Core Instability Research Articles

Dynamic neuromuscular stabilization and its efficiency on sports performance

Neuromuscular stability is necessary for optimal sport performance. Stability is not achieved only by abdominal muscles, spine extensors and gluteals, but it is accomplished by precise coordination of these muscles and intra-abdominal pressure by the central nervous system. A primary role of the core muscles stability is to raise the intra-abdominal pressure and to increase the tension in the thoracolumbar fascia. Postural core instability is associated with poor dynamic balance control and with a high risk of injury or fall. Dynamic neuromuscular stabilization (DNS) is a rehabilitative approach to optimize the movement system based upon the scientific principles of developmental kinesiology and provides an effective tool in rehabilitation of sport injuries.

Minimally Invasive Stapled Abdominal Wall Repair: A New Surgical Technique.

Background: Diastasis recti (DR) is a common condition, especially in women after pregnancy, often associated with concomitant hernia defects and defined as a rupture of the midline and a separation of the rectus muscle more than 2 cm. Symptoms related to this are low back pain, urinary incontinence and pelvic prolapse, as well as abdominal bulging and core instability. We analyzed clinical and functional outcomes after treatment of DR alone or associated with midline hernias in 219 patients who underwent a midline reconstruction using miSAR® technique (minimally invasive stapled abdominal wall reconstruction). Methods: Between April 2019 and April 2022, 219 patients were treated with miSAR®. All patients were requested to quantify preoperative and postoperative functional symptoms (urinary incontinence, low back pain, abdominal swelling, and respiratory distress). Results: Twenty-seven men and 192 women underwent the miSAR® technique. The mean body mass index was 23.9 kg/m2. We performed the miSAR® technique in patients affected by incisional midline hernia and umbilical hernia alone or associated with DR. Composite mesh was used in 91.8% of cases. The average operating time was 90 minutes. Seven percent of the patients had postoperative complications, including two retromuscular hematomas, two retromuscular seromas, and one postoperative bleeding event. Two patients were readmitted for bowel obstruction. After surgery, there was symptomatic improvement in urinary incontinence, low back pain, respiratory symptoms, and abdominal swelling; this improvement was confirmed at 6 months and at 1- and 2-year follow-up. At the 1-year follow-up, the overall recurrence rate was 2.83%. Conclusion: miSAR® is a feasible and effective technique and shows promising results in the treatment of DR and ventral hernia. Possible enhancements include use of preoperative Botox to treat defects larger than 6 cm. Multicentric analysis is needed to validate the technique, and longer follow-up is required to assess the recurrence rate.

Enhanced relief of low back pain following surgical repair of a ventral hernia: A case report

The effectiveness of core muscle strengthening in treating Low Back Pain (LBP) is well-established. The laxity or defect of the important portion of core muscle groups, transverse abdominis muscle, as seen in ventral hernia could be a contributing factor for core weakness and instability and thereafter results in LBP. The contribution of ventral hernia to LBP is scantily documented. Ventral hernias can be easily missed if a thorough physical exam is not performed. A 50-year-old male patient presented to the clinic with a 10- year history of LBP; a physical exam revealed a previously undiscovered ventral hernia. He reported a reduction in LBP and improvement in back support after his ventral hernia repair surgery. This case report highlights the importance of a thorough assessment and treatment of the underlying connection between ventral hernia and chronic LBP.

Effect of Core Stability Trainings on Functional Movement Screening Scores and Trunk Muscle Endurance in Female Kyokushin Karate Athletes

Background: The objective of this study was to examine the impact of six weeks of core instability training on functional movement screening (FMS) scores and core trunk endurance in female Kyokushin karate athletes. Methods: Thirty female Kyokushin Karate athletes aged 14 - 18 years were recruited and randomly assigned to either an experimental group or a control group (n = 15 per group). Functional movement patterns, including the FMS, Sorenson, and McGill tests, were assessed before and after the intervention. The experimental group underwent six weeks of Kyokushin Karate training, while the control group performed core stability exercises. The statistical analysis involved paired t-tests and analysis of covariance (ANCOVA), with a significance level set at P ≤ 0.05. Results: The paired t-test results indicated a significant difference in pre- and post-test scores in both the control and experimental groups (P < 0.05). However, the ANCOVA showed no significant differences between the groups (P > 0.05). Conclusions: Both Kyokushin training and core stability exercises have been found to increase core stability and FMS scores. Therefore, it can be suggested that Kyokushin Karate athletes may not need to perform separate core stability exercises as part of their training routine.

Force plate testing is correlated with jumping performance in elite Nordic skiers

IntroductionSki jumping (SJ) and Nordic combined (NC) athletes are at higher risk for femoroacetabular impingement (FAI) compared to the general population. ObjectivesThe purpose of this study was to determine the relationship between force plate testing metrics, Functional Movement Screen (FMS) scores, and radiographic signs of FAI and SJ performance. MethodsElite SJ and NC athletes were prospectively recruited. FMS testing was performed to assess muscular imbalance, instability, and immobility. Vertical jump testing was performed using a commercially available force plate device. Ski jump score and distance score were measured on a single jump for each athlete. ResultsTwenty-one athletes (10 SJ, 11 NC) with competition scores were included. On FMS testing, most SJ (67%) and NC (73%) athletes demonstrated core instability. There were higher rates of hip instability and ankle stiffness among SJ athletes, although not statistically significant (P > .05). Ski jump distance score was significantly positively correlated with force plate vertical jump height, maximum acceleration, maximum velocity, concentric impulse, counter-movement depth, and flight time (P < .05). FMS testing results and radiographic FAI were not significantly associated with competition scores. ConclusionsOur results show significant positive correlations between competition scores and force plate jump testing performance as measured by jump height, acceleration, maximum velocity, counter-movement depth, and concentric impulse in elite SJ and NC athletes. Our findings suggest that ski jumpers may benefit from training that emphasizes stretch-shortening cycles and eccentric-to-concentric contraction transition, which may optimize their performance and promote joint stability.

Numerical investigation about the unsteady behavior of a free submerged cavitation jet using the SBES approach

Submerged cavitation jet has emerged as an efficient method for the removal of ship fouling. Due to the complicated revolution of cavitation cloud, it has attracted great research interest. Ascertaining the internal flow dynamics of cavitating jets is always a challenge. Thus, this paper investigates the unsteady behavior of a free submerged cavitating jet numerically in three dimensions. The turbulent cavitation flow is simulated utilizing the Stress-Blended Eddy Simulation (SBES) turbulent model combined with the Schnerr-Sauer cavitation model. The results are compared with the data from a famous experiment, and they exhibit good agreement in both time-averaged and unsteady characteristics. The cavitation life stages, i.e., the cavitation growth, shedding, contraction, and collapse are explored. In results, cavitation cloud forms around the jet core. Cavitation cloud shedding involves complex factors, including shear layer instability, complex pressure gradients, and re-entrant motion, and it may also be related to the potential core and jet core instability. Additionally, cavitation cloud development is closely related to the jet core and exhibits synchronous behavior. After the cavitation cloud collapse, a local high pressure is observed and then cavity rebound is generated, where the collapse can be either mild or intensive.

Hysteretic behavior of SMA energy dissipater with shape memory effect induced by heating recovery

The buckling restrained energy dissipater is one small axial yield type energy dissipation device usually attached to the prefabricated structure to improve seismic performance. In this paper, a shape memory alloy bamboo-shaped energy dissipater (SMA-BED) was proposed, which used bamboo-shaped SMA rod as the energy dissipation core. The special shape memory effect of SMA material was expected to recover the residual deformation, and the outer restraining tube was used to prevent the core buckling and instability. The tests of 8 SMA-BED specimens were completed to compare the effect of repeated loadings on hysteretic behavior. The results showed that all specimens exhibited stable and full hysteretic loops. After loading, the average deformation recovery ratio of all specimens was about 97.9% by heating in a water bath and cooling to room temperature. The load-displacement curve obtained by reloading the specimen basically coincided with the previous curve, and the results were consistent after repeated 3 loading times. The compression and deformation modes of the SMA-BED core with different construction forms were analyzed theoretically, meanwhile a lateral displacement computation model of the yielding part was proposed, which could better estimate the contact between yielding part and restraining tube.

The TOR concept (training, operation, and rehabilitation) applied to a cohort of postpartum women with training-resistant symptomatic rectus diastasis: evaluation 1 year after surgery.

Rectus diastasis is a common sequela of pregnancy and is associated with functional disabilities such as back pain, abdominal core instability, abdominal muscle weakness, urinary incontinence, and psychological issues such as a negative body image. The aim of this study was to evaluate the effect of the TOR concept (training, operation, and rehabilitation), a novel concept for treating abdominal wall insufficiency combined with rectus diastasis, after pregnancy. TOR consists of preoperative evaluation of symptoms and custom-designed abdominal core training, tailored rectus diastasis repair, and individual progressive postoperative rehabilitation. A consecutive series of women diagnosed with rectus diastasis and core dysfunction resistant to training, underwent plication of the linea alba between 2018 and 2020. After surgery, all patients participated in an individually designed rehabilitation programme over a 4-month interval. Physical function was recorded before surgery and 1 year after surgery using the disability rating index questionnaire. Symptoms associated with core instability were recorded before and 1 year after surgery. Quality of life was assessed using the SF-36. The abdominal wall anatomy was assessed with ultrasound before and 1 year after surgery. Seventy-one women were included and all attended 1-year follow-up. Response rate was 81.7 per cent (58) for the disability rating index, and 59.2 per cent (42) for SF-36. Self-reported physical function (disability rating index) improved in 54 of 58 patients (93.1 per cent), with a median score reduction of 91.3 per cent. Core instability symptoms decreased significantly. All SF-36 subscales improved significantly compared with preoperative scores, reaching levels similar to or higher than the normative Swedish female population. No recurrence of rectus diastasis was seen at the 1-year follow-up. Surgical reconstruction within the TOR concept resulted in significant improvements in physical function and quality of life as well as a significant decrease in symptoms of core instability.

Experimental study of the core instability before and after internal transport barrier formation in EAST

In a reversed shear discharge in the Experimental Advanced Superconducting Tokamak (EAST), an internal transport barrier (ITB) was formed. For the first time, the turbulence in the plasma core before and after the formation of the ITB in EAST was investigated by microwave reflectometry. It was found that during the formation of the ITB, the turbulence inside the barrier was not completely suppressed. The density fluctuation level decreased in the early phase of ITB and significantly increased later. It was found that the density fluctuation level increased with the density gradient after the appearance of reversed shear Alfvén eigenmodes (RSAEs). The change in turbulence, measurable by the reflectometer, did not affect the rate of increase in core density. Through the measurement of RSAEs, it was found that the formation of this ITB may be related to the minimum q (q min). q min was close to 2.

Three-dimensional density measurements of a heated jet using laser-speckle tomographic background-oriented schlieren

Tomographic background-oriented schlieren (TBOS) is a promising optical technique for 3D density field measurement in turbulent flows. Path-integrated information on refractive index gradients is captured by cameras looking through the flow at textured background patterns in the form of apparent displacements of the patterns. A tomographic reconstruction of the three-dimensional refractive index gradients is performed, from which the instantaneous three-dimensional density field is obtained. Most TBOS measurements to date have been limited by large temporal blurring and/or large defocus blurring. Our 15-camera experimental set-up uses a pulsed laser for both illumination and creation of a laser-speckle background pattern. The high-power laser ensures adequate exposures in nanoseconds, so temporal integration is minimised in each measurement. The beam is spread to illuminate a surface that is observed by fifteen cameras that are evenly spaced circumferentially around the flow. Laser speckle patterns are observed by the cameras due to the diffuse reflection and interference of coherent light from roughness on the surface. We develop a methodology for selecting the optimal focal length, focus distance, and lens aperture by considering the compromise between displacement sensitivity, defocus blurring and speckle size. Low temporal- and spatial-blurring 3D temperature field measurements with excellent resolution of turbulent flow features are obtained and good agreement with thermocouple. Classical behaviours of the potential core instability such as vortex rollup and radial ejections are identified. The behaviour of the potential core is examined further, which reveals that the potential core undergoes considerable deformation and fragmentation during the transition to turbulence.

Association Between Inter-Recti Distance and Impaired Abdominal Core Function in Post-Partum Women With Diastasis Recti Abdominis.

Background and Aim: The definition and management of Diastasis Recti Abdominis (DRA) is under debate. This study aimed to understand the correlation between the post-partum inter-recti distance (IRD) and functional impairments associated with core instability, with the hypothesis that IRD could serve as a proxy for core instability symptoms and constitute a tool in decision-making for DRA treatment. Material and Methods: A cohort of post-partum women with abdominal core instability symptoms combined with DRA were studied. The size of IRD was measured with ultrasonography and cross-sectionally analysed against functional impairments registered with the self-report Disability Rating Index (DRI), which grades the ability to perform 12 different daily activities. Results: A total of 224 women were included in the study. In univariable analysis, IRD was associated with impairment of the activities running (p = 0.007), heavy work (p = 0.036) and exercise/sports (p = 0.047), but not with dressing, walking, sitting for long periods, standing bent over a sink, carrying a suitcase, making a bed, light manual labour or heavy lifting. No significant correlations were seen in the multivariable analysis when adjustments were made for BMI and parity. Conclusion: IRD and post-partum functional impairments had no significant correlation in multivariable analysis. The post-partum core instability condition is complex and probably associated with more factors than solely the IRD. The IRD alone does not seem to be a sufficient proxy for decision-making regarding optimal treatment. A more complete instrument to assess the post-partum abdominal core is warranted.

P-095 RECTUS DIASTASIS REPAIR: VARIATIONS OF POSTPARTUM ABDOMINAL WALL ANATOMICAL CHANGES PROPOSE A TAILORED SURGICAL REPAIR. EARLY RESULTS OF THE EXTENDED REPAIR TECHNIQUE STUDY

Abstract Aim A pregnancy can result in permanent anatomical changes such as a persistent rectus diastasis (RD), a widened linea semilunaris and retracted oblique muscles. The diverse anatomical changes contribute to the abdominal deformation and may present in a variety of combinations. A standardized suture repair of the RD may not be sufficient in severe abdominal wall deformation cases. This observational cohort study evaluated an extended repair technique. Method A cohort of 44 postpartum women with training resistant core instability symptoms planned for surgical repair were examined with ultrasonography prior to surgery. Participants with severe anatomical changes i.e. diastasis of the linea semilunaris exceeding one cm, were offered an extended repair, re-approximation of both linea alba and linea semilunaris. Results were evaluated with ultrasonography and the Disability Rating Index (DRI), two and twelve months after surgery. A standardized rectus diastasis suture repair was used in 24 participants with an isolated rectus diastasis. A combined repair with reapproximation of both the linea alba and the linea semilunaris was performed in 20 participants. Results Preoperative mean rectus diastasis (widest measurement) was 45 mm (30–75 mm), a mean diastasis of the linea semilunaris (umbilical level) of 15 mm (0–35 mm). There were no recurrencies at the 12-month follow-up. Early results showed significant improvements of physical function (DRI) but no differences between the two repair technique groups. Conclusion The extended repair seems to be a safe and sufficient repair technique in cases with a RD combined with a linea semilunaris diastasis.

OC-063 BASELINE DATA AND NORMAL ANATOMY OF THE ABDOMINAL WALL IN AN OBSERVATIONAL PROSPECTIVE COHORT STUDY OF NULLIPAROUS WOMEN

Abstract Aims The aim of this study was to describe the pre-partum anatomy of the abdominal wall in a cohort of nulliparous women, with the main purpose to use as a reference for management of patients with postpartum abdominal core instability. Materials &amp; Methods Seventy consecutive women were examined with ultrasonography measuring inter-recti distance (IRD), anatomical variations of linea semilunaris and the oblique muscles. Waistline was assessed during activated and relaxed abdominal core. Participant characteristics were registered. Questionnaires regarding habitual physical activity (Baecke), low back pain (Oswestry), physical functioning (DRI), urinary incontinence (UDI-6 and IIQ-7) and quality of life (SF-36) were answered. Results Response rate was 100%. Mean age was 30.5 years (19–50), mean BMI 23.5 kg/m2 (18.4–37.1). Ultrasonography showed a mean IRD 1.02 mm (0.27–2.35) at the superior border of the umbilicus, 0.93 mm (0.36–2.01) three cm above the umbilicus, 0.21 mm (-0.53–0.98) two cm below the umbilicus; mean thickness of the linea alba 0.28 mm (0.15–0.5); mean distance between the lateral lining of the rectus muscle and the external, internal and transverse oblique muscles of respectively 1.19 (-0.99–2.82), 0.09 mm (-1.37–1.3) and 1.46 mm (-1.36–3.19) at umbilicus level. Responses to the questionnaires showed overall low values on DRI, UDI-6, IIQ-7 and Oswestry; and overall values on Baecke and SF-36 similar to the normative population. Conclusions This study provides baseline data on the normal abdominal wall anatomy as well as mean values of activity, physical function, disabilities and quality of life, in a healthy nulliparous female cohort.

Investigation of flame structure and precessing vortex core instability of a gas turbine model combustor with different swirler configurations

Numerical simulation of a dual-swirl gas turbine model combustor is performed under cold and reacting flow conditions using a three-dimensional unsteady Reynolds-averaged Navier–Stokes approach. A multi-species chemical mechanism is used in this study for the analysis of the numerous radicals participating in the ignition process and the flame structure. The other objective of this study is to investigate the flow field under different injector configurations, including both co-rotating and counter-rotating swirler arrangements, different swirl intensities, and vane areas. A comparison of the results with experimental data shows that the predicted velocity and temperature profiles follow the experimental data reasonably. In these studies, a precessing vortex core is found in the shear layer of the inner recirculation zone for all injector arrangements considered, and a co-rotating vortex exists in the outer shear layer for some of these arrangements. OH mass fraction field shows that the reactions take place mostly near the vortex core. Furthermore, it is shown that the build-up process of H2O2 and CH2O inside the cold jet has an important effect on combustion initiation. In addition, the formation and consumption of the H atoms in the recirculation zones and the balance between OH and H2O2 are shown to have important roles in the flame formation process. Finally, the precession frequency of the PVC is found to scale almost linearly with the spatial gradient of swirl velocity in the inner swirler and almost independent from the inclusion of the combustion reactions.

Comparison of core stabilization techniques on ultrasound imaging of the diaphragm, and core muscle thickness and external abdominal oblique muscle electromyography activity.

To restore core stability, abdominal drawing-in maneuver (ADIM), abdominal bracing (AB), and dynamic neuromuscular stabilization (DNS) have been employed but outcome measures varied and one intervention was not superior over another. The purpose of this study was to compare the differential effects of ADIM, AB, and DNS on diaphragm movement, abdominal muscle thickness difference, and external abdominal oblique (EO) electromyography (EMG) amplitude. Forty-one participants with core instability participated in this study. The subjects performed ADIM, AB, and DNS in random order. A Simi Aktisys and Pressure Biofeedback Unit (PBU) were utilized to measure core stability, an ultrasound was utilized to measure diaphragm movement and measure abdominal muscles thickness and EMG was utilized to measure EO amplitude. Analysis of variance (ANOVA) was conducted at P< 0.05. Diaphragm descending movement and transverse abdominis (TrA) and internal abdominal oblique (IO) thickness differences were significantly increased in DNS compared to ADIM and AB (P< 0.05). EO amplitude was significantly increased in AB compared to ADIM, and DNS. DNS was the best technique to provide balanced co-activation of the diaphragm and TrA with relatively less contraction of EO and subsequently producing motor control for efficient core stabilization.

Initially generated pure mode A in the three-dimensional wake transition of a circular cylinder

The initially generated pure mode A, as a transitional stage, is investigated in the three-dimensional wake transition of a circular cylinder. Direct numerical simulations are carried out over a range of Reynolds numbers from 100 to 210. According to the different dynamic behaviors of hydrodynamic parameters and similar features in the spatiotemporal evolution of vorticity in the near wake, two stages are identified. The first, investigated here, is the initial generation of pure mode A at Reynolds numbers less than 195, while the second, already reported, is the full development of pure mode A at Reynolds numbers greater than 195. The relationship between the volume-RMS (root-mean-square) vorticity and Reynolds number indicates two critical Reynolds numbers, 145 and 195 (at most). The first critical Reynolds number denotes the initial appearance of three-dimensional instability. The second critical Reynolds number indicates the transition of pure mode A from the initially generated state to the fully developed state in the near wake. After the first critical Reynolds number, the evolution of the vorticity in the near wake and on the rear surface of the cylinder clearly shows that the appearance of pure mode A is a gradual process, rather than a sudden process accompanied by a jump in vortex shedding frequency. In particular, as the Reynolds number increases, the streamwise vorticity first appears on and near the cylinder surface, then in the shear layers, and finally in the shedding primary vortices, instead of appearing instantaneously in the shedding vortices after the instability of primary vortex cores.

On the Inner Horizon Instability of Non-Singular Black Holes

Regular black holes represent a conservative model in which the classical singularity is replaced by a non-singular core without necessarily modifying the spacetime outside the trapping horizon. Given the possible lack of phenomenological signatures, it is crucial to study the consistency of the model. In this short work, we review the physical mechanism leading to the instability of the central core, arguing that that non-perturbative backreation is non-negligible and must be taken into account to provide a meaningful description of physical black holes.

Concurrent Validity and Test-Retest Reliability of The Core Stability Test Using Ultrasound Imaging and Electromyography Measurements

<h3>Research Objectives</h3> To establish the concurrent validity and test-retest reliability of the formal test. <h3>Design</h3> Two-group test-retest reliability design. <h3>Setting</h3> 1) A certified physical therapist uses a formal test as a pressure biofeedback unit (PBU) to classify the participants into core stability groups and instability groups. 2) Perform a formal test on each group and measure the thickness of abdominal muscles with real-time ultrasound (US). 3) Investigate the correlation between the thickness of abdominal muscles and PBU pressure. 4) Re-measure after 24 hours to verify test-retest reliability. <h3>Participants</h3> 11 young adults with core instability (8 men and 3 women) were able to successfully perform the formal test three consecutive times and completed the abdominal draw-in maneuver core stabilization training augmented by PBU-US-EMG feedback, for 20 minutes a day, 7 days a week, over two weeks.11 young adults with core stability (8 men and 3 women) were unable to successfully perform the formal test three consecutive times. <h3>Interventions</h3> No intervention. <h3>Main Outcome Measures</h3> 1) Real-time US and surface EMG to measure the thickness of deep abdominal and superficial trunk muscle activity. 2) PBU pressure under the abdomen. <h3>Results</h3> The Pearson's correlation analysis showed an excellent correlation between transverse abdominal (TrA) thickness and PBU pressure as well as internal oblique (IO) thickness and PBU pressure, ranging from r=0.856 – 0.980, P < 0.05. The test-retest reliability was good, ICC1,2 = 0.876 for the core stability pressure measure and ICC1,2 = 0.939 to 0.989 for the abdominal muscle thickness measure. <h3>Conclusions</h3> Our findings demonstrate that the formal test, using a PBU and real-time US imaging without confirming the minimal contraction of superficial trunk muscles, as evidenced by EMG, leads to incorrect results. For example, such results in adults or individuals with core instability pathology ultimately influence rehabilitation programs designed to improve core stability. Therefore, the combination of a PBU, real-time US, and surface EMG measurements may help obtain more reliable results from the formal tests and better understand the neuromuscular control mechanisms of core stability. <h3>Author(s) Disclosures</h3> There are no conflicts.

Laser Welding of Metal-Polymer-Metal Sandwich Panels

In the production of metal-polymer multilayer composite parts, e.g., for automotive applications, the possibilities of thermal joining are limited due to the instability of the polymer core at elevated temperatures. Accordingly, such materials require a special approach to their welding. The three-layered metal-polymer-metal samples were made of DPK 30/50+ZE dual-phase steel as cover sheets that were electrolytic galvanized, and a polypropylene-polyethylene foil as core material, with thicknesses of 0.48/0.3/0.48 mm. The samples were welded on both sides using a 1.06 µm Nd:YAG ROFIN StarWeld Manual Performance laser. Significant improvements of the welding conditions are achieved by machining the edges of materials to be welded. The parameters of laser welding were chosen in such a way that the polymer structure remained almost unchanged. The weld thickness was about 40% of the thickness of each steel layer. It was established that within the selected laser processing parameters the melting occurred uniformly, while the polymer layer practically did not change its structure. Therefore, it can be stated that two-sided joint welding of metal-polymer-metal composite sandwich panels, without significant degradation of the polymer core layer, is feasible.

Analysis of numerical studies on the thermal-hydraulic and neutronic thermal-hydraulic stability of supercritical water reactors

The paper presents a review of modern studies on the potential types of coolant flow instabilities in the supercritical water reactor core. These instabilities have a negative impact on the operational safety of nuclear power plants. Despite the impressive number of computational works devoted to this topic, there still remain unresolved problems. The main disadvantages of the models are associated with the use of one simulated channel instead of a system of two or more parallel channels, the lack consideration for neutronic feedbacks, and the problem of choosing the design ratios for the heat transfer coefficient and hydraulic resistance coefficient under conditions of supercritical water flow. For this reason, it was decided to conduct an analysis that will make it possible to highlight the indicated problems and, on their basis, to formulate general requirements for a model of a nuclear reactor with a light-water supercritical pressure coolant. Consideration is also given to the features of the coolant flow stability in the supercritical water reactor core. In conclusion, the authors note the importance of further computational work using complex models of neutronic thermal-hydraulic stability built on the basis of modern achievements in the field of neutron physics and thermal physics.