Search Results (12,305)

Dietary supplements are commonly employed to provide additional nutritional support for athletes. In taekwondo, there is a need for evidence-based analyses to evaluate the effects of dietary supplements on training outcomes, competitive performance, and injury recovery. Taekwondo primarily relies on oxidative metabolism, yet decisive lower-limb attacks depend on non-oxidative pathways. A comprehensive literature search was conducted in PubMed, Scopus, and Web of Science databases in November 2024, utilizing keywords including ‘Dietary Supplements’, ‘Supplements’, ‘Food Supplementations’, and ‘Taekwondo’. Of the 203 articles identified, 26 met the inclusion criteria, collectively assessing the impact of 14 different dietary supplements. Among these studies, eight provided strong evidence that acute ingestion of 3–5 mg/kg of caffeine significantly enhanced athletes’ physical performance and psychological well-being. However, the ergogenic effects of the compound Fufang Ejiaojiang, creatine, sodium bicarbonate, beetroot, vitamins, and long beans require further investigation to validate their efficacy. Additionally, dietary supplements, such as amino acids, turmeric powder, ginger, spirulina, octacosanol, nucleotides, and yogurt, can reduce fatigue, supporting injury recovery, and boosting immune function, although current evidence remains insufficient. Future research should pay closer attention to reporting adverse reactions linked to dietary supplements. Doing so would provide coaches and athletes with more reliable safety information, supporting safer choices and reducing potential health risks. Full article

The aims of this pilot study were to design a training protocol to improve the padel smash, based on the practice of medicine ball throws (shot put) and smashes (powerful smashes and smashes over the side fence), and to test the effectiveness of the designed training protocol. Four high-level male Finnish players completed two weekly sessions, each consisting of four sets of five medicine ball throws (2 kg), followed by five smashes. Sufficient rest between sets and repetitions was ensured to minimize fatigue and reduce injury risk while maximizing power output. Performance was assessed through pre- and post-tests. A paired t-test analyzed the powerful smash, while contingency tables and the Chi-square test (χ²) evaluated the smash over the side fence. Three of the four players showed a significant increase in powerful smash distance, while the success rate of smashes over the side fence improved but did not reach statistical significance. These findings suggest that the designed training protocol improves powerful smashes and smashes over the side fence, potentially optimizing performance. Future research with larger samples is needed to refine training guidelines and explore broader implications for performance, injury prevention, and long-term athlete development. Full article

During the charging and discharging process of lithium-ion batteries, lithium-ions are embedded and removed from the active particles, leading to volume expansion and contraction of the active particles, and hence diffusion-induced stress (DIS) is generated. DIS leads to fatigue damage of the active particles during periodic cycling, causing battery aging and capacity degradation. This article establishes a two-dimensional particle-binder system model in which a linear elastic model is used for the active particle, and an elastic-viscoplastic model is used for the binder. The state of charge, stress, and strain of the particle-binder system under different charge rates are investigated. The simulation results show that the location of particle crack excitation is related to two factors: the concentration gradient of lithium-ion and the binder confinement effect. Under a lower charge rate, the crack excitation position of the particle located at the edge of the particle-binder interfacial (PBI) is mainly attributed to the binder confinement effect, while under a higher charge rate, the crack excitation position occurs at the center of the particle due to the dominance of concentration gradient effect. Furthermore, analysis reveals that the binder undergoes plastic deformation due to the traction force caused by particle expansion, which weakens the constraint on the particle and prevents PBI debonding. Finally, a binder with lower stiffness and higher yield strength behavior is recommended for rapid stress release of particles and could reduce plastic deformation of the binder. Full article

Many countries around the world are in a race against time to decarbonise their energy systems. One of the avenues being explored in detail is Offshore Renewable Energy (ORE), with technologies such as wind, wave, and tidal. All of these technologies are in their infancy within the marine environment and required heavy Research and Development (R&D) to make them commercially viable. With so much demand for these industries, the supply chain is heavily constrained. A solution that has shown great potential to alleviate the pressure on the supply chain is the use of Wire Arc Additive Manufacturing (WAAM) for the use of onsite repair or manufacture for components. This is due to its ability to produce large-scale parts, with low emissions and at a lower cost than other Additive Manufacturing (AM) processes. The opportunity to use this technology could result in shorter downtimes and lead to a reduction in the Levelised Cost of Energy (LCOE). However, knowing that offshore structures are subject to cyclic loading conditions during their operational lifespan, fatigue properties of new materials and manufacturing processes must be well documented and studied to avoid any catastrophic failures. An issue often seen with WAAM is the presence of residual stresses. This study looks at fatigue cracking on Compact Tension C(T) specimens that have undergone laser shock peening and rolling, surface treatment processes that form compressive residual stresses at the surface of the material. In this study, the influence of fatigue overloading on the residual stress distribution in surface-treated WAAM specimens is evaluated and the effectiveness of the post-processing techniques on the subsequent fatigue behaviour is explored. Full article

The role of notch stress and surface defects on fatigue crack initiation and small-crack propagation behavior has been investigated using groove simulation specimens. The naturally initiated small-crack growth tests have been performed on a FGH4099 superalloy at 500 °C and 700 °C. The findings indicate that elevated testing temperature significantly reduced the proportion of fatigue crack initiation life, with a less pronounced effect on the proportion of life for cracks to grow to First Engineering Crack size. Competing crack initiation modes were observed in the fatigue test of groove simulation specimens. The location of maximum principal stress was dominant fatigue crack initiation sites, and for specimens with surface inclusions, the defect location can also serve as a crack initiation site. Furthermore, crack initiation modes were found to have a more pronounced effect on the small-crack growth rate. A turning point observed in the crack growth rate curves for specimens with multi-site crack initiation was attributed to crack shielding and subsequent coalescence. Full article

Background. Fibromyalgia Syndrome (FMS) is characterized by chronic widespread pain, sleep disturbances, fatigue and cognitive impairment. Methods. In this retrospective study, we analyzed data collected between 2017 and 2022 regarding Acetyl-L-Carnitine (ALC) as an add-on treatment in 183 adult patients with FMS according to the 2016 ACR (American College of Rheumatology) criteria and patients’ pain lasting for over three months. Patients with prior exposure to ALC or without informed consent were excluded. Results. Regarding efficacy, in the 137 analyzed patients, the change from baseline to the end of observation in Visual Analogue Scale score (VAS) was statistically significant, ranging from 75.9 ± 1.56 to 51.9 ± 1.99 (p < 0.001). Patients without FMS concomitant drug treatments achieved better VAS reduction than patients who were not drug-free at baseline. Regarding quality of life, a significant improvement in the Revised Fibromyalgia Impact Questionnaire (FIQ-R) score was evidenced, ranging from 75.1 ± 1.13 to 53.5 ± 1.34 (p < 0.001). The Short Form 12 Health Survey (SF12) scores showed a statistically significant improvement in both physical and mental components. Finally, the Pittsburgh Sleep Quality Index (PSQI) did not show a statistically significant difference from baseline. In the whole population, 23 patients (16.7%) reported Adverse Events (AEs), predominantly insomnia, shivering, headaches, and nausea. Only six patients reporting AEs discontinued the ALC treatment. Conclusions. This retrospective study evidenced the efficacy and safety of ALC in FMS patients. This may represent a useful approach, particularly for long-term treatments. Methodologically stronger studies will be necessary to validate our observations. Full article

Insufficient sleep causes muscle fatigue, impacting performance. The mechanism of brain–muscle signaling remains uncertain. In this study, we examined the impact of sleep deprivation on muscle endurance during isometric contractions and explored the changes in brain–muscle connectivity. Methods: The research involved 35 right-handed male participants who took part in an exercise test that included isometric contractions of the left and right biceps in both sleep-deprived and well-rested states. Muscle contraction duration and electroencephalogram (EEG) and electromyography (EMG) signals were recorded. Functional connectivity between brain regions was assessed using the phase locking value (PLV), while partial directed coherence (PDC) was used to analyze signal directionality between motor centers and muscles. Results: The connectivity strength between Brodmann areas (BAs) 1-5 and the right BA6, 8 regions was significantly decreased in the isometric contractions after sleep deprivation. Insufficient sleep enhanced the PDC signals from the motor center of the right brain to the left biceps, and it decreased the PDC signals from both biceps to their opposite motor centers. Conclusions: Sleep deprivation shortened muscle isometric contraction duration by affecting the interaction between the somatosensory motor cortex and the right premotor cortex, reducing biceps feedback signal connectivity to the contralateral motor center in the brain. Full article

(1) Background: This study compares the immediate effects of Rest Redistribution Training (RR) and Traditional Set Structure Training (TS) on vertical jump performance, heart rate variability (HRV), and perceived exertion (RPE) in anxious female college students. (2) Methods: In a randomized experimental design, 14 anxious female college students (ages 18–25, screened via Zung’s Self-Rating Anxiety Scale (SAS) with scores ≥50) underwent a familiarization session followed by two trials involving either a RR or TS conditioning routine. Vertical jump, HRV, and RPE were measured pre- and post-session, and during training, respectively. (3) Results: Both protocols induced significant decrements in squat jump (SJs) and countermovement jump (CMJs) metrics (p < 0.05), but no statistically significant between-group differences emerged (p > 0.05; SJ height: d = 0.059, 95% CI [−0.05, 0.05]; CMJ peak power: d = 0.253, 95% CI [−0.02, 0.02]). TS induced significant decreases in time-domain HRV indices (SDNN: d = 0.888, 95% CI [1.07, 16.13; RMSSD: d = 1.511, 95% CI [8.87, 27.63]) and high-frequency power (HF: d = 0.788, 95% CI [2.73, 379.71]), whereas RR preserved these indices. RR significantly reduced RPE compared to TS (p < 0.05; barbell bench press: d = 1.132, 95% CI [0.28, 1.48]; leg press: d = 0.784, 95% CI [0.01, 1.31]). (4) Conclusions: RR and TS protocols induced comparable decrements in vertical jump performance among untrained anxious female college students under equivalent loads; however, RR demonstrated superior autonomic regulation, reduced perceived fatigue, and equivalent performance outcomes, highlighting its potential as a low-stress alternative to traditional resistance training for anxiety-prone populations. Full article

Rubber materials can endure substantial deformation while avoiding permanent damage or rupture, making them highly suitable for applications in the automotive industry and other sectors, particularly for noise and vibration reduction. However, rubber experiences degradation over time as defects or cracks appear and propagate under fluctuating loads. Therefore, it is of critical importance to prevent the failure of rubber components during service. As highlighted in prior literature surveys by Tee et al. in 2018, Mars and Fatemi in 2002 and 2004, significant research has focused on the mechanics and analysis of rubber fatigue. This body of work has grown rapidly and continues to evolve. Therefore, this study aims to compile and analyze the vast body of recent research on rubber fatigue conducted over the last decade, supplementing the reviews by Tee et al. in 2018, Mars and Fatemi in 2002 and 2004. The gathered studies were analyzed to identify current trends and emerging research gaps in the fatigue study of rubber, including advanced composite rubber materials such as magnetorheological elastomers (MREs). This review emphasizes the analysis techniques and fatigue experiments available for fatigue life prediction in rubber materials, while illustrating their practical applications in engineering analyses through specific examples. Full article

Background and Clinical Significance: Nephrotic syndrome predisposes patients to venous thromboembolism. This case highlights the challenges of diagnosing pulmonary embolism in nephrotic syndrome patients with renal dysfunction, and emphasizes the utility of ventilation–perfusion lung scintigraphy when the contrast is contraindicated. Case Presentation: A 52-year-old male presented with fatigue, left back pain, dyspnea, and lower limb edema. The laboratory findings indicated nephrotic syndrome with significant proteinuria, hypoalbuminemia, and impaired renal function. Elevated inflammatory markers and lung infiltrates on chest CT suggested pneumonia. Despite antibiotic therapy, lung shadows, and elevated D-dimer persisted. Lower extremity ultrasound was negative for deep vein thrombosis. Due to concerns about contrast-associated nephropathy, ventilation–perfusion lung scintigraphy was performed, revealing a right lung base mismatch, leading to a diagnosis of pulmonary embolism and infarction. A kidney biopsy confirmed minimal change in disease. The patient achieved complete remission of nephrotic syndrome and was discharged on oral anticoagulation. His oral anticoagulation was discontinued after 3 months due to sustained remission and the absence of deep vein thrombosis. Conclusions: Pulmonary embolism and infarction can occur even in the absence of deep vein thrombosis. ventilation–perfusion lung scintigraphy is useful for detecting pulmonary embolism in patients with impaired renal function. Full article

This study investigated the effects of caffeine supplementation, carbohydrate mouth rinsing, and combined caffeine supplementation with carbohydrate mouth rinsing on the pulling performance and ratings of perceived exertion in indoor tug-of-war athletes. Eighteen tug-of-war athletes were recruited as participants. They underwent four supplementation protocols in a double-blind, single-factor, repeated-measures design: caffeine supplementation (CAF), carbohydrate solution mouth rinsing (CHO), combined caffeine supplementation with carbohydrate mouth rinsing (CAF-CHO), and a placebo (PLA). Each participant performed a maximal pulling test at 80% of their maximum pulling force, and the duration was recorded. Ratings of perceived exertion were also assessed. Data were analyzed using SPSS version 25.0 for Windows, and effect sizes (ES) were calculated. The main findings were as follows: (1) The CAF-CHO group showed a significantly longer pulling duration than the PLA and CHO groups (165.0 ± 69.2 s vs. 137.4 ± 48.9 s vs. 135.6 ± 66.6 s). (2) The CAF group also demonstrated a significantly longer pulling duration than the CHO group (162.0 ± 14.1 s vs. 135.6 ± 66.6 s). (3) Both the CAF-CHO and CAF groups exhibited large effect sizes (ω² > 0.14) compared to the PLA and CHO groups. Both caffeine supplementation combined with carbohydrate mouth rinsing and caffeine supplementation alone can significantly enhance the duration of 80% maximal pulling performance in indoor tug-of-war athletes, with the primary effect attributed to caffeine. These results provide practical strategies for coaches and athletes to suppress fatigue and improve pulling performance during competitions or training sessions for indoor tug-of-war. Full article

This article invites reflection upon the spiritual theological nature of the conscience as a means to discern God’s word in the depths of the soul. Coming from the depths of love and truth, the conscience is an extraordinary, demanding the force of grace. This is because God nurtures the formation of human conscience with the prevenience of grace to give light in darkness. This article explores the darkness and weariness of human existence in terms of self-interest, indolence, fatigue, and boredom, and then seeks to reflect upon how the conscience evidences the invincibility of goodness through blessing, humour, and prayer. This means that the conscience, pronouncing love in truth, and the nearness of the Kingdom of God, is called to be a “light” shining “out of darkness” (2 Cor 4:6). The conscience serves to animate a pastoral and spiritual life and testimony of faith, labour, responsibility, humility, and wisdom, as St. Paul relates: “we commend ourselves to the conscience of everyone in the sight of God” (2 Cor 4:2). Encountering “God’s mercy” (2 Cor 4:1), the conscience evidences a theophanic encounter of God’s grace that needs to be pronounced in the goodness of love in truth, of responsibility for-and-with-the-other. Full article

This review paper investigates the comprehensive impact of various nanomaterials on the mechanical properties and durability of pavement-quality concrete (PQC) with a specific focus on compressive strength, flexural strength, split tensile strength, permeability, abrasion resistance, fatigue performance, and crack relief performance. Despite significant advancements in the use of nanomaterials in concrete, existing research lacks a comprehensive evaluation of their comparative effectiveness, optimal dosages, and long-term durability in PQC. While conventional PQC faces challenges such as low fatigue resistance, high permeability, and susceptibility to abrasion, studies on nanomaterials have largely focused on individual properties rather than a holistic assessment of their impact. Nano SiO₂ and graphene oxide (GO) emerged as the most effective, with optimal dosages of 2% and 0.03%, respectively, leading to substantial improvements in compressive strength (up to 48.88%), flexural strength (up to 60.7%), and split tensile strength (up to 78.6%) through improved particle packing, reduced permeability, and refined microstructure. Nano TiO₂, particularly at a 1% dosage, significantly enhanced multiple properties, including a 36.30% increase in compressive strength, over 100% improvement in abrasion resistance, and a 475% increase in fatigue performance. However, a critical research gap exists in understanding the combined effects of multiple nanomaterials, their interaction mechanisms within cementitious systems, and their real-world performance under prolonged environmental and loading conditions. Most studies have been limited to laboratory-scale investigations, with minimal large-scale validation for pavement applications. The findings indicate that nanomaterials like nano TiO₂, nano CaCO₃, nano Al₂O₃, nano clay, and carbon nanomaterials play crucial roles in improving characteristics like permeability, abrasion resistance, and fatigue performance, with notable gains observed in many cases. This review systematically analyzes the influence of these nanomaterials on PQC, identifies key research gaps, and emphasizes the need for large-scale field validation to enhance their practical applicability. Full article

A testing method is developed to evaluate the acceleration- and strain-based fatigue life of a thermal interface layer in the high-cycle fatigue regime. The methodology adopts vibration-based fatigue testing, where adhesively bonded beams are excited at their resonant frequency under variable amplitude loading using an electrodynamic shaker. Fatigue failure is monitored through shifts in modal frequency and modal damping. Key findings include the identification of a 4% frequency shift as the failure criterion, corresponding to macro-delamination. The thickness of the thermal interface material influences acceleration-based fatigue life, decreasing by a factor of 0.2 when reduced from 0.3 mm to 0.15 mm and increasing by 5.5 when increased to 0.5 mm. Surface quality has a significant impact on both acceleration-based and strain-based fatigue curves. Beams from chemically etched aluminum–magnesium alloy specimens exhibit a sevenfold increase in fatigue life compared to beams from untreated printed circuit boards. Strain-based fatigue life increases with temperature, with a 0.2 reduction at $-40{}^{\circ }$C and an eightfold increase at $100{}^{\circ }$C relative to $23{}^{\circ }$C. The first principal strain ${\epsilon }_{1,\mathrm{rms}}$ is validated as a reliable local damage parameter, effectively characterizing fatigue behavior across varying TIM thicknesses. Full article

Background: It has been reported that forest bathing significantly reduced negative emotions and increased the positive feelings in both healthy males and females, as well as increasing blood serotonin in healthy males, indicating the potential for a beneficial effect on depressive status. However, an improvement effect of forest bathing on participants with depression has not been reported so far. Therefore, in order to fill this gap, this study examined the effect of forest bathing on depression in female participants with depression/depressive tendencies. Methods: Thirty-one females aged 40.1 ± 2.4 years with depression/depressive tendencies were recruited after obtaining informed consent. The study employed a randomized crossover design to compare forest bathing with city walking. They participated in day trips to a Japanese cypress forest park and to a city area of Nagano Prefecture as a control in June 2023. On both trips, they walked 2.5 km (for 90 min) in the morning and afternoon, respectively, for a total of 5.0 km per day. Blood samples were taken at 4 pm for the measurements before forest bathing on the first day and after the walking in forest and unban sites on the second and third days, at the same hospital. Concentrations of oxytocin, IGF-1, serotonin and lactic acid in blood were measured. SDS scores were calculated and the POMS test and questionnaires for subjective fatigue symptoms and sleep quality were administered before and after each trip. Temperature, humidity and illuminance were also measured in the forest and urban environments. The Nippon Medical School Central Ethics Committee approved this study. Results: Forest bathing significantly decreased SDS scores compared to city walk and the baseline, and the effect lasted for one week after forest bathing. Forest bathing also significantly increased the concentrations of blood serotonin in participants who were not taking antidepressants, significantly increased the levels of oxytocin and IGF-1 in blood, significantly increased the scores for positive feelings, and reduced the scores for negative emotions compared with city walking in the POMS test. In addition, forest bathing reduced subjective fatigue symptoms and improved sleep quality. Conclusions: These findings provided scientific evidence to contribute to understanding forest bathing as a potential intervention for preventing depression, and future research on males should further explore these effects. Full article