Individuals with chronic low back pain do not modulate the level of transversus abdominis muscle contraction across different postures

The aim of this study was to evaluate the thickness of the transversus abdominis (TrA) muscle in three basic postures in subjects with and without chronic low back pain. Subjects were classified into a chronic low back pain group (n = 27) and a healthy control group (n = 23). The thickness of the TrA muscle was measured at rest and during the abdominal drawing-in manoeuvre (ADIM) in supine, sitting and standing postures using B-mode ultrasound imaging. Contraction ratio (TrA thickness during the ADIM/TrA thickness at rest) was calculated for each posture. At rest, the TrA thickness in the sitting and standing postures was significantly greater than in the supine posture (p < 0.017) in the control group, but similar in all three postures in the low back pain group. TrA thickness was similar in the low back pain and control group in all three postures. During the ADIM, TrA thickness was significantly greater in the control group than in the chronic low back pain group in all three postures. The contraction ratio was also significantly higher in the control group than in the chronic low back pain group in all three postures. These results indicate that the automatic postural contraction of the TrA observed in the control subjects in the sitting and standing postures was not demonstrated in subjects with chronic low back pain. The present study revealed the one aspect of different response of the TrA muscle to changing posture between two groups.     

Abdominal muscle contraction thickness and function after specific and general exercises: A randomized controlled trial in chronic low back pain patients

The aim of this study was to assess changes in deep abdominal muscle function after 8 weeks of exercise in chronic low back pain patients. Patients (n = 109) were randomized to specific ultrasound guided, sling or general exercises. Contraction thickness ratio in transversus abdominis (TrA), obliquus internus (OI) and externus (OE), and TrA lateral slide were assessed during the abdominal drawing-in maneuver by b-mode ultrasound. Changes in abdominal muscle function were also regressed on changes in pain. Only modest effects in deep abdominal muscle function were observed, mainly due to reduced activation of OI (contraction thickness ratio: 1.42–1.22, p = 0.01) and reduced TrA lateral slide (1.26–1.01 cm, p = 0.02) in the ultrasound group on the left side. Reduced pain was associated with increased TrA and reduced OI contraction ratio (R² = 0.18). It is concluded that 6–8 treatments with specific or general exercises for chronic low back patients attained only marginal changes in contraction thickness and slide in deep abdominal muscles, and could only to a limited extent account for reductions in pain.     

The effect of lumbar posture on abdominal muscle thickness during an isometric leg task in people with and without non-specific low back pain

This study investigated the effect of lumbar posture on function of transversus abdominis (TrA) and obliquus internus (OI) in people with and without non-specific low back pain (LBP) during a lower limb task. Rehabilitative ultrasound was used to measure thickness change of TrA and OI during a lower limb task that challenged the stability of the spine. Measures were taken in supine in neutral and flexed lumbar postures in 30 patients and 30 healthy subjects. Data were analysed using a two-way (groups, postures) ANOVA. Our results showed that lumbar posture influenced percent thickness change of the TRA muscle but not for OI. An interaction between group and posture was found for TrA thickness change (F_1,56 = 6.818, p = 0.012). For this muscle, only healthy participants showed greater thickness change with neutral posture compared to flexed (mean difference = 6.2%; 95% CI: 3.1–9.3%; p < 0.001). Comparisons between groups for both muscles were not significant. Neutral lumbar posture can facilitate an increase in thickness of the TrA muscle while performing a leg task, however this effect was not observed for this muscle in patients with LBP. No significant difference in TrA and OI thickness change between people with and without non-specific LBP was found.     

The influence of Pilates training on the ability to contract the Transversus Abdominis muscle in asymptomatic individuals

The neuromuscular system acts to maintain postural stability and reduce the impact of deleterious loads on the spine. Exercising of the abdominal muscles has become widely used in the management of low back pain in order to provide this supplement to spinal stability. Several exercise programmes have been advocated to promote stabilization but evaluation is difficult. This study evaluates two common forms of exercise effects on the ability to appropriately contract Transversus Abdominis (TrA) muscle, whose normal function is regarded as significant in spinal stability.Thirty-six asymptomatic females were examined. Twelve formed the Pilates trained group, 12 the abdominal curl group (both attending a minimum of 25 classes in 6 months) and 12 were non-training controls. A pressure biofeedback unit (PBU) was used to assess performance of the TrA muscle during an abdominal hollowing activity (TrA isolation test) and under limb load (Lumbo-pelvic stability test).The percentage of subjects passing the TrA isolation test was 10 subjects (83%) from the Pilates group, four subjects (33%) from the abdominal curl group, and three subjects (25%) from the control group. The percentage of subjects passing the lumbo-pelvic stability test was five subjects (42%) from the Pilates group, all the subjects from both the abdominal curl and control groups failed the test. The study appears to indicate that Pilates trained subjects could contract the TrA and maintain better lumbo-pelvic control than do those who perform regular abdominal curl exercises, or no abdominal muscle exercises.     

Effect of 2 lumbar spine postures on transversus abdominis muscle thickness during a voluntary contraction in people with and without low back pain

Objective

The present study investigated the effect of 2 different lumbar spine postures, neutral and flexed lumbar postures, on transversus abdominis (TrA) muscle function during a voluntary contraction (hollowing and draw-in maneuver) in people with and without low back pain (LBP).

Methods

Thirty participants with LBP and 30 healthy participants were recruited for this cross-sectional study. Transversus abdominis muscle function was measured as a change in thickness with ultrasound imaging. Participants performed voluntary TrA contraction in a supine lying position with the lumbar spine in neutral and flexed postures. Data were analyzed using a 2-way (groups, postures) analysis of variance.

Results

Lumbar posture influenced TrA function during a voluntary contraction in people with and without LBP. There was a significant main effect of posture (F_1,58 = 16.140, P < .001). Neutral lumbar posture improved participants' ability to recruit TrA in both group (mean difference, 7.5%; 95% confidence interval, 3.8%-11.3%). No significant differences were found between healthy subjects and those with LBP.

Conclusions

The results of the present study showed that, in subjects performing a voluntary TrA contraction, the neutral lumbar posture improves the ability to increase change in TrA thickness. This study found no significant difference in TrA thickness change between healthy subjects and those with nonspecific LBP.     

The response of the transverse abdominis and internal oblique muscles to different postures

The purpose of this study was to consider how the deep abdominal muscles responded to alterations in seated stability. The thickness of the right transverse abdominis (TrA) and internal oblique (IO) muscles were measured with ultrasound imaging in 30 healthy human subjects (mean age 27.7, years 22 females) in supine lying, relaxed sitting on a chair with both feet on the ground, relaxed sitting on a gym ball with both feet on the ground and sitting on a gym ball lifting the left foot off the floor. Measurements were taken at the end of both inspiration and expiration. The results showed that muscle thickness expressed as a percentage of the actual muscle thickness in supine lying did not differ between relaxed sitting on a chair and sitting on a gym ball for either muscle (P=0.012-0.054) where Bonferroni corrected P-value for significance=0.002. Raising the foot off the floor produced a significant increase in thickness for TrA and IO, when compared with the other seated postures (P<0.001). It was also found that both muscles were thicker at the end of expiration (P<0.001) which has also been established by other authors. These findings suggest that both deep abdominal muscles respond in the same way to postural changes. It also demonstrates that these muscles are automatically targeted by significantly decreasing the base of support, but in normal subjects sitting on a gym ball is not sufficient to increase their activity.     

Abdominal hollowing and lateral abdominal wall muscles' activity in both healthy men & women: An ultrasonic assessment in supine and standing positions

The objective of this study was to investigate the effects of Abdominal Hollowing (AH) maneuver on External Oblique (EO), Internal Oblique (IO) and Transversus Abdominis (TrA) muscles in both healthy men and women during the two postures of supine and upright standing. The study was conducted on 43 asymptomatic volunteers (22 males and 21 females) aged 19-44 (27.8±6.4) years. Rehabilitative Ultrasonic Imaging (RUSI) was simultaneously performed to measure muscle thickness in both rest and during AH maneuvers while activation of the TrA during AH was controlled by Pressure Biofeedback (PBF) device. Mixed-model ANOVA with repeated measures design, and Pearson correlation tests were used to analyze the data. Muscle thickness of all muscles was significantly higher for male subjects (F>6.2, p<0.017). The interaction effect of gender and muscle status was significant only for IO (F=7.458, p=0.009) indicating that AH maneuver increased the thickness of IO in men. Interaction effect of posture and muscle status on muscular thickness indicated that changing position only affects the resting thickness of TrA (F=5.617, p=0.023). Standing posture significantly affected the TrA contraction ratio (t=3.122, p=0.003) and TrA preferential activation ratio (t=2.76, p=0.008). There was no relationship between age and muscle thickness (r=0.262, p=0.09). The PBF has been introduced as a clinical and available device for monitoring TrA activity, while RUSI showed that both TrA and IO muscles had activated after AH maneuver. We recommend performing further investigations using electromyography and RUSI simultaneously at more functional postures such as upright standing.     

Deep and superficial abdominal muscle activation during trunk stabilization exercises with and without instruction to hollow

The deepest muscle of the human ventro-lateral abdominal wall, the Transversus Abdominis (TrA), has been ascribed a specific role in spine stabilization, which has motivated special core stability exercises and hollowing instruction to specifically involve this muscle. The purpose here was to evaluate the levels of activation of the TrA and the superficial Rectus Abdominis (RA) muscles during five common stabilization exercises performed in supine, bridging and four-point kneeling positions, with and without instruction to hollow, i.e. to continuously pull the lower part of the abdomen towards the spine. Nine habitually active women participated and muscle activity was recorded bilaterally from TrA and RA with intramuscular fine-wire electrodes introduced under the guidance of ultrasound. Results showed that subjects were able to selectively increase the activation of the TrA, isolated from the RA, with the specific instruction to hollow and that side differences in the amplitude of TrA activity, related to the asymmetry of the exercises, remained even after the instruction to hollow. The exercises investigated caused levels of TrA activation from 4 to 43% of that during maximal effort and can thus be used clinically to grade the load on the TrA when designing programs aiming at training that muscle.     

Pilates experience vs. muscle activation during abdominal drawing-in maneuver

The purpose of this study was to compare the activation of deep abdominal and spine stabilizer muscles of subjects with and without Pilates experience. Twenty-three subjects were divided into a no-experience group (n = 13) and an experienced group (n = 10). The subjects performed three 12-s drawing-in maneuver trials at 50% TrA/IO maximal voluntary contraction (MVC). The experienced group presented greater activation of both muscles than the no-experience group (62% vs. 32% MVC for the TrA/IO, and 52% vs. 12% MVC for the LD, p < 0.001). The no-experience group had higher variability among trials and did not reach 50% MVC for the TrA/IO, while the experienced group was able to reach and keep the TrA/IO activation at or above 50% MVC. Pilates experience and muscle activation were strongly associated. Pilates trained subjects were able to sustain concomitant abdominal and low back muscle contraction during the drawing-in maneuver, while subjects with no Pilates experience were not able to reach the same levels of abdominal activation and did not present significant low back muscle co-activation.     

Abdominal muscle recruitment during a range of voluntary exercises

Various exercises are used to retrain the abdominal muscles in the management of low back pain and other musculoskeletal disorders. However, few studies have directly investigated the activity of all the abdominal muscles or the recruitment of regions of the abdominal muscles during these manoeuvres. This study examined the activity of different regions of transversus abdominis (TrA), obliquus internus (OI) and externus abdominis (OE), and rectus abdominis (RA), and movement of the lumbar spine, pelvis and abdomen during inward movement of the lower abdominal wall, abdominal bracing, pelvic tilting, and inward movement of the lower and upper abdominal wall. Inward movement of the lower abdominal wall in supine produced greater activity of TrA compared to OI, OE and RA. During posterior pelvic tilting, middle OI was most active and with abdominal bracing, OE was predominantly recruited. Regions of TrA were recruited differentially and an inverse relationship between lumbopelvic motion and TrA electromyography (EMG) was found. This study indicates that inward movement of the lower abdominal wall in supine produces the most independent activity of TrA relative to the other abdominal muscles, recruitment varies between regions of TrA, and observation of abdominal and lumbopelvic motion may assist in evaluation of exercise performance.     

The effects of bridge exercise with the abdominal drawing-in maneuver on an unstable surface on the abdominal muscle thickness of healthy adults

[Purpose] The purpose of this study was to determine the impact of a bridge exercise with an abdominal drawing-in maneuver (ADIM) performed with different surface conditions on abdominal muscle thickness. [Subjects] Thirty subjects were randomly divided into an unstable bridge exercise group (UBE group, n=15) and a stable bridge exercise group (SBE group, n=15). [Methods] After 6 weeks of performing bridge exercises accompanied by ADIM, the change in the muscle thicknesses of the transverse abdominis (TrA) and internal oblique abdominis (IOA) muscles was assessed using ultrasonography. [Results] After 6 weeks of exercise, the TrA was significantly altered in the SBEG, and the TrA and IOA were both significantly changed in the UBEG. [Conclusion] When performing bridge exercises to increase the Tra and the IO muscle thicknesses, exercising on an unstable surface is recommended.Key words: Transversus abdominis, Bridge exercise, Abdominal drawing-in maneuver     

Ultrasound Evaluation of the Abdominal Wall and Lumbar Multifidus Muscles in Participants Who Practice Pilates: A 1-year Follow-up Case Series

Objective

The purpose of this study was to describe ultrasound (US) changes in muscle thickness produced during automatic activation of the transversus abdominis (TrAb), internal oblique (IO), external oblique (EO), and rectus abdominis (RA), as well as the cross-sectional area (CSA) of the lumbar multifidus (LM), after 1 year of Pilates practice.

Automatic activity of deep and superficial abdominal muscles during stable and unstable sitting positions in individuals with chronic low back pain

Objective

The purpose of this study was to assess muscle thickness changes in the deep and superficial abdominal muscles, during sitting on stable and unstable surfaces in subjects with and without chronic low back pain (CLBP).

Abdominal draw-in maneuver combined with simulated weight bearing increases transversus abdominis and internal oblique thickness

The abdominal draw-in maneuver (ADIM) is a method commonly used to reestablish neuromuscular control of the deep spine muscles among individuals with musculoskeletal problems. The purpose of this study was to evaluate the effect of ADIM combined with simulated weight-bearing (SWB) activities in the facilitation of the deep spine muscles. The subjects were 30 young healthy individuals. Ultrasound images were used to measure the relative changes in transverse abdominal (TrA), internal oblique (IO) and external oblique (EO) muscle thickness during a simulated weight-bearing ADIM (SWB-ADIM). A paired t-test was used to determine the differences between the ADIM and SWB-ADIM conditions. The results showed that the thickness of the TrA and IO muscles in the SWB-ADIM condition was significantly higher than in the ADIM-alone condition. Our findings suggest that SWB-ADIM is more effective than ADIM alone for improving the deep spine muscles in real-life situations.     

Comparison of changes in the contraction of the lateral abdominal muscles between the abdominal drawing-in maneuver and breathe held at the maximum expiratory level

The abdominal drawing-in maneuver (ADIM) is commonly used as a fundamental component of lumbar stabilization training programs. One potential limitation of lumbar stabilization programs is that it can be difficult and time consuming to train people to perform the ADIM.The transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles are the most powerful muscles involved in expiration. However, little is known about the differences in the recruitment of the abdominal muscles between the ADIM and breathe held at maximum expiratory level (maximum expiration).The thickness of the TrA and IO muscles was measured by ultrasound imaging, and the activity of the EO muscle was measured by electromyography (EMG) in 33 healthy male performing the ADIM and maximum expiration.Maximum expiration produced a significant increase in the thickness of the TrA and IO muscles compared to the ADIM (p < 0.001). The EMG activity of the EO muscle was significantly higher during maximum expiration than during the ADIM (p < 0.001). The intensity of the EMG activity of the EO muscle was approximately 30% of the maximal voluntary contraction during maximum expiration.Thus, maximum expiration may be an effective method for training of co-activation of the lateral abdominal muscles.     

Effects of posture on the thickness of transversus abdominis in pain-free subjects

The role of transversus abdominis (TrA) on spinal stability may be important in low back pain (LBP). To date, there have not been any investigations into the influence of lumbo-pelvic neutral posture on TrA activity. The present study therefore examines whether posture influences TrA thickness. A normative within-subjects single-group study was carried out. Twenty healthy adults were recruited and taught five postures: (1) supine lying; (2) erect sitting (lumbo-pelvic neutral); (3) slouched sitting; (4) erect standing (lumbo-pelvic neutral); (5) sway-back standing. In each position, TrA thickness was measured (as an indirect measure of muscle activity) using ultrasound. In erect standing, TrA (mean TrA thickness: 4.63 ± 1.35 mm) was significantly thicker than in sway-back standing (mean TrA thickness: 3.32 ± 0.95 mm) (p = 00001). Similarly, in erect sitting TrA (mean thickness = 4.30 mm ± 1.58 mm) was found to be significantly thicker than in slouched sitting (mean thickness = 3.46 mm ± 1.13 mm) (p = 0002). In conclusion, lumbo-pelvic neutral postures may have a positive influence on spinal stability compared to equivalent poor postures (slouched sitting and sway-back standing) through the recruitment of TrA. Therefore, posture may be important for rehabilitation in patients with LBP.     

The Relationship of Abdominal Muscles Balance and Body Balance

This study aimed to identify what impact the thickness differences between the leftside and rightside transversus abdominis (TrA), internal obliquus (IO) and external obliquus (EO) have on balance ability in the abdominal drawing-in maneuver (ADIM) and resting postures. [Subjects and Methods] In this study, 41 young adults were asked to adopt a resting posture and to perform ADIM. The thicknesses of the abdominal muscles (TrA, IO, EO) were measured using ultrasound imaging, Then balance ability was measured, so that a comparative analysis could be carried out. [Results] According to the results, the thicknesses of TrA and IO very significantly increased when ADIM was performed. The changes in thickness of the muscles on the left and right sides showed no significant correlations with balance ability. [Conclusion] According to the study results, the difference in thickness between the left and right side muscles in a normal person is small (symmetric), and the differences in the thickness of TrA and IO on the left and right side reduced when the ADIM, which is a re-education method for abdominal muscles was performed. Therefore, we consider that the ADIM should be used in future clinical trials to induce symmetric contraction of the abdominal muscles. Also, the correlation results of muscle balance and body balance can be used as empirical data.Key words: Ultrasound, Abdominal muscle, Imbalance     

Effect of corporal suspension and pendulum exercises on neuromuscular properties and functionality in patients with medullar thoracic injury

BackgroundTraumatic spinal cord injury (TSCI) is one of the most devastating injuries that has a physical impact on patients. The CHORDATA® method involves suspension and pendulous exercises and has been clinically used to treat patients with TSCI. Although empirically used to treat neurological patients, there is no scientific evidence of the efficacy of this method.PurposeTo evaluate the chronic effects of CHORDATA® method on torque, muscle activation, muscle thickness, and functionality in patients with traumatic spinal cord injury.MethodsTwenty-six male patients with medullar thoracic injury were randomly categorised into two groups: intervention group (n = 14) and control group (n = 12). Rehabilitation program comprised of 16 sessions of body suspension and pendulum exercises (twice/week). The maximal voluntary isometric trunk flexion and extension torques, muscle activation and thickness (external and internal oblique, rectus and transversus abdominis, longissimus, and multifidus muscles), and functionality (adapted reach test) were evaluated before and after of rehabilitation program.FindingsA significant increase was observed in maximal voluntary isometric torque (flexion, 58%; extension, 76%), muscle activation of the rectus abdominis muscle, and muscle thickness of all intervention group muscles, without changes in the control group. Compared to the pre-intervention period, the intervention group also showed improvement in functionality at post-intervention, but no such differences were noted in the control group.InterpretationThe corporal suspension and pendulum exercises training improved rectus abdominis muscle activation, trunk muscles structure and strength, and reaching capacity in medullar thoracic injury patients.     

Transversus abdominis: Changes in thickness during the unsupported upper limb exercise test in older adults

Novel, short-lived upper limb tasks performed by young adults have been used to investigate the role of transversus abdominis (TrA) in maintaining postural stability. Little information exists concerning the behaviour of TrA in older adults during protracted postural challenges. The primary aim of this study was to describe the change in thickness of TrA during an incremental upper limb exercise test in older adults. A secondary analysis was undertaken to compare the results between younger and older subjects. Healthy subjects aged between 40 and 70 years performed the Unsupported Upper Limb Exercise Test (UULEX) while activity of TrA was continuously monitored by using rehabilitative ultrasound imaging. Changes in muscle dimensions were measured every minute during the test. The thickness of TrA increased significantly and exponentially between minutes 8 and 13 of the UULEX. Although there was a significant difference between older and younger subjects in absolute measures of TrA thickness, the change in TrA thickness as a percentage of resting thickness during the UULEX demonstrated an identical pattern between younger and older subjects. This study suggests that TrA is continually and increasingly active during an upper limb task in both younger and older asymptomatic subjects.