Abdominal Activity Research Articles

Utilizing Synergism between the Transverse Abdominal and Pelvic Floor Muscles at Different Postures in Nulliparous Women: A Randomized Case-Control Study

Introduction: The aim of the study was to determine the effects of the pelvic floor muscle (PFM) training (PFM-T) in combination with transverse abdominal (TRA) muscle activation (cPFM-T) in female urinary incontinence. Methods: We enrolled nulliparous women in supine (SUG) (n = 22), sitting (SIG) (n = 19), and control (COG) (n = 14) groups. We conducted an 8-week cPFM-T programme. We examined the effect of training on the parameters with the Kruskal-Wallis test, the pairwise comparisons with the Mann-Whitney U test, and the Wilcoxon rank test with the Bonferroni correction. Results: Before training, 15 participants reported occasional urinary leakage. After cPFM-T, 7 participants reported that urinary leakage had disappeared. Maximal isometric contraction of the PFMs until fatigue improved significantly in the SUG (p < 0.001) and SIG (p = 0.015) groups but not significantly in the COG group (p = 0.499). Holding time increased in the SUG (p = 0.972) and the SIG (p = 0.717) groups and decreased in the COG group (p = 0.132). The dynamic endurance of the PFM improved significantly in the SUG group (p < 0.001) but not in the SIG (p = 0.798) and the COG (p = 0.153) groups. The number of maximal fast contractions within 1 min increased in both the SUG (p < 0.001) and SIG (p = 0.813) groups and decreased in the COG group (p = 0.257). Relaxation improved significantly in the SIG group (p = 0.011). TRA mucle thickness increased in both training groups. Conclusion: Slow-twitch fibres of the PFM can be trained effectively with PFM-T in both the body positions.

Effect of Sprinter Pattern Bridging Exercise using Theraband on Activation of Lower Extremity and Abdominal Muscle

Effect of Sprinter Pattern Bridging Exercise using Theraband on Activation of Lower Extremity and Abdominal Muscle

Effects of the Biofeedback Units during PNF Pattern on the Abdominal Muscle Activity and Pelvic Rotation Angle in Patients with Chronic Back Pain

Purpose: The purpose of this study was to provide clinical information by comparing abdominal muscle activity and lumbopelvic rotation angle according to proprioceptive neuromuscular facilitation (PNF) lower pattern with pressure biofeedback unit or PNF lower pattern without pressure biofeedback unit in patients with chronic back pain. Methods: In this study, 20 patients with low back pain were instructed to perform PNF lower pattern with biofeedback unit and PNF lower pattern without biofeedback unit. Surface electromyography data were collected from the ipsilateral internal oblique (IIO), contralateral external oblique (CEO), ipsilateral rectus abdominal (IRA) muscles, and lumbopelvic rotation angle were measured using the motion analysis device. Results: The activation of all abdominal muscles was found greater in PNF lower pattern with biofeedback unit than that PNF lower pattern without biofeedback unit. The degree of lumbopelvic rotation angle in PNF lower pattern with biofeedback unit was found lower than that PNF lower pattern without biofeedback unit(p<0.05). Conclusion: The results of this study suggest that PNF lower pattern with biofeedback unit is effective in increasing abdominal muscle activity and decreasing unwanted lumbopelvic rotation in patients with chronic low back pain. Therefore, if you want to apply the PNF lower pattern to patients with chronic low back pain, it is considered effective to control the pelvis using the biofeedback unit.

The content and effects of trunk rehabilitation on trunk and upper limb performance in people with multiple sclerosis: a systematic review.

Persons with multiple sclerosis (pwMS) could have an impaired trunk and reduced postural control, which negatively impacts activities of daily living. Evidence is growing to consider the positive effects of trunk training on fall incidence and balance problems. Effects on trunk and upper limb performance is unknown. This systematic review provides an overview of trunk training programs and their effects in MS, specifically focusing on the content of training modalities and the effects on trunk and upper limb performance. Two electronic databases were used: PubMed and Web Of Science (WOS). Intervention studies (with- and without control group) published in English, investigating the effects of active trunk training on trunk and upper limb performance in pwMS, were included. Sixteen studies met the criteria, investigating different rehabilitation modalities. The included interventions in the review varied between more generic postural interventions such as Pilates (N.=8) and Ai Chi (N.=1), with a focus on abdominal muscle activation, breathing, neutral position and lower extremity movements. Further, specifically developed trunk training programs like GroupCoreDIST/ SIT / CoDuSe (N.=6) and Bobath based trunk training (N.=1) are detected, with the main focus on trunk strengthening and dynamic movements. An overall improvement in trunk performance was reported in several tests on trunk strength, stability and coordination. While the majority of the programs integrated the upper limb, only half of them used upper limb outcome measures to evaluate the effect. Here, overall significant improvements were found for the upper limb. This systematic review showed that different types of trunk training programs can improve trunk and upper limb function in PwMS. The findings of this review suggest that a focus on trunk training to achieve effects on upper limb is reasonable. Future research is needed to further explore relations and the effect sizes.

Infant inclined sleep product safety: A model for using biomechanics to explore safe infant product design

Over 450 adverse incidents have been reported in infant inclined sleep products over the past 17 years, with many infants found dead in both the supine and prone positions. The unique design of inclined sleep products may present unexplored suffocation risks related to how these products impact an infant’s ability to move. The purpose of this study was to assess body movement and muscle activity of healthy infants when they lie supine and prone on different inclined sleep products. Fifteen healthy full-term infants (age: 17.7 ± 4.9 weeks) were recruited for this IRB-approved study. Three inclined sleep products with unique features, representative of different sleeper designs, were included. Surface electromyography (EMG) was recorded from infants’ cervical paraspinal, abdominal, and lumbar erector spinae muscles for 60 s during supine and prone positioning. Neck and trunk sagittal plane movements were evaluated for each testing condition. Paired t-tests and Wilcoxon signed-rank tests were performed to compare each inclined sleeper to a flat crib mattress (0° baseline condition). During prone positioning, abdominal muscle activity significantly nearly doubled for all inclined sleep products compared to the flat crib mattress, while erector spinae muscle activity decreased by up to 48%. Trunk movement significantly increased compared to the flat crib mattress during prone lying. During prone lying, inclined sleep products resulted in significantly higher muscle activity of the trunk core muscles (abdominals) and trunk movement, which has the potential to exacerbate fatigue and contribute to suffocation if an infant cannot self-correct to the supine position.

Effect of core stability exercise on activation of abdominal muscles and lumbar flexibility in men with specific chronic low back pain

Introduction: Lumbar disc herniation is the most common specific cause of chronic low back pain and exercise therapy is one of the goals of its management. The aim of this study was to investigate the effect of core stability exercises on activation of abdominal muscles and flexibility of lumbar in men with disc herniation.Materials and Methods: The subjects of this clinical trial study were 20 young and middle-aged men with lumbar disc herniation referred to physiotherapy in rasht in first half of year 1399 who were randomly divided into two groups of core stability exercises (n=10) and control (n=10). The electrical activity of the internal oblique, external oblique, and rectus abdominis muscles was measured by electromyography and abdominal muscle strength by straight leg raising test and flexibility by sit and reach test. Training protocol of intervention group included 8 weeks of core stability exercise, while the control group was only followed up. Statistical analysis was performed using paired t test an analysis of covariance test with SPSS software.Results: Activation of 3 muscles and strength and flexibility after 8 week of exercise had a significant improvement(p<0/05)but changes were not significant in control group. However, analysis of covariance showed a difference between two groups in activation of all three muscles and flexibility(p<0/05)But no significant difference was observed in muscle strength.Conclusion: Our findings showed, people with disc herniation experience greater activation, strength, and flexibility in trunk muscles after core stability exercise thus can be considered in rehabilitation.

A self-oblique exercise that activates the coordinated activity of abdominal and hip muscles–A pilot study

The importance of an interaction between trunk stability muscles and hip muscle function has been suggested. However, reported exercises rarely act on the trunk and hip muscles simultaneously. Here, we devised an abdominal oblique and hip muscle exercise, the Self-oblique exercise (SOE). We examined whether SOE activated abdominal and hip muscles in the supine and half-kneeling positions, compared with abdominal crunch (AC) and plank exercises; and whether participants could modulate the exercise load. Participants were 20 healthy males with some sports experience such as football and baseball on average 10.5 ± 4.0 years. Participants applied self-pressure to their right thighs using the contralateral upper limb with 40% or 70% of the maximum force in Supine SOE and Half- kneeling SOE. The following abdominal and hip muscles were measured using surface electromyography: bilateral external obliques (EO), bilateral internal obliques (IO), right rectus abdominis, right gluteus medius (GMed), and right adductor longus (ADD). All evaluated muscle groups showed significant differences between exercises (p < 0.001). Supine SOE-70% showed 80.4% maximal voluntary contraction (MVC) for left EO (p < 0.017), 61.4% MVC for right IO (p < 0.027), 24.3% MVC for GMed (p < 0.002), and 42.4% MVC for ADD (p < 0.004); these were significantly greatest among all exercises. Muscle activity during Supine SOE-70% was greater than that during Supine SOE-40%. Similarly, Half-kneeling SOE-40% promoted abdominal and hip muscle exertion, and showed more significant activity in GMed (p < 0.006) and ADD (p < 0.001) than AC and plank. SOE could activate abdominal and hip muscles depends on the pressure applied by upper limb. Also, SOE allows participants to modulate the exercise load in a self-controlled step by step manner. Modulation of the exercise load is difficult in AC or plank compared to SOE, and AC or plank cannot obtain simultaneous oblique and hip muscle activity. SOE could be practiced anywhere, in various positions, without any tools.

Abdominal bracing changes lower quarter muscle activity but not reach distances during active forward reach on an unstable surface

ObjectiveThis study examined the effects of abdominal bracing maneuver (ABM) performance on stable and unstable surfaces on active forward reach (AFR) distance as a measure of trunk control, measuring changes in reach distance and muscle activation patterns. DesignSingle-group, repeated measures design. MethodsTwenty-eight subjects (mean age 25 ± 5.09 years) performed an AFR with and without ABM while on stable and unstable surfaces. Lower quarter muscle activity and forward reach distances were recorded. ResultsForward reach distances on the unstable surface were significantly decreased compared to the stable condition with and without ABM (p < .001). The surface-by-contraction interaction was significant for the tibialis anterior (TA) and gastrocnemius (GS). Significant main effects were found for internal oblique, external oblique, gluteus maximus, biceps femoris, TA, and GS, where muscle activity significantly increased during the ABM trials. The interaction between surface and contraction was significant for the TA and GS muscles. TA (p = .007) and GS (p < .001) activity increased with ABM on the unstable surface. TA activity increased with ABM on the stable surface (TA: p < .001). ConclusionReach distances decreased on the unstable surface, but ABM did not change reaching distance. Ankle muscle co-contraction occurred during ABM trials and posterior chain activity increased. These changes suggest ABM may be beneficial during forward reaching activities.

The Effects of Core Stabilization Exercise with the Abdominal Drawing-in Maneuver Technique versus General Strengthening Exercise on Lumbar Segmental Motion in Patients with Clinical Lumbar Instability: A Randomized Controlled Trial with 12-Month Follow-Up.

Trunk stability exercises that focus on either deep or superficial muscles might produce different effects on lumbar segmental motion. This study compared outcomes in 34 lumbar instability patients in two exercises at 10 weeks and 12 months follow up. Participants were divided into either Core stabilization (deep) exercise, incorporating abdominal drawing-in maneuver technique (CSE with ADIM), or General strengthening (superficial) exercise (STE). Outcome measures were pain, muscle activation, and lumbar segmental motion. Participants in CSE with ADIM had significantly less pain than those in STE at 10 weeks. They showed significantly more improvement of abdominal muscle activity ratio than participants in STE at 10 weeks and 12 months follow-up. Participants in CSE with ADIM had significantly reduced sagittal translation at L4-L5 and L5-S1 compared with STE at 10 weeks. Participants in CSE with ADIM had significantly reduced sagittal translations at L4-L5 and L5-S1 compared with participants in STE at 10 weeks, whereas STE demonstrated significantly increased sagittal rotation at L4-L5. However, at 12 months follow-up, levels of lumbar sagittal translation were increased in both groups. CSE with ADIM which focuses on increasing deep trunk muscle activity can reduce lumbar segmental translation and should be recommended for lumbar instability.

A passive back exoskeleton supporting symmetric and asymmetric lifting in stoop and squat posture reduces trunk and hip extensor muscle activity and adjusts body posture – A laboratory study

The influence of a passive exoskeleton was assessed during repetitive lifting with different lifting styles (squat, stoop) and orientations (frontal/symmetric, lateral/asymmetric) on trunk and hip extensor muscle activity (primary outcomes), abdominal, leg, and shoulder muscle activity, joint kinematics, and heart rate (secondary outcomes). Using the exoskeleton significantly and partially clinically relevant reduced median/peak activity of the erector spinae (≤6%), biceps femoris (≤28%), rectus abdominis (≤6%) and increased median/peak activity of the vastus lateralis (≤69%), trapezius descendens (≤19%), and median knee (≤6%) and hip flexion angles (≤11%). Using the exoskeleton had only limited influence on muscular responses. The findings imply the exoskeleton particularly supports hip extension and requires an adjusted body posture during lifting with different styles and orientations. The potential of using exoskeletons for primary/secondary prevention of musculoskeletal disorders should be investigated in future research including a greater diversity of users in terms of age, gender, health status.

How Do the Abdominal Muscles Change during Hypopressive Exercise?

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

Comparison of the Effect of Plank Exercise and Hip Walking on Abdominal Muscles Activity

Purpose: The purpose of this study is to determine changes to the abdominal muscle activity, after Plank exercise and Hip walking exercise and to compare the effects of the two exercise methods. Methods: Thirty-two subjects were randomly assigned to either a Plank exercise group (n=16 ; 8 male and 8 female) or a Hip walking exercise group (n=16 ; 8 male and 8 female). Plank exercise was performed five times per week during 6 weeks. The first week was performed 3sets a day(1set program; 30 second hold-30 second rest), and then increased by 1set per week. Hip walking exercise was performed for 30 second, once a day, five times per week, during 6 weeks. The muscle activities of abdominal muscles(external oblique, rectus abdominis) were measured before, after 3 weeks and after 6 weeks of exercise by using a wireless surface electromyogram(EMG). The normalized EMG activities were compared using a one-way repeated ANOVA, and if there is statistically significant difference, a Bonferroni was used as post-hoc. Independent t-test was used to compare differences between groups. All statistical significance level was set at p<.05. Results: The results of this study were as follows. In both groups, there were a variation of abdominal muscle activities. It has been increased significantly after exercise more than before. To be specific, the activity has been increased more 6 weeks later than 3 weeks. But there was no significant difference between the both groups. Conclusion: These results suggest that plank exercise and hip walking exercise can be useful method for people to increase muscle activity in a short time, regardless of place.

The Immediate Effects of Single Leg Bridge Exercise on Abdominal Muscle Activity in Subacute Stroke Patients : a Preliminary Study

The Immediate Effects of Single Leg Bridge Exercise on Abdominal Muscle Activity in Subacute Stroke Patients : a Preliminary Study

The Effects of Abdominal Draw-in Maneuver on Hip, Abdominal Muscle Activation Pattern and Trunk, Pelvic Displacement during One Leg Standing

The Effects of Abdominal Draw-in Maneuver on Hip, Abdominal Muscle Activation Pattern and Trunk, Pelvic Displacement during One Leg Standing 의 이용 수, 등재여부, 발행기관, 저자, 초록, 목차, 참고문헌 등 논문에 관한 다양한 정보 및 관련논문 목록과 논문의 분야별 BEST, NEW 논문 목록을 확인 하실 수 있습니다.

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

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

Dose‐dependent multiple physiologic effects of systemic fentanyl in awake adult goats

It is well known that opioid analgesics induce life-threatening respiratory depression. A few studies have also documented additional deleterious effects of opioids on multiple physiologic functions. Moreover, there are reports of interindividual variation in susceptibility, magnitude, and duration of physiologic effects of opioids such as fentanyl. Here we tested the dose-dependent effects of intravenous injected fentanyl on physiologic functions in 7 awake, adult goats. Goats were instrumented for recording of multiple cardiorespiratory variables including respiratory pump and airway muscle activity. After a 30-minute control period, 0, 10, 20, or 50 µg/kg fentanyl was infused intravenously. We found that rapid IV infusion of fentanyl over 2 min caused a dose-dependent decrease in minute ventilation due to dramatic suppression of breathing frequency within 5 min after IV injection. These effects were coupled with dose-dependent increases in VT, which represents a more human like ventilatory response to opioids. The major suppression of ventilation occurred in 5 of the 7 goats, whereas in 2 of the goats IV fentanyl injections increased breathing frequency in a dose-dependent manner. This variation in ventilatory response to opioids agrees with findings that in a subset of humans, opioids have an excitatory effect on physiologic functions (Br. J. Anaesth 81, 1998). The suppression of ventilation seen in the majority of goats is transient, lasting for 3-10 minutes post-injection and is accompanied by an increased or normal VT up to 30-90 minutes. Over the initial 10 minutes after injection, there were obstructive and central apneas often exceeding one minute resulting in arterial hypoxemia (PaO2<50 mmHg) and hypercapnia (PaCO2>50mmHg). Heart rate was decreased for up to 15 minutes following 50µg/kg injection, whereas arterial blood pressure was increased for at least 90 minutes post-injection. Particularly over the initial minutes after 50µg/kg, fentanyl infusion decreased the duration but increased the intensity of diaphragm and intercostal muscle activity while increasing tonic activity of abdominal and airway muscles. Infusion of naloxone before or after infusion of fentanyl prevented or reversed the acute and delayed physiologic effects induced by fentanyl. Injection of Naloxone alone had no effect on physiological measures of goats. We conclude that goats have multiple dose- and individual-dependent physiologic responses to systemic infusion of fentanyl. Furthermore, our reversal data suggests the effects of fentanyl in goats are likely mediated by activation of µ-opioid receptors.

중년여성의 요실금 예방을 위한 심부근육 자극 운동의 효과

This study was conducted to investigate the changes in deep muscles related to urinary incontinence in middle-aged women using gyrotonic exercise of deep muscles. The subjects of this study were 40 middle-aged women with symptoms of urinary incontinence with a score of 1 to 3 points for UDI-6, an objective evaluating tool for urinary symptoms, among premenopausal middle-aged women aged 40 to 65 years. The gyrotonic exercise group consisted of 20 people and the control group 20 people, and in the case of the exercise group, exercise was performed for 60 minutes per exercise at a frequency of exercise 3 times a week for 12 weeks. As a result of statistical analysis, significant interaction effects were found in both pelvic floor muscle thickness and pelvic floor muscle activity (p<.01), which was significantly increased post-mortem compared to before in the gyrotonic exercise group. After 12 weeks, the gyrotonic exercise group was significantly higher than the control group (p<.05). Significant interaction effects were also found in both the right transverse abdominal muscle and transverse abdominal muscle activity (p<.01) (p<.001), which in the gyrotonic exercise group was compared with before and after post-mortem. It was found to be significantly increased (p<.01), and after 12 weeks, the gyrotonic exercise group was significantly higher than that of the control group (p<.01) (p<.001). Significant interaction effects were also found in both the left transverse abdominis muscle and the left transverse abdominis muscle activity (p<.05), which was significantly decreased in the control group compared to before. (p<.05), after 12 weeks, the gyrotonic exercise group was significantly higher than the control group (p<.01). There was no interaction effect in the diaphragm.

Postural Sensorimotor Control on Anorectal Pressures and Pelvic Floor Muscle Tone and Strength: Effects of a Single 5P® LOGSURF Session. A Cross-Sectional Preliminary Study.

Pelvic floor dysfunction (PFD) is a functional condition present most frequently in women. Despite pelvic floor muscle training being considered by the International Continence Society (ICS) as the first-line treatment in uncomplicated urinary incontinence, other more comprehensive postural methods as 5P® LOGSURF have emerged. This preliminary cross-sectional study explores the effects of a single 5P® LOGSURF session on pelvic floor muscle (PFM) tone and strength (MVC), resting anal tone, intrarectal pressure, and deep abdominal muscles activation. Thirty women were included (11 without PFD and 19 with PFD). Primary outcome measures were PFM tone, PFM MVC and resting anal tone and secondary measures outcomes were intrarectal pressure and deep abdominal activation. All outcome measures were collected before, throughout and after a single 30′ 5P® LOGSURF session. The findings from this study suggest that PFM tone (PFD group: p = 0.09, d = 0.72; non-PFD group: p = 0.003, d = 0.49) and PFM MVC (PFD group: p = 0.016; non-PFD group: p = 0.005) decreased in both groups after a single 5P® LOGSURF session, with a medium effect size for women with PFD. Contrarily, deep abdominal muscle MVC increased (PFD group: p < 0.001; non-PFD group: p = 0.03). Intrarectal pressure and resting anal tone decreased in both groups throughout the session. These results suggest that 5P® LOGSURF method may be interesting if is performed by women with mild symptoms of PFD or healthy women to achieve a decrease in PFM tone in women who manifested pain to intracavitary techniques or practices. Further research with higher sample sizes and long-term are necessary for generalizing.

Effects of Core Stabilization Exercise versus General Trunk-Strengthening Exercise on Balance Performance, Pain Intensity and Trunk Muscle Activity Patterns in Clinical Lumbar Instability Patients: A Single Blind Randomized Trial

Postural balance is important for activities of daily living. Patients with chronic low back pain (CLBP) exhibit balance problems, such as difficulty performing daily activities. Specifically, CLBP patients with clinical lumbar instability (CLI) have demonstrated deep trunk muscular dysfunction that induces poor postural control and may result in a high risk of falling. This study aimed to investigate the effect of a 10-week core stabilization exercise (CSE) regimen versus a strengthening trunk exercise (STE) regimen and conduct a 3-month follow-up on balance, pain, and trunk muscle activity patterns in CLI patients. A single-blind randomized controlled trial was used to compare the effects of CSE and STE on balance, pain, and trunk muscle activity patterns in 38 CLBP patients with CLI. The results of the 5-times-sit-to-stand test (FTSST) and pain intensity revealed significant improvements in both groups after ten weeks of exercise and at the 3-month follow-up point. However, the differences in the FTSST scores and pain intensity between the CSE and STE patients were not significant. Moreover, the CSE group presented significantly greater deep abdominal muscle activation than the STE group after ten weeks of exercise. In addition, both groups exhibited a trend of improvement in terms of deep back muscle activation. Therefore, the current study results suggest that both exercise regimens can improve balance performance and pain intensity. Moreover, the CSE group showed more significant improvements in deep abdominal muscle activation than the STE group.

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

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