Enhanced hepatotoxicity assessment through encapsulated HepG2 spheroids in gelatin hydrogel matrices: Bridging the gap from 2D to 3D culture.

Conventional 2D drug screening often fails to accurately predict clinical outcomes. We present an innovative approach to improve hepatotoxicity assessment by encapsulating HepG2 spheroids in gelatin hydrogel matrices with different mechanical properties. Encapsulated spheroids exhibit sustained liver-specific functionality, enhanced expression of drug-metabolizing enzymes, and increased drug sensitivity compared to 2D cultures. The platform detects critical variations in drug response, with significant differences in IC50 values between 2D and spheroid cultures ranging from 1.3-fold to > 13-fold, particularly for acetaminophen. Furthermore, drug-metabolizing enzyme expression varies across hydrogel concentrations, suggesting a role for matrix mechanical properties in modulating hepatocyte function. This novel spheroid-hydrogel platform offers a transformative approach to hepatotoxicity assessment, providing increased sensitivity, improved prediction, and a more physiologically relevant environment. The use of such advanced in vitro models can accelerate drug development, reduce animal testing, and contribute to improved patient safety and clinical outcomes.

Clinical effectiveness of postoperative prostaglandin E1 administration in reducing flap necrosis following microsurgical reconstruction.

BACKGROUND: Extensive experimental evidence has suggested the potential efficacy of prostaglandin E1 (PGE1) in enhancing flap survival, leading to its widespread empirical use following free flap operation. However, the translation of these experimental findings into clinical benefits remains uncertain. This study aimed to assess the clinical effectiveness of postoperative PGE1 administration on the outcomes of microsurgical reconstruction. METHODS: A retrospective review was conducted for patients who underwent free flap-based reconstruction between September 2020 and November 2022, dividing into two cohorts. For all consecutive cases conducted during the formal half, PGE1 was administered for postoperative 7 days (PGE1 cohort), and for those during the latter, PGE1 was not given (non-PGE1 cohort). The profiles of perfusion-related complications (PRC) were compared between the two cohorts. Further analyses after propensity-score matching were performed. RESULTS: In total, 274 cases were analyzed, consisting of 142 in PGE1 and 132 in non-PGE1 cohort. Baseline characteristics were similar between the two cohorts, except for higher rates of comorbidities and chronic wound-related defects in the PGE1 cohort. Overall PRC developed in 37 cases (13.5%), including 6 (2.1%) total loss and 38 (10.2%) partial necrosis. Compared to the control, the PGE1 cohort exhibited significantly lower rates of overall PRC and partial flap necrosis. This difference remained significant on multivariable analyses. The rate of total flap loss did not differ between the cohorts. Consistent associations were observed in the propensity-score matching analysis. CONCLUSION: Postoperative administration of PGE1 appears to be associated with reduced risks for the development of partial flap necrosis.

Development of ultra-high surface area polyaniline-based activated carbon for the removal of volatile organic compounds from industrial effluents.

Removing volatile organic compounds (VOCs) from aqueous solutions is critical for reducing VOC emissions in the environment. Activated carbons are widely used for removal of VOCs from water. However, they show less application feasibility and low removal due to less surface area. Here, a cost-effective and high surface area activated carbonized polyaniline (ACP) was synthesized to sustainable removal of VOCs from water. The ACP microstructure, surface properties, and pore structure were investigated using Brunauer-Emmett-Teller (BET) theory, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The specific surface area of ACP6:1 (2988.13 m2/g) was greater than that of commercial activated carbon (PAC) (1094.49 m2/g), indicating that it has excellent VOC adsorption capacity. The effects of pH, initial VOC concentration, time, temperature, and ionic strength were studied. According to kinetic and thermodynamic studies on VOCs adsorption, it is an exothermic and spontaneous process involving rate-limiting kinetics. Adsorption isotherms follow the Freundlich isotherm model, suggesting that the adsorbent surface is heterogeneous with multilayer adsorption and maximum ACP adsorption capacities of 1913.9, 2453.3, 1635.8, and 3327.0 mg/g at 293 K for benzene, toluene, ethylbenzene, and perchloroethylene, respectively, representing a 3- to 5-fold improvement over PAC. ACP is a promising adsorbent with a high adsorption efficiency for VOC removal.

Use of Super-thin Superficial Circumflex Iliac Artery Perforator Flap for Reconstruction of Lower Lip Defect.

SUMMARY: Wide local excision remains the main treatment modality for primary lip cancer, which often results in considerable deficits of lip tissue and requires reconstruction using free tissue transfer. Although diverse free flaps, such as radial forearm flap or anterolateral thigh flap, have been used, their application is often limited by their inherent limitations including donor morbidity and flap bulkiness. This report details our experience of lower lip reconstruction using a super-thin superficial circumflex iliac artery perforator (SCIP) free flap.

Spectro-Microscopic Perceptions into Oxidation Behavior of Large-Scale Molybdenum Disulfide and its Photoelectrical Correlation.

Despite the encouraging properties and research of 2D MoS2 , an ongoing issue associated with the oxidative instability remains elusive for practical optoelectronic applications. Thus, in-depth understanding of the oxidation behavior of large-scale and homogeneous 2D MoS2 is imperative. Here the structural and chemical transformations of large-area MoS2 multilayers by air-annealing with altered temperature and time via combinatorial spectro-microscopic analyses (Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy) are surveyed. The results gave indications pertaining to temperature- and time-dependent oxidation effects: i) heat-driven elimination of redundant residues, ii) internal strain stimulated by the formation of MoO bonds, iii) deterioration of the MoS2 crystallinity, iv) layer thinning, and v) morphological transformation from 2D MoS2 layers to particles. Photoelectrical characterization of the air-annealed MoS2 is implemented to capture the link between the oxidation behavior of MoS2 multilayers and their photoelectrical properties. The photocurrent based on MoS2 air-annealed at 200 °C is assessed to be 4.92 µA, which is 1.73 times higher than that of pristine MoS2 (2.84 µA). The diminution in the photocurrent of the photodetector based on MoS2 air-annealed above 300 °C in terms of the structural, chemical, and electrical conversions induced by the oxidation process is further discussed.

Modified Chemoselective Reduction and Consecutive Regioselective Deuteration Reaction Catalyzed by B(C6F5)3.

An efficient chemoselective reduction of isatin derivatives using catalyst B(C6F5)3, benzyldimethylsilane, and H2O is described. Notably, a small amount of water is shown to be a highly effective reaction promoter that decreases the reaction time and temperature for the synthesis of indolin-3-ones. Moreover, using method, excellent deuterium incorporation is achieved via the catalytic α-deuteration of indolin-3-ones using B(C6F5)3 and D2O.

Could we prove the nursing outcomes utilising clinical data warehouse? Effectiveness of pressure ulcer intervention in Korean tertiary hospital.

The use of Clinical Data Warehouse (CDW)  for research and quality improvement has become more frequent in the last 10 years. In this study, we used CDW to determine the effectiveness of pressure ulcer interventions offered by ward nurses and wound care nursing specialists. A retrospective clinical outcomes study that utilise CDW has been carried out. We identified 1415 patients who were evaluated as pressure ulcer risk group from 1 July 2019 to 31 December 2019. Kaplan-Meier survival analyses were used to estimate the time to occurrence of pressure ulcers. We compared the survival curves of each group by applying the log-rank test for significance. The overall median time to occurrence for both groups was 13 days (95% CI range: 11-14 days). The control group showed a longer median time (14 days) to occurrence than the case group (12 days). In the pressure ulcer stage I, the case group showed a longer median time (14 days) to occurrence than the control group (8 days), indicating that the intervention provided by the wound care nursing specialist was effective in stage I, and delayed the occurrence of pressure ulcers. The findings may be used as preliminary data for the utilisation of the CDW in the field of nursing research in the future. Also, facilitating the accessibility of the wound care nursing specialist in the general wards should be effective to decrease the incidence rates.

The change in Geriatric Nutritional Risk Index is associated with mortality in patients who start hemodialysis: Korean Renal Data Registry, 2016-2018.

Malnutrition is common in patients undergoing hemodialysis (HD) and is associated with mortality. This study aimed to investigate the association between changes in nutrition status measured by the Geriatric Nutritional Risk Index (GNRI) and all-cause mortality in patients who started HD. A nationwide retrospective cohort study was conducted based on the Korean Renal Data System database. Patients who started HD from January 2016 to December 2018, and were eligible for GNRI and GNRI trend were included. GNRI trend was a longitudinal change of GNRI, assessed by random slope in a mixed-effect model. Positive and negative random slopes in each patient were assigned to positive and negative GNRI trends. A total of 2313 patients were included and median follow-up period was 3.1 (2.6-3.7) years. GNRI values decreased over time (estimate - 1.212, 95% confidence interval (CI) - 1.116-0.692) and positive GNRI trend was associated with survival benefit (hazard ratio 0.55, 95% CI 0.36-0.84) after multivariate adjustment. These findings show that serial GNRI assessment, besides GNRI, is a useful prognostic factor for mortality in patients who start HD.

Comparison among low intensity bridge exercises using suspension devices based on muscle activity and subjective difficulty.

BACKGROUND: Recent clinical studies have revealed the advantages of using suspension devices. Although the supine, lateral, and forward leaning bridge exercises are low-intensity exercises with suspension devices, there is a lack of studies directly comparing exercise progression by measuring muscular activity and subjective difficulty. OBJECTIVE: To identify how the variations in the bridge exercise affects trunk muscle activity, the present study investigated changes in neuromuscular activation during low-intensity bridge exercises. We furthermore explored whether the height of the suspension point affects muscle activation and subjective difficulty. METHODS: Nineteen asymptomatic male participants were included. Three bridge exercise positions, supine bridge (SB), lateral bridge (LB), forward leaning (FL), and two exercise angles (15 and 30 degrees) were administered, thereby comparing six bridge exercise conditions with suspension devices. Surface electromyography and subjective difficulty data were collected. RESULTS: The rectus abdominis activity was significantly higher with the LB and FL exercises compared with the SB exercise (p< 0.05). The erector spinae muscle activity was significantly higher with the SB and LB exercises, compared with the FL exercise (p< 0.05). The LB exercise significantly increased the internal oblique muscle activity, compared with other exercise variations (p< 0.05). The inclination angle of the exercise only affected the internal oblique muscle and subjective difficulty, which were significantly higher at 30 degrees compared with 15 degrees (p< 0.05). CONCLUSIONS: Relatively higher inclination angle was not effective in overall activation of the trunk muscles; however, different bridge-type exercises could selectively activate the trunk muscles. The LB and SB exercises could be good options for stimulating the internal oblique abdominis, and the erector spinae muscle, while the FL exercise could minimize the erector spinae activity and activate the abdominal muscles.

Effects of Two Foot-Ankle Interventions on Foot Structure, Function, and Balance Ability in Obese People with Pes Planus.

Obese people are prone to foot deformities such as flat feet. Foot management programs are important to prevent them. This study investigated the effects of two foot-ankle interventions on balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions in obese people with pes planus for four weeks. The experiment was designed as a randomized controlled trial. Twenty-four participants who met the inclusion criteria were selected, and they were randomly assigned to either a short foot group (SFG) or proprioceptive neuromuscular facilitation group (PNFG) according to foot-ankle intervention. Two interventions were commenced three times a week for 20 min over four weeks. The tests were conducted at two intervals: pre-intervention and at four weeks. The tests were conducted in the following order: the patient-specific functional scale test (PSFS), an ultrasound of the plantar fascia, the navicular drop test, balance test, and the four-way ankle strength test. Two groups showed significant differences in balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions between pre-test and post-test (p < 0.05). PNFG had significantly higher dorsiflexor and invertor strength than SFG (p < 0.05). SF and PNF interventions were effective to improve balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions in obese people with pes planus. Additionally, PNF intervention is more beneficial in increasing the dorsiflexor and invertor strength compared to SF intervention.

Strategic Customization of Polymeric Nanocomposites Modified by 2D Titanium Oxide Nanosheet for High-k and Flexible Gate Dielectrics.

Organic polymer-based dielectrics with intrinsic mechanical flexibility and good processability are excellent candidates for the dielectric layer of flexible electronics. These polymer films can become even more rigid and electrically robust when modified through cross-linking processes. Moreover, the composites formed by dispersing nanoscale inorganic fillers in a polymer matrix can exhibit further improved polarization property. However, these strategies can be challenging as homogeneous dispersion of nanomaterials in the matrix is difficult to achieve; thus, degradation of electrically insulating properties of nanocomposite layers is often observed. Here, a high-k, pinhole-free, and flexible poly(vinyl alcohol) (PVA)-based nanocomposite dielectric is presented, incorporating 2D TiO2 nanosheets (NSs) for the first time. Despite the attractive dielectric constant, exceptional flexibility, and electrically insulating property of PVA-TiO2 nanocomposites, only few studies on these materials have been reported. The organic/inorganic nanosheet hybrid layer, which reaches an unprecedentedly high dielectric constant of 43.8 (more than four times higher than that of cross-linked PVA), also exhibits an outstanding leakage current density as low as 10-9 A cm-2 . Furthermore, the repeated bending tests for nanocomposite capacitors reveal their capability of operating without any deterioration of their performances even after 1000 iterations of bending cycles at a bending radius of 3 mm.

A three-week intervention emphasized diagonal eccentric contraction on balance and joint position sense and ankle strength in subjects with ankle instability: A randomized controlled trial.

BACKGROUND: Problems related to ankle instability, decreased proprioceptive sensation, altered static and dynamic balance abilities are suggested as major representative factors that contribute to the recurrence of ankle sprains. OBJECTIVE: To assess the effect of a three-week intervention (intervention emphasizing diagonal eccentric contraction (IEDEC) and intervention of general exercise (IGE)) on static and dynamic balance abilities, ankle strength and joint position sense at pre- and post-intervention, and at two- and three-week post-intervention. METHODS: Twenty-five participants with ankle instability, including a history of ankle sprain and recurrent episodes of giving way, were enrolled in the study. They were randomly classified into the IEDEC group (n= 12) and the IGE group (n= 13). Dynamic balance was examined using the Y Balance Test, four-way ankle strength was measured, and the static balance was evaluated using the total displacement of the center of pressure (COP). To identify the joint position error, eversion and inversion of the ankle angle were measured. RESULTS: The results revealed significant increases in ankle dynamic stability and strength at two and three weeks post-intervention (p< 0.05). Similarly, the total displacement of the COP differed significantly over time, with a higher COP during the initial measurement than at two and three weeks intervention (p< 0.05) General balance training with IEDEC can improve position sense during ankle inversion (p< 0.05). CONCLUSION: General balance training with IEDEC improved the position sense of the inversion. Combined therapeutic intervention, such as with the manual technique, could be a beneficial approach to maximize the treatment effects.

Reduction in MLKL-mediated endosomal trafficking enhances the TRAIL-DR4/5 signal to increase cancer cell death.

Mixed lineage kinase domain-like (MLKL) is an essential molecule of necroptosis, a cell death process that is initiated by direct disruption of the plasma membrane. During necroptosis, MLKL is phosphorylated by receptor interacting protein kinase-3 (RIPK3 or RIP3), and then translocates to the plasma membrane to disrupt membrane integrity. Recent data suggest that MLKL also has a RIP3-indendent function in the generation of intraluminal and extracellular vesicles (EVs), as well as in myelin sheath breakdown when promoting sciatic nerve regeneration. Here we show that depletion of MLKL enhances TRAIL-induced cell death in a RIP3-independent manner. Depletion of MLKL leads to prolonged cytotoxic signals that increase TRAIL-induced cell death. Initially, TRAIL binds to DR5 at the cell surface and is endocytosed at similar rates in MLKL-expressing and MLKL-depleted cells, eventual degradation of intracellular TRAIL by the lysosome is delayed in MLKL-depleted cells, corresponding with prolonged/enhanced intracellular signals such as p-ERK and p-p38 in these cells. Colocalization of TRAIL with the marker of early endosomes, EEA1 suggests that TRAIL is accumulated in early endosomes in MLKL-depleted cells compared to MLKL-expressing cells. This indicates that depletion of MLKL reduces receptor-ligand endosomal trafficking leading to increased TRAIL-cytotoxicity. An MLKL mutant that compromises its necroptotic function and its function in the generation of EVs was sufficient to rescue MLKL deficiency, suggesting that the N-terminal structural elements necessary for these functions are not required for the function of MLKL in the intracellular trafficking associated with regulating death receptor cytotoxicity. A reduction in MLKL expression in cancer cells would therefore be expected to result in enhanced TRAIL-induced therapeutic efficacy.

Comparison of Foot Structure, Function, Plantar Pressure and Balance Ability According to the Body Mass Index of Young Adults.

OBJECTIVES: This study compared foot arch height, plantar fascia thickness, a range of motion assessments of the ankle joint, strength of the ankle joint, plantar pressure, and balance between obese and normal weight young adults. METHODS: Fifty-two participants were required for the present study design to achieve 80% power, 0.8 effect size (η2), and an alpha level of 0.05. The participants were categorized to normal weight or obese groups based on BMI (≤ 24 kg/m2 and ≥ 25 kg/m2, respectively). The foot and ankle disability index and Sport survey were completed by the participants before the measurements. Foot arch height was measured using the navicular drop test, and plantar fascia thickness was measured using ultrasound. Plantar pressure and balance tests were also conducted, followed by ankle joint range of motion and strength tests. RESULTS: Foot arch height and plantar fascia thickness was significantly higher in the obese group compared with the normal weight group (p < 0.01). There were significant differences in eversion of ankle strength, plantar pressure in the big toe and heel and anterior-posterior balance between normal and obese weight groups (p < 0.05). CONCLUSION: Obese young adults had more abnormalities in the medial longitudinal arch, plantar fascia, and plantar pressure as well as weakened ankle eversion strength and balance problems compared with the normal weight group.

Which trunk exercise most effectively activates abdominal muscles? A comparative study of plank and isometric bilateral leg raise exercises.

BACKGROUND: Various forms of trunk exercise have been used for increasing abdominal strength. The plank exercise and bilateral leg raise exercise are one of these trunk exercises. However, there are few studies that compared the effects of these exercise variations. OBJECTIVE: The present study aimed to investigate how effectively the trunk muscles during plank and bilateral leg raise exercises are activated. METHOD: Surface electromyography responses of the rectus abdominis, internal oblique, and erector spinae muscles were investigated during the plank and bilateral leg raise exercise with different hip position. A total of 18 healthy, physically active female volunteers completed the normal plank exercise, plank exercise with placing the lower leg in a horizontal condition, bilateral leg raise exercise, and bilateral leg raise with lower leg as horizontal condition. RESULTS: The horizontal condition caused significant increases in activity of the internal oblique muscles compared with the general condition (p< 0.05). The bilateral leg raise exercise showed significantly greater activation in the rectus abdominis compared to the plank exercise (p< 0.05). CONCLUSION: The present study showed that the horizontal condition had the advantage of activating the internal oblique muscles, and the leg raise exercise is effective in strengthening global muscle such as the rectus abdominis.

Comparison of muscular activities between subjects with and without scapular downward rotation impairment during diagonal pattern of exercises.

BACKGROUNDS: One form of abnormal scapular alignment is scapular downward rotation (SDR). Changes in muscle function in SDR have not been clearly identified, and SDR exercises also require investigation. Although a diagonal pattern of exercise is commonly used as part of the exercise protocol, a direct comparison of shoulder and scapular diagonal exercises has not yet been conducted. The objectives of this study were to determine the altered activation of the scapular musculature in the SDR group and to investigate which diagonal pattern of exercise effectively activates the scapular musculature. METHODS: Thirty-two participants (18 in the control group and 14 in the SDR group) volunteered to participate in this study. Electromyographic signals were collected from four muscles, the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and anterior deltoid (AD), during standing performance of diagonal shoulder and scapular exercises. RESULTS: The control group showed significantly lower UT activity, UT/LT ratio, and UT/SA values than the SDR group (p < .05). Activation of the AD was significantly higher in the SDR than in the control group (p < .05). SA and AD activation were significantly higher in shoulder diagonal pattern exercises than in scapular diagonal pattern exercises (p < .05). The scapular posterior elevation pattern exercise showed significantly higher UT and LT activities than anterior elevation and shoulder diagonal pattern exercises (p < .05). CONCLUSION: Our findings suggest that reduced activation of the UT could lead to greater activation in the AD in SDR. Scapular posterior elevation exercise is advantageous as selectively activates the trapezius musculature, and shoulder diagonal pattern exercise is advantageous in activating the SA and AD.

Immediate effects of isometric trunk stabilization exercises with suspension device on flexion extension ratio and strength in chronic low back pain patientss.

BACKGROUND: Recent clinical research has supported the use of suspension devices in rehabilitation procedures both in practice and in theory. Although a longitudinal study has reported on the use of suspension devices among asymptomatic subjects, it is necessary to investigate the immediate effects of suspension exercises in patients with CLBP. OBJECTIVE: The present study aims to investigate changes in neuromuscular activation after the prescription of suspension exercises in patients with CLBP. A secondary aim was to determine whether practical flexion and extension strength can be effectively enhanced. METHODS: Before and after suspension exercise, flexion extension (FE) ratio and trunk strength of flexion and extension were measured. Patients performed two types of suspension exercises: supine bridge and forward leaning exercises. The paired t-test was used to compare the FE ratio and strength data. Pearson correlation coefficient was performed to study the correlation between measured variables. RESULTS: Compared to the pre-exercise measurements, the flexion-extension ratio and trunk extension strength was significantly increased at the post-exercise measurement (p< 0.05). The FE ratio in the right lumbar erector spine muscle was significantly correlated with post-exercise trunk extension strength (p< 0.05). CONCLUSIONS: For patients with chronic lower back pain, stimulation of the lumbar extensor muscle and of proprioception is effective both for strengthening lumbar extensors and for improving the flexion-extension ratio. Consequently, forward leaning and supine bridge exercises with a suspension device are beneficial for normalising neuromuscular control of the erector spinae muscles.

Long-term effects of diagonal active stretching versus static stretching for cervical neuromuscular dysfunction, disability and pain: An 8 weeks follow-up study.

BACKGROUND: A high prevalence and incidence of neck and shoulder pain are common problems that require more attention from health service providers and researchers. Recent findings have indicated that the neck stretching is the one of the most effective physical therapy interventions. Although the recovery of the pain through the stretching exercise has been described in a previous study, functional advantages and changes of the neuromuscular control has not been suggested. Additionally, there was a lack of studies that considered methods of stretching. OBJECTIVE: The purpose of the present study was to examine the long-term effects of stretching methods for cervical neuromuscular dysfunction, disability and pain in a sample of sedentary workers with neck pain. METHODS: Twenty-four sedentary workers with neck pain participated in this study and were assigned to the following two groups: static stretching (SS), and diagonal active stretching (DS). Active cervical range of motion (ROM), pressure pain threshold (PPT), self reported questionnaire (Neck Disability Index, NDI), and the flexion - relaxation ratio (FRR) from the cervical erector spinae muscles were measured at pre-treatment, post-treatment (after 4 weeks) and follow-up (after 6 and 8 weeks). RESULTS: In both groups, the values obtained for the cervical ROM as flexion, extension, lateral flexion, were significantly increased in comparison to pre-treatment (p< 0.05). Significant increases of the left and right neck rotation, left and right FRR were only observed in the DS group (p<0.05). The NDI score of the SS group was significantly lower than that of the DS group (p< 0.05). CONCLUSIONS: Our findings suggest that both static and diagonal stretching exercises were effective for reducing disability of the neck and increasing cervical range of motion. Compared to the SS, in addition, present results suggest that changes of the activation patterns as FRR, and cervical rotational movement could be accomplished with the DS.

Effect of slope angle on muscle activity during variations of the Nordic exercise.

This study investigated the muscular activity of the lower muscles during variation of Nordic exercises following changes of the Nordic angles and the base slope angles. Twenty-one healthy participants were participated in this study. Participants performed six variations of Nordic exercises including two Nordic angles positions and three base slope angles. Each Nordic exercise defined as Nordic angle 10°, 15° and base slope angle 0°, 10°, 15°. During the Nordic exercises, erector spine, gluteus maximus, biceps femoris, gastrocnemius activities and subjective difficulties (Borg RPE score) were measured. The activities of all muscles and subjective difficulties were significantly greater with the 15° of Nordic exercise compared to the 10° of Nordic exercise, regardless of base slope angles. There were significant differences in gluteus maximus, biceps femoris, gastrocnemius, and the Borg RPE score between three base slope conditions (P<0.05). The Borg RPE score and activities of the gluteus maximus were increased with the increases of base slop angles from 0° to 15°. Conversely, the activities of the gastrocnemius and biceps femoris were decreased with the increases of base slop angles from 0° to 15°. Present study indicates that application of the greater Nordic angle during the Nordic exercise is advantageous for activating lower extremity muscles. Using the base slopes during the Nordic exercise could be used for selective activation of the lower muscles. High base slope angles inducing greater knee flexion could maximize the exercise effects for activating gluteal muscles rather than lower leg muscles such as biceps femoris and gastrocnemius.

Effect of the body mass index and sexual difference on the muscle activity during trunk exercise: a preliminary study.

There was lack of study which evaluated the effects of characteristics of subjects such as the body mass index (BMI) or waist circumference (WC), as well as sexual differences on trunk muscle activities. The purpose of the present study was to compare the abdominal muscle activities among the groups dividing criterion as the BMI, WC, and the gender. As a criterion of BMI and WC, subjects were arranged to three groups. Female subjects who were less than 25 kg/m2 BMI, and less than 90 WC were arranged as female with underweight group (FU), male subjects who were greater than 25 kg/m2 BMI and greater than 85 WC were arranged as male with overweight group (MO), male subjects who were less than 25 kg/m2 BMI and less than 85 WC were arranged in male with underweight group (MU). Surface electromyography responses of the rectus abdominis, internal oblique, external oblique muscles and lumbar level of erector spinae were obtained during the plank and maximal voluntary isometric contraction (MVIC). The MO group showed significantly higher %MVIC value of the internal oblique and lumbar level of erector spinae, compared to the MU group (P<0.05). The %MVIC of the rectus abdominis was significantly greater with the FU group (P<0.05). There were significant differences in the root mean squared (RMS) values from MVIC among the three groups (P<0.05). Regardless of muscles differences, the MO group showed significantly lower RMS activity values than the FU and the MU groups (P<0.05). Present study indicates some considerations of interpreting surface electromyography (sEMG) signal from region overlapping large fat tissue especially for trunk muscles. Individual characteristics such as gender, BMI, and WC could affect the sEMG signals. The female and male with overweight represent relatively high %MVICs during exercise, but it might be due to relatively low RMS values from procedure of MVICs.