Interface Pressure Research Articles

Impact of shear stress on sacral pressure injury from table rotation during laparoscopic colorectal surgery performed in the lithotomy position

This study aimed to evaluate the impact of shear stress on surgery-related sacral pressure injury (PI) after laparoscopic colorectal surgery performed in the lithotomy position. We included 37 patients who underwent this procedure between November 2021 and October 2022. The primary outcome was average horizontal shear stress caused by the rotation of the operating table during the operation, and the secondary outcome was interface pressure over time. Sensors were used to measure shear stress and interface pressure in the sacral region. Patients were divided into two groups according to the presence or absence of PI. PI had an incidence of 32.4%, and the primary outcome, average horizontal shear stress, was significantly higher in the PI group than in the no-PI group. The interface pressure increased over time in both groups. At 120 min, the interface pressure was two times higher in the PI group than in the no-PI group (PI group, 221.5 mmHg; no-PI group, 86.0 mmHg; p < 0.01). This study suggested that shear stress resulting from rotation of the operating table in the sacral region by laparoscopic colorectal surgery performed in the lithotomy position is the cause of PI. These results should contribute to the prevention of PI.

Modeling pore wetting in direct contact membrane distillation—effect of interfacial capillary pressure

In this study, we aimed to develop a model for computing direct contact membrane distillation (DCMD) performance, taking into account capillary pressure effects at the liquid–gas interface within membrane pores. We developed a simulation model to investigate how factors such as pore radius, feed/permeate temperature, pressure, and contact angle influenced the distance of liquid intrusion into the pore, the weight flow rate in a single pore, and the temperature at the liquid–gas interface. The model predicted that the permeation rate would decrease with an increase in the feed pressure when the permeate pressure was kept constant and also when the pressure difference between the feed and permeate was kept constant. It also predicted that the permeation rate would increase with an increase in the permeate pressure when the feed pressure was kept constant. The model also indicated that partial pore wetting would be enhanced with an increase in feed pressure when the pore size was as large as 1 μm but would diminish when the pore size was as small as 0.1 μm. According to the model, partial pore wetting diminished with a decrease in the permeate pressure. The model’s predictions were in line with the trends observed in the experimental DCMD flux data by many authors, particularly those regarding the effects of feed and permeate temperature and the effect of contact angle. The model’s predictions were compared with the experimental data recorded in the literature, validating the model’s accuracy.

Prediction of thermal contact resistance for reusable heat-pipe cooled thermal protection system based on an inverse thermo-mechanical coupling method

Thermal contact resistance (TCR) is a critical characteristic on increasing or decreasing thermal energy transmission efficiency between two bodies in thermal management systems. However, it is difficult to accurately determine the thermal contact resistance in actual engineering structures, due to the complicated influence factors, such as pressure, temperature, and physical properties. In the work, a new method is presented to estimate the thermal contact resistance for a three-dimensional (3D) reusable heat-pipe cooled thermal protection system based on boundary measurements, by solving transient inverse thermo-mechanical coupling problems. Moreover, the thermal contact resistance varies with interface pressure, temperature, and spatial position, which is more practical and challenging. The thermo-mechanical coupling analysis is conducted by the finite element method, and the inversion is carried out by the gradient-based algorithm. First, the present method is validated by identifying the constant TCR, based on the available experimental data. Then, the thermal contact resistance with the functional form in the 3D reusable thermal protection system is accurately estimated. Finally, the convergence stability and robustness of the proposed method are evaluated, by considering the effects of initial guess value and measurement error, respectively. The accurate determination of thermal contact resistance of the reusable thermal protection system effectively avoids the overweight of aircraft and improves its utilization. The present work provides a novel approach for the determination of thermal contact resistance in actual engineering applications.

Prediction of tensile behavior of compression therapeutic biomedical materials by mesoscale laid-in loop model

Tubular laid-in weft-knitted compression (LWC) therapeutic materials have been extensively applied in medical clinic treatment and daily healthcare management. Limited studies have explored the mechanical mechanisms through the numerical analytical models for the development and performance prediction of laid-in fabrics. This study developed the three-dimensional (3D) finite element (FE) laid-in loop model to simulate and predict the tensile behaviors of LWC materials based on the determination of geometric models and investigation of yarn mechanical properties. Through the constructed FE mesoscale models with various physical-mechanical characteristics of inlay yarn materials, it was found that the ground yarns and inlay yarns played distinct roles in producing tensile stresses under the course and wale direction of stretching strains. These tensile stresses determined the selection of yarn materials for controlling the tension of laid-in knitted fabrics in end applications. Then, the interfacial pressure dosages exerted by LWC materials were quantitively obtained based on the simulated Young's moduli values and modification of Laplace's Law model. The accuracy and acceptability of proposed mechanical laid-in models (mean error: 10.22 %) and pressure prediction models (mean error: 14.70 %) were validated by the comparative studies. The simulation methods and results created a visual tool for dynamically illustrating the tensile behaviors and predicting pressure performances of the elastic therapeutic materials in functional material design of biomedical compression textiles.

Upper extremity contact pressure measurement in robot-assisted pelvic surgery

Upper extremity complications are often a problem in robot-assisted pelvic surgery (RAPS) with the lithotomy-Trendelenburg position (LT-position). This study focused on upper extremity contact pressure (UEP) and examined the relationship between UEP and upper extremity complications. From May 2020 to April 2022 at the University of Tokyo Hospital, UEP was measured in 155 patients undergoing RARP and 20 patients undergoing RARC. A total of 350 sets of UEP were investigated in this study. UEP was measured using a portable interface pressure sensor (Palm Q, Cape CO., Kanagawa, Japan) in the preoperative lithotripsy position (L-position), preoperative LT-position, and postoperative L-position. UEP was increased in the preoperative LT-position than in the preoperative L-position (right side 5.2 mmHg vs. 17.1 mmHg, left side 5.3 mmHg vs. 17.1 mmHg, P < 0.001, respectively), and was decreased in the postoperative L-position than in preoperative LT-position (right side 17.1 mmHg vs. 10.8 mmHg, left side 17.1 mmHg vs. 10.6 mmHg, P < 0.001, respectively). Eleven upper extremities developed shoulder pain. UEP of the preoperative LT-position tended to be higher in the upper extremity exhibiting shoulder pain (25.6 mmHg (15.4–30.3) vs. 17.1 mmHg (12.0–24.4) P = 0.0901). UEP measurements may help prevent postoperative shoulder pain.

High Pressure 3 × 30 Minute Compression Methods for Advanced Lower Limb Lymphedema Patients.

Introduction: In advanced lymphedema of lower limbs, stage III bandaging under the routinely applied pressure of 40-60 mmHg remains largely ineffective. This is caused by skin and subcutaneous tissue stiffness due to fibrosis. Edema fluid accumulates deep in the subcutaneous tissue. Evacuating this fluid requires a high external compression force to overcome the resistance of fibrous tissue. We aimed to investigate the effectiveness of the compression method, with high pressure lasting for 3 days. Methods and Results: Twenty-one patients with lower limb lymphedema, stage III, of the postinflammatory type were included. Patients with acute inflammatory symptoms, venous thrombosis, profuse varicose veins, diabetes, and cardiac insufficiency with edema were excluded. A 10-cm-wide rubber bandage was applied to the foot and calf. The interface pressure measured using PicoPress ranged from 58 to 120 mmHg. Skin and deep tissue tonometry, skin water concentration, leg circumference, and drop of interface pressure were measured. Ultrasound examination was done before and after each compression session. The calf circumference decreased by 15.9 ± 5.4%, deep tissue stiffness by 58.9 ± 18.9%, skin stiffness by 69.6 ± 13.5%, and skin water concentration by 43.8 ± 11.5%. Interface pressure dropped to 66.3 mmHg (28-110 mmHg); ultrasonography images showed less fluid in the tissue. Conclusions: High-pressure 30-minute leg compression can remove excess edema fluid within 3 days and enable adjustment of nonstretch compression stockings. This method is more effective in advanced lymphedema at the beginning of therapy than the standard 30-50-mmHg bandaging as it provides an immediate effect.

Testing and identification method for the interfacial heat transfer coefficient between CFRTP and tools under fast hot-stamping conditions

Carbon fiber reinforced thermoplastic composites (CFRTP) are increasingly applied in automobile structures. Hot-stamping is a fast forming process for complex components of CFRTP. During hot-stamping process, the variations of temperature field occur in entire forming process, which ultimately have an impact on the forming quality and dimensional precision of the part. The interfacial heat transfer behaviour between CFRTP and tools directly determines the temperature distribution in the part. However, the existing heat transfer testing and identification methods are designed for sheet metal, which may not be applicable for CFRTP due to the differences in material properties and forming processes. Therefore, in this work, a new test device was developed to reproduce the interfacial heat transfer behaviour of CFRTP under various hot-stamping conditions, and an inverse identification method of the interfacial heat transfer coefficient (IHTC) between CFRTP and tools was proposed. The influences of contact conditions on the IHTC were investigated, including the interfacial contact pressure, interfacial clearance, heating temperature of tools and sheets. The results showed that the IHTC demonstrated a positive correlation with the contact pressure. However, the IHTC would significantly decrease with the existence of a clearance at the interface. Within the entire heat transfer process, it was also found that an increase in tool temperature resulted in a decrease in the IHTC, while initial sheet temperature didn't exert a significant influence. Furthermore, the reliability of proposed testing and identification methods had been verified by the hot-stamping for U-shaped CFRTP parts. The temperature error between the simulation and experiment was less than 5 %.

A Triboelectric Nanogenerator-Based Wide Range Self-Powered Flexible Pressure Sensor

Self-powered flexible pressure sensors are needed in applications such as human-machine interaction. Here, we present a triboelectric nanogenerator (TENG) based self-powered flexible pressure sensor capable of operating over a wide-range of pressures (3.2 - 1176 kPa). The sensor exhibits excellent sensitivities in various regions of the pressure range, i.e., 3.16, 0.023 and 0.031 V/kPa in the low (1-10 kPa), medium-high (10-500 kPa) and ultra-high (>500 kPa) pressure regimes respectively. Stable and repeatable TENG responses are achieved for all three pressure regimes, and this is due to the way the real contact area at the TENG interface varies with contact pressure. These results highlight the potential for TENGs in a wide range of applications such as: detecting pressure in wearable devices, human-machine interface, biomedical and automotive applications. As a proof-of-concept, we have demonstrated the use of the presented device in applications such as detection of human and robot finger tapping, collection of human gait information, and detection of impact forces.

Plastein reaction enhances the emulsifying and rheological properties of silver carp hydrolysates in oil-in-water emulsions

The plastein reaction was ubiquitously acknowledged for its capacity to enhance the functional properties of protein hydrolysates. Despite this, the specific impact of the plastein reaction on emulsification, a critical functional aspect of protein hydrolysates, remains incompletely understood. In this study, the plastein reaction in silver carp protein hydrolysate (SCPH) was explored. A detailed comparison between the primary product (PP) and the blended product (SCPH–P) in terms of their oil-water interfacial adsorption kinetics and the shear strain of oil-in-water emulsions was reported. The interfacial adsorption kinetics suggested that the higher molecular weight imparted a slow rate of diffusion, penetration, and reorganization to the PP compared to SCPH-P. Furthermore, the elevated surface hydrophobicity also resulted in higher surface activity (i.e., high interfacial pressure) for PP. Simultaneously, nonlinear rheological analysis revealed that PP possessed enhanced resistance to shear strain due to its strong affinity for the oil-water interface of emulsion. These improvements manifested in PP-stabilized emulsions with reduced mean particle size (71.6 μm–9.5 μm), diminished instability index (nearly 3-fold prolongation of stabilization time), and increased electrostatic repulsion (zeta potential values increased from 6-15 mV to 21–27 mV), which underscored a substantial enhancement in the emulsification of SCPH through the plastein reaction. Notably, the emulsifying and rheological properties of PP at a 1% (w/w) concentration were nearly equivalent to those of soybean protein isolate at 0.5% (w/w), highlighting the plastein reaction's innovative potential in utilizing SCPH as a promising emulsifier.

Phosphate type dependent phosphorylation on the interfacial and emulsion stabilizing behaviors of goose liver protein: Perspective of protein charging

Elucidation on the emulsifying behaviors of goose liver protein (GLP) from interfacial perspective was scarce when protein charging was altered. This work aimed to elucidate the role of phosphorylation on the interfacial associative interaction and then emulsion stabilizing properties of GLP using three structurally relevant phosphates of sodium trimetaphosphate (STMP), sodium tripolyphosphate (STPP) and sodium pyrophosphate (TSPP). A monotonic increment of protein charging treated from STMP, STPP to TSPP caused progressively increased particle de-aggregation, surface hydrophobicity and structural flexibility of GLP. Compared with STMP and TSPP, STPP phosphorylation rendered the most strengthened interfacial equilibrium pressure (11.98 ± 0.24 mN/m) due to sufficient unfolding but moderated charging character conveyed. Desorption curve and interfacial protein microstructure indicated that STPP phosphorylation caused the highest interfacial connectivity between proteins adsorbed onto the same droplet, as was also verified by interfacial elastic modulus (10.3 ± 0.21 mN/m). STPP treated GLP also yielded lowest droplet size (8.16 ± 0.10 μm), flocculation (8.18%) and Turbiscan stability index (8.78 ± 0.36) of emulsion but most improved microrheological properties. Overall, phosphorylation functioned itself in fortifying the intradroplet protein-protein interaction but restraining the interdroplet aggregation, and STPP phosphorylation endowed the protein with most enhanced interfacial stabilization and emulsifying efficiency.

An explicit approximation of the central angle for the curved interface in double-circle model for horizontal two-phase stratified flow

Stratified flow in horizontal tubes is frequently observed in gas-liquid two-phase flow system. In the two-fluid modeling, it is important to define the interface shape in solving the balance equations to determine the key parameters such as the interfacial transfer terms, void fraction, and pressure drop. A double-circle model is usually introduced to depict the concave-down interface in a horizontal circular tube under the stratified-wavy flow condition. However, calculation of the central angle in the double-circle model, which represents the interfacial curvature, requires an appropriate iterative numerical root-finding scheme to solve the implicit transcendental equation. In this study, an explicit approximate equation has been proposed without requirement of the iterative scheme and numerical instability, which is expected to improve the coding process and computation efficiency in the analysis code with the two-fluid model.

Phosphorylation altered structural flexibility of goose liver protein: Relation to interfacial and emulsifying properties

This work elucidated the roles of ultrasonication (GLP-U), phosphorylation (GLP-S) and their combination (GLP-US) on the emulsifying properties of goose liver protein (GLP-N) from an interfacial perspective. Results of interfacial pressure (11.98 ± 0.24 mN/m) and elastic modulus (10.63 ± 0.12 mN/m) showed that combined ultrasonication and phosphorylation rendered the highest interfacial interaction of GLP-N by facilitating its structural flexibility. Microrheology and multiple light scattering indicated that the enhanced electrostatic repulsion among GLP-US favored the interdroplet dissociation. Consequently, both the droplet size and flocculation index of emulsions were markedly decreased using either low (19.53 μm ± 1.06 and 8.18%) or high particle concentration (7.75 ± 0.24 μm and 6.85%) of GLP-US when compared with the sole treated groups and the control. Overall, phosphorylation fortified the intradroplet protein-protein interaction but restrained the interdroplet interaction of GLP-N, and the assistance of ultrasonication endowed the protein with enhanced interfacial stabilization and emulsifying efficiency.

Custom orthotic design by integrating 3D scanning and subject-specific FE modelling workflow

The finite element (FE) foot model can help estimate pathomechanics and improve the customized foot orthoses design. However, the procedure of developing FE models can be time-consuming and costly. This study aimed to develop a subject-specific scaled foot modelling workflow for the foot orthoses design based on the scanned foot surface data. Six participants (twelve feet) were collected for the foot finite element modelling. The subject-specific surface-based finite element model (SFEM) was established by incorporating the scanned foot surface and scaled foot bone geometries. The geometric deviations between the scaled and the scanned foot surfaces were calculated. The SFEM model was adopted to predict barefoot and foot-orthosis interface pressures. The averaged distances between the scaled and scanned foot surfaces were 0.23 ± 0.09 mm. There was no significant difference for the hallux, medial forefoot, middle forefoot, midfoot, medial hindfoot, and lateral hindfoot, except for the lateral forefoot region (p = 0.045). The SFEM model evaluated slightly higher foot-orthoses interface pressure values than measured, with a maximum deviation of 7.1%. These results indicated that the SFEM technique could predict the barefoot and foot-orthoses interface pressure, which has the potential to expedite the process of orthotic design and optimization.Graphical abstract

Experiment of contact angle hysteresis of a droplet on hydrophobic fibrous membrane

Fibrous membranes are widely used in liquid-gas filtration and separation, porous structures formed by randomly cross-layered fibers have a significant influence on interfacial free energies, showing complex changes in contact angle. The present paper aims to measure the pore structures of a hydrophobic ((C2F4)n, PTFE) fibrous membrane by Confocal Laser Scanning Microscope (CLSM), and analyze the droplet contact angle hysteresis along its circumference. The capillary force of the solid-liquid interface is calculated by the surface integral of Laplace pressure on half droplet surface, and the solid-liquid and liquid-vapor interface area ratios are obtained according to the Cassie-Baxter model. The liquid penetration depth in pore structures is calculated by the quasi-equilibrium of the interface free energy. The experimental result shows that for the PTFE fibrous membrane, the liquid-vapor interface area ratio (f2The experimental result shows that for the PTFE fibrous membrane, the liquid-vapor interface area ratio (f2

Development of Cyclic Pressure Offloading Insole for Diabetic Foot Ulcer Prevention.

Introduction. The likelihood of developing a diabetic foot ulcer (DFU) during one's lifetime for individuals with diabetes mellitus is around 19% to 34%. Continuous and repetitive loading on soft tissues are the major causative factors for DFU. This paper introduces an air cell array insole designed for cyclically offloading pressure from plantar regions to reduce repetitive stress and loading on foot. Materials and Methods. The insole comprises an air cell array insole and a pneumatic control unit. The interface pressure was evaluated in static and dynamic conditions at 3 different air cell internal pressures (6.9, 10.3, and 13.8 kPa). Plantar interface pressure was measured using a commercial pressure system, and data were analyzed using paired t test. Average interface pressure and peak pressure (PP) were studied to evaluate the functionality and effectiveness of the insole. Results. The analysis of static pressure data revealed that cyclic offloading significantly (p < .05) reduced PP in 4 tested cells corresponding to big toe, metatarsal heads, and heel areas with the maximum mean difference of 12.9 kPa observed in big toe region. Similarly, dynamic pressure data analysis showed that cyclic offloading significantly (p < .05) reduced PP in these areas, with the highest mean PP reduction of 36.98 kPa in the big toe region. Discussion. Results show the insole's capability to reduce plantar pressure through cyclic offloading. Internal pressure of air cells significantly affects the overall pressure reduction and must be chosen based on the user's weight. Conclusion. Results confirm that the insole with offloading capabilities has the potential to reduce the risk of developing DFUs by alleviating the plantar stress during both static and dynamic conditions.

Enzymatic digestion does not compromise sliding-mediated cartilage lubrication

Articular cartilage's remarkable low-friction properties are essential to joint function. In osteoarthritis (OA), cartilage degeneration (e.g., proteoglycan loss and collagen damage) decreases tissue modulus and increases permeability. Although these changes impair lubrication in fully depressurized and slowly slid cartilage, new evidence suggests such relationships may not hold under biofidelic sliding conditions more representative of those encountered in vivo. Our recent studies using the convergent stationary contact area (cSCA) configuration demonstrate that articulation (i.e., sliding) generates interfacial hydrodynamic pressures capable of replenishing cartilage interstitial fluid/pressure lost to compressive loading through a mechanism termed tribological rehydration. This fluid recovery sustains in vivo-like kinetic friction coefficients (µk<0.02 in PBS and <0.005 in synovial fluid) with little sensitivity to mechanical properties in healthy tissue. However, the tribomechanical function of compromised cartilage under biofidelic sliding conditions remains unknown. Here, we investigated the effects of OA-like changes in cartilage mechanical properties, modeled via enzymatic digestion of mature bovine cartilage, on its tribomechanical function during cSCA sliding. We found no differences in sliding-driven tribological rehydration behaviors or µk between naïve and digested cSCA cartilage (in PBS or synovial fluid). This suggests that OA-like cartilage retains sufficient functional properties to support naïve-like fluid recovery and lubrication under biofidelic sliding conditions. However, OA-like cartilage accumulated greater total tissue strains due to elevated strain accrual during initial load application. Together, these results suggest that elevated total tissue strains—as opposed to activity-mediated strains or friction-driven wear—might be the key biomechanical mediator of OA pathology in cartilage. Statement of SignificanceOsteoarthritis (OA) decreases cartilage's modulus and increases its permeability. While these changes compromise frictional performance in benchtop testing under low fluid load support (FLS) conditions, whether such observations hold under sliding conditions that better represent the joints’ dynamic FLS conditions in vivo is unclear. Here, we leveraged biofidelic benchtop sliding experiments—that is, those mimicking joints’ native sliding environment—to examine how OA-like changes in mechanical properties effect cartilage's natural lubrication. We found no differences in sliding-mediated fluid recovery or kinetic friction behaviors between naïve and OA-like cartilage. However, OA-like cartilage experienced greater strain accumulation during load application, suggesting that elevated tissue strains (not friction-driven wear) may be the primary biomechanical mediator of OA pathology.

Investigating Transducer–Tissue Interface Pressure for Soft Tissue Stress–Strain Behavior and the Effects on Echoic Intensities in Ultrasound Imaging of Periodontium

AbstractDiagnostic ultrasound (US) is a major imaging modality to visualize soft tissues and blood flow with the advantages of real‐time imaging, high acceptability to patients, and absence of ionizing radiation. US imaging provides important clinical measurements, e.g., thickness of gingiva for treatment planning in orthodontics, periodontics, and implantology; or thickness of subcutaneous adipose for optimizing insulin injection. However, the image quality and measurements of anatomical structures can be inconsistent, i.e., due to varying pressure exerted by an US transducer. Herein, a simple device is developed to real‐time measure the interface pressure applied on tissues by the US transducer. A thin‐film piezo‐resistive sensor with a small footprint is integrated to sense the pressure. A theoretical model, based on hyperelastic material behavior, is verified using the pressure measured by the thin film sensor and the thickness determined on ultrasonograms. The device is also tested on porcine samples in the pressure range of 50–300 kPa for imaging gingiva boundaries, identifying tissue thickness, and probing tissue biomenchanical properties. The device enables the understanding on the optimal range of applied pressure for higher contrast imaging. The information of the on‐tissue pressure and the tissue deformation determined on the US images help to derive the biomechanical stress–strain behavior of the tissues.

Compressive Behavior of Stainless Steel–Concrete–Carbon Steel Double-Skin Tubular (SCCDST) Members Subjected to External Hydraulic Pressure

The new-type stainless steel–concrete–carbon steel double-skin tubular (SCCDST) members, characterized by their exceptional corrosion resistance and mechanical bearing capacity, have promising applications in ocean engineering, particularly in deep-water engineering. The external hydraulic pressure and interfacial action of various materials intensify the complexity of composite performance of SCCDST members. This paper describes an analytical investigation on the concentric compressive performance of SCCDST members under external hydraulic pressure. The full-range mechanism, including load–displacement response, bearing capacity contribution, and contact pressures, was investigated through the finite element (FE) model that was validated by the failure mode, bearing capacity, and response of axial load versus strain. Subsequently, influences of key geometric–physical parameters were analyzed, e.g., diameter-to-thickness ratios (Do/to, Di/ti), material strengths (fyo, fyi, and fc), hollow ratios (χ), and water depths (H). Typical results indicate that: the initial active confinement action derived from the hydraulic pressure can enhance the interfacial contact pressure and axial compression capacity of SCCDST members due to the tri-axial compression state; the enhancement of confinement effect is mainly from the interfacial interaction between outer stainless steel tube and concrete infill; influence of water depth on bearing capacity cannot be ignored, e.g., the bearing capacity of an SCCDST member with larger hollow ratio (χ = 0.849) is not enhanced under a higher hydraulic pressure (H = 900 m) because of the cross-sectional buckling failure risk. Finally, a modified method considering the effect of water depth was proposed and verified for SCCDST members under hydraulic pressure.

Interface pressures and stiffnesses of different bandages studied on a Hiraï leg

Hirai et al. have developed a tool to assess the in vitro pressures of different compression devices. This tool has the advantage of being easy to use and finally inexpensive. The study of 7 bandages (Biflex 16, Urgo K2, Urgo K1, Coban 2, Biflex kit, Rosidal K and Rosidal Sys) on a Hirai leg allowed a precise analysis of the evolution of pressures and stiffnesses. Interface pressures were measured using the Picopress system and a 5 cm diameter probe. The difference between pre-stretch and stretch pressures in mmHg characterized stiffness. If the difference is greater than 10 mmHg, the bandage is considered stiff. These bandages were applied with a pressure of 45±2 mmHg at point B1. One hundred extension maneuvers were then performed. A decrease in mean pre-stretch pressures was noted more frequently for Rosidal K, Urgo K1 and Coban 2 than for the other bandages. Biflex 16 has a stiffness of less than 10 mmHg (p&lt;0.001). Urgo K1, Urgo K2, Coban 2, Kit Biflex have very similar stiffnesses (p=ns). Rosidal K and Rosidal Sys have higher stiffness (p&lt;0.001).

Effects of lower limb muscle strengthening on interface pressure in older adults undergoing inelastic compression: Randomized controlled clinical trial.

To analyze the effects of lower limb muscle strengthening on interface pressure (IP), static stiffness index (SSI), dynamic stiffness index (DSI), and walking pressure amplitude (WPA) in older adults undergoing inelastic compression therapy. Forty-three healthy older adults of both sexes (Age: 66.2 ± 4.4 years) met the eligibility criteria and completed all stages of the study (Resistance Training - RT: N = 20; Control - CONT: N = 23). Body composition, strength and functional mobility of lower limbs, IP, SSI, DSI, and WPA were evaluated before and after intervention. The two-way ANOVA with repeated measures demonstrated a significant time-group interaction effect on muscular strength for 1-RM [F (1, 41) = 21.091; p ≤ 0.001], IP in the orthostatic position [F (1, 41) = 5.124; p ≤ 0.05], minimum WPA [F (1, 41) = 10.999; p ≤ 0.05], maximum WPA [F (1, 41) = 8.315; p ≤ 0.05], DSI minimum (F (1, 41) = 4.608; p ≤ 0.05), DSI maximum (F (1, 41) = 8.926; p ≤ 0.05), and on the delta DSI (F (1, 41) = 7.891; p ≤ 0.05). In RT group, the increase in lower limb muscle strength was accompanied by an increase in IP in foot dorsiflexion and plantar flexion maneuvers, both in the standing position (DSI) and during gait (WPA).