Search Results (350)

Background: While existing research has examined the association between the atherogenic index of plasma (AIP) and the incidence of new-onset diabetes, there is a paucity of evidence concerning the influence of physical activity (PA) on this relationship. This study aims to elucidate the intricate relationships among AIP, PA, and new-onset diabetes in middle-aged and older adults. Methods: Data from the 2011–2020 CHARLS cohort were analyzed. Multivariable logistic regression and restricted cubic splines (RCS) assessed the association between AIP and diabetes risk. Effect modification by physical activity was examined via interaction terms and subgroup analyses, with sensitivity analyses excluding participants with dyslipidemia. Results: During follow-up, 717 participants developed diabetes. Each one-standard-deviation increase in AIP was associated with a significantly increased risk of diabetes (odds ratio (OR) = 2.266, 95% confidence interval (CI): 1.807–2.843), with a linear dose–response relationship. A significant interaction was observed between AIP and physical activity. The association between AIP and diabetes was robust among non-exercisers (OR = 2.735, 95% CI: 2.087–3.582), but was markedly attenuated and non-significant among regular exercisers (OR = 1.471, 95% CI: 0.962–2.247). Sensitivity analysis yielded consistent results (OR = 2.259, 95% CI: 1.776–2.873). Conclusions: AIP is independently associated with an increased risk of new-onset diabetes in Chinese adults aged ≥45 years. Subgroup analyses indicated that physical activity significantly modified this association. The association was robust among non-exercisers but was markedly attenuated and became non-significant among regular exercisers. Full article

Background: Wushu, a traditional Chinese exercise, has been demonstrated to be effective in promoting lower-limb strength in children. However, studies comparing the effects of different intervention durations on preschool children remain limited. Objectives: The present study examined the short- and long-term effects of Wushu exercise programs on lower-limb explosive power in preschool children aged 5–6 years. Methods: This study was conducted across two experiments, with separate cohorts of children. The children were randomly assigned to either an intervention (INT) or a control (CON) group based on their Kindergarten classes. In Experiment 1, the INT-1 group (n = 55) completed a 4-week ‘Twelve Zodiac’ Wushu exercise program, which comprised three 30-minute sessions per week, while the CON-1 group (n = 49) participated in construction and carrying-based unstructured free play, which was designed to provide a comparable amount of moderate-to-vigorous physical activity. In Experiment 2, the INT-2 group (n = 57) undertook a 10-week Wushu program, and the CON-2 group (n = 38) engaged in similar activities as CON-1 for a 10-week period. The standing long jump (SLJ) was the primary outcome measure in both experiments. Secondary outcomes included the double-leg continuous jump, 15 m zigzag run, grip strength, sit-and-reach, and anthropometric measurements. In Experiment 2, countermovement jump (CMJ) and squat jump (SJ) heights were also measured using a force plate as additional secondary outcomes. A linear mixed-effects model (LMM) was used to analyze the data. Results: At baseline, no significant outcome measures were observed between CON-1 and INT-1, nor between CON-2 and INT-2. In Experiment 1, SLJ exhibited a significant enhancement in INT-1 in comparison to CON-1 (p = 0.007). The INT-2 in Experiment 2 showed significant improvements compared with CON-2 in the SLJ (p = 0.048), double-leg continuous jump (p = 0.005), and 15 m zigzag run (p = 0.043). A strong correlation was observed between SLJ and 15 m zigzag run time (r = −0.53, p < 0.001), and between double-leg continuous jump time and 15 m zigzag run time (r = 0.56, p < 0.001). Conclusions: The findings of this study indicate that 4-week and 10-week Wushu exercise programs enhance explosive power in the lower limbs of children aged 5–6 years. The 10-week Wushu program improves lower limb coordination and jumping agility. These task-specific adaptations support the value of Wushu interventions for fostering comprehensive lower-limb motor competence in preschoolers. Full article

Calcium propionate (Ca(CH₃CH₂COO)₂) was successfully synthesized from cockle shell biowaste through a reaction with propionic acid at concentrations of 80%, 90%, and 99%, valorizing seafood processing biowaste as a renewable calcium source in support of circular economy principles. The synthesis was conducted at ambient temperature with a fixed CaCO₃: propionic acid molar ratio of 1:2, enabling rapid reaction completion without external heating or complex purification steps. The prepared samples were characterized by FTIR, XRD, TGA, and SEM techniques, which confirmed the formation of calcium propionate monohydrate (Ca(CH₃CH₂COO)₂·H₂O), while XRF confirmed more than 97 wt% CaO across all samples with non-toxic impurities corresponding to compositional requirements for food additive calcium propionate (E282). The sample prepared using 80% propionic acid exhibited the highest yield (90.24%) and soluble percentage (98.23%). The proposed approach demonstrates an effective valorization of cockle shell waste into a food additive, calcium propionate, offering advantages in terms of sustainability, cost efficiency, and scalability, and highlighting its strong potential for industrial food additive production within a circular economy framework. Full article

Elite karate performance depends on neuromuscular power, joint mobility, and postural stability, yet sex-specific biomechanical profiles in this population remain insufficiently characterized. This study examined differences in lower-limb explosive power, joint kinematics, and visual-dependent postural control in 28 international-level karatekas. Assessments included vertical jump tests, joint mobility tasks performed at preferred and maximum velocities, and stabilometric evaluations under eyes-open and eyes-closed conditions. Males demonstrated significantly longer flight and phase times across all jump tests (all p < 0.05), and higher maximum angular velocities during shoulder flexion and extension, while females exhibited greater hip abduction range of motion during the Wall Split test (all p < 0.05). In postural control, females showed larger Ellipse Area and Path Length under eyes-open conditions (p < 0.05), but these differences were eliminated when vision was removed. The Romberg Index indicated comparable reliance on visual input between sexes. These findings may support the development of more individualized, sex-specific conditioning strategies in elite karate. Full article

(1) Background: This study aims to investigate the differences in body composition, muscle strength, and power between young karate athletes from different competitive disciplines. (2) Methods: The study sample consisted of 131 participants (69 boys and 62 girls) aged 10–14 years divided into three groups: kata (n = 48), kumite (n = 40), and athletes competing in both disciplines (n = 43). The set of variables included 1 anthropometric variable, 6 variables for assessing body composition (InBody 270), 8 variables for assessing handgrip strength (handgrip strength test, Fmax, RFD, absolute and relative, both hands), and 3 variables for assessing lower limb muscle power (force plate, CMJ height and power). Of the statistic analysis, MANOVA and ANOVA, along with MANCOVA and ANCOVA were performed. (3) Results: The adjusted results revealed significant general differences between groups (from p = 0.005 to p = 0.009). Regarding body composition, kumite athletes are taller, have greater body mass, body water, proteins, minerals, and muscle mass content than kata athletes and athletes specialized in both disciplines (from p = 0.002 to p = 0.045). The young karate athletes specialized in kumite competition exhibit higher levels of absolute handgrip muscle strength, rate of force development, and absolute lower limb muscle power than kata athletes and athletes specialized in both disciplines (from p = 0.002 to p = 0.041). There were no significant differences in any measured parameters between kata athletes and young karate athletes specialised in both disciplines. (4) Conclusions: The results are associated with higher values of body composition, muscle strength, and power in kumite athletes compared to kata athletes and athletes competing in both disciplines. Full article

This study presents a green bio-upcycling strategy for converting mussel shell biowaste into three value-added products: chitin, chitosan, and calcium lactate. Mussel shells were treated chemically with lactic acid during demineralization, yielding a solid fraction rich in chitin and a liquid fraction containing calcium and lactate ions. The solid fraction was sequentially purified by deproteinization and decolorization, then deacetylated to obtain chitosan, while the liquid fraction was evaporated to obtain calcium lactate. Notably, 2.37 g of raw chitin, 2.15 g of purified chitin, and 275.87 g of calcium lactate were obtained from 100 g of mussel shells, demonstrating the efficiency of the process. FTIR spectra revealed characteristic absorption bands corresponding to α-chitin and chitosan functional groups, while XRD patterns indicated the crystalline α-chitin structure and the formation of calcium lactate pentahydrate. TGA demonstrated the high thermal stability of chitin and chitosan and confirmed the presence of crystallization water in calcium lactate. In conclusion, these results confirmed the successful preparation of α-chitin, chitosan, and calcium lactate pentahydrate, with improved purity compared to previous studies. This approach highlights the potential of the green bio-upcycling process of mussel shell waste as a renewable source for the eco-friendly production of biopolymers and calcium salts, supporting sustainable waste management and the development of the Bio-Circular-Green (BCG) economy. Full article

Objectives: Post-activation performance enhancement (PAPE) has been explored for its potential to improve performance in combat sports. This part II of the systematic review and meta-analysis investigated the acute effects of PAPE protocols on sport-specific performance outcomes and evaluated the influence of moderating variables, specifically competitive level and training experience. Methods: A PRISMA-guided search (2010–2024) identified 13 studies examining PAPE in combat sports athletes. Inclusion criteria required human trials using defined PAPE protocols and evaluating sport-specific tests, primarily the Frequency Speed of Kick Test (FSKT-10) and the Taekwondo-Specific Agility Test (TSAT). A random-effects meta-analysis (Hedges’ g) was conducted on data from 176 athletes. Results: The meta-analysis revealed a profound moderating effect of training status on PAPE responsiveness. For the FSKT-10, amateur athletes demonstrated large, significant improvements (g = 1.28, p < 0.001), whereas elite athletes showed trivial, non-significant changes (g = 0.11, p = 0.357). Similarly, athletes with <6 years of training experience exhibited substantially larger enhancements in both FSKT-10 (g = 1.60) and TSAT agility (g = −1.64) compared to their more experienced (>6 years) counterparts (g = 0.42 and g = −0.65, respectively). Furthermore, dynamic and biomechanically specific conditioning activities (e.g., repeated high-intensity techniques) were most effective at driving sport-specific potentiation. Conclusions: PAPE protocols may enhance acute sport-specific performance when utilizing dynamic, highly specific conditioning activities. However, a possible “ceiling effect” may blunt this potentiation in elite and highly experienced athletes, suggesting a potential need for highly individualized priming strategies at the top competitive levels, specifically in taekwondo. Full article

Calcium formate (Ca(HCOO)₂) is an important industrial chemical widely used in construction, feed additives, and various chemical processes. In this work, calcium formate was synthesized from cockle shell waste and concentrated formic acid (50%, 60%, and 70% w/w) by a simple, rapid, low-cost, and environmentally friendly process, denoted as CF50, CF60, and CF70, respectively. The chemical and physical properties of as-synthesized calcium formate using cockle shells as a renewable calcium source were investigated by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray fluorescence (XRF), Thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) techniques. The FTIR and XRD results revealed that the samples prepared using 50% and 60% formic acid produced well-crystallized α-calcium formate. In contrast, the reaction using 70% formic acid generated a strongly exothermic reaction, which hindered the complete conversion of calcium carbonate and resulted in the presence of residual CaCO₃ in the final product. Similarly, the SEM images of the CF50 and CF60 samples show the slick surface of orthorhombic crystals of calcium formate; on the other hand, the SEM image of CF70 shows some small particles of aragonite on the surface of the calcium formate crystals. The 60% formic acid provided the optimal synthesis condition, yielding pure calcium formate with the shortest synthesis time. Overall, the proposed approach provides a simple, rapid, and cost-effective route for producing calcium formate from shell waste. Furthermore, the utilization of cockle shell waste as a renewable calcium source contributes to waste valorization, reduces environmental impacts associated with shell disposal, and minimizes dependence on mined limestone resources, supporting sustainable resource utilization within a circular economy. Full article

Background: In the year 2022 more than 390 million kids and teenagers aged between 5 and 19 years old were overweight, including 160 million individuals who were suffering from obesity. It is commonly known that, in order to have a possitive change in physical and mental health, physical activity is needed. The aim of this study was to determine whether the type of physical activity undertaken influenced changes in body mass and physical fitness scores in children aged 7–10 years who practice taekwondo, swimming, and team sports, using tag rugby as an example. Material and Methods: A total of 200 children were eligible to participate in the research project and the analysis was conducted on 150 subjects (49% girls and 51% boys). Group IA (n = 20) trained in taekwondo, group IB (n = 42) trained in swimming, and group IC (n = 20) trained in rugby tag. Group II control subjects (n = 68) did not participate in any additional sports activities. Children’s body height was determined with a SECA 213 heightometer and body mass and body composition using Tanita’s MC-780 eight-electrode body composition analyser. Selected Eurofit tests were used to assess physical fitness. Results: A peripheral distribution of fat mass was found in all subjects, with the highest levels determined in the upper limbs. The highest values, apart from arm muscle strength, were found in the swimming group. Significant changes were observed in the subjects training in taekwondo. Conclusions: Results suggest that physical activity targeting the development of different motor skills should be part of preventive health care for children. Full article

Background/Objectives: Acute high-intensity exercise may transiently alter circulating vitamin D metabolites. However, the effects of training status, supplementation dose, and vitamin D-binding protein (VDBP) on the exercise-induced redistribution and bioavailability of vitamin D remain unclear. This pilot study examined whether training status and vitamin D₃ supplementation dose modulate vitamin D status, anaerobic performance, and acute post-exercise changes in vitamin D metabolites and VDBP. Methods: Thirty-four healthy young men participated, comprising 22 mixed martial arts (MMA) athletes and 12 untrained controls. MMA athletes received either 3500 or 6000 IU/day of vitamin D₃ for four weeks, while untrained participants received 3500 IU/day or a placebo. Before and after the intervention, participants performed a supramaximal anaerobic exercise protocol (3 × 30 s Wingate tests). Blood samples were collected at rest and 30 min and 24 h post-exercise to assess vitamin D metabolites, VDBP, bioavailable and free 25(OH)D₃, interleukin-6, and lactate. Results: Supplementation with 3500 IU/day significantly increased serum 25(OH)D₃ in untrained men (p = 0.003) but not in MMA athletes. In contrast, 6000 IU/day increased 25(OH)D₃ in MMA athletes to a sufficient concentration (p = 0.001) and improved maximal power (+7.5%), mean power (+4.9%), and total work (+5.0%). Acute exercise increased circulating vitamin D metabolites in trained athletes but reduced them in untrained men supplemented with vitamin D. Conclusions: The efficacy of vitamin D₃ supplementation and the acute exercise-induced vitamin D responses appear to be training-dependent. A daily dose of 6000 IU is more effective in achieving vitamin D sufficiency and performance benefits in MMA athletes, whereas 3500 IU is sufficient for untrained men. Full article

Martial arts have evolved from self-defense practices into structured competitive sports that demand high levels of neuromotor control, where improper execution remains a major source of injury. This study evaluates lower-limb control during the execution of the karate lateral kick using videogrammetry biomechanical analysis. Three participants were recorded during regular training sessions and selected according to their level of expertise. Each participant performed lateral kicks at three predefined distances (close, comfortable, and long), selected based on common training practice and individual biomechanical considerations. Videogrammetry data were generated using Kinovea version 0.9.5 software to extract sagittal ankle trajectories. Statistical analyses were carried out in MATLAB version 2025b using spatial coordinates to obtain kinematic data on the practitioner’s performance. The results revealed skill-dependent differences in movement control, characterized by temporal evolution of kinematic variables and their corresponding time–frequency representations. Novice practitioners exhibited limited control during the raising and recovery phases, despite reaching the target. In contrast, expert practitioners demonstrated consistent posture, controlled acceleration during impact, and stable limb trajectories during descent. These observations provide a foundation for data-driven classification of kick execution quality and outline potential applications in supervised learning, real-time feedback systems, and injury risk reduction during karate training. Full article

Background/Objectives: Combat sports are characterised by successive high-intensity and short-duration episodes (rounds) interspersed with short rest periods (intermittent nature). Athletes’ body composition and dietary intake are closely related to physiological demands, and they are determining factors in athletic performance. The aim of this systematic review was to describe the body composition, dietary intake, and food habits of male and female combat sports athletes, and to verify whether they met nutritional recommendations. Methods: A search was performed in the PubMed, Web of Science, and Scopus databases following the PRISMA statement. The timeframe for the search included studies from the year 2000 until 2 February 2026. Risk of bias was assessed using the STROBE and the Newcastle–Ottawa checklists. Initially, 328 documents were identified. The research focused on amateur, semi-professional, or professional athletes in boxing, karate, kickboxing, jiu-jitsu, taekwondo, judo, muay thai, and mixed martial arts (MMA). Results: After screening, 23 studies met the inclusion criteria and were included in the review. Most of the athletes, both men and women, had normal body mass indices (BMIs), with low or normal fat percentages and adequate muscle mass during both reference and pre-competitive periods. Regarding dietary intake, most of the athletes, male and female, had energy and carbohydrate intakes below official recommendations. Energy and nutrient intake decreased during pre-competition periods as a strategy for achieving pre-competitive rapid weight loss, which mainly occurred at the expense of lean mass. Conclusions: Despite maintaining adequate body composition, combat sports athletes reported an inadequate dietary pattern, especially during pre-competitive periods, which may negatively affect athletic performance. Full article

Introduction: Judo is a type of combat sport in which athletes must be able to constantly control their position and maintain a constant dynamic balance to respond to their opponent’s moves. In this scenario, the aim of this systematic review was to evaluate the role of core strength and stability in supporting balance, neuromuscular control, and functional performance-related determinants in judo athletes. Methods: PubMed, Scopus, and Web of Science databases were systematically used for articles published from inception to 4 April 2025, to identify any sort of manuscript indicating judo athletes as its population and core training approaches as the intervention (PROSPERO registry with the code: CRD420251032685). Results: Out of 401 studies, after the removal of 206 duplicates, we screened 195 records. Then, seven articles were included in the systematic review. We found that a strong core might improve balance and neurodynamic control. International-level judokas showed greater trunk extensor strength and less trunk angular displacement. Previous research suggests that core training improves physical fitness, balance, and lower limb recovery; moreover, the lack of core muscle strength might predispose athletes to injury, while solid core stability could ensure good support for the body to perform any movement in a balanced, coordinated, and functional manner. Core stability training and strengthening protocols might also decrease the risk of falling, which could have a beneficial effect on judoka athletes. Conclusions: Despite the wide variety of protocols used for core strengthening, it has been documented that a strong core might improve balance and neurodynamic control of movement during competition. Full article

Immersive virtual reality (VR) offers promising opportunities for skill acquisition in complex motor domains, yet its specific potential for martial arts training remains underexplored. This pilot study examined how visual and auditory feedback are associated with subjective immersion and motor performance during the execution of a standardized martial arts sidekick in VR. Ten technically experienced participants completed four training conditions, while full-body kinematics were captured using a synchronized VR-MoCap setup. Subjective ratings of immersion and presence were collected after each condition, and three expert interviews provided complementary qualitative perspectives. Exploratory analyses indicated that high-fidelity visual feedback elicited higher immersion and more stable chamber-phase posture, while voice feedback was associated with smoother timing and improved kick alignment. Experts highlighted multisensory coherence as a key design principle and pointed to concrete opportunities for VR-supported technique refinement. These convergent findings suggest that immersive VR can support technically relevant performance cues in martial arts training while also highlighting design considerations for future high-precision VR coaching systems. As a pilot study, the results provide methodological groundwork and signal directions for larger, confirmatory investigations. Full article

Background/Objectives: The front kick is among the most commonly used techniques in martial arts. This study aimed to analyze the range of motion during the mae-geri kick in advanced-level Kyokushin karate practitioners compared to an intermediate-level control group under three conditions: before warm-up, after warm-up, and after a shadow fight. Methods: The study group [N = 28, M: 27.6 years, body mass 81.9 kg, height 1.8 m] consisted of advanced-level Kyokushin karate practitioners (3rd kyu and higher), and the control group consisted of intermediate-level practitioners (6th to 4th kyu). A wireless surface electromyography (EMG) system was used to record muscle activity and an inertial measurement unit (IMU) was used to measure joint angles. Before the study began, the maximum voluntary contraction was determined for each muscle tested. Each participant performed three consecutive kicks in three conditions: before warm-up, after warm-up, and after a shadow fight. Results: The intermediate-level practitioners used the soleus muscle more than advanced practitioners during the front kick (48.92% vs. 35.94% before the warm-up kick, p = 0.042, η²_p = 0.27). After the warm-up, both groups began to use the soleus muscle more intensively (intermediate: 48.92% vs. 61.72% MVC, p = 0.046; advanced: 35.94% vs. 48.69% MVC, p = 0.045), and the advanced group’s activity in the medial gastrocnemius muscle increased compared to before the warm-up (58.23% vs. 39.20% MVC, p = 0.016). Conclusions: Advanced vs. intermediate Kyokushin karate practitioners display distinct neuro-muscular activation strategies in the mae-geri kick, particularly in soleus and gastrocnemius recruitment. Combined EMG and IMU systems can identify trends and in-form training feedback in Kyokushin karate training and effectively prepare the musculoskeletal system for rapid activity, which is important during sports competitions. Full article