and LM muscles was measured simultaneously using two ultrasound machines. Analysis of variance designs indicated that during hollowing, the bird dog and side plank exercises resulted in the greatest increase in the muscle's relative thickness overall. The relative thickness of all muscles was significantly greater (p < 0.001) during hollowing (22.7 ± 7.80 to 106 ± 24.5% of rest) compared to bracing (18.7 ± 7.40 to 87.1 ± 20.9% of rest). The TrA showed the greatest increase in thickness (p < 0.001) compared to the IO and LM. Additionally, the IO had a greater increase in thickness (p < 0.001) than the LM. In conclusion, our findings indicate that the bird dog and side plank exercises, when performed with hollowing, showed the most significant total muscle thickness increase. Notably, the hollowing maneuver enhances the thickness of the TrA, IO, and LM muscles more than the bracing maneuver. This contributes to the discussion on optimal strategies for dynamic core stabilization.

Innovations in the Assessment of Skeletal Muscle Health: A Glimpse into the Future

Skeletal muscle is the largest organ system in the human body and plays critical roles in athletic performance, mobility, and disease pathogenesis. Despite growing recognition of its importance by major health organizations, significant knowledge gaps remain regarding skeletal muscle health and its crosstalk with nearly every physiological system. Relevant public health challenges like pain, injury, obesity, and sarcopenia underscore the need to accurately assess skeletal muscle health and function. Feasible, non-invasive techniques that reliably evaluate metrics including muscle pain, dynamic structure, contractility, circulatory function, body composition, and emerging biomarkers are imperative to unraveling the complexities of skeletal muscle. Our concise review highlights innovative or overlooked approaches for comprehensively assessing skeletal muscle in vivo. We summarize recent advances in leveraging dynamic ultrasound imaging, muscle echogenicity, tensiomyography, blood flow restriction protocols, molecular techniques, body composition, and pain assessments to gain novel insight into muscle physiology from cellular to whole-body perspectives. Continued development of precise, non-invasive tools to investigate skeletal muscle are critical in informing impactful discoveries in exercise and rehabilitation science.

Lateral abdominal muscle thickness and contractile function in women with and without stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) primarily results from the weakness of pelvic floor muscles, working synergistically with the abdominal muscles. The current study aimed to compare thickness and contractile function of lateral abdominal muscles in women with and without SUI.

METHODS

Thirty-nine women with SUI (SUI group; age: 38.87 ± 8.96 years, body mass index (BMI): 24.03 (5.94) kg/m2) and 42 healthy women (control group; age: 36.21 ± 11.46 years, BMI: 23.90 (5.85) kg/m2) were included. Transverse abdominis (TrA) and internal oblique (IO) muscle thickness at rest and during abdominal drawing-in maneuver (ADIM) were measured with ultrasound imaging in B-mode using a Logiq S7/Expert device and a 9-11 MHz linear transducer. Percentage change in thickness and contractile function of these muscles were also calculated.

RESULTS

No significant differences in the thickness of TrA and IO muscles at rest and during ADIM between the groups were found (p > 0.05). The percent change in thickness and contractile function of both right and left side TrA muscles and the right side IO muscle were lower in SUI group than control group (p < 0.05). The percentage change in thickness and the contractile function of the left side IO muscle did not change (p > 0.05).

CONCLUSION

Women with SUI had a smaller percentage change in thickness and contractile function of TrA and IO muscle than women without SUI. However, there was no difference in the morphological features of these muscles between the groups. Considering the lateral abdominal muscle, training may be important for management of SUI.

Effect of verbal instructions on trunk muscle activity during volitional preemptive abdominal contraction

OBJECTIVE

This study investigated the effect of Verbal Instruction (VI) strategies on trunk muscle contraction among healthy subjects. The effect of three VI Abdominal Drawing-In Maneuver (ADIM) and two VI Abdominal Bracing Maneuver (ABM) strategies on left Internal (LIO) and External Oblique (LEO) and bilateral superficial Multifidi (sMf) activation was examined.

DESIGN

Within-subjects, repeated measure design.

METHODS

Surface EMG (sEMG) measured LIO, LEO, and sMf activity in 28 subjects (mean age 23.5 ± 5.5 years). Testing included five supine hook-lying and five quiet standing conditions.

RESULTS

One-way ANOVAs demonstrated no significant main effect for ADIM or ABM in supine or standing (p > .05). Muscle activation amplitudes during VPAC conditions demonstrated higher mean values for standing versus supine (p < .05) except for two conditions involving LEO. Friedman Tests for dominant strategy demonstrated a significant main effect for ADIM-VI and ABM-VI strategies. Post-hoc testing generally showed the dominant strategy to be significantly higher versus others.

CONCLUSION

No single preferred VI cue for ADIM or ABM was observed. Each subject's dominant strategy dictated the most suitable VI. Standing was preferred for LIO and sMf activation, whereas position did not change LEO activation. Non-significant correlations between all muscle pairings during all ADIM and ABM strategies were observed. These findings may suggest the need for healthcare providers who understand the intricacies of trunk stability to teach and monitor VPAC with either ADIM or ABM options.

Effect of exercise on the inter-rectus distance in pregnant women with diastasis recti abdominis: an experimental longitudinal study

OBJECTIVE

To investigate the effect of acute contraction of the pelvic floor muscles (PFM) and abdominal exercises on the inter-rectus distance (IRD) compared to resting values, and differences between gestation weeks 27 and 37, in pregnant women with diastasis recti abdominis (DRA).

DESIGN

Experimental longitudinal design.

SETTING

Physiotherapy clinic, primary health care.

PARTICIPANTS

Thirty-eight pregnant women with DRA ≥ 2.8 cm.

INTERVENTIONS

Two-dimensional ultrasound images of IRD 2 cm above and below the umbilicus were taken at rest and during PFM and abdominal exercises at gestation week 27 and 37. Repeated measures analyses of variance (ANOVAs) with post hoc tests was performed for each exercise for both locations and timepoints.

MAIN OUTCOME MEASURES

Change in IRD.

RESULTS

There was a mean increase of the IRD from rest during a PFM contraction (2 mm, 95% CI: 2, 3), drawing-in (4 mm, 95% CI: 3, 5) and a combination of these (5 mm, 95% CI: 4, 6) There was a mean decrease of the IRD from rest during the headlift (-3 mm, 95% CI: -4, -2), the curl-up (-3 mm, 95% CI: -4, -2) and the diagonal curl up (-4 mm, 95% CI: -5, -3). Effect of time from gestation week 27-37 was a mean increase of 8 mm (95% CI: 6, 9).

CONCLUSION

Pelvic floor and drawing-in exercise increased the IRD, whilst headlift, curl up and diagonal curl up decreased the IRD in pregnant women with DRA at gestation week 27 and 37. CONTRIBUTION OF THE PAPER.

Real-time ultrasound evaluation of CORE muscle activity in a simultaneous contraction in subjects with non-specific low back pain and without low-back pain. Protocol of an observational case-control study

Non-specific low back pain represents 90-95% of all cases of low back pain and it has a prevalence of 18% in the adult population, assuming a great socioeconomic impact. The main objective of this observational case-control study study is to evaluate if there are differences in the simultaneous contraction of the core muscles between nonspecific low back pain and healthy subjects. This study will be carried out in the Physiotherapy department of the University of Alcalá. Eighty-two participants <18 years old, will be recruited, paired with NSLBP (n = 41) and healthy (n = 41). The main outcome will be the onset muscle contraction of lateral abdominal wall (internal oblique, external oblique and transversus abdominis), pelvic floor, lumbar multifidus and respiratory diafragm. The maneuvers that the subjects will perform will be abdominal drawing in maneouver, contralateral arm lift, valsalva, and voluntary pelvic floor contraction in sitting and standing. As a secondary objective, to analyze the amount of contraction of each muscle group and the capacity of the diaphragms to be excreted in both groups of subjects. Finally, to relate pain and disability.

Transversus Abdominis Ultrasound Thickness during Popular Trunk-Pilates Exercises in Young and Middle-Aged Women

The transversus abdominis (TrA) is a core muscle that contributes to functional mobility and lumbar stability. This study aimed to compare the changes in TrA thickness during different Pilates exercises, and to identify the exercise that elicited the greatest TrA activation. Forty-four healthy women were divided into two groups: young (25-35 years old) and middle-aged (36-55 years old). TrA thickness was assessed by ultrasound while the participants performed five Pilates exercises: basic position, hundred, hip roll, side plank, and dead bug. A repeated measures analysis of variance revealed that the dead bug exercise induced a significantly higher increase in TrA thickness (relative to rest) than the other exercises (p < 0.05). The young group also showed a significantly higher overall TrA thickness than the middle-aged group (p < 0.05). The findings suggest that the dead bug exercise is the most effective for enhancing TrA activation among the Pilates exercises tested. The basic position and the hundred exercises can be used as warm-up exercises before performing more challenging exercises such as the hip roll, the side plank, and the dead bug. The sequence of exercises can be similar for both young and middle-aged women.

Investigation of Real-Time Diagnostic Ultrasound as a Means of Biofeedback Training in Transversus Abdominus Re-Education of Patients with Non-Specific Low Back Pain: A Prospective Randomized Controlled Pilot Study

Background: It is believed that ultrasound-guided imaging of activation/contraction of the deep abdominal muscles (such as transervsus abdominis) is useful for assisting deep muscle re-education, which is often dysfunctional in non-specific low back pain (NSLBP). Thus, this pilot study aimed to evaluate the use of real-time ultrasound (US) as a feedback device for transverse abdominis (TrA) activation/contraction during an exercise program in chronic NSLBP patients. Methods: Twenty-three chronic NSLBP patients were recruited and randomly assigned to a US-guided (n = 12, 8 women, 47.6 ± 2.55 years) or control group (n = 11, 9 women, 46.9 ± 4.29 years). The same motor control-based exercise program was applied to both groups. All patients received physiotherapy twice per week for seven weeks. Outcome measures, tested at baseline and post-intervention, included Numeric Pain Rating Scale, TrA activation level (measured through a pressure biofeedback unit-based developed protocol), seven established motor control tests, Roland-Morris Disability Questionnaire and Hospital Anxiety and Depression Scale. Results: For each group, all outcome variables yielded statistical differences post-intervention (p < 0.05), indicating significant improvements. However, there were no significant group x time interactions for any of the outcomes (p > 0.05), thus, indicating no superiority of the US-guided group over the control. Conclusions: The addition of US as a visual feedback device for TrA re-education during a motor control exercise program was not proven superior to traditional physiotherapy.

Activation of Anterolateral Abdominal Muscles During Sling Bridge Exercises: Comparison of Different Pelvic Positions

CONTEXT

Inappropriate activation of the anterolateral abdominal muscles affects the stability of the lumbopelvic zone and increases the appearance of pain and lesion in the area. Therefore, ways to improve its effective contraction are crucial in rehabilitation. The aim of this study was to compare the activation of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles in 3 different pelvic positions (down pelvis [DP], horizontal pelvis [HP], and up pelvis [UP]) during sling bridge exercise (SBE) to determinate which position is more effective to promote a correct contraction of the anterolateral abdominal muscles.

DESIGN

Cross-sectional study.

METHODS

Fifteen participants performed 3 variations (DP, HP, and UP) of a one-legged exercise called "supine pelvic lift" on a sling device. The thicknesses of the TrA, IO, and EO were recorded at rest and at the 3 positions using ultrasound imaging. Thickness, change ratio, lateral slide of TrA, and preferential and contraction activation ratio of TrA, IO, and EO were analyzed.

RESULTS

TrA and IO showed greater activation (P = .01) in the UP position than the other pelvic positions. In addition, UP position decreased the activation of the EO (P = .01).

CONCLUSION

Based on the results of this study, SBE in the UP position has the potential to improve normal contraction patterns of the musculature and can be used in future intervention of the lumbopelvic zone.

Comparison of transversus abdominis activation characteristics between healthy and chronic low back pain population during upright functional movement

BACKGROUND

Previous literature suggests that transversus abdominis (TrA) activation is diminished in chronic low back pain (cLBP) subjects compared to healthy subjects in less-functional positions. However, few studies have investigated the effects of upright functional movement on TrA activation in cLBP individuals.

OBJECTIVE

This pilot study aimed to compare TrA activation characteristics in healthy and cLBP subjects during the movement of double leg standing (DLS) to single leg standing (SLS) and to a 30∘ single leg quarter squat (QSLS).

METHODS

TrA activation was determined by the percentage change in TrA thickness from DLS to SLS and DLS to QSLS. TrA thickness was measured in 14 healthy and 14 cLBP participants using ultrasound imaging with a probe holder at 20 mm and 30 mm from the fascia conjunction point.

RESULTS

At both measurement points (20 and 30 mm), there were no significant main effects of body sides, lower limb movements and the interactions between them on TrA activations between the healthy and cLBP participants even after covariates were adjusted for (all p> 0.05).

CONCLUSIONS

Results from this study suggest the evaluation of TrA activation during upright functional movements as part of an assessment for cLBP management may not be suggested.

Core Synergies Measured with Ultrasound in Subjects with Chronic Non-Specific Low Back Pain and Healthy Subjects: A Systematic Review

Low back pain represents the leading cause of disability since 1990. In 90% of cases, it is classified as non-specific low back pain, being chronic in 10% of subjects. Ultrasound has proven to be an effective measurement tool to observe changes in the activity and morphology of the abdominal muscles. This article reviews which core synergies are studied with ultrasound in healthy subjects and with chronic non-specific low back pain. A systematic review was conducted on studies analyzing synergies between two or more core muscles. Publications from 2005 until July 2021 were identified by performing structured searched in Pubmed/MEDLINE, PEDro and WOS. Fifteen studies were eligible for the final systematic review. A total of 56% of the studies established synergies between the core muscles and 44% between the homo and contralateral sides of the core muscles. The most studied core synergies were transversus abdominis, internal oblique and external oblique followed by the rectus abdominis and the lumbar multifidus. No studies establishing synergies with diaphragm and pelvic floor were found. Eight studies were conducted in healthy subjects, five studies in subjects with chronic non-specific low back pain compared to healthy subjects and two studies in subjects with chronic non-specific low back pain.

Lateral abdominal muscles of adults with hypermobility may be partially impaired during contraction

Background

Muscle function may be impaired in people with generalised hypermobility, yet prior studies have primarily focused on muscles within the extremities. We aimed to examine changes in lateral abdominal muscle (transversus abdominis (TrA) and the external (EO) and internal abdominal obliques (IO)) thickness and length during contraction between participants with and without hypermobility.

Methods

This cross-sectional study examined 12 participants with hypermobility and 12 age-matched, sex-matched, height-matched and weight-matched participants without hypermobility. The Beighton and Belavy-Owen-Mitchell score assessed systemic hypermobility. Muscle thickness and length were measured via panoramic ultrasound scans at rest and during contraction.

Results

When compared with rest across all lumbar levels (L1–L5), contraction produced a lesser increase in TrA thickness (β=0.03, p=0.034) for participants with hypermobility compared with control. No group-by-condition interaction was observed for TrA length across all lumbar levels (L1–L5; p=0.269). Contraction produced a greater decrease in EO thickness (β=0.08, p=0.002) at L3 only for participants with hypermobility compared with control. No group-by-condition interactions were observed for IO thickness.

Conclusion

Participants with hypermobility had partially impaired lateral abdominal muscle function given a lesser ability to increase TrA muscle thickness during contraction compared with controls.

Neuromuscular Consequences of Lumbopelvic Dysfunction: Research and Clinical Perspectives

Injuries involving the lumbopelvic region (ie, lumbar spine, pelvis, hip) are common across the lifespan and include pathologies such as low back pain, femoroacetabular impingement syndrome, labrum tear, and osteoarthritis. Joint injury is known to result in an arthrogenic muscle response which contributes to muscle weakness and altered movement patterns. The purpose of this manuscript is to summarize the arthrogenic muscle response that occurs across lumbopelvic region pathologies, identify methods to quantify muscle function, and propose suggestions for future research. While each lumbopelvic region pathology is unique, there are a few common impairments and a relative consistent arthrogenic muscle response that occurs across the region. Hip muscle weakness and hip joint range of motion limitations occur with both lumbar spine and hip pathologies, and individuals with low back pain are known to demonstrate inhibition of the transversus abdominis and multifidus. Assessment of muscle inhibition is often limited to research laboratory settings, but dynamometers, ultrasound imaging, and electromyography offer clinical capacity to quantify muscle function and inform treatment pathways. Future studies should systematically determine the arthrogenic muscle response across multiple muscle groups and the timeline for changes in muscle function and determine whether disinhibitory modalities improve functional outcomes beyond traditional treatment approaches.

The effect of activation of thoracolumbar fascia on the thickness of abdominal muscles: An ultrasonographic study

Objectives

This study aims to evaluate the changes in the ultrasonographic thickness of transversus abdominis and internal oblique muscles during bridge with arm extension compared to bridge and abdominal hollowing.

Patients and methods

Between March 1^st, 2019 and March 29^th, 2019, a total of 30 healthy individuals (15 males, 15 females; mean age: 28.8±8.1 years; range, 21 to 52 years) among hospital staff were included. Thickness of transversus abdominis, internal, and external oblique muscles of the participants were evaluated using ultrasound during four positions (rest, abdominal hollowing, bridge, and bridge with arm extension).

Results

The mean body mass index was 23.8±4.1 kg/m². The thickness of transversus abdominis and internal oblique muscles increased during all positions (p<0.001), compared to rest. The thickness during bridge with arm extension was greater than abdominal hollowing and bridge.

Conclusion

Co-activation of latissimus dorsi and gluteus maximus muscles during abdominal contraction increases the thickness of internal oblique and transversus abdominis muscles greater than abdominal contraction alone or co-activation of gluteus maximus alone. Simultaneous isometric contraction of latissimus dorsi muscle may enhance abdominal muscle function.

Real-Time Visual Biofeedback via Wearable Ultrasound Imaging Can Enhance the Muscle Contraction Training Outcome of Young Adults

ABSTRACT

Huang, Z-H, Ma, CZ-H, Wang, L-K, Wang, X-Y, Fu, S-N, and Zheng, Y-P. Real-time visual biofeedback via wearable ultrasound imaging can enhance the muscle contraction training outcome of young adults. J Strength Cond Res 36(4): 941-947, 2022-Real-time ultrasound imaging (RUSI) can serve as visual biofeedback to train deep muscle contraction in clinical rehabilitative settings. However, its effectiveness in resistance training in sports/fitness fields remains unexplored. This article introduced a newly developed wearable RUSI system that provided visual biofeedback of muscle thickening and movement and reported its effectiveness in improving the training outcomes of muscle thickness change (%) during dynamic contraction. Twenty-five healthy young men participated and performed pec fly exercise both with and without RUSI biofeedback. Statistical analysis was conducted to examine the reliability of the measurements and the immediate effects of (a) RUSI biofeedback of muscle contraction and (b) training intensity (50 vs. 80% of 1-repetition maximum [1RM]) on the pectoralis major (PMaj) thickness change measured by ultrasound images. In addition to significantly high inter-contraction reliability (ICC3,1 > 0.97), we observed significantly increased PMaj thickness change for both training intensities upon receiving biofeedback in subjects, compared with without biofeedback (p < 0.001). We also observed significantly larger PMaj thickness change at 80% of 1RM compared with 50% of 1RM (p = 0.023). The provision of visual biofeedback using RUSI significantly enlarged the magnitude of PMaj thickness change during pec fly exercises, potentially indicating that RUSI biofeedback could improve the ability of targeted muscle contraction of PMaj in healthy young adults. To our knowledge, this study has pioneered in applying RUSI as a form of biofeedback during weight training and observed positive effectiveness. Future iterations of the technique will benefit more subject groups, such as athletes and patients with neuromuscular disorders.

Comparison of two different feedback techniques for activating the transversus abdominis: An observational study

BACKGROUND

The transversus abdominis (TrA) is an important muscle for spinal stabilization. The abdominal draw-in maneuver (ADIM) is a method that selectively activates the TrA without overactivation of the external oblique (EO) and internal oblique (IO). Individuals with low back pain may have trouble in understanding proper contraction of the TrA.

OBJECTIVE

The aim of this study was to investigate the differences between two feedback techniques to re-educate the TrA.

METHODS

One hundred eighty healthy volunteers (123 female, 57 male) were randomized into two groups. The ADIM was performed with different feedback methods: conventional (verbal and tactile) feedback and visual feedback from real-time ultrasound images.

RESULTS

A within-group comparison revealed a significant increase in the thickness of the TrA, IO, and EO during the ADIM (p< 0.001) in both groups. The mean change (SD) in the thickness of the TrA and IO between rest and the ADIM was an increase of 2.541.25 and 1.882.14 in group 1 and 1.821.27 and 1.241.87 in group 2, respectively (p< 0.001). No significant differences were observed in EO thickness between the two groups.

CONCLUSIONS

Although visual biofeedback shows a greater effect on ADIM training, both approaches are applicable, and clinicians may decide on which to use based on their clinical environment and experience.

Ultrasonographic Changes of Abdominal Muscles in Subjects with and without Chronic Low Back Pain

Chronic low back pain (CLBP) is a prevalent disfunction in the spine, affecting both women and men. The implication of the abdominal muscles in this disfunction has been studied, including wrong breathing patterns or inactivity of this area. However, there is a lack of studies examining changes in thickness of abdominal with ultrasonography. Thus, the aim of this study is to analyze the differences in the thickness of abdominal muscles at rest and during breathing between subjects with and without CLBP. A total of 72 subjects were divided in two groups: participants with CLBP (n = 36) and participants without CLBP (n = 36). In both groups, the thickness of the four abdominal muscles was measured and compared at rest and during breathing with ultrasonography. In TrA and IO there were no significant differences between groups, but those subjects with CLBP increased the muscle thickness more than participants without pain during breathing. In EO there were no differences in muscle thickness between groups and between rest and breathing. In RA, subjects with CLBP showed less muscle thickness than subjects without pain during breathing, but no changes were found at rest. In conclusion, the deepest abdominal muscles, TrA and IO, appear to increase their thickness and RA appear to decrease more in subjects with CLBP, in comparison with healthy participants.

The Role of Rehabilitative Ultrasound Imaging Technique in the Lumbopelvic Region as a Diagnosis and Treatment Tool in Physiotherapy: Systematic Review, Meta-Analysis and Meta-Regression

Rehabilitative ultrasound imaging (RUSI) technique seems to be a valid and reliable tool for diagnosis and treatment in physiotherapy and has been widely studied in the lumbopelvic region the last three decades. The aims for this utility in clinical settings must be review through a systematic review, meta-analysis and meta-regression. A systematic review was designed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines with PROSPERO registration and per review in all phases of the process using COVIDENCE, analysis of risk of bias and meta-analysis using REVMAN, and meta-regression calculation using STATA. Database screening provided 6544 references, out of which 321 reported narrative synthesis, and 21 reported quantitative synthesis, while only 7 of them provided comparable data to meta-analyze the variables pain and muscle thickness. In most cases, the forest plots showed considerable I2 heterogeneity indexes for multifidus muscle thickness (I2 = 95%), low back pain (I2 = 92%) and abdominal pain (I2 = 95%), not important for transversus abdominis muscle thickness (I2 = 22%), significant heterogenity (I2 = 69%) depending on the subgroup and not important internal oblique muscle thickness (I2 = 0%) and external oblique muscle thickness (I2 = 0%). Meta-regression did not provide significant data for the correlations between the variables analyzed and the intervention, age, and BMI (Body Mass Index). This review reveals that RUSI could contribute to a high reliability of the measurements in the lumbopelvic region with validity and reliability for the assessments, as well as showing promising results for diagnosis and intervention assessment in physiotherapy compared to the traditional model, allowing for future lines of research in this area.

Effects of core stabilization exercise and strengthening exercise on proprioception, balance, muscle thickness and pain related outcomes in patients with subacute nonspecific low back pain: a randomized controlled trial

Background

Therapeutic exercises are used in clinical practice for patients with low back pain (LBP). Core stabilization exercises can retrain the important function of local trunk muscles and increase the accuracy of the sensory integration process for stability of the spine in individuals with LBP. The aim of this study was to compare the effects of two different exercise regimes, Core stabilization exercises (CSE) and Strengthening exercise (STE), on proprioception, balance, muscle thickness and pain-related outcomes in patients with subacute non-specific low back pain (NSLBP).

Methods

Thirty-six subacute NSLBP patients, [mean age, 34.78 ± 9.07 years; BMI, 24.03 ± 3.20 Kg/m²; and duration of current pain, 8.22 ± 1.61 weeks], were included in this study. They were randomly allocated into either CSE (n = 18) or STE groups (n = 18). Exercise training was given for 30 min, three times per week, for up to 4 weeks. Proprioception, standing balance, muscle thickness of transversus abdominis (TrA) and lumbar multifidus (LM), and pain-related outcomes, comprising pain, functional disability and fear of movement, were assessed at baseline and after 4 weeks of intervention.

Results

The CSE group demonstrated significantly more improvement than the STE group after 4 weeks of intervention. Improvements were in: proprioception [mean difference (95% CI): − 0.295 (− 0.37 to − 0.2), effect size: 1.38, (p <  0.001)], balance: single leg standing with eyes open and eyes closed on both stable and unstable surfaces (p <  0.05), and percentage change of muscle thickness of TrA and LM (p <  0.01). Although both exercise groups gained relief from pain, the CSE group demonstrated greater reduction of functional disability [effect size: 0.61, (p <  0.05)] and fear of movement [effect size: 0.80, (p < 0.01)]. There were no significant adverse effects in either type of exercise program.

Conclusion

Despite both core stabilization and strengthening exercises reducing pain, core stabilization exercise is superior to strengthening exercise. It is effective in improving proprioception, balance, and percentage change of muscle thickness of TrA and LM, and reducing functional disability and fear of movement in patients with subacute NSLBP.

Trial registration

Thai Clinical Trial Registry (TCTR20180822001; August 21, 2018).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04858-6.

Intra-examiner and inter-examiner reliability of rehabilitative ultrasound imaging for lumbar multifidus and anterolateral abdominal muscles in females with recurrent low back pain: an observational, cross-sectional study

Aim: To examine the reliability of rehabilitative ultrasound imaging performed to measure the thickness of the transverse abdominis, internal oblique, external oblique, and lumbar multifidus muscles in females with recurrent low back pain. Material and methods: A sample of 15 women was recruited. Two independent examiners recorded the thickness of their deep abdominal and spinal muscles by rehabilitative ultrasound imaging. Imaging scans of the transverse abdominis, internal oblique, and external oblique muscles were performed in the supine position and in the midaxillary line, between the lower edge of the ribcage and the iliac crest. Imaging of the lumbar multifidus was done in the prone position and at the level of the L5/S1 zygapophyseal joints. Imaging scans were performed bilaterally in rest and contraction, three times by the first examiner (at baseline, after two hours, and one week later) and once by the second examiner. Results: Good to excellent within-session intra-rater (ICC = 0.76, 0.97), good to excellent between-session intra-rater reliability (ICC = 0.73, 0.93), and good to excellent inter-rater reliability (ICC = 0.73, 0.98) were obtained. Conclusions: The results showed that rehabilitative ultrasound imaging can be used as an excellent reliable instrument by one or two examiners to measure the thickness of the transverse abdominis, internal oblique, external oblique and lumbar multifidus muscles in females with recurrent low back pain.

Comparison of linea alba length and core-muscles engagement during core and lower back orientated exercises

BACKGROUND

A comparison of Linea Alba (LA) length and engagement of the Transverse Abdominis (TrA), External Oblique (EO) and Internal Oblique (IO) between core-orientated and lower back orientated exercises (e.g. glute bridge and hip extension) is lacking. Therefore, the aim of this study was to compare the length of the LA and the engagement of TrA, EO and IO when performing the prone plank, bird dog, dead bug, lateral plank, glute bridge and hip extension.

METHODS

Thirteen apparently healthy participants volunteered to this study. Ultrasound scanning of the anterior and antero-lateral abdominal walls at baseline and whilst performing prone plank, bird dog, dead bug, lateral plank, glute bridge and hip extension exercises was performed. LA length and thickness of the TrA, EO and IO were measured from ultrasound images.

RESULTS

LA length (p = 0.77) and TrA thickness (p = 0.23) were not different between exercises. EO thickness was larger for the lateral plank compared to the bird dog (p = 0.01, d = 1.73), glute bridge (p < 0.01, d = 2.64), and hip extension (p < 0.01, d = 1.89). The dead bug was also larger in comparison to the glute bridge (p < 0.01, d = 2.05) and to the hip extension (p = 0.01, d = 1.45). For the IO thickness, the lateral plank was larger than the bird dog (p = 0.03, d = 1.21) and the dead bug (p = 0.04, d = 1.12).

CONCLUSION

No difference was observed between exercises for the length of the LA or for the thickness of the TrA, which suggests that this muscle is similarly engaged in the assessed exercises, leading to a consistent stretch for the LA.

An Investigation of the Association between Transversus Abdominis Myofascial Structure and Activation with Age in Healthy Adults using Ultrasound Imaging

BACKGROUND

Because of their importance in core stability, training the deep abdominal muscles, fascial structures and particularly the transversus abdominis, is a key component of many sport and physical therapy programs. However, there are gaps in knowledge about age-related changes in the structure and activation capacity of these muscles.

HYPOTHESIS/PURPOSE

This study investigated the association between deep abdominal muscles and fascial structures and transversus abdominis activation with age in healthy adults.

STUDY DESIGN

A cross-sectional study.

METHODS

Eighty-six adults aged 18 to 77 participated in this study. An ultrasound image of their transversus abdominis, internal oblique, external oblique and associated fasciae was first captured at rest, then during a contraction of the transversus abdominis. Bivariate correlation analyses and hierarchical analyses were performed (significance level: p < 0.05).

RESULTS

The thickness of these three muscles decreases with age ( ρ = -0.66 for external oblique, -0.51 for internal oblique and -0.58 for transversus abdominis), whereas the thickness of their fasciae increases ( ρ = 0.39 for the fascia of external oblique, 0.54 for the fascia between internal oblique and external oblique, and 0.74 for the fascia between internal oblique and transversus abdominis). Transversus abdominis activation decreases with age (r =-0.44). Age accounts for 19.5% of the variance in transversus abdominis activation.

CONCLUSION

These results demonstrate that normal aging is associated with changes in deep abdominal myofascial structures and transversus abdominis activation. Assessment of these metrics can provide valuable baseline information for physical therapists involved in rehabilitation and strengthening programs targeting older individuals.

LEVEL OF EVIDENCE

Level 2.

The Effect of Virtual Reality Training on Anticipatory Postural Adjustments in Patients with Chronic Nonspecific Low Back Pain: A Preliminary Study

Objectives

This study is aimed at exploring the effects of virtual reality (VR) training on postural control, measured by anticipatory and compensatory postural adjustments (APAs and CPAs, respectively), in patients with chronic nonspecific low back pain (CNLBP) and the potential neuromuscular mechanism of VR training.

Methods

Thirty-four patients were recruited and randomly assigned to the VR group (n = 11), the motor control exercise group (MCE, n = 12) and the control group (CG, n = 11). The VR group received VR training using Kinect Xbox 360 systems and magnetic therapy. Besides magnetic therapy, the participants in the MCE group performed real-time ultrasound-guided abdominal drawing-in maneuver (ADIM) and four-point kneeling exercise. The CG only received magnetic therapy. Surface muscle electromyography (sEMG) was used to record the muscle activities of transverse abdominis (TrA), multifidus (MF), lateral gastrocnemius (LG), and tibialis anterior (TA) during ball-hitting tasks. The muscle activation time and integrals of the electromyography activities (IEMGs) during the APA and CPA stages were calculated and used in the data analysis. The visual analogue scale (VAS) and Oswestry dysfunction index (ODI) scores were also recorded.

Results

A significant interaction effect of time × group was observed on the activation time of TrA (p = 0.018) and MF (p = 0.037). The post-intervention activation time of the TrA was earlier in the VR group (p = 0.029). In contrast, the post-intervention activation time of the MF was significantly delayed in the VR group (p = 0.001). The IEMGs of TrA (p = 0.002) and TA (p = 0.007) during CPA1 significantly decreased only in the VR group after the intervention. The VAS scores of three group participants showed significant decreases after intervention (p < 0.001).

Conclusions

Patients with CNLBP showed reciprocal muscle activation patterns of the TrA and MF muscles after VR training. VR training may be a potential intervention for enhancing the APAs of the patients with CNLBP.

Ultrasound Imaging as a Visual Biofeedback Tool in Rehabilitation: An Updated Systematic Review

Rehabilitative ultrasound imaging (RUSI) is used by physical therapists as a feedback tool for measuring changes in muscle morphology during therapeutic interventions such as motor control exercises (MCE). However, a structured overview of its efficacy is lacking. We aimed to systematically review the efficacy of RUSI for improving MCE programs compared with no feedback and other feedback methods. MEDLINE, PubMed, SCOPUS and Web of Science databases were searched for studies evaluating efficacy data of RUSI to improve muscular morphology, quality, and/or function of skeletal muscles and MCE success. Eleven studies analyzing RUSI feedback during MCE were included. Most studies showed acceptable methodological quality. Seven studies assessed abdominal wall muscles, one assessed pelvic floor muscles, one serratus anterior muscle, and two lumbar multifidi. Eight studies involved healthy subjects and three studies clinical populations. Eight studies assessed muscle thickness and pressure differences during MCE, two assessed the number of trials needed to successfully perform MCE, three assessed the retain success, seven assessed the muscle activity with electromyography and one assessed clinical severity outcomes. Visual RUSI feedback seems to be more effective than tactile and/or verbal biofeedback for improving MCE performance and retention success, but no differences with pressure unit biofeedback were found.

How Do the Abdominal Muscles Change during Hypopressive Exercise?

Background and objective: Prior studies have reported an activation of abdominal muscles during hypopressive exercises in women with pelvic floor disfunction. However, no previous research analyzed the effects of hypopressive exercise on abdominal muscles in healthy populations to understand the normal biomechanics of this area. The aim of this study was to examine the thickness of abdominal muscles at rest and during hypopressive exercise in supine and standing positions with ultrasound imaging in healthy adults. Methods: A cross-sectional study was carried out in 99 healthy university students. The thickness of the abdominal muscles at rest and during hypopressive exercise was assessed with ultrasound imaging in supine and standing positions. Results: During hypopressive exercise, there was a significant increase in the muscle thickness of transversus abdominis (p < 0.001) and internal oblique (p < 0.001) in supine and standing positions. External oblique only increased its thickness significantly in the standing position (p < 0.001) and rectus abdominis did not change during the hypopressive exercise in any position (p > 0.05). In conclusion, hypopressive exercises seem to increase the thickness of the deepest and most stabilized muscles such as transversus abdominis and internal oblique. Conclusions: These findings should be considered for future interventions with hypopressive exercises in healthy subjects.

Spine Injury Prevention

Spinal injury and back pain are a common problem facing patients seeking medical care including athletes, which can lead to significant disability, medical costs, and impaired performance for these patients. Rehabilitation including core muscle stabilization, Kinesio taping, and flexibility have been shown to help with treatment and prevention. Critical factors such as equipment, technique, and rule changes can also be an important part of spine injury prevention.

Are There Any Differences in Abdominal Activation between Women and Men during Hypopressive Exercises?

This study analyzes the effects of hypopressive exercises on the abdominal thickness of healthy subjects and compares the performance between women and men. We conducted a transversal observational study in 98 subjects (63% women). The muscle thickness is analyzed in transversus abdominis, internal oblique, external oblique, and rectus abdominis with ultrasound imaging at rest and during the hypopressive exercise (HE) in supine and standing position. Comparisons between rest and hypopressive exercise are carried out in the two different positions and between women and men. In the supine position, there is a significant activation of the transversus abdominis and internal oblique during hypopressive exercise (p < 0.001), and it is similar in both sexes, the external oblique is only activated significantly by men (p < 0.001) and rectus abdominis had no significant activation (p > 0.05). Our results show that standing transversus abdominis and external oblique significantly increased their thickness during HE with higher effects in men. Internal oblique also increased significantly, but with higher effects in women, and rectus abdominis had no significant increase. Men had similar effects to women during HE, with an activation of the deepest abdominal muscles. The unequal anatomy and the position could explain the different results obtained between the sexes.

Ultrasound Measurement of the Transverse Abdominis, Internal Oblique, and External Oblique Muscles Associated with Forward Head Posture and Reduced Cranio-Vertebral Angle

Background

Abnormal posture can affect the alignment of the cervical spine, which can lead to various physical problems. There are many ways to solve the problem by limiting the area around the neck to restore abnormal neck condition. However, there is a need to look at these problems from an enlarged perspective through the relationship between the cervical spine and trunk. This study aimed to investigate the significance of the thickness of the transverse abdominis, internal oblique, and external oblique muscles in patients with forward head posture and reduced cranio-vertebral angle.

Material/Methods

We included 24 healthy adult males in their 20s without lower back pain. The cranio-vertebral angle (CVA) in all the subjects was measured with the help of pictures taken in the sagittal plane using a digital camera. The thickness of muscles, including transverse abdominis (TrA), internal oblique (IO), and external oblique (EO), was measured using a diagnostic ultrasound device. Pearson’s correlation analysis was used to identify the correlation between the variables measured.

Results

CVA showed a statistically significant correlation with TrA thickness (r=0.506/p=0.012), and among the abdominal muscles, there was a significant correlation between IO and EO thickness (r=0.663/p=0.000).

Conclusions

A reduced CVA due to FHP was significantly associated with reduced TrA thickness. Therefore, increasing the bulk of the abdominal muscles with restoration of the abnormal CVA is a potential treatment approach and requires further study.

ENHANCED ACTIVE CONTRACTION OF THE TRANSVERSUS ABDOMINIS DURING WALKING

ABSTRACT Introduction: We applied three-dimensional gait analysis to assess the effects of enhanced active contraction of the transversus abdominis (EACTA) during walking. We sought to evaluate the effect of EACTA during walking in order to improve walking quality. Methods: Thirty college students were recruited and trained to perform EACTA during walking. We examined gait parameters under different conditions, including EACTA and habitual ACTA (natural walking with mild contraction of the feedforward mechanism of ACTA, HACTA) during walking using three-dimensional gait analysis. We compared differences in gait parameters under the two walking conditions using SPSS 16.0 statistical software. Results: The following gait parameters were significantly lower under EACTA conditions than under HACTA conditions (P < 0.05): stance phase, 59.151% ± 1.903% vs. 59.825% ± 1.495%; stride time, 1.104 s ± 0.080 s vs. 1.134 s ± 0.073 s:; stance time, 0.656 s ± 0.057 s vs. 0.678 s ± 0.053 s; and swing time, 0.447 s ± 0.028 s vs. 0.454 s ± 0.031 s, respectively. Gait parameters single support phase and mean velocity were significantly higher for EACTA than for HACTA conditions (both P < 0.05). Conclusions: Overall, the results revealed that EACTA during walking can improve gait. This method is simple, and EACTA training during walking to improve gait quality in daily life could provide a positive basis for people to strengthen the transverse abdominal muscle. Level of evidence III; Retrospective comparative study .

The reliability of rehabilitative ultrasound to measure lateral abdominal muscle thickness: A systematic review and meta-analysis

BACKGROUND

Variations in rehabilitative ultrasound imaging (RUSI) protocols may alter lateral abdominal muscle (LAM) thickness measurements. A standardised protocol is required for clinicians to accurately compare LAM thickness changes.

OBJECTIVE

In healthy and lower back pain (LBP) populations, to assess the 1) overall reliability of RUSI to diagnose LAM thickness via meta-analysis, 2) reliability of ultrasound variables to diagnose LAM thickness via systematic review, and 3) propose a RUSI protocol for the LAM using variables associated with excellent reliability (intraclass correlation coefficient [ICC] >0.9).

DESIGN

Systematic review and meta-analysis.

METHOD

Databases were searched from January 2000 for studies reporting the reliability of RUSI on the LAM at rest. Title, abstract and full-text screening were performed. Reference lists of reviews and included full-text articles were scanned for further articles. Study characteristic, ultrasound procedure and reliability data were extracted, and article quality assessed. Data was synthesised using meta-analysis to determine the overall reliability for RUSI in different subgroups; calculation of the mean ICCs and standard error of measurements of protocol variables; and narrative synthesis of protocols to contrast those of differing reliability.

RESULTS

Twenty-seven articles, involving 884 participants were included. Reliability ranged from good-to-excellent (ICC 0.859-0.958) in all subgroups. Protocols ranged in subject selection and position, examiner experience, transducer position with the comprehensiveness of protocol description the main limitation of the reviewed literature. Based on the findings an ultrasound protocol was proposed.

CONCLUSIONS

RUSI variables for the LAM at rest show moderate-to-excellent reliability; future research should explore reliability following the proposed protocol.

Abdominal Expansion versus Abdominal Drawing-In Strategy on Thickness and Electromyography of Lumbar Stabilizers in People with Nonspecific Low Back Pain: A Cross-Sectional Study

The abdominal expansion (AE) strategy, involving eccentric contraction of the abdominal muscles, has been increasingly used in clinical practices; however, its effects have not been rigorously investigated. This study aimed to investigate the immediate effects of the AE versus abdominal drawing-in (AD) strategy on lumbar stabilization muscles in people with nonspecific low back pain (LBP). Thirty adults with nonspecific LBP performed the AE, AD, and natural breathing (NB) strategies in three different body positions. Ultrasonography and surface electromyography (EMG) were, respectively, used to measure the thickness and activity of the lumbar multifidus and lateral abdominal wall muscles. The AE and AD strategies showed similar effects, producing higher EMG activity in the lumbar multifidus and lateral abdominal wall muscles when compared with the NB strategy. All muscles showed higher EMG activity in the quiet and single leg standing positions than in the lying position. Although the AE and AD strategies had similar effects on the thickness change of the lumbar multifidus muscle, the results of thickness changes of the lateral abdominal muscles were relatively inconsistent. The AE strategy may be used as an alternative method to facilitate co-contraction of lumbar stabilization muscles and improve spinal stability in people with nonspecific LBP.

Exercising on Different Unstable Surfaces Increases Core Abdominal Muscle Thickness: An Observational Study Using Real-Time Ultrasound

BACKGROUND

The training of abdominal muscles has a positive impact on the functional capacity of healthy adults, being applied practically in fields of athletics and fitness through rehabilitation for lower back pain.

OBJECTIVE

The study compares abdominal muscle activity while performing graded isometric exercises on stable and unstable surfaces. The authors also examined perceived stability and comfort for the different surfaces.

METHODS

A total of 30 young, healthy adults performed 3 graded isometric exercises on a Pilates table, foam roller, and Oov (a newly developed tool). Ultrasound investigation measured transversus abdominis, internal oblique abdominis, and external oblique abdominis thickness during each task, comparing muscle thickness between conditions using general linear modeling.

RESULTS

Core abdominal activation was greater on the foam roller than the Oov and Pilates table during crook lying (bilateral leg support). Both Oov and foam roller elicited greater contralateral transversus abdominis and internal oblique abdominis thickness than the Pilates table during tabletop and straight leg raises (unilateral leg exercises). For transversus abdominis only, the foam roller elicited more muscle thickness than the Oov during straight leg raises. The Oov was rated more comfortable than the foam roller.

DISCUSSION

Exercises performed on the Oov and foam roller elicit core greater abdominal muscle thickness than those performed on a Pilates table. Unilateral leg exercises in a supine position elicit more contralateral muscle thickness than those with bilateral leg support.

CONCLUSIONS

These results provide information to support choices in exercise progression from flat stable to more unstable surfaces and from those with bilateral foot support to unilateral foot support. The Oov was more comfortable that the foam roller, and this may help with exercise adherence.

Reliability of Sonography Measures of the Lumbar Multifidus and Transversus Abdominis during Static and Dynamic Activities in Subjects with Non-Specific Chronic Low Back Pain

PURPOSE

The purpose of this study was to investigate the test-retest reliability of ultrasound (US) thickness measurements and the muscle contraction ratio (CR) of lumbar multifidus (LM) and transversus abdominis (TA) muscles in participants with and without nonspecific chronic low back pain (NCLBP).

METHODS

A total of 62 participants (37 with NCLBP, 25 without NCLBP) with participated in the study. The within-day and between-day reliability of US thickness measurements and CR in a lying (supine for TA and prone for LM) and sitting positions for both muscles (sitting on a gym ball with both feet on the ground or lifting one foot off the floor) were assessed. Reliability analysis was performed with intraclass correlations (ICCs) for these two static and dynamic positions.

RESULTS

Test-retest reliability was calculated to be good to high for the static position (ICC = 0.72-0.95) and the dynamic position (ICC = 0.74-0.94) sonographic measurements in both group of TA measurement. Test-retest reliability of LM measurements was good to high for the static position (ICC = 0.82-0.95) and the dynamic position (ICC = 0.85-0.97) sonographic measurements in both groups.

CONCLUSIONS

US imaging is a highly reliable method for the assessment of TA and LM thickness muscles in the dynamic position in participants with and without NCLBP. The CR measures may be adequately reliable in assessing the function of the TA and LM muscles in participants with NCLBP and healthy ones.

Recovery of Abdominal Muscle Thickness and Contractile Function in Women after Childbirth

Abdominal muscles may be both morphologically and functionally affected by pregnancy. Dysfunction of the muscles can lead to persistent postpartum low back pain. The recovery process of the abdominal muscles following childbirth is not well understood. This study aimed to demonstrate the changes in the thickness and contractile function of abdominal muscles during the first six months postpartum. Nine perinatal and 15 nulliparous females participated. The thicknesses and contraction/relaxation thickness ratios of the rectus abdominis (RA), external abdominal oblique (EO), internal abdominal oblique (IO), and transverse abdominis (TrA) were measured using ultrasound images from 36–39 weeks’ gestation until six months postpartum. The RA, IO, and TrA muscles were thinner in perinatal females than controls at 36–39 weeks of gestation (4.8 vs. 9.47 mm (RA), 5.45 vs. 7.73 mm (IO), 2.56 vs. 3.38 mm (TrA), respectively). The thinner IO muscle persisted for six months after delivery. The decreased TrA thickness ratio persisted until four months post-delivery. Abdominal muscle thickness and contractile function decreased in the postpartum period. Therefore, abdominal muscle exercises might help prevent postpartum symptoms; however, because deterioration of muscle function is significant in the first four months, careful attention should be paid to exercise intensity. The study limitation was a relatively small sample size, thus future studies should involve more participants.

The Efficacy of Pilates on Urinary Incontinence in Korean Women: A Metabolomics Approach

Pilates has been known as exercise intervention that improves the function of pelvic floor muscle (PFM) associated with impacting urinary incontinence (UI). This study investigated the effect of Pilates on UI in Korean women by determining the change in functional movement of PFM (FMP) and metabolic profiles. UI group with Pilates (UIP, n = 13) participated in 8-weeks Oov Pilates program, and 8 subjects were assigned to Control and UI group with no Pilates (UINP), respectively. Before and after 8 weeks, plasma samples were collected from all participants, and ultrasonography was used to measure the functional change of PFM for calculating FMP ratio. Plasma samples were analyzed by mass spectrometry to identify the change of metabolic features. After 8-weeks intervention, FMP ratio was remarkably decreased in UIP (48.1% ↓, p < 0.001), but not in Control and UINP (p > 0.05). In metabolic features, L-Glutamine (m/z: 147.07 [M + H]⁺), L-Cystathionine (m/z: 240.09 [M + NH₄]⁺), L-Arginine (m/z: 197.1 [M + Na]⁺), and L-1-Pyrroline-3-hydroxy-5-carboxylate (m/z: 147.07 [M + NH₄]⁺) were significantly elevated solely in UIP (p < 0.001). Our study elucidated that Pilates can ameliorate the FMP and enhance the specific metabolic characteristics, which was potentially associated with invigorated PFM contractility to effectively control the bladder base and continence.

Reproducibility and Concurrent Validity of Manual Palpation with Rehabilitative Ultrasound Imaging for Assessing Deep Abdominal Muscle Activity: Analysis with Preferential Ratios

The abdominal drawing-in maneuver (ADIM) is a clinical tool used for identifying preferential activity of deep abdominal muscles. However, concurrent validity and reproducibility of palpation during the ADIM has not been formally investigated. The aims of this study were (1) to assess intra- and interrater reliability of manual palpation during the ADIM, and (2) to determine the concurrent validity of manual palpation during the ADIM by calculating preferential activation ratio cut-off as assessed with ultrasound imaging (RUSI). Thirty-two subjects (n = 16 patients with nonspecific low back pain and 16 comparable healthy individuals) performed the ADIM in a supine hook-lying position. Two experienced assessors evaluated the presence or absence of preferential contraction of the deep abdominal muscles by palpation during the ADIM on 2 different days. Intrarater (test-retest) and interrater reliability of palpation were calculated using Cohen's kappa coefficients. Muscle thickness of the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles at rest and during the ADIM were also measured. TrA-Contraction Ratio (TrA-CR), TrA-Preferential Activation Ratio (TrA-PAR), and Modified-TrA-PR (M-TrA-PAR) were calculated. The concurrent validity of manual palpation was determined using the correlation between manual palpation and imaging and by calculating ROC curve (operating characteristics curve), Youden index, and sensitivity and specificity. Intra- and interrater reliability of manual palpation during the ADIM was excellent (k: 0.82-1.00) and good to excellent (k: 0.71-1.00), respectively. Interrater reliability for muscle thickness ranged from good to excellent (ICC3,1 0.79-0.91). Manual palpation and TrA ratio showed low to moderate correlations (r: 0.36-0.60). When evaluating the diagnostic accuracy of manual palpation, the best predictive model (ROC value: 0.89; p < 0.001) for correct a preferential contraction of TrA was obtained when the M-TrA-PAR was ≥0.08 (sensitivity: 0.95-1.00; specificity: 0.62). Good to excellent intra- and interrater reliability of manual palpation was found during the ADIM in both patients and healthy groups. Manual palpation showed concurrent validity for identifying the preferential activity of the TrA muscle supporting its use in clinical practice.

Effect of real-time ultrasound imaging for biofeedback on trunk muscle contraction in healthy subjects: a preliminary study

Background

Real-time ultrasound imaging (RUSI) has been increasingly used as a form of biofeedback when instructing and re-training muscle contraction. However, the effectiveness of the RUSI on a single sustained contraction of the lumbar multifidus (LM) and transversus abdominis (TrA) has rarely been reported. This preliminary study aimed to determine if the use of RUSI, as visual biofeedback, could enhance the ability of activation and continuous contraction of the trunk muscles including LM and TrA.

Methods

Forty healthy individuals were included and randomly assigned into the experimental group and control group. All subjects performed a preferential activation of the LM and/or TrA (maintained the constraction of LM and/or TrA for 30 s and then relaxed for 2 min), while those in the experimental group also received visual feedback provided by RUSI. The thickness of LM and/or TrA at rest and during contraction (T_c-max, T_15s, and T_30s) were extracted and recorded. The experiment was repeated three times.

Results

No significant differences were found in the thickness of LM at rest (P > 0.999), T_c-max (P > 0.999), and T_15s (P = 0.414) between the two groups. However, the ability to recruit LM muscle contraction differed between groups at T_30s (P = 0.006), with subjects in the experimental group that received visual ultrasound biofeedback maintaining a relative maximum contraction. Besides, no significant differences were found in the TrA muscle thickness at rest (P > 0.999) and T_c-max (P > 0.999) between the two groups. However, significant differences of contraction thickness were found at T_15s (P = 0.031) and T_30s (P = 0.010) between the two groups during the Abdominal Drawing-in Maneuver (ADIM), with greater TrA muscle contraction thickness in the experimental group.

Conclusions

RUSI can be used to provide visual biofeedback, which can promote continuous contraction, and improve the ability to activate the LM and TrA muscles in healthy subjects.

Effects of progressive neuromuscular stabilization exercise on the support surface on patients with high obesity with lumbar instability: A double-blinded randomized controlled trial

BACKGROUND

Intensive neuromuscular stabilization exercise on highly obese patients with low back pain results in positive effects of body fat decline and prevention of complications. The purpose of this study is to investigate the effects of progressive neuromuscular stabilization exercise on unstable surface on pain, motor function, psychosocial factors, balance, and abdominal contraction with highly obese patients with lumbar instability.

METHODS

This study is a double-blinded randomized controlled trial. A total of 46 highly obese patients (body mass index [BMI] ≥ 30 kg/m2) with lumbar instability were assigned randomly to experimental group (n = 23) and control group (n = 23). The control group performed the intensive progressive exercise on a stable surface and the experimental group on an unstable surface.

RESULT

Significant differences were shown for BMI, QVAS, K-ODI, FABQ, and balance ability for both groups before and after the intervention (P < .05), and only the experimental group showed significant difference for transverse abdominis muscle thickness in contraction and contraction rate (P < .05). Compared to the control group, the experimental group showed significant difference (P < .05) in the amount of changes for QVAS, K-ODI, balance ability, transverse abdominis muscle thickness in contraction, and contraction rate.

CONCLUSION

Progressive neuromuscular stabilization exercise program on unstable surfaces demonstrated to be an effective and clinically useful method to decrease pain level, increase motor function, balance, and transverse abdominis muscle thickness in contraction and contraction rate for highly obese patients with lumbar instability.

Comparison of the Pressure Biofeedback Unit and Real-Time Ultrasound Imaging as Feedback Tools to Contract the Transversus Abdominis Muscle: A Randomized Controlled Trial in Healthy Older Adults

BACKGROUND AND PURPOSE

The transversus abdominis (TrA) is a key muscle for lumbar stabilization and is often retrained in physical therapy. Feedback tools, such as the pressure biofeedback unit (PBU) and rehabilitative ultrasound imaging (RUSI), are frequently used by physical therapists to train their patients and improve their patients' ability to contract this muscle. However, the effect of these tools in rehabilitating the TrA in older adults remains to be demonstrated, as is their efficiency in transferring the skill of recruiting the TrA from a supine position to a standing position.The objective of the study was to compare the immediate effectiveness of the PBU and RUSI to reeducate the TrA muscle in a population of asymptomatic older adults (without pain).

METHODS

Forty participants were randomized into 2 groups (RUSI or PBU). The intervention included a training session involving 15 TrA contractions held for 10 seconds with the corresponding feedback device. The dependent variable, TrA thickness (a muscle activation indicator), was measured using ultrasound images before and after the intervention in a supine and standing position. Nonparametric analyses were used for inter- and intragroup comparisons.

RESULTS AND DISCUSSION

The results showed no between-group differences in TrA activation ratio (AR) in the supine or standing position (supine AR: TrA RUSI thickness change P = .53 vs PBU thickness change P = .73, comparison between groups P = .51; standing AR: TrA RUSI thickness change P = .003 vs PBU thickness change P = .10; comparison between groups P = .61). However, the change in TrA thickness compared to the other abdominal wall muscles in a standing position was significantly less post-intervention for the RUSI group only (RUSI P = .006 vs PBU P = .72). Both groups remained similar post-intervention for this outcome (P = .20).

CONCLUSIONS

Neither the RUSI nor the PBU seems to have the desired effect on the activation of TrA in asymptomatic older adults.

Recovery of the lumbar multifidus muscle size in chronic low back pain patients by strengthening hip abductors: A randomized clinical trial

INTRODUCTION

Decrease in cross-sectional thickness of lumbar multifidus (MF) muscles during prolonged low back pain episodes commonly occurs. Restoration of the MF muscle size can be an effective way of treating chronic low back pain (CLBP) patients. Traditionally, clinicians apply muscle stabilization exercises for these patients. Recent studies support the need for active strengthening exercises for treatment of the CLBP patients.

OBJECTIVE

The MF muscles provide lumbar stability, and therefore we hypothesized that strengthening of these muscles can be more effective than the MF muscle stabilization exercises in restoration of the muscle size.

DESIGN

Study design was a randomized allocation control trial with two groups of adult female CLBP patients (n = 12 each; age range of 20-45). Patients in the control group underwent stabilization exercises and the patients in the intervention group underwent the hip abductor strengthening exercises.

SETTING

For all subjects of each group, the trials continued in 24 sessions distributed over 8 weeks and the MF muscles were measured in the beginning of the first session and one week after completion of the last session.

MAIN OUTCOME MEASURES

Statistical significance (p-value) of the change in the average MF muscle thickness, pain, and disability scores along with for each group were estimated.

RESULTS

Both regimens of exercises can significantly decrease the pain and disability: average pain and disability reductions of 46% (p-value of 0.001) and 33% (p-value of 0.02) via stabilization versus average pain and disability reductions of 65% (p-value of 0.001) and 59% (p-value of 0.001) via hip abductor strengthening. However, the hip abductor strengthening is the sole statistically significant exercise regimen (p-value of 0.014 vs 0.94) for increasing the MF muscle size.

CONCLUSION

Replacement of the traditional stabilization exercises with the hip abductor strengthening exercises for effective treatment of female adults with CLBP is recommended.

Effect of trunk stabilization exercise on abdominal muscle thickness, balance and gait abilities of patients with hemiplegic stroke: A randomized controlled trial

BACKGROUND: Trunk stability has been identified as an important prerequisite of functional movement. OBJECTIVE: To investigate the effectiveness of core muscle contraction training on abdominal muscle thickness, balance, and gait ability in stroke patients. METHODS: Thirty patients with stroke were randomly assigned to two experimental groups and a control group. All groups received conventional therapeutic exercise program for six weeks. The experimental groups additionally trained trunk stability exercise with abdominal hollowing or bracing maneuvers within training time. Primary outcome measures were evaluated abdominal muscle thickness using the sonography. Secondary outcome measures were evaluated by the Functional Reach Test (FRT), Berg Balance Scale (BBS), 10-meter walk test (10MWT), and Timed Up and Go test (TUG). RESULTS: Compared with the control group, the effect of trunk stability training for the experimental groups on the abdominal muscles thickness change was observed (p < 0.05). The values in balance and gait measures, BBS, FRT, 10MWT, and TUG, showed significant improvement after the intervention periods (p < 0.05), although no significant differences were found in scores of gait and balance scales among groups. CONCLUSIONS: Trunk stability training with selective abdominal muscles activation has beneficial effects on abdominal muscles, balance, and mobility in stroke patients. Our findings might provide support for introducing stroke rehabilitation.

Comparing muscle thickness and function in healthy people and subjects with upper trapezius myofascial pain syndrome using ultrasonography

BACKGROUND

The reliability of the muscle function using ultrasonography is not reported in patients with myofascial pain syndrome and healthy individuals. The main aim of this study was to compare muscle thickness and function of two matched healthy and patients groups with neck pain due to upper trapezius myofascial pain syndrome.

METHODS

40 subjects (20 healthy and 20 patients) participated in this study. Two examiners measured the upper trapezius thickness and function 3 times by ultrasonography independently in the test and retest sessions.

RESULTS

There were not significant differences between two groups with respect to demographic characteristics. The ICC values were good to excellent for both measurements. There were no significant differences between the two groups, in terms of upper trapezius muscle thickness in rest (p = 0.63), fair (p = 0.75) and normal (p = 0.73) contractions. On the other hand, % rest-thickness fair (p = 0.006), % rest-thickness normal (p = 0.006), % MVC-thickness (p = 0.02) showed significant differences between two healthy and myofascial pain syndrome groups.

CONCLUSIONS

Ultrasonography is a reliable technique used to measure muscle thickness and function. Muscle thickness in rest, fair and normal contractions is not different between the matched groups of healthy people and myofascial pain syndrome subjects. Additionally, muscle function is less in myofascial pain syndrome subjects than healthy people specially % MVC thickness.

Ultrasound Imaging Is Reliable for Tibialis Posterior Size Measurements

OBJECTIVES

The tibialis posterior (TP) is a vital muscle for controlling the medial longitudinal arch of the foot during weight-bearing activities. Dysfunction of this muscle is associated with a variety of pathologic conditions; thus, it is important to reliably assess its morphologic characteristics. Ultrasound (US) has been used to assess characteristics of TP tendons but not the muscle cross-sectional area (CSA). The purpose of this study was to establish a reliable US technique to measure the TP CSA and thickness.

METHODS

Twenty-three healthy volunteers participated. We evaluated the CSA and thickness at 4 measurement locations (anterior and posterior views at both 30% and 50% of the shank length).

RESULTS

The participants included 12 female and 11 male volunteers (mean age ± SD, 31.23 ± 14.93 years). Excellent reliability was seen for the CSA and thickness at all locations (intraclass correlation coefficients, 0.988-0.998). Limits of agreement (LoA) and standard errors of the measurement (SEMs) were slightly lower at the 30% locations (LoA at 30%, 4.6-9.2; LoA at 50%, 6.4-9.7; SEM at 30%, 0.03-0.05; SEM at 50%, 0.04-0.07). Strong correlations were seen between anterior and posterior measurements of the CSA (30%, r = 0.99; P < .0001; 50%, r = 0.94; P < .0001) and thickness (30%, r = 0.98; P < .0001; 50%, r = 0.95; P = .0001).

CONCLUSIONS

Based on these results, the TP can be measured accurately with US at any of the tested locations. Due to the ease of collection and the quality of the data, we recommend the anterior view at 30% of the shank length to measure the CSA. The ability to assess muscle size of the TP will aid in a variety of medical and research applications.

Effect of the Abdominal Draw-In Maneuver and Bracing on Abdominal Muscle Thickness and the Associated Subjective Difficulty in Healthy Individuals

We evaluated the trunk abdominal muscle thickness while performing different exercises to identify the most effective training and to investigate the subjective difficulty associated with exercising. Twenty-eight men (mean age: 21.6 ± 0.9 years) without orthopedic diseases were enrolled. Ultrasonic imaging was used to measure the thickness of the transversus abdominis (TA), internal oblique, and external oblique muscles while at rest and while performing the abdominal draw-in maneuver and abdominal bracing. Measurements were made in the supine and sitting positions, and the subjective difficulty in performing each exercise was examined using a 5-level evaluation scale. The TA and internal oblique muscle thicknesses were significantly greater during the abdominal draw-in maneuver (ADIM) than during bracing or resting, in the supine and sitting positions. The subjective difficulty of abdominal bracing (AB) was graded significantly higher than that of ADIM. Additionally, a correlation between subjective difficulty and muscle thickness was found for the TA and IO. Our results may contribute to the choice of more effective exercises for spinal stability.

Transverse abdominis activity and ultrasound biofeedback in college golfers with and without low back pain

OBJECTIVES

To compare transverse abdominis (TrA) muscle activity in college golfers with and without a history of low back pain (LBP) and examine the effects of ultrasound biofeedback and a functional golf-setup position on TrA activity.

DESIGN

Crossover study.

SETTING

Laboratory.

PARTICIPANTS

Thirty-two (n = 32) collegiate golfers were stratified into either the LBP group (n = 16, 4.6 ± 4.5 LBP episodes) or non-LBP group (n = 16, 0.1 ± 0.3 LBP episodes) based on LBP episodes in the last 6-months.

MAIN OUTCOME MEASURES

Ultrasound measures of TrA activity were performed during standard contractions and contractions with ultrasound biofeedback. Contraction-type order was randomized between two visits. Testing was performed in two positions, supine and golf-setup positions.

RESULTS

We observed no significant differences in TrA activity between the LBP and non-LBP groups. Overall, TrA activity was greater during biofeedback contractions compared to standard contractions, and TrA activity was lower in the golf-setup position compared to the supine position.

CONCLUSIONS

We observed no differences in TrA activity between college golfers with and without LBP. College golfers with and without LBP demonstrated a greater ability to contract their TrA with real-time ultrasound biofeedback and a lower ability to contract their TrA in the functional golf-setup position compared to the traditional supine position.

The Effects of Thrust Joint Manipulation on the Resting and Contraction Thickness of Transversus Abdominis in Patients With Low Back Pain: A Randomized Control Trial

OBJECTIVE

To investigate the immediate changes in resting and contracted thickness of the transversus abdominis (TrA) muscle after application of thrust joint manipulation (TJM) vs sham manipulation in participants with low back pain.

METHODS

A pretest-posttest randomized controlled trial design was performed. Consecutive subjects satisfying eligibility criteria completed patient-report outcome baseline measures, pretreatment rehabilitative ultrasound imaging (RUSI) measurements, followed by the randomly assigned intervention then, post-treatment RUSI measurements, and post-treatment & final patient-reported outcome measures. To compare the outcomes of TJM and sham manipulation on the TrA muscle thickness, a 2-by-2 analysis of variance (treatment [TJM and sham manipulation]) by time (pretreatment and post-treatment) was completed for both the TrA muscle thickness at rest and muscle thickness during contraction. Descriptive statistics including independent-sample t tests for continuous variables and χ² tests for categorical variables were used to analyze differences in patient-reported outcome measures between groups.

RESULTS

Sixty-seven eligible participants agreed to participate. No significant interactions were identified for either muscle thickness at rest or contraction.

CONCLUSION

This study did not support the hypothesis that manipulation would result in greater changes in TrA thickness at rest or during contraction in participants with low back pain. Based on prior research that identified subgroups of participants likely to respond to manipulation, future research should include participants more likely to respond favorably to TJM. This study was a priori registered with clinicaltrails.gov (NCT02558855).