The automatic activity of abdominal muscles during stable and unstable standing postural tasks in older adults with and without low back pain- A cross-sectional study.

BACKGROUND: The postural control and abdominal muscles' automatic activity were found to be impaired in subjects with low back pain (LBP) during static activities. However, the studies are predominantly conducted on younger adults and a limited number of studies have evaluated abdominal muscles' automatic activity during dynamic standing activities in subjects with LBP. The present study investigated the automatic activity of abdominal muscles during stable and unstable standing postural tasks in older adults with and without LBP. METHODS: Twenty subjects with and 20 subjects without LBP were included. The thickness of the transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles was measured during rest (in supine), static, and dynamic standing postural tasks. To estimate automatic muscle activity, each muscle's thickness during a standing task was normalized to its thickness during the rest. Standing postural tasks were performed using the Biodex Balance System. RESULTS: The mixed-model analysis of variance revealed that task dynamicity significantly affected thickness change only in the TrA muscle (P = 0.02), but the main effect for the group and the interaction were not significantly different (P > 0.05). There were no significant main effects of the group, task dynamicity, or their interaction for the IO and EO muscles (P > 0.05). During dynamic standing, only the TrA muscle in the control group showed greater thickness changes than during the static standing task (P < 0.05). CONCLUSIONS: Standing on a dynamic level increased the automatic activity of the TrA muscle in participants without LBP compared to standing on a static level. Further research is required to investigate the effects of TrA muscle training during standing on dynamic surfaces for the treatment of older adults with LBP.

Ultrasound imaging of core muscles activity in multiparous women with vaginal laxity: a cross-sectional study.

Vaginal laxity (VL) is a common condition among multiparous women, especially those who have delivered vaginally. Since pelvic floor muscles (PFMs) work synergistically with other core muscles, physical therapy protocols that aim to treat VL should train the PFMs in combination with other core muscles. To investigate the activity of core muscles in multiparous women with and without VL, and its relation to sexual function. An observational, cross-sectional study. The study included 100 multiparous women, who were divided into two groups according to their scores on the vaginal laxity questionnaire (VLQ). Women who scored between 1 and 3 on the VLQ were categorized as having VL (n = 48), while those who scored between 5 and 7 were placed in the control group (n = 52). The primary outcomes were PFM displacement, diaphragmatic excursion, transversus abdominis activation ratio, and lumbar multifidus thickness measured by ultrasound imaging. The secondary outcome was sexual functioning, evaluated using the Arabic female sexual function index (ArFSFI). The VL group had significantly lower PFM displacement (mean difference (MD) - 0.42; 95% confidence interval (CI) - 0.49 to - 0.33; p = 0.001), diaphragmatic excursion (MD - 2.75; 95% CI - 2.95 to - 2.55; p = 0.001), lumbar multifidus thickness (MD - 10.08; 95% CI - 14.32 to - 5.82; p = 0.02), and ArFSFI scores (MD - 9.2; 95% CI - 10.59 to - 7.81; p = 0.001) in comparison to the control group (p < 0.05). Nevertheless, the transversus abdominis activation ratio demonstrated no significant difference between the two groups (MD 0.06; 95% CI - 0.05 to 0.17; p = 0.33). Multiparous women with VL had significantly lower PFM displacement, diaphragmatic excursion, lumbar multifidus thickness, and sexual function index scores than women in the control group. The only exception was transversus abdominis activation, which did not differ significantly between the VL and control groups.

Evaluation of the lumbar and abdominal muscles behavior in different sagittal plane angles during maximum voluntary isometric extension.

Physical positions and lumbar movements are directly related to lumbar disorders. It is known that the sagittal plane angle affects the person's ability to apply extension torque. However, there is no consensus on whether or not muscle activity and co-contractions change at these angles. This paper aimed to investigate the abdominal and lumbar muscles' behavior at different sagittal plane angles during maximum voluntary isometric extension (MVIE). We have evaluated our findings with the aid of a computational biomechanical model. Fourteen healthy males participated. A total of 16 muscles EMG were recorded during the lumbar MVIE on the Sharif Lumbar Isometric Strength Tester device in 5°, 15°, 30°, and 45° flexion. The torque and muscle activity changes and all co-contraction indexes (CCI) between 120 possible muscle pairs were calculated. Finally, the experimental test conditions were modeled in the AnyBody software, and the MVIE torque, muscle activity, and all CCIs were calculated. Also, muscle torque lever arms were calculated at different angles. Results show that MVIE at four angles is 137.94 ± 36.08, 148.63 ± 47.96, 168.09 ± 50.48, and 171.44 ± 53.95 N · m, respectively. Muscle activity and CCI are similar at all angles. The AnyBody model gives similar findings. Muscles torque lever arms change with angle. In conclusion, to determine the safety mode of lifting in the sagittal plane, it seems that the torque differences are due to changes in the geometrical muscle parameters (including the torque lever arm). Despite the almost constant muscular effort, subjects in the 30°-45° bending positions can apply more MVIE.

Low Back Pain-Induced Dynamic Trunk Muscle Control Impairments Are Associated with Altered Spatial EMG-Torque Relationships.

PURPOSE: We quantified the relationship between high-density surface electromyographic (HDsEMG) oscillations (in both time and frequency domains) and torque steadiness during submaximal concentric/eccentric trunk extension/flexion contractions, in individuals with and without chronic low back pain (CLBP). METHODS: Comparisons were made between regional differences in HDsEMG amplitude and HDsEMG-torque cross-correlation and coherence of the thoracolumbar erector spinae (ES), rectus abdominis (RA), and external oblique (EO) muscles between the two groups. HDsEMG signals were recorded from the thoracolumbar ES with two 64-electrode grids and from the RA and EO muscles with a single 64-electrode grid placed over each muscle. Torque signals were recorded with an isokinetic dynamometer. Coherence (δ band (0-5 Hz)) and cross-correlation analyses were used to examine the relationship between HDsEMG and torque signals. For this purpose, we used principal component analysis to reduce data dimensionality and improve HDsEMG-based torque estimation. RESULTS: We found that people with CLBP had poorer control during both concentric and eccentric trunk flexion and extension. Specifically, during trunk extension, they exhibited a higher HDsEMG-torque coherence in more cranial regions of the thoracolumbar ES and a higher HDsEMG cross-correlation compared with asymptomatic controls. During trunk flexion movements, they demonstrated higher HDsEMG amplitude of the abdominal muscles, with the center of activation being more cranial and a higher contribution of this musculature to the resultant torque (particularly the EO muscle). CONCLUSIONS: Our findings underscore the importance of evaluating torque steadiness in individuals with CLBP. Future research should consider the value of torque steadiness training and HDsEMG-based biofeedback for modifying trunk muscle recruitment strategies and improving torque steadiness performance in individuals with CLBP.

Numerical investigation of a finite element abdominal wall model during breathing and muscular contraction.

BACKGROUND AND OBJECTIVE: Ventral hernia repair is faced with high recurrence rates. The personalization of the diagnosis, the surgical approach and the choice of the prosthetic implant seem relevant axes to improve the current results. Numerical models have the potential to allow this patient-specific approach, yet currently existing models lack validation. This work extensively investigated a realistic finite element abdominal wall model including the implementation of muscle activation. METHODS: A parametric 3D finite element model composed of bone, muscle and aponeurotic structures was introduced. Hyperelastic anisotropic materials were implemented. Two loading scenarios were simulated: passive inflation of the abdominal cavity to represent, e.g., breathing, and passive inflation followed by muscular activation to simulate other daily activities such as cough. The impact of the inter-individual variability (e.g., BMI, tissue thickness, material properties, intra-abdominal pressure (IAP) and muscle contractility) on the model outputs was studied through a sensitivity analysis. RESULTS: The overall model predictions were in good agreement with the experimental data in terms of shape variation, muscles displacements, strains and midline forces. A total of 34 and 41 runs were computed for the passive and active sensitivity analysis respectively. The regression model fits rendered high R-squared in both passive (84.0 ± 6.7 %) and active conditions (82.0 ± 8.3 %). IAP and muscle thickness were the most influential factors for the selected outputs during passive (breathing) activities. Maximum isometric stress, muscle thickness and pre-activation IAP were found to drive the response of the simulations involving muscular contraction. The material properties of the connective tissue were essential contributors to the behaviour of the medial part of the abdominal wall. CONCLUSIONS: This work extensively investigated a realistic abdominal wall model and evaluated its robustness using experimental data from literature. Such a model could improve patient-specific simulation for ventral hernia surgical planning, prevention, and repair or implant evaluation. Further investigations will be conducted to evaluate the impact of the surgical technique and the mechanical characteristic of prosthetic meshes on the model outputs.

Age influences the specific force and fatigability of the external abdominal obliques but not pectoralis major muscles.

In the elderly, airway infections are associated with impaired airway defense behaviors, leading to an increased risk of airway infection. The muscles of the chest and abdominal wall are essential for performing effective airway defense manoeuvres, however, very little is known about their function in aging. Here in the 6- and 24-months old Fischer 344 rat model of aging, we assess the contractility and fatigability of chest (the pectoralis major muscle) and abdominal wall (external abdominal oblique) muscles. We assessed muscle function using an ex vivo approach, measuring isometric specific forces normalised to muscle CSA, via a platinum plate field stimulations at a range of frequencies (5-150 Hz) for 1 s. Surprisingly, we did not observe any effect of age on the specific force and fatigue properties of the pectoral muscle. However, in 24-months old rats, EAO specific force was reduced by ∼32 %. These finding suggest that not all respiratory muscles are equally vulnerable to age-associated weakness.

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.

Muscle activation and coordinated movements of infant rolling.

Rolling is a critical step of infant development, encouraging muscle coordination and enabling independent exploration. Understanding muscle activity during infant rolling movements on a flat surface is necessary to more fully characterize how the rolling milestone is achieved. The purpose of this study was to determine infants' muscle activation throughout roll initiation for six previously established coordinated movements. Thirty-eight healthy infants (age: 6.5 ± 0.7 months; 23M/15F) were enrolled in this IRB-approved in-vivo biomechanics study. Surface electromyography sensors recorded muscle utilization from the erector spinae, abdominal muscles, quadriceps, and hamstrings while infants rolled. Each rolling movement was categorized as one of six roll types, and the mean muscle activity was analyzed. All roll types required initial activation of all measured muscle groups. Movements featuring axial rotation of the torso relative to the pelvis required highly active erector spinae muscles. Movements featuring trunk and hip flexion required highly active abdominal muscles. Infants used distinct coordinated muscle activations to achieve the six different roll types on a flat surface. A foundational understanding of the different muscle activation patterns required during infant rolling will provide crucial insight into motor development. This study quantified muscle coordination required of infants to achieve rolling on a firm flat surface. Previous research indicates that the mechanical environment in which an infant is placed impacts muscle activity and body position during normal lying. Therefore, future work should explore if mechanical environments that differ from a flat and firm surface also influence these coordinated movements and muscle activations.

Immediate Effects of Sprinter-Pattern Exercise on the Lordotic Curve and Abdominal Muscle Activity in Individuals with Hyperlordosis.

Background and Objectives: Abdominal muscle exercises with limb movements are more effective for trunk stabilization than traditional exercises involving trunk flexion alone. This study examined the effects of abdominal exercises incorporating sprinter pattern and crunch exercises on changes in the lordotic curve and abdominal muscle activation in individuals with low back pain caused by hyperlordosis resulting from weak abdominal muscles. Materials and Methods: In this single-blind, randomized controlled trial, a total of 40 participants with hyperlordosis were recruited and randomly assigned to perform either sprinter-pattern abdominal exercises or crunch exercises. The participants assigned to each group performed three sets of ten abdominal exercises. The lumbar lordotic angle (LLA) and sacrohorizontal angle (SHA) were assessed prior to and following the intervention, whereas abdominal muscle activity was gauged throughout the intervention period. Changes in the LLA and SHA were measured by radiography. Abdominal muscle activity was measured using electromyography. Results: The LLA and SHA decreased significantly in both groups (p < 0.001), while the sprinter-pattern exercise group showed a statistically significant decrease compared to the crunch exercise group (p < 0.001). In the activity of the abdominal muscles, there was no significant difference in the rectus abdominis muscle between the two groups (p > 0.005). However, a significant difference between the external and internal oblique muscles was observed, and the activities of both muscles were significantly higher in the sprinter-pattern exercise group than in the crunch exercise group (p < 0.005). Conclusions: Abdominal exercise using a sprinter pattern may be effective in reducing lumbar lordosis by strengthening the abdominal muscles in patients with hyperlordosis.

Numerical investigation of intra-abdominal pressure and spinal load-sharing upon the application of an abdominal belt.

Chronic low back pain patients may experience spinal instability. Abdominal belts (ABs) have been shown to improve spine stability, trunk stiffness, and resiliency to spinal perturbations. However, research on the contributing mechanisms is inconclusive. ABs may increase intra-abdominal pressure (IAP) and reduce paraspinal soft tissue contribution to spine stability without increasing spinal compressive loads. A finite element model (FEM) of the spine inclusive of the T1-S1 vertebrae, intervertebral discs (IVDs), ribcage, pelvis, soft tissues, and abdominal cavity, without active muscle forces was developed. An identical FEM with an AB was developed. Both FEMs underwent trunk flexion. Following validation, the models' intervertebral rotation (IVR), IAP, IVD pressure, and tensile stress in the multifidus (MF), erector spinae (ES), and thoracolumbar fascia (TLF) were compared. The inclusion of an AB resulted in a 3.8 kPa IAP increase, but a decreased average soft tissue tensile stress of 0.28 kPa. The TLF withstood the majority of tension being transferred across the paraspinal soft tissues (>70 %). The average IVR in the AB model decreased by 10 %, with the lumbar spine experiencing the largest reduction. The lumbar IVDs of the AB model likewise showed a 31 % reduction in average IVD pressure. Using an AB improved trunk bending stiffness, primarily in the lumbar spine. Wearing an AB had minimal effect on reducing tensile stress in theES. The skewed stress distribution towards the TLF suggests its large contribution to spine stability and the potential advantage in unloading the structure when wearing an AB, measured herein at8 %.

Diaphragm and core stabilization exercises in low back pain: A narrative review.

INTRODUCTION: Core stabilization is a vital concept in clinical rehabilitation (including low back pain rehabilitation) and competitive athletic training. The core comprises of a complex network of hip, trunk and neck muscles including the diaphragm. AIMS: The paper aims to discuss the role of the diaphragm in core stability, summarize current evidence and put forth ideal core training strategies involving the diaphragm. METHOD: Narrative review RESULTS: The diaphragm has a dual role of respiration and postural control. Evidence suggests that current core stability exercises for low back pain are superior than minimal or no treatment, however, no more beneficial than general exercises and/or manual therapy. There appears to be a higher focus on the transversus abdominis and multifidi muscles and minimal attention to the diaphragm. We propose that any form of core stabilization exercises for low back pain rehabilitation should consider the diaphragm. Core stabilization program could commence with facilitation of normal breathing patterns and progressive systematic restoration of the postural control role of the diaphragm muscle. CONCLUSION: The role of the diaphragm is often overlooked in both research and practice. Attention to the diaphragm may improve the effectiveness of core stability exercise in low back pain rehabilitation.

Surface electromyography analysis of core stabilizing muscles during isometric shoulder contractions in athletes with low back pain.

BACKGROUND: The study was carried out in the athletes with and without Low Back Pain (LBP) to determine the surface electromyography activity of core stabilizing muscles while performing isometric shoulder and trunk contractions. STUDY DESIGN: Cross-sectional study. METHODS: This study enlisted the participation of 40 athletes. Group A included 20 athletes (18 males and 2 females) without LBP, and Group B included 20 athletes (12 males and 8 females) with LBP. Athletes with LBP were assessed using the Modified Oswestry Disability Questionnaire (MODQ) and Visual Analog Scale (VAS) to determine their level of disability and pain severity, respectively. EMG activity of the rectus abdominis, external oblique, longissimus, and multifidus was recorded in both groups as they performed bilateral isometric shoulder and trunk contractions. RESULTS: In the LBP group, EMG activity of the rectus abdominis and external oblique muscles was significantly lower (P < 0.05). The LBP group had significantly more multifidus activity (P = 0.03) than the NLBP group. Among all the exercises, bilateral isometric shoulder extension contraction activated the rectus abdominis, right external oblique, and longissimus group of muscles significantly more (P < 0.05) in both groups. In both groups, bilateral isometric shoulder flexion contraction resulted in significantly higher multifidus muscle activation (P = 0.002). CONCLUSION: The activation of core stabilizing muscles was altered in athletes with LBP. When athletes are unable to contract and activate trunk muscles owing to pain, upper extremity exercises can be used to activate these muscles.

Effects of Pilates on inter-recti distance, thickness of rectus abdominis, waist circumference and abdominal muscle endurance in primiparous women.

BACKGROUND: Pilates is expected to have a positive effect on women with weakened abdominal muscles after childbirth. Pilates may have a beneficial effect on the structure and function of the abdominal muscles in pregnant women. Therefore, the objective of this study was to investigate the effects of Pilates on inter-recti distance, thickness of the rectus abdominis, waist circumference, and abdominal muscle endurance in primiparous women. METHODS: Thirty-five primiparous postpartum women were assigned to either the Pilates exercise group (n = 20) or the control group (n = 15). Pilates was undertaken by the exercise group for 50 min/day, 5 days/week, for 4 weeks. The control group maintained their daily activities without any intervention. The inter-recti distance was measured at three locations along the linea alba, and the thickness of the rectus abdominis was measured using ultrasound. Abdominal muscle endurance was measured using a repeated 1-min curl-up test. Waist circumference was also measured. RESULTS: The exercise group showed significant improvements from baseline in inter-recti distance, waist circumference, and abdominal muscle endurance (p < 0.05). The control group showed no significant improvement in these variables. Compared with the control group, the exercise group showed significantly improved performance in terms of inter-recti distance, waist circumference, and abdominal muscle endurance (p < 0.05). CONCLUSIONS: The results of this study demonstrate that Pilates was effective in reducing inter-recti distance and waist circumference and improving abdominal muscle endurance in primiparous postpartum women. Pilates is considered an effective exercise for improving muscle structure and function in primiparous postpartum women, helping in the recovery from, and preventing, diastasis rectus abdominis.

Effect of strengthening and weakening of abdominal and dorsal muscles on lumbar spine loads in parents of disabled children.

Pain in the lower part of the back is one of the most common chronic illnesses globally. This work aimed to determine the impact of the reinforcement of particular groups of abdominal and dorsal muscles on the loads exerted on the lumbar section of the spine in 30 mothers of children with motor disabilities. An optical Ariel Performance Analysis System recorded and processed the kinematics data of everyday activities. Tests investigating the effects of the strengthening or weakening of abdominal and dorsal muscles on loading in the lumbar section of the spine utilized the AnyBody Modelling System. Input data for the simulations included mean values of body positions, while the effects of strengthening or weakening of muscles were simulated in the muscle forces model by introducing different values for muscle physiological cross-sectional area (PCSA). Simulations used decreasing or increasing PCSA values of abdominal muscles and the erector spinae. The analysis involved component and resultant force values on the lumbosacral joint (L5-S1) of the spine and intra-abdominal pressure values. The highest reduction of the resultant reaction value in L5-S1 was observed in the simulations that increased the PCSA of the transverse abdominal (TrA). Indeed, a double increase in the TrA cross-section caused a reduction of the resultant reaction in L5-S1 by 30% and the anterior-posterior and proximal-distal forces by approximately 20-30%. Increased PCSA of the erector spinae exerted higher loads on the spine. These results indicate that strengthening weakened abdominal muscles, particularly TrA, in parents of children with motor disabilities reduces lower spinal loads during daily activities.

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.

Ultrasound assessment of the abdominal, diaphragm, and pelvic floor muscles during the respiratory and postural tasks in women with and without postpartum lumbopelvic pain: a case-control study.

INTRODUCTION AND HYPOTHESIS: Postpartum lumbopelvic pain (PLPP) is common among women. Abdominal, diaphragm, and pelvic floor muscles (PFMs) modulate intraabdominal pressure as a part of the force closure mechanism. These muscles are exposed to changes during pregnancy that compromise the force closure mechanism. It was hypothesized that abdominal and PFMs activity, the direction of bladder base displacement, diaphragm thickness, and excursion might differ between women with and without PLPP during respiratory and postural tasks. METHODS: Thirty women with and 30 women without PLPP participated in this case-control study. Ultrasound imaging was used to assess the abdominal, diaphragm, and PFMs during rest, active straight leg raising (ASLR) with and without a pelvic belt, and deep respiration. RESULTS: The bladder base descent was significantly greater in the PLPP group than in the controls during deep respiration and ASLR without a belt (p = 0.026; Chi-squared = 6.40). No significant differences were observed between the groups in the abdominal muscles activity and diaphragm muscle thickness. There was a significant interaction effect of the group and the task for diaphragm excursion (F (2, 116) = 6.08; p = 0.00) and PFM activity (F (2, 116) = 5.22; p = 0.00). In the PLPP group, wearing a belt compromised altered PFM activation and direction of bladder base displacement. CONCLUSION: The PFM activity, direction of bladder base displacement, and diaphragm excursion differed between groups during postural and respiratory tasks. Therefore, it is recommended to involve retraining of the PFMs and diaphragm muscle in the rehabilitation of women with PLPP.

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.

Measuring transversus abdominis activity using pressure biofeedback unit-A technical report.

BACKGROUND AND PURPOSE: Pressure biofeedback is a tool that can detect the movement of a structure and may be used as an indicator of muscle function. It's widely used to measure the transversus abdominis (TrA) muscle activity. Pressure biofeedback (PBU) monitors the abdominal wall movement by measuring the pressure change during abdominal hollowing and can indirectly evaluate the TrA muscle function, which is considered as a valuable tool. The evaluation of the training of core muscles, including the transversus abdominis, requires a reliable outcome. Various methods using different positions are used to evaluate the transversus abdominis muscle function. However, it is noted that a standard way of evaluation and training still needs to be improved in research and clinical practice. This technical report discusses the optimal position and technique to measure the TrA muscle activity using PBU, with discussions on the merits and demerits of the body positions. METHODS: The technical report is presented with a literature review of the PBU measurement of TrA and through observation in the clinical practice. The evaluation methods of TrA, including the position to activate and isolate, are discussed in detail. RESULTS: Training core muscles does not imply TrA activation, and evaluating isolated TrA and multifidus is essential before intervention. The abdominal drawing-in maneuver effectively activates TrA in various evaluation positions of the body, but when using PBUs, it would be valid in a prone position. DISCUSSION: Different body positions are practiced to train TrA and core muscles using PBU, commonly adopted by practice are in supine. It's noted that most of the studies lack in establishing the effectiveness of the position in evaluating the TrA muscle activity using PBU. The need for insight into an appropriate technique for evaluating TrA activity is addressed in this technical report. This report presents key points on the complete technique and concludes that the prone position is superior to other positions and recommended for measuring and recording the TrA activity using a PBU.

Is the function of the core muscles affected during pregnancy?

INTRODUCTION AND HYPOTHESIS: The aim of our study is to examine the changes in core muscle functions during pregnancy. METHODS: Our study was carried out in 67 primigravida pregnant women. Superficial electromyography (EMG) and non-invasive 2D/3D ultrasonography (USG) were used to evaluate core muscle (diaphragm, transversus abdominus [TA], internal oblique [IO]-external oblique [EO] muscles, pelvic floor muscles, multifidus) function during pregnancy. Pelvic floor muscle strength was also measured by a digital palpation method (PERFECT system). USG was used to measure expected fetal weight and the diastasis recti (DR) distance. Mann-Whitney U test was used to show changes in trimesters in the core muscles, and Spearman correlation analysis was used to determine the relationship. RESULTS: In the third trimester, an nonsignificant increase in EMG parameters was observed in all of the core muscles. Although a statistically significant decrease was observed in muscle thickness values measured by EO and IO USG in the third trimester, DR was found to increase at all levels (p < 0.005). When we evaluated both trimesters and all pregnant women together, no relationship was found between all core muscles and pelvic floor muscles in the data evaluated by EMG and USG. We found a negative correlation in USG values between fetal weight and IO and the upper part of the rectus abdominus muscle, and a positive correlation between the EMG data of the EO and rectus abdominus muscles. CONCLUSIONS: In women, the coactivation relationship between the core muscles may disappear during pregnancy. As the trimesters progress during pregnancy, a decrease in thickness and an increase in muscle activity can be observed in the core muscles. Pregnant women can be given exercise training for core muscles for protection in both the prenatal and postnatal periods. But more research needs to be done.

Interaction of breathing pattern and posture on abdominal muscle activation and intra-abdominal pressure in healthy individuals: a comparative cross-sectional study.

We aimed to assess the effects of interaction between several breathing patterns and postures on abdominal muscle activation and intra-abdominal pressure (IAP). This comparative cross-sectional study enrolled fourteen healthy university students majoring in sports science and/or physical education. They performed four active breathing tasks: quiet nasal breathing (Q-Bre), nasal deep breathing (Deep-Bre), completely forced expiration (Forced-Expi), and exertional nasal inhalation with abdominal muscles with isometric contraction (Exertion-Inspi) in the elbow-toe plank and supine postures. Breathing volume; IAP; and transverse abdominis-internal oblique muscle (TrA-IO) and external oblique muscle (EO) activities were recorded. Abdominal muscle activity and IAP significantly interacted with breathing pattern and postures during the expiratory phase (p < 0.05). In the inspiratory phase, TrA-IO activity was significantly affected by breathing pattern and EO activity with posture (p < 0.05). TrA-IO activity significantly increased during Forced-Expi in the supine posture (47.6% of the maximum voluntary contraction) and Exertion-Inspi in the elbow-toe posture (35.7%), whereas no differences were found during Deep-Bre or Q-Bre (< 20%). EO activity increased in the elbow-toe posture (22.5-30.6%) compared with that in the supine posture (< 5%) during all breathing tasks. IAP values were low during all tasks (< 15%) except for Forced-Expi (24.9%). Abdominal muscle activation and IAP interacted with the breathing pattern and posture.