Contraction Of Transversus Abdominis Research Articles

The effects of hip flexor stretching with and without abdominal exercises in asymptomatic individuals with hyperlordosis

Background/AimsHyperlordosis is associated with shortened hip flexor muscles, causing low back pain. The aim of this study was to investigate the effects of hip flexor stretching with and without abdominal exercises in individuals with hyperlordosis.MethodsA total of 30 participants with hyperlordosis, aged between 20 and 30 years, were divided into three groups. Participants in the hold-relax group performed hold-relax stretching for 10 seconds, five repetitions, on both legs. Participants in the abdominal hollowing group performed hold-relax stretching and added an abdominal hollowing exercise for 10 seconds a repetition, 10 repetitions a set for three sets. Participants in the curl-up group performed hold-relax stretching and then performed curl-up exercises for 10 repetitions a set for three sets. The angle of lumbar lordosis, hip muscle length (degrees), percentage of maximum voluntary contraction of transversus abdominis and internal abdominal oblique, external abdominal oblique, rectus abdominis, lumbar erector spinae and multifidus muscles were investigated at pre-test, post-test and followed up 3 days after the end of the intervention.ResultsSignificant within-group differences were found in the angle of lumbar lordosis for all groups (P<0.05), muscle length of hip flexor, and percentage of maximum voluntary contraction of the lumbar erector spinae and multifidus muscles in the curl-up group (P<0.05). The significant difference between pre-test and follow up in the hold-relax group and curl-up group reflects the retention of at least 3 days.ConclusionsHold-relax stretching can reduce the angle of lumbar lordosis and increase hip muscle length. In the curl-up group, the lumbar erector spinae and multifidus muscles decreased. Therefore, performing curl-up exercises after hold-relax stretching is recommended to decrease the angle of lumbar lordosis and percentage of maximum voluntary contraction of lumbar erector spinae and multifidus muscles.

Effects of mouthpiece shape and expiratory threshold loading on contraction of the lateral abdominal muscles: A cross-sectional study

BackgroundExpiratory tasks may facilitate transversus abdominis (TrA) activity for spinal stabilization. The purpose of this study was to verify whether a combination of pursed-lip breathing (PLB) and use of an expiratory threshold loading (ETL) device to increase expiratory resistance would promote TrA contraction comparable to that for a stabilization exercise. MethodsTwenty healthy men performed expiratory tasks or an abdominal drawing-in maneuver (ADIM). Expiratory tasks comprised combinations of ETL settings with 0%, 5%, or 15% of maximum expiratory pressure, and mouthpieces with a normal shape or pursed-lip shape. B-mode ultrasound imaging of the TrA, internal oblique, and external oblique muscles was performed to determine percentage changes in muscle thickness. Percentage changes among tasks were statistically compared for each muscle. FindingsTrA thickness increased with normal lips at 15% ETL, with PLB with 5% ETL, and with ADIM (p < 0.01 each). Internal oblique thickness increased under all PLB conditions (p < 0.01 each). No significant differences in external oblique thickness were seen for any tasks. The total thickness of the lateral abdominal muscles was significantly increased not only for 15% ETL tasks and ADIM, but also for PLB with 5% ETL (p < 0.02 each). InterpretationThese results indicated that PLB with 5% ETL could facilitate the same level of TrA activity as the ADIM. PLB with 5% ETL was the only task that simultaneously increased overall lateral abdominal muscles, including the internal obliques, and might be readily applicable in clinical situations.

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

BackgroundReal-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.MethodsForty 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 (Tc-max, T15s, and T30s) were extracted and recorded. The experiment was repeated three times.ResultsNo significant differences were found in the thickness of LM at rest (P > 0.999), Tc-max (P > 0.999), and T15s (P = 0.414) between the two groups. However, the ability to recruit LM muscle contraction differed between groups at T30s (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 Tc-max (P > 0.999) between the two groups. However, significant differences of contraction thickness were found at T15s (P = 0.031) and T30s (P = 0.010) between the two groups during the Abdominal Drawing-in Maneuver (ADIM), with greater TrA muscle contraction thickness in the experimental group.ConclusionsRUSI 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.

Increased Joint Mobility Is Associated With Impaired Transversus Abdominis Contraction.

Mitchell, UH, Owen, PJ, Rantalainen, T, and Belavý, DL. Increased joint mobility is associated with impaired transversus abdominis contraction. J Strength Cond Res 36(9): 2472-2478, 2022-Increased joint mobility is a risk factor for joint injury, but muscle function may be able to compensate for it. Current evidence suggests reduced force production capacity in people with hypermobility. However, little is known about the lumbar spine. The purpose of this cross-sectional study was to assess whether there was a link between joint mobility and transverse abdominis and multifidus muscles contraction, muscles ascribed a core-stability role. Using a modified quantitative version of the Beighton scale (BOM score), we measured joint mobility of 30 middle-aged individuals without low back pain. These scores were correlated with magnetic resonance imaging-derived measures of transverse abdominis and multifidus muscle contraction during a spinal loading maneuver. The level of significance was set for p ≤ 0.05. The results showed greater joint mobility (a higher BOM score) correlated ( r = 0.468; p = 0.009) with reduced transversus abdominis (TrA) shortening during contraction (i.e., less muscle shortening in people with greater joint mobility). The trunk subdomain score exhibited a correlation of 0.354 with TrA length change, but this did not reach statistical significance ( p = 0.055). The subdomains of the BOM score did not correlate significantly with each other ( p ≥ 0.097). No association was seen between multifidus contraction and joint mobility. The results suggest that greater general joint mobility is associated with impaired contraction of the TrA muscle. This should be considered when coaching athletes or treating patients with (functional) spinal instability. The quantitative approach we developed to measure joint mobility could be used in the future studies of global flexibility.

Axial loading and posture cues in contraction of transversus abdominis and multifidus with exercise

Astronauts are at increased risk of spine injury. With a view to developing training approaches for the muscles of the spine in microgravity, this study examined the effects of axial loading and postural cues on the contraction of transversus abdominis and lumbar multifidus in supine lying using a novel exercise device (GravityFit). Thirty (18 males and 12 females) endurance-trained runners without a history of spinal pain aged 33–55 years were recruited. Magnetic resonance imaging (MRI) was performed under one rest and five exercise conditions, which involved variations in axial loading and postural cues. Whole volume of the abdominal and lumbar paraspinal muscles was imaged and transversus abdominis thickness and length and multifidus anteroposterior and mediolateral thickness measured. Transversus abdominis contraction was greatest in the ‘stretch tall plus arm extension’ (length, − 15%, P < 0.001; thickness, + 19%, P < 0.001) and ‘stretch tall plus arm extension and thoracic cue’ (length, − 16%, P < 0.001; thickness, + 18%, P < 0.001) conditions. The contraction of multifidus was the greatest in the ‘arm extension and thoracic cue’ (anteroposterior, + 3.0%, P = 0.001; mediolateral, − 4.2%, P < 0.001) and ‘stretch tall plus arm extension and thoracic cue’ (anteroposterior, + 6.0%, P < 0.001; mediolateral, − 2.1%, P = 0.022) conditions. This study provides proof-of-principle for an exercise approach that may be used to facilitate the automatically contraction of the transversus abdominis and multifidus muscles. Axial loading of the body, with or without arm loading, most consistently led to contraction of the transversus abdominis and lumbar multifidus muscles, and regional differences existed in the contraction within the muscles.

Low back pain in Parkinson's disease: A cross-sectional study of its prevalence, and implications on functional capacity and quality of life

ObjectiveThe aim of this study was to estimate the prevalence of low back pain (LBP) in patients with Parkinson’s disease (PD) and its impact on functional capacity and quality of life. MethodsPatients with idiopathic PD answered a questionnaire and were submitted to a clinical and functional assessment. Unified Parkinson’s Disease Rating Scale (UPDRS), Hoehn and Yahr Scale, Beck Depression Inventory (BDI), McGill Pain Questionnaire (McGill), Roland Morris Disability Questionnaire (RMDQ), 39-item Parkinson’s Disease Questionnaire (PDQ-39) were used. In addition, the ability to contract transversus abdominis (TrA) was assessed. ResultsOne hundred and fifteen patients answered the questionnaire, and 95 (82.6 %) reported painful symptoms. Of these, 67 (58.3 %) had chronic LBP, and approximately 40 % patients reported its onset before diagnosis of PD. Higher scores in pain intensity, depressive symptoms and UPDRS II and III, more advanced stages of PD, and absence of TrA contraction determined poor functional limitation induced by LBP. However, pain intensity (McGill), severity of PD symptoms (UPDRS III) and absence of TrA contraction were identified as predictive factors for functional limitation and explained 66.1 % of the variance in the RMDQ. Pain intensity and LBP-related disability caused negative impact on the quality of life. ConclusionLBP is common in patients with PD and it causes disability and poor quality of life. Pain intensity, UPDRS III and absence of TrA contraction were the most significant predictive factors for disability assessed by the RMDQ.

The Critical Role of Development of the Transversus Abdominis in the Prevention and Treatment of Low Back Pain

The Critical Role of Development of the Transversus Abdominis in the Prevention and Treatment of Low Back Pain

Reliability and Validity of the Feedback Sensor for Activating the Transversus Abdominis Muscle

Background: Core muscle activation is an effective intervention for the management of Low Back Pain (LBP). This study developed new feedback for detecting activation of the transversus abdominis muscle in the lumbar spine. The purpose of this study was to examine the validity and reliability of the feedback device for transversus abdominis muscle contraction. Methods: The participants in this study were 20 healthy males and females (aged 24.1 ± 6.8 years). The feedback sensor was attached to the lumbar support at the front of the trunk. The participants performed an abdominal drawing-in maneuver in order to activate the transversus abdominis muscle, and values from the feedback sensor were collected at the same time. Ultrasound imaging of the transversus abdominis muscle was also collected simultaneously. The feedback sensor collected values at different clinical levels of the pressure biofeedback unit at 64, 66, 68, and 70 mmHg. The protocol was repeated with a 24-hr interval. Intra-class correlation coefficient, coefficient of variation and standard error of measurements were used to examine reliability. The validity of the values obtained from the relationship between the feedback sensor and transversus abdominis muscle thickness was analyzed using Pearson’s correlation coefficients. Results: Test–retest reliability of the feedback sensor was excellent (ICC = 0.946, CV = 2.6%, SEMs = 0.54%). Values of the feedback sensor reported a significantly moderate correlation with the gold standard ultrasound measurement (r = - 0.514, p &lt; 0.001). Conclusion: The feedback device demonstrated potential reliability and validity for clinical use by indicating activation of the transversus abdominis muscle.

Abdominal girth as an index of muscle tension during abdominal hollowing: Selecting the optimal training intensity for the transversus abdominis muscle

The abdominal hollowing technique is used for training the transversus abdominis (TrA). However, the optimal intensity of hollowing is still unclear. The objective of the present study is to verify the validity of estimating the tension of the TrA by measuring the girth of the abdomen with a tape and to determine the optimum intensity of hollowing to effectively train the TrA. Sixteen healthy males performed hollowing with an intensity of 0%, 25%, 50%, 75%, and 100%, estimated from the girth of the abdomen. The shear elastic modulus was measured for the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and TrA at all intensities via ultrasonic shear wave elastography. The shear elastic modulus was considered as the index of the tension of the abdominal muscles at each intensity, and the ratio of the TrA to RA, EO, and IO respectively was calculated as the index of TrA selectivity. As the intensity of hollowing increased, the girth of abdomen decreased and tension of all the four muscles increased. The ratio of TrA to the RA, EO, and IO did not exhibit a significant variation among hollowing intensities of 25% to 100%. It is rational to estimate the tension of the TrA by measuring the girth of the abdomen. Moreover, considering both TrA contraction intensity and selectivity, abdominal hollowing performed at maximum intensity was effective for the maximum contraction training of the TrA.

Risk Factors for Lower-Extremity Injuries in Female Ballet Dancers: A Systematic Review.

Ballet dancers have a high prevalence of injuries to the lower extremity. Many studies have investigated the relationship between dance injury and risk factors. However, risk factors for lower-extremity injury comparing recreational- and elite-level ballet dancers are scarce. To systematically review available original studies to assess risk factors for lower-extremity injury in female ballet dancers between recreational and elite ballet dancers. Five online databases [Web of Science, PubMed, OVID (Medline), EBSCO, and ProQuest] were searched systematically. Included studies had an analytic study design published in the past 11 years and investigated an association between potential risk factors and lower-extremity injury in female ballet dancers. Assessed independently by 2 reviewers using the Downs and Black (DB) criteria and Oxford Centre of Evidence-Based Medicine. Seventeen studies were included. Alignment was a risk factor for lower-extremity injury in both recreational and elite ballet dancers. In elite ballet dancers, poor lumbopelvic movement control, inappropriate transversus abdominis contraction, decreased lower-extremity strength, and poor aerobic fitness were risk factors for lower-extremity injury. In recreational ballet dancers, hypermobility of the hip and ankle and longer training hours were risk factors for lower-extremity injury. Mean DB score was 15.94 (SD 1.57). The majority of studies were retrospective cohort studies or had poor follow-up, with 7 level 2b studies, 6 level 3b studies (cross-sectional), and 4 level 1b studies (prospective cohort with good follow-up). Alignment was identified as a common risk factor for recreational and elite ballet dancers. Other risk factors differed between recreational ballet dancers and elite ballet dancers. Future studies are warranted to use a prospective study design, identify dance level-specific risk factors, and implement evidence-based prevention strategies.

Effect of pelvic floor and transversus abdominis muscle contraction on inter-rectus distance in postpartum women: a cross-sectional experimental study

ObjectivesTo investigate the effect of acute isometric contraction of the pelvic floor muscles (PFM) and transversus abdominis muscle (TrAM) on inter-rectus distance (IRD) from resting values in postpartum women with diastasis rectus abdominis (DRA). DesignCross sectional experimental study. SettingPhysiotherapy clinic. ParticipantsThirty eight postpartum women presenting with DRA of at least two finger widths. MethodsTwo dimensional ultrasound images of IRD were recorded using a linear probe (5 to 10MHz) at rest, during PFM contraction, during TrAM contraction, and during combined PFM and TrAM contraction. IRD data were normally distributed. Main outcome measureChange in IRD. ResultsThere was a significant increase in IRD during PFM and TrAM contraction compared with IRD at rest. At 2cm above the umbilicus, mean PFM was 26.9 [standard deviation (SD) 8.8] mm vs rest 25.7 (SD 8.5) mm {mean difference 1.2 [95% confidence interval (CI) 0.7 to 1.7] mm}; and mean TrAM was 28.4 (SD 9.0) mm vs rest 25.7 (SD 8.5) mm [mean difference 2.8 (95% CI 1.9 to 3.6) mm]. Similarly, 2cm below the umbilicus, mean PFM was 22 (SD 8.3) mm vs rest 21 (SD 7.9) mm [mean difference 0.9 (95% CI 0.4 to 1.6) mm]; and mean TrAM was 23.3 (SD 8.7) mm vs rest 21 (SD 7.9) mm [mean difference 2.3 (95% CI 1.5 to 3.1) mm]. Combined TrAM and PFM contraction measured 2cm above the umbilicus caused the greatest increase in IRD: mean PFM+TrAM 29.6 (SD 9.4) mm vs rest 25.7 (SD 8.5) mm [mean difference 3.9 (95% CI 2.8 to 5.0) mm]. ConclusionBoth PFM and TrAM contraction, and combined PFM and TrAM contraction increased IRD in postpartum women with DRA.

Changes in the contraction ratio of transversus abdominis and quality of life in patients after total hip replacement and three-compartment knee arthroplasty with implant posterior stabilization

Core stability is a reference term for the performance of the deep trunk muscles, which provide functional stability of the lumbopelvic area and control the human body in static and dynamic positions. The study group consisted of 30 patients between the age of 42 and 76 years (mean=61.4) after total hip arthroplasty (total hip replacement, Group I) and total knee arthroplasty (three-compartment arthroplasty with posterior stabilization of the implant - Group II). In 18 (60%) patients, hip endoprosthesis was performed, whereas in 12 (40%), three-compartment knee endoprosthesis with posterior stabilization has been implanted. In the study group, Rehabilitative Ultrasound Imaging (RUSI) of the transversus abdominis muscle thickness was conducted at rest and in contraction, the transversus abdominis activation ratio was specified, the SF-36 Life Quality Questionnaire was applied and a three-week treatment cycle was performed. The tests were carried out twice, i.e. before and after treatment. In the group of patients after total hip replacement, the transversus abdominis (TrA) contraction ratio before the beginning of the exercise programme was 0.79±0.06, and after its completion 0.9 ±0.02. The observed difference was statistically significant at p&lt;0.001. In the group of patients after three-compartment knee arthroplasty, the TrA contraction ratio before the beginning of the exercise programme was 0.78±0.09, and after its completion0 0.91±0.02. The difference of these values was statistically significant at the level of p&lt;0.05. The results of the SF-36 questionnaire in both groups indicate improvement in physical functioning. The observed difference was statistically significant at p&lt;0.001. The performed three-week physiotherapy treatment in conjunction with deep muscle training increases the thickness of the TrA muscle during rest and contraction testing, and increases the transversus abdominis contraction ratio in Rehabilitative Ultrasound Imaging in the study groups. Furthermore, improvement in the level of physical functioning was observed within the studied groups.

Comparison Between Transcutaneous Electrical Nerve Stimulation and Stabilization Exercises in Fatigue and Transversus Abdominis Activation in Patients With Lumbar Disk Herniation: A Randomized Study

ObjectiveThe purpose of this study was to compare transcutaneous electrical nerve stimulation (TENS) and stabilization exercises in an attempt to prevent fatigue and improve muscle activation in patients with lumbar disk herniation associated with low back pain. MethodsThis study involved 29 patients (age range 25-58 years) randomized into 2 groups: the segmental stabilization group (n = 15), who received stabilization exercises on the transversus abdominis (TrA) and lumbar multifidus muscles; and the TENS group (n = 14), who received electrotherapy. Groups underwent 16 sessions, for 60 minutes, twice per week, and they were evaluated before and after intervention. Pain was measured using a visual analog scale, functional disability using the Oswestry Disability Index, muscle activation and fatigue with electromyography, and patients’ ability to contract the TrA with a pressure biofeedback unit. Analyses within and between groups were performed. ResultsThe stabilization group improved lumbar multifidus fatigue (median frequency [MF] initial [P = .002], MF final [P < .001], MF slope [P = .001], and resistance time [P < .001]), ability to contract the TrA (P < .001), pain (P < .001), and functional disability (P < .001). TENS only was effective for pain (P = .012). ConclusionAlthough it relieved pain, TENS was not effective as a single treatment to prevent fatigue, increase TrA contraction, and reduce functional disability in herniated disk patients. Stabilization exercises alone improved all measured outcomes.

Orthopaedic Section Poster Presentations (Abstracts OPO1-OPO300).

These abstracts are presented here as prepared by the authors. The accuracy and content of each abstract remain the responsibility of the authors. In the identification number above each abstract, OPO designates an Orthopaedic Section poster presentation. J Orthop Sports Phys Ther 2018;48(1):A67-A202. doi:10.2519/jospt.2018.48.1.A67.

TRANSVERSUS ABDOMINIS ACTIVATION AND TIMING IMPROVES FOLLOWING CORE STABILITY TRAINING: A RANDOMIZED TRIAL.

Patients with non-specific low back pain (LBP) often present with a decrease in transversus abdominis (TrA) muscle activation and delayed onset of contraction with extremity movements, potentially contributing to recurrent LBP. Core stability is required for extremity movement and if the timing of when the TrA contracts is not corrected patients may continue to experience LBP. The purpose of this study was to assess the effects of a four-week core stability rehabilitation program on TrA activation ratio and when the TrA initiates contraction during upper extremity movements in subjects with and without LBP. It was hypothesized that those with LBP would experience greater changes in TrA activation and onset of contraction by the TrA compared to the healthy group. Randomized Clinical Trial. Forty-two participants volunteered (21 healthy and 21 LBP). Ultrasound imaging measured the TrA activation ratio and time of initial contraction of the TrA during upper extremity movement into flexion. Half of the healthy and LBP participants were assigned to the exercise group. Participants reported twice a week to the athletic training facility to complete an exercise progression of three exercises. After four weeks, all participants returned to have TrA activation and timing measured again. Pertaining to demographics, there were no differences between the healthy and LBP participants. There was a group interaction for both TrA activation ratio (p=.049) and onset of initial contraction (p=.008). Those in the exercise group showed an increase in TrA activation ratio (1.85 ± 0.09) compared to the control group (1.79 ± 0.08), as well as an improvement in the onset of contraction (2.07 ± 0.08 seconds) compared to the control group (2.23 ± 0.09 seconds) after the four-week rehabilitation program. Strong effect sizes for TrA activation ratio (0.71 [0.06-1.35]) and initial onset of TrA contraction (-1.88 [-2.63 - -1.11]) were found indicating clinical differences related to the interventions. TrA activation and timing were altered following a four-week core stability program in people with and without LBP. Clinicians should consider incorporating these exercises for improving the function of the TrA. Therapy, level 2b.

Immediate Changes in Resting and Contracted Thickness of Transversus Abdominis After Dry Needling of Lumbar Multifidus in Healthy Participants: A Randomized Controlled Crossover Trial

ObjectiveThe purpose of this study was to investigate changes in resting and/or contraction thickness of the transversus abdominis (TrA) muscle after dry needling (DN) of the lumbar multifidus (LM) in asymptomatic participants. MethodsA randomized controlled laboratory trial with crossover design was performed. Forty-seven healthy individuals who had not experienced low back pain in the previous 6 months were randomly assigned to receive DN to the LM or a sham-DN intervention. Participants received both interventions separated at least 7 days apart. They were instructed on how to perform a concentric contraction of TrA. Resting and contraction thicknesses of the TrA were obtained through real-time ultrasound measurements before and immediately after each intervention by an assessor blinded to the intervention received. Data from 4 individuals had to be excluded because of poor image quality. ResultsTwo-way analysis of variance revealed a significant contraction with treatment interaction (F[1,42] = 11.489; P = .002). Simple main effects using paired-samples t tests and a Bonferroni post hoc analysis revealed differences in contracted states of the TrA for DN vs sham-DN (P = .009) and between contracted and resting states for the DN group (P = .001): after DN, TrA thickness at rest exhibited a mean decrease of 0.03 cm and a mean increase of 0.05 cm during contraction. ConclusionThis study suggests that application of DN to LM was accompanied by a decreased resting thickness and an increased contraction thickness of the TrA in asymptomatic participants.

Behavior of the Linea Alba During a Curl-up Task in Diastasis Rectus Abdominis: An Observational Study.

Study Design Cross-sectional repeated measures. Background Rehabilitation of diastasis rectus abdominis (DRA) generally aims to reduce the inter-rectus distance (IRD). We tested the hypothesis that activation of the transversus abdominis (TrA) before a curl-up would reduce IRD narrowing, with less linea alba (LA) distortion/deformation, which may allow better force transfer between sides of the abdominal wall. Objectives This study investigated behavior of the LA and IRD during curl-ups performed naturally and with preactivation of the TrA. Methods Curl-ups were performed by 26 women with DRA and 17 healthy control participants using a natural strategy (automatic curl-up) and with TrA preactivation (TrA curl-up). Ultrasound images were recorded at 2 points above the umbilicus (U point and UX point). Ultrasound measures of IRD and a novel measure of LA distortion (distortion index: average deviation of the LA from the shortest path between the recti) were compared between 3 tasks (rest, automatic curl-up, TrA curl-up), between groups, and between measurement points (analysis of variance). Results Automatic curl-up by women with DRA narrowed the IRD from resting values (mean U-point between-task difference, -1.19 cm; 95% confidence interval [CI]: -1.45, -0.93; P<.001 and mean UX-point between-task difference, -0.51 cm; 95% CI: -0.69, -0.34; P<.001), but LA distortion increased (mean U-point between-task difference, 0.018; 95% CI: 0.0003, 0.041; P = .046 and mean UX-point between-task difference, 0.025; 95% CI: 0.004, 0.045; P = .02). Although TrA curl-up induced no narrowing or less IRD narrowing than automatic curl-up (mean U-point difference between TrA curl-up versus rest, -0.56 cm; 95% CI: -0.82, -0.31; P<.001 and mean UX-point between-task difference, 0.02 cm; 95% CI: -0.22, 0.19; P = .86), LA distortion was less (mean U-point between-task difference, -0.025; 95% CI: -0.037, -0.012; P<.001 and mean UX-point between-task difference, -0.021; 95% CI: -0.038, -0.005; P = .01). Inter-rectus distance and the distortion index did not change from rest or differ between tasks for controls (P≥.55). Conclusion Narrowing of the IRD during automatic curl-up in DRA distorts the LA. The distortion index requires further validation, but findings imply that less IRD narrowing with TrA preactivation might improve force transfer between sides of the abdomen. The clinical implication is that reduced IRD narrowing by TrA contraction, which has been discouraged, may positively impact abdominal mechanics. J Orthop Sports Phys Ther 2016;46(7):580-589. doi:10.2519/jospt.2016.6536.

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.

Effect of Recurrent Low Back Pain History on Volitional Pre-emptive Abdominal Activation During a Loaded Functional Reach Activity

A 2 (group) × 2 (abdominal contraction) × 2 (reach activity) crossover mixed design with repeated measures for contraction and activity examined the effects of a loaded (4.6 kg) forward-reach activity and abdominal drawing-in maneuver (ADIM) on transversus abdominis (TrA) contraction in subjects with nonspecific low back pain (NSLBP) history versus controls. We measured TrA contraction during a loaded forward-reach activity while using the ADIM and examined if a NSLBP history affects TrA activity. The ADIM supports trunk stability during function. Clinicians incorporate ADIM during patients' functional tasks. Pain-free individuals can sustain ADIM during function, such as forward-reach. However, this has not been tested in those with a NSLBP history. Eighteen normal subjects and 18 subjects with a history of NSLBP participated. A blinded investigator recorded M-mode ultrasound imaging measurements of TrA thickness (mm) during 4 conditions as follows: (1) quiet standing without ADIM; (2) quiet standing with ADIM; (3) loaded forward-reach without ADIM; and (4) loaded forward-reach with ADIM. A mixed analysis of variance demonstrated a significant main effect for group (F [1, 34] = 5.404, P = 0.026; ), where TrA thickness was greater for NSLBP history (7.41 + 2.34 mm) versus controls (5.9 + 2.46 mm). A significant main effect was observed for abdominal contraction (F [1, 34] = 49.57, P < 0.0001; ), where TrA thickness was greater during ADIM (7.47 + 2.7 mm) versus without ADIM (5.84, 1.92 m). A significant main effect was observed for forward-reach activity (F [1, 34] = 12.79, P = 0.001; ), where TrA thickness was greater during a loaded forward-reach (7.04 + 2.6 mm) versus quiet standing (6.2 + 2.4 mm). There were no significant interactions. Individuals can use a volitional pre-emptive ADIM for trunk protection during loaded forward-reach, potentially reducing injury risk. A NSLBP history increases TrA activation during ADIM, suggesting an enhanced protective role. 2.

The effect of transversus abdominis activation on exercise-related transient abdominal pain

Exercise-related transient abdominal pain (ETAP) affects 40-60% of the physically active population, is detrimental to performance but of unknown aetiology. Excessive movement of abdominal peritoneum is one proposed mechanism. Transversus abdominis (TrA) function may play a role reducing in the incidence of Exercise-related transient abdominal pain via the tensioning of the thoracolumbar fascia or increasing intra-abdominal pressure. The aim of this study is to identify any relationship between transversus abdominis function and exercise-related transient abdominal pain, hypothesing that those with stronger transversus abdominis will have lower incidence of exercise-related transient abdominal pain. Observational study design. Trunk muscle strength was measured clinically using the functional Sahrmann test. Contraction of transversus abdominis was measured by ultrasound imaging of resting muscle size and calculating the change in thickness with a voluntary contraction. Participants completed questionnaires describing any exercise-related transient abdominal pain symptoms, and were divided into four groups dependent upon frequency of any symptoms (never, yearly, monthly and weekly). Between group differences were analysed using analysis of covariance, with Bonferroni correction adjusting for age and training of participants using STATA. Poisson regression determined incident rate ratios for relevant variables. Data was obtained from fifty runners (28 male, 25.8 ± 7.0 years). Sahrmann test score and frequency of Exercise-related transient abdominal pain were significantly different between groups (p=0.002) with asymptomatic runners having significantly higher Sahrmann test scores (stronger muscles) than weekly and yearly Exercise-related transient abdominal pain groups (p=0.001, p=0.02). There were significant between group differences for resting transversus abdominis thickness (p=0.034) but not for transversus abdominis thickness change (p=0.555). Participants who had stronger trunk muscles and larger resting Transversus abdominis size experienced Exercise-related transient abdominal pain less.