Pressure Muscle Research Articles

Overview of risk factors for stress urinary incontinence and strategies in its prevention and treatment

Stress urinary incontinence is a medical problem that afflicts women worldwide. The causes can be mainly divided into 4 parts: increased abdominal pressure and chronic ischemia of pelvic floor muscles, endocrine changes, pelvic structural damages, inflammatory and consumptive states. The choice of prevention and treatment should also be based on a comprehensive assessment of individualized factors. Treatment techniques which are more minimally invasive or even non-invasive than surgery are currently a hot topic of research in the field of pelvic floor and urinary control, including laser and radiofrequency therapy, periurethral injection therapy, exogenous stem cell therapy and technology for activation of endogenous stem cells. They are expected to solve the clinical problem of stress urinary incontinence with a wider scope of application, lower trauma and fewer complications in the future.

Impact of Lumbar Postures on the Functioning of Pelvic Floor Muscles Among Osteoporotic Post-Menopausal Women.

Introduction Maintaining continence and providing support to the abdominal contents and sexual functioning are among the primary roles of pelvic floor muscles. The pelvic floor muscles work in synergy with the abdominal muscle to perform these functions. Abdominal muscle activation in the sagittal plane is influenced by the lumbar spine posture. As pelvic floor dysfunction is common among post-menopausal women, this study aims to find out the relationship between lumbar posture and electromyographic (EMG) activity of the rectus abdominis (RA) muscle and vaginal pressure (VP) as a functioning of the pelvic floor muscles among osteoporotic post-menopausal females. Methods A total of 78 osteoporotic post-menopausal women were recruited and allocated into three groups depending on lumbar lordotic angle, namely normal lordosis (n=26) hyperlordosis (n=26), and hypolordosis (n=26). All the subjects were recorded for RA EMG activity and VP for pelvic floor function in the quiet standing (QS) position, and voluntary dynamic tasks such as maximal coughing (MC) and Valsalva maneuver (VM). Data were analyzed using one-way analysis of variance (ANOVA) and post hoc analysis. A 5% probability level was considered statistically significant, i.e., p<0.05. Results The results showed a significant reduction in the RA activity and VP during the dynamic tasks (MC and VM) among subjects with the altered lumbar lordotic angle (p<0.05). The reduction in RA activity and VP was found to be significantly higher (p<0.05) in subjects with hyperlordotic lumbar spine than in those with hypolordotic lumbar spine as compared to normal lordosis during QS, MC, and VM. Conclusion We conclude that osteoporotic post-menopausal women with different lumbar lordotic angle show variations in RA activity and pressure generated by the vagina as a function of the pelvic floor during voluntary dynamic tasks.

The Effect of the Contraction Pressure of the Hip Adductor Muscles on Thickness of Transversus Abdominis: A Randomized Controlled Trial

The Effect of the Contraction Pressure of the Hip Adductor Muscles on Thickness of Transversus Abdominis: A Randomized Controlled Trial

Age- and sex-related differences in 3D facial shape and muscle pressure in subjects with normal occlusion

Background and objective(s)(1) To derive descriptive statistics of three-dimensional (3D) facial shape, lip and cheek muscle pressure in subjects of European descent with normal dental occlusion. (2) To analyse the effect of age and sex on 3D-facial soft tissue morphology and muscle pressure in the same sample. (3) To assess the independent effect of muscle pressure on face shape. Method129 subjects with normal occlusion were cross-sectionally recruited and divided into: children (mixed dentition), adolescents and adults (permanent dentition, < and ≥18 years respectively). Muscle pressure was recorded using the Iowa Oral Performance Instrument. MeshLab, MeVisLab and Meshmonk tool box were used to clean, annotate landmarks and generate the 3D images. Two-way analysis of variance and post-hoc tests were used to analyse age and sex differences in face shape and muscle pressure. The effect of muscle pressure on face shape was analysed by Pearson correlation and Partial Least Square regression. ResultsSignificant facial differences were observed between adults and adolescents and adults and children in both sexes, showing flattening of cheeks and lips and protrusion of nose and chin. Significant cheek protrusion and retrusion of the vertical midface were found in adult women compared to men. Lip and cheek pressure increased with age, but their effect on face shape was not significant. ConclusionsThis study provides 3D age- and sex-specific facial models and muscle pressure of subjects without malocclusion. These can be used as a reference for clinicians focused on facial assessment in treatment planning and follow-up.

Spinal dopaminergic D1 and D5 receptors contribute to reserpine-induced fibromyalgia-like pain in rats

Fibromyalgia is a complex pain syndrome without a precise etiology. Reduced monoamines levels in serum and cerebrospinal fluid in fibromyalgia patients has been reported and could lead to a dysfunction of descending pain modulatory system producing the painful syndrome. This study evaluated the role of D1-like dopamine receptors in the reserpine-induced fibromyalgia-like pain model in female Wistar rats. Reserpine-treated animals were intrathecally injected with different dopamine receptors agonists and antagonists, and small interfering RNAs (siRNAs) against D1 and D5 receptor subtypes. Withdrawal and muscle pressure thresholds were assessed with von Frey filaments and the Randall-Selitto test, respectively. Expression of D1-like receptors in lumbar spinal cord and dorsal root ganglion was determined using real time polymerase chain reaction (qPCR). Reserpine induced tactile allodynia and muscle hyperalgesia. Intrathecal dopamine and D1-like receptor agonist SKF-38393 induced nociceptive hypersensitivity in naïve rats, whilst this effect was prevented by the D1-like receptor antagonist SCH-23390. Moreover, SCH-23390 induced a sex-dependent antiallodynic effect in reserpine-treated rats. Furthermore, transient silencing of D1 and D5 receptors significantly reduced reserpine-induced hypersensitivity in female rats. Reserpine slightly increased mRNA D5 receptor expression in dorsal spinal cord, but not in DRG. This work provides new insights about the involvement of the spinal dopaminergic D1/D5 receptors in reserpine-induced hypersensitivity in rats.

The association between forward head posture and masticatory muscle pressure pain thresholds in patients with temporomandibular joint dissorders: a cross-sectional observational study.

Forward head posture (FHP) is common in patients with temporomandibular joint disorders (TMDs); however, whether it contributes to TMD symptoms remains unclear. The aim of this study was to investigate the association between (1) FHP and masticatory muscle pressure pain thresholds (PPTs) and (2) neck muscle and masticatory muscle PPTs. A total of 145 patients diagnosed with TMD were recruited between December 2020 and April 2021. Data regarding FHP and neck and masticatory muscle PPTs were collected. FHP was characterized by the craniocervical angle (CVA) measured between the horizontal line through C7 and the line between the tragus of the ear and C7. Patients were divided into either the FHP group (CVA ≤ 51°) or the non-FHP group. Differences in the masseter and temporalis muscle PPTs between the two groups were analyzed using the Mann-Whitney U test. The correlation between the CVA, neck, and masticatory muscle PPTs in all patients was determined by Spearman's correlation analysis. There were 70 patients in the FHP group and 75 patients in the non-FHP group. No significant difference in masseter and temporalis muscle PPTs was found between the two groups (p > 0.05). No correlation was found between FHP and masticatory muscle PPTs (p > 0.05). A significant association was found between the neck muscle and masticatory muscle PPTs (p < 0.05). The C5-C6 pillar and masticatory PPTs were either moderately (r = 0.435, masseter muscle) or strongly (r = 0.608, temporalis muscle) correlated, while the correlation between the trapezius and masticatory muscles was moderate (r = 0.378, masseter muscle and r = 0.461, temporalis muscle). FHP was not directly associated with masticatory muscle PPTs. Masticatory muscle PPTs were strongly or moderately associated with neck muscle PPTs. Therefore, the presence of neck pain, not the degree of FHP, in patients with TMD is of significance. In TMD treatment, we should pay attention to and actively relieve neck pain.

Voice Alterations, Dysarthria, and Respiratory Derangements in Patients With Parkinson's Disease.

Almost 90% of people with Parkinson's disease (PD) develop voice and speech disorders during the course of the disease. Ventilatory dysfunction is one of the main causes. We aimed to evaluate relationships between respiratory impairments and speech/voice changes in PD. At Day 15 from admission, in consecutive clinically stable PD patients in a neurorehabilitation unit, we collected clinical data as follows: comorbidities, PD severity, motor function and balance, respiratory function at rest (including muscle strength and cough ability), during exercise-induced desaturation and at night, voice function (Voice Handicap Index [VHI] and acoustic analysis [Praat]), speech disorders (Robertson Dysarthria Profile [RDP]), and postural abnormalities. Based on an arbitrary RDP cutoff, two groups with different dysarthria degree were identified-moderate-severe versus no-mild dysarthria-and compared. Of 55 patients analyzed (median value Unified Parkinson's Disease Rating Scale Part II 9 and Part III 17), we found significant impairments in inspiratory and expiratory muscle pressure (&gt; 90%, both), exercise tolerance at 6-min walking distance (96%), nocturnal (12.7%) and exercise-induced (21.8%) desaturation, VHI (34%), and Praat Shimmer% (89%). Patients with moderate-severe dysarthria (16% of total sample) had more comorbidities/disabilities and worse respiratory pattern and postural abnormalities (camptocormia) than those with no-mild dysarthria. Moreover, the risk of presenting nocturnal desaturation, reduced peak expiratory flow, and cough ability was about 11, 13, and 8 times higher in the moderate-severe group. Dysarthria and respiratory dysfunction are closely associated in PD patients, particularly nocturnal desaturation and reduced cough ability. In addition, postural condition could be at the base of both respiratory and voice impairments. https://doi.org/10.23641/asha.21210944.

Validation of the flow index to detect low inspiratory effort during pressure support ventilation

BackgroundBedside assessment of low levels of inspiratory effort, which are probably insufficient to prevent muscle atrophy, is challenging. The flow index, which is derived from the analysis of the inspiratory portion of the flow–time waveform, has been recently introduced as a non-invasive parameter to evaluate the inspiratory effort. The primary objective of the present study was to provide an external validation of the flow index to detect low inspiratory effort.MethodsDatasets containing flow, airway pressure, and esophageal pressure (Pes)–time waveforms were obtained from a previously published study in 100 acute brain-injured patients undergoing pressure support ventilation. Waveforms data were analyzed offline. A low inspiratory effort was defined by one of the following criteria, work of breathing (WOB) less than 0.3 J/L, Pes–time product (PTPes) per minute less than 50 cmH2O•s/min, or inspiratory muscle pressure (Pmus) less than 5 cmH2O, adding “or occurrence of ineffective effort more than 10%” for all criteria. The flow index was calculated according to previously reported method. The association of flow index with Pes-derived parameters of effort was investigated. The diagnostic accuracy of the flow index to detect low effort was analyzed.ResultsModerate correlations were found between flow index and WOB, Pmus, and PTPes per breath and per minute (Pearson’s correlation coefficients ranged from 0.546 to 0.634, P < 0.001). The incidence of low inspiratory effort was 62%, 51%, and 55% using the definition of WOB, PTPes per minute, and Pmus, respectively. The area under the receiver operating characteristic curve for flow index to diagnose low effort was 0.88, 0.81, and 0.88, for the three respective definition. By using the cutoff value of flow index less than 2.1, the diagnostic performance for the three definitions showed sensitivity of 0.95–0.96, specificity of 0.57–0.71, positive predictive value of 0.70–0.84, and negative predictive value of 0.90–0.93.ConclusionsThe flow index is associated with Pes-based inspiratory effort measurements. Flow index can be used as a valid instrument to screen low inspiratory effort with a high probability to exclude cases without the condition.

Pediatric Simulation of Intrinsic PEEP and Patient-Ventilator Trigger Asynchrony During Mechanical Ventilation.

Intrinsic PEEP during mechanical ventilation occurs when there is insufficient time for expiration to functional residual capacity before the next inspiration, resulting in air trapping. Increased expiratory resistance (RE), too rapid of a patient or ventilator breathing rate, or a longer inspiratory to expiratory time ratio (TI/TE) can all be causes of intrinsic PEEP. Intrinsic PEEP can result in increased work of breathing and patient-ventilator asynchrony (PVA) during patient-triggered breaths. We hypothesized that the difference between intrinsic PEEP and ventilator PEEP acts as an inspiratory load resulting in trigger asynchrony that needs to be overcome by increased respiratory muscle pressure (Pmus). Using a Servo lung model (ASL 5000) and LTV 1200 ventilator in pressure control mode, we developed a passive model demonstrating how elevated RE increases intrinsic PEEP above ventilator PEEP. We also developed an active model investigating the effects of RE and intrinsic PEEP on trigger asynchrony (expressed as percentage of patient-initiated breaths that failed to trigger). We then studied if trigger asynchrony could be reduced by increased Pmus. Intrinsic PEEP increased significantly with increasing RE (r = 0.97, P = .006). Multivariate logistic regression analysis showed that both RE and negative Pmus levels affect trigger asynchrony (P < .001). A passive lung model describes the development of increasing intrinsic PEEP with increasing RE at a given ventilator breathing rate. An active lung model shows how this can lead to trigger asynchrony since the Pmus needed to trigger a breath is greater with increased RE, as the inspiratory muscles must overcome intrinsic PEEP. This model will lend itself to the study of intrinsic PEEP engendered by a higher ventilator breathing rate, as well as higher TI/TE, and will be useful in ventilator simulation scenarios of PVA. The model also suggests that increasing ventilator PEEP to match intrinsic PEEP can improve trigger asynchrony through a reduction in RE.

Sub-occipital muscle pressure pain thresholds correlate to direction of symptomatic active comfortable sustained neck rotation testing in post-concussive headache: a retrospective observational cross-sectional study

ABSTRACT Objectives To compare sub-occipital muscle pressure sub pain thresholds (PPTs) in individuals with persistent-post-traumatic-headache (PPTH) in relation to the presence or not of cranial nerve and/or autonomic symptoms reported during sustained neck rotation (SNR). Background Previously 81% of military service members with PPTH demonstrated symptoms with SNR up to 60 seconds. Of these, 54% reported symptoms in one (Uni-Symp) and 46% in both directions of rotation (Bi-Symp). Sub-occipital PPTs, in relation to SNR direction, were of interest. Methods Retrospective review of records of 77 individuals, with PPTH with both SNR and PPTs. Average suboccipital and scalene PPTs were compared between Asymptomatic (n = 13), upon SNR testing, or Symptomatic (Uni-Symp, n = 32, Bi-Symp, n = 32), groups. Results The Bi-Symp group had significantly reduced sub-occipital PPTs relative to the Asymptomatic group on both sides [p < 0.009] with no side-to-side differences in either group. The Uni-Symp group had significantly lower sub-occipital PPTs on the symptomatic SNR test direction compared to the asymptomatic side [t(31) = 3.37, p = 0.002]. There were no differences within or between groups in the scalene PPTs(p’s > 0.08). Conclusions An upper cervical mechanical trigger of symptoms during SNR tests in some individuals with PPTH is possible. The direction of symptomatic SNR tests may indicate direction of guarded hypermobile dysfunction and direct treatment.

Freedive Training Gives Additional Physiological Effect Compared to Pulmonary Rehabilitation in COPD.

Introduction: Pulmonary rehabilitation (PR) is beneficial for lung mechanics, chest kinematics, metabolism, and inspiratory and peripheral muscle function. Freediving training (FD) can be effective in sportsmen and can improve breath-holding time. Aims: We sought to determine the effectiveness of freediving training in the pulmonary rehabilitation of COPD patients. Patients and methods: Twenty-three COPD patients (15 men and 8 women; median age 63 years; FEV1: 41% pred; BMI: 28 kg/m2) participated in the FD + PR group (3 weeks PR and 3 weeks FD + PR) and 46 patients with COPD (25 men and 21 women; median age 66 years; FEV1: 43% pred; BMI: 27 kg/m2) participated in an inpatient PR program (6 weeks). Patients performed comfort zone breath holding for 30 min/day. Patients increased their breath-holding time within their comfort zone for 30 min. We detected lung function, chest expansion (CWE), inspiratory muscle pressure (MIP), peripheral muscle function (GS), and exercise capacity (6MWD), and we included breath-holding time (BHT), quality of life score (COPD Assessment Test (CAT)), modified Medical Research Dyspnea Scale (mMRC) score, and the severity of the disease assessed by the BODE index (FEV1, BMI, 6MWD, and mMRC) and an alternative scale (FEV1, BMI, 6MWD, and CAT). Result: There were significant differences in the characteristics of the two groups. Significant improvement was detected in all functional and quality of life parameters except lung function in both groups. Significantly higher improvement was detected in CWE, GS, 6MWD, BHT, CAT, mMRC, alternative scale, and MIP. The improvement in forced vital capacity (FVC) was not significant. There were no side effects of FD training. Conclusion: The FD method can potentiate the effect of PR, improving not only BHT but also other parameters. Trial registration: ISRCTN ISRCTN13019180. Registered 19 December 2017.

The effects of tongue elevation using a weighted plastic bottle on the tongue pressure and activity of suprahyoid muscles.

A rise in tongue pressure coincides with an increase in the suprahyoid muscle activity. The aim was to investigate the effects of holding a weighted plastic bottle on tongue pressure and the suprahyoid muscle activity. Eighteen participants (8 men and 10 women; mean age 42 ± 16 years) participated in this study. All participants had no history of speech, language, hearing or swallowing disorders and no tooth loss, and they did not require dentures. Healthy participants held gauzes connected with a plastic bottle with increasing resistive loads of 0g, 250 g, 500 g and 750 g, between their palate and tongue. The maximum tongue pressure and average tongue pressure were measured during a 5s hold. The average tongue pressure was defined as the mean tongue pressure data in each task. The suprahyoid muscle activity was measured using the electromyogram (EMG). The root mean square of the EMG signals measured while lifting different loads and while performing the head lifting exercises was compared. All variables were examined using the Friedman's test and Wilcoxon signed-rank test. The maximum tongue pressure (p < .05) and average tongue pressure values (p < .05) increased gradually in the anterior-median region with increasing resistive loads, and the root mean square amplitudes for 250 g, 500 g and 750 g were not significant compared with head lifting exercises. These results indicated that plastic bottle holding could be a potential strength training tool for the tongue and the suprahyoid muscles.

The Effects Of Age On Exercise-induced Abdominal Muscle Fatigue In Healthy Younger And Older Men.

PURPOSE: Older men have a greater amount of expiratory flow limitation and abdominal muscle pressure generation during high intensity exercise compared to younger men. This may result in a higher prevalence of exercise-induced abdominal muscle fatigue. However, this is currently unknown. Therefore, we investigated the effects of age on exercise-induced abdominal muscle fatigue in healthy younger and older men. METHODS: Eight younger (29 ± 4 years) and eight older (69 ± 4 years) men completed a constant load cycling test at 85% of maximal power output to the limit of tolerance. The percentage of expiratory flow limitation was quantified by superimposing pre-exercise maximum flow volume loops with tidal breaths meeting or exceeding the expiratory portion of the maximum flow volume loops. Gastric pressures were measured using a micro-transducer esophageal catheter. To determine supramaximal nerve stimulation, three single twitches were obtained at intensities of 50, 60, 70, 80, 85, 90, 95, and 100% of maximal stimulator output pre-exercise. Fatigue of the abdominal muscles was assessed by measuring the reduction in magnetically evoked gastric twitch pressure (Pga,tw) responses pre- and post-exercise at 0, +15 and + 30 min. Abdominal muscle fatigue was defined as ≥10% reduction in potentiated Pga,tw relative to pre-exercise values. Comparisons between younger and older men for the prevalence of abdominal muscle fatigue were made using Fisher’s exact test. RESULTS: As the power output of the stimulator increased there were proportional increases in Pga,tw. Supramaximality was achieved from 90% for younger men (P ≥ 0.230) and from 95% for older men (P ≥ 0.940). Older men had higher expiratory flow limitation and gastric pressure time products than younger men (P < 0.05). Five of eight (63%) younger men (-28 ± 14%) vs. seven of eight (88%) older men (-37 ± 18) exhibited abdominal muscle fatigue (P = 0.038). CONCLUSION: We investigated the effects of age on exercise-induced abdominal muscle fatigue in healthy younger and older men. Older men experienced a greater amount of expiratory flow limitation and abdominal muscle pressure generation compared to younger men which resulted in a higher prevalence of exercise-induced abdominal muscle fatigue.

Некоторые особенности экстрахрусталиковой аккомодации в условиях горизонтальных конвергентных и дивергентных напряжений

Purpose. To study the features of extralenticular accommodation in horizontal convergence and divergence stresses. Material and methods. The study involved 25 students including 18 girls and 7 boys (50 eyes) with mild myopia, whose average age was 21.7 years. The refraction value was determined by the subjective method and averaged (-) 1.5 dptr. Pairs of prismatic lenses with a power of 2.0 dptr were used as an effective optical accommodation model. The lenses were mounted in a spectacle frame with their bases either to the temple or to the nose. A comparative assessment of the features of the extralenticular capabilities of the visual system was carried out by determining the binocular stability of visual perception to hypermetropic retinal defocus. Results. The study of visual perception stability in far-vision mode in the absence of vergence stress revealed that the total value of the visual resolution was 564 %. Under convergence stress, the total value of the visual resolution was equal to 989 %, and under divergence stress, it was 988 %. In studies without any vergenсe stress, the avergence accommodation curve had a smooth downward trend. In studies of visual systems under vergence stresses, curves had a concave arc shape and turned downward abruptly in the middle. Conclusions. Convergence and divergence movements can stimulate combined lenticular and extralenticular accommodation caused by ciliary muscle contraction and oculomotor muscle pressure on the eye sclera. Extraocular muscle pressure causes temporary deformation of the eyeball, that leads to a temporary change in the eye refraction. Keywords: extralenticular accommodation, convergence and divergence stresses, temporary deformation of the eyeball.

Evaluating the Grip Strength and Pen Pressure in Handwriting Performance among Children with Developmental Coordination Disorder in India

Handwriting difficulties were predominant among children with developmental coordination disorder. Poor muscle strength and pressure exerted by pen were factors assessed by the clinicians and they play a role in determining the handwriting efficiency. There is no empirical evidence on the handwriting efficiency and the factors associated with it for Indian children with developmental coordination disorder. The study aims in evaluating the grip strength and pen pressure in handwriting performance among children with developmental coordination disorder. Ten children of age group 5-10 years with developmental coordination disorder were compared with typically developing children. Hand dynamometers were used in evaluating the palmar and tripod grip strength. Handwriting task was compared between the typically developing children and Developmental coordination disorder children and the results of the study assured that there was no significant difference documented in the hand dynamometer measures of grip strength. DCD children exhibit less pressure on writing surface as compared to typically developing peer group children. There was no correlation between grip strength and pen pressure over handwriting efficiency in children with developmental coordination disorder. Clinicians should create awareness on the importance of enhancing handwriting skill among children with developmental coordination disorder.

Spontaneous Splenic Rupture in Plasmodium Vivax Malaria

Splenomegaly is one of the common complications of malaria most commonly associated with Plasmodium Vivax. Due to inadequate treatment, spleen can harbor parasite, which causes recurrent infection leading to splenomegaly and splenic rupture. Spleen is more prone to rupture in acute phase of infection. The exact mechanism of splenic rupture is still unknown but trauma, pressure of abdominal muscles on spleen due to sneezing and coughing plays important rule. Spontaneous splenic rupture although very rare in normal sized spleen, as in case presented here, is life-threatening complication. Therefore, early diagnosis and management plays important role in saving life.

This Month in Anesthesiology

This Month in Anesthesiology

The Effect of Inspiratory Effort on Circuit Compensation for Volume-Targeted Modes.

Critical-care ventilators provide patient circuit compensation (CC) to counteract the loss of volume due to patient circuit compliance. No studies show the effect of inspiratory efforts (indicating maximal value of the muscle pressure waveforms [Pmax]) on CC function. The goal of this study was to determine how Pmax affects volume delivery with or without CC for both volume control continuous mandatory ventilation with set-point targeting scheme (VC-CMVs) and pressure control continuous mandatory ventilation with adaptive targeting scheme (PC-CMVa) modes on the Servo-u ventilator. A breathing simulator was programmed to represent an adult with moderate ARDS with different Pmax. It was connected to a ventilator set to VC-CMVs or PC-CMVa. The change in tidal volume (ΔVT) was defined as the difference between VT with CC on versus off. VT error was defined as the difference between the simulator displayed VT and the set VT with CC on versus off. For both VC-CMVs and PC-CMVa modes, ΔVT decreased as Pmax increased. The VT error decreased as Pmax increas-ed for VC-CMVs. In contrast, VT error increased on PC-CMVa mode as Pmax increased and peaked 39.0% for Pmax = 15 cm H2O. For both modes, the difference in VT errors for CC on versus CC off decreased as Pmax increased. CC corrected the delivered VT for volume lost due to compression in the patient circuit as expected. This compensation volume decreases as airway pressure drops due to patient Pmax.

The Association between Postpartum Pelvic Girdle Pain and Pelvic Floor Muscle Function, Diastasis Recti and Psychological Factors-A Matched Case-Control Study.

There is uncertainty regarding the association between abdominal morphology, pelvic floor function, and psychological factors in women with postpartum pelvic girdle pain (PGP). The aim of this case-control study was to evaluate the differences between women with and without persistent PGP regarding pelvic floor function, diastasis recti, and psychological factors 6–24 weeks postpartum. Pelvic floor manometry, palpation examination of abdominal muscles, the International Consultation on Incontinence Questionnaire Short Form, The Depression, Anxiety and Stress Scale—21, and the Pain Catastrophizing Scale were used. The PGP group presented with lower vaginal resting pressure (p < 0.001), more tenderness (p = 0.018) and impaired voluntary activation of pelvic floor muscles (p ≤ 0.001). Women with pain also had more distortion on the level of the anterior abdominal wall (p = 0.001) and more severe diastasis recti (p = 0.046) when compared to pain-free controls. Lower vaginal resting pressure was the strongest factor explaining PGP (OR 0.702, 95%CI 0.502–0.981). There were no differences in terms of the pelvic floor strength, endurance, severity of urinary incontinence and reported distress between the groups. Women with PGP 6–24 weeks postpartum differ in pelvic floor and abdominal muscle function from the pain-free controls. Vaginal resting pressure may be an important factor in pelvic girdle pain shortly postpartum. Further studies are needed to see a trend in changes over time.

Formulation and exploration of novel, intramuscular pressure based, muscle activation strategies in a spine model

Optimization models are often devised to assess spinal stability via estimating individual muscle forces. However, neglecting muscles' fluidic behavior remains an approximation due to the role of muscle pressure in force transmission. The purpose of this study was to leverage a validated Finite Element (FE) model of the spine, inclusive of Intra-Muscular Pressure (IMP), to explore muscle activation strategies towards maintaining equilibrium spinal stability. Three conventional strategies governing minimizing muscle effort, minimizing IVD compressive forces, and maintaining stability at all costs were first investigated to explore model's validity. Thereafter, two novel IMP-based strategies were devised and explored, specifically minimizing and maximizing IMP. The model was previously shown valid in light of in vivo and in silico observations with an average discrepancy of 6%. This being the case, the conventional strategies dictated efficacy in muscular activations whilst maintaining an equilibrium stable position, as quantified in the present paper, with a difference of 9.8% from documented data. In addition, the explored novel IMP-based strategies suggested the presence of a threshold individual muscles IMP, approximately 272 mmHg for the longissimus muscle for example, beyond which muscles potentially start to share radial loads with surrounding tissues, whilst limiting the contraction of the underlying muscles. In conclusion, this study theoretically supports the possibility of activation strategies based on muscular pressure, which the developed, verified, and validated FE spine model was leveraged to investigate. The explored novel IMP-based strategies may have significance in informing clinical applications such as motion analysis and functional electrical stimulation of muscles.