Search Results (3,274)

The lactate threshold (LT) and the associated running velocities are important markers used to define physical readiness and prescribe exercise intensity in athletes. This study examined blood LT during maximal cardiopulmonary exercise testing using four methods: visual inspection, log-to-log transformation, the Dmax method, and the 4 mmol/L fixed blood lactate accumulation (FBLA) method. The participants included 96 soccer players, comprising 52 professional (27.37 ± 5.67 years) and 44 elite youth players (16.20 ± 0.8 years). A total of 554 capillary blood lactate samples were analyzed. Bland–Altman and ICC analyses for running velocities, determined using the four LT detection methods, demonstrated poor agreement in both groups. Results indicated that the youth players had significantly (p < 0.05) higher V̇O₂ max (59.89 ± 5.6 mL·kg⁻¹·min⁻¹) compared to the professional players (56.43 ± 4.81 mL·kg⁻¹·min⁻¹). However, the professional players had significantly better running performance and running economy. A two-way ANOVA revealed a main effect of playing standard, with professional players exhibiting significantly higher 4 mmol/L FBLA LT compared to youth players. A mixed-design ANOVA indicated a significant (p < 0.01) interaction, with the youth exhibiting higher lactate accumulation only after completing the 18 Km/h stage. Therefore, youth and professional players should not use the different LT concepts interchangeably. Additionally, the 4 mmol/L FBLA LT method appears to be more robust for youth soccer players. Full article

Background: This study analyzes the biomechanical contributions of the non-throwing arm during the completion phase of the glide shot put technique, focusing on its roles in performance optimization. Methods: Data from a Chinese elite female shot-putter were collected during a national championship, with three-dimensional kinematic analyses and Spearman correlation to assess joint displacement, velocity, and angular changes. Results: Distal joints of the non-throwing arm exhibited greater displacement but lower peak velocity than proximal joints. Angular changes showed a flexion trend in the elbow and shoulder, with brief extension phases in the elbow. During the completion phase, the shoulder velocity of the non-throwing arm positively correlated with shot put velocity (rs = 0.72, p < 0.05) but negatively correlated with the velocity of the elbow (rs = −0.46, p < 0.05), wrist (rs = −0.41, p < 0.05), and center of mass (rs = −0.66, p < 0.05). The elbow velocity positively correlated with shot put velocity (rs = 0.56, p < 0.05) but negatively correlated with velocities of the shoulder (rs = −0.59, p < 0.05), wrist (rs = −0.79, p < 0.05), and center of mass (rs = −0.91, p < 0.05). Wrist velocity exhibited similar correlations. Conclusions: These findings underscore the active role of the non-throwing arm in enhancing shot put performance by influencing the center of mass movement, rotational mechanics, and energy transfer, providing actionable guidance for elite training optimization. Full article

This study aimed to assess the effectiveness of various active recovery strategies in youth female soccer players during competitive tournaments with limited recovery periods (i.e., 24–48 h). Twenty-two elite under-17 female football players participated in this randomized controlled trial, which encompassed fourteen 90 min official matches. Participants were randomly allocated to one of three recovery protocols: passive stretching, foam rolling, or lumbopelvic mobility exercises, which were implemented ten minutes after each match. Countermovement jump with free arm (CMJA) height was measured pre-intervention, immediately post-intervention, and 5 h post-intervention. Wellness perception was evaluated 24 h later. Significant enhancements in CMJA height were observed immediately after all recovery protocols and at 5 h post-intervention compared with pre-intervention (p < 0.001). The lumbopelvic mobility protocol yielded the most substantial improvement, significantly surpassing both stretching and foam rolling. Moreover, significant increases in wellness perception were observed following the foam rolling (p < 0.001, ES = 0.95) and mobility (p < 0.05, ES = 0.88) protocols, with the mobility protocol demonstrating a marginally larger effect size than stretching. Active recovery strategies significantly enhanced neuromuscular function and wellness perception in under-17 female soccer players. Lumbopelvic mobility exercises exhibited superior efficacy, suggesting that they should be prioritized in post-match recovery regimens. Full article

Padel is a racket sport that has grown internationally, both in the number of players and in the number of competitions. Inertial measurement devices enable a comprehensive analysis of competitive load in padel by providing kinematic variables that enhance players’ performance in this discipline. This study aimed to analyse the external load variables recorded with an inertial device in elite padel players, comparing metrics based on the players’ positions (left and right sides of the court). A total of 83 players were monitored during 23 matches of the professional circuit. The results revealed specific load metrics, including distance covered, frequency of accelerations and decelerations per hour, maximum speeds reached, and acceleration profiles relative to distance covered, which were all measured using the Wimu Pro™ device. Left-side players showed more frequent accelerations and decelerations per hour compared to right-side players. The results of this study will, on one hand, enable the adjustment of new specific parameters for professional padel training, such as acceleration and deceleration profiles, player load, and distances covered at explosive speeds. On the other hand, the results will provide a more objective evaluation of padel players’ performance based on their positions. Full article

Borehole trajectory optimization is a key issue in oil and gas drilling engineering. The traditional wellbore trajectory design method faces great challenges in optimizing the trajectory length and complexity, and it is difficult to meet the actual engineering requirements. In this paper, the three-stage wellbore trajectory optimization problem is studied, and a multi-objective optimization model including two objective functions of trajectory length and trajectory complexity is constructed. In this paper, an improved multi-objective particle swarm optimization algorithm is proposed, which combines the clustering strategy to improve the diversity of solutions, and enhances the local search ability and global convergence performance of the algorithm through the elite learning strategy. In order to verify the performance of the algorithm, comparative experiments were carried out using classical multi-objective benchmark functions. The results showed that the improved algorithm is superior to the traditional method in terms of diversity and convergence of solutions. Finally, the proposed algorithm was applied to the actual three-stage wellbore trajectory optimization problem. In summary, the research results of this paper provide theoretical support and engineering practice methods for wellbore trajectory optimization, and serve as an important reference for further improving the efficiency and quality of wellbore trajectory design. Full article

The purpose of the study is to identify variations in wellness parameters among elite female athletes, considering simultaneously the influence of natural menstrual cycle (MC) or hormonal contraception (HC) phases and weekly and seasonal variations. A total of 54 elite female athletes were followed up with through a 6-month daily monitoring of their reported fitness, sleep quality, mood, and menstrual symptoms. Estimated cycle phases, days of the week, and seasons were all integrated into a single model to study cyclicities concomitantly. A total of 263 cycles were analyzed, totaling 7370 pieces of daily self-reported data. We observed more frequent symptoms during the menstruation and the pause phase. Reported fitness was greater in the mid-cycle and mood was lower at the end of the cycle for the MC group. Wellness parameters were rather stable for HC users. For both groups, symptoms were more frequent in summer. Reported fitness levels were lower on Monday, while mood scores were highest on Saturday and Sunday. In summer and autumn, fitness, sleep quality, and mood were greater. A cyclical wellness rhythm was identified in the menstrual cycle and persists even when considering weekdays and seasons cyclicities. This comprehensive approach helps to identify physiological influence on human behaviors, considering the specificities of women. Full article

Uniform design is a powerful and robust experimental methodology that is particularly advantageous for multidimensional numerical integration and high-level experiments. As its applications expand across diverse disciplines, the theoretical foundation of uniform design continues to evolve. In real-world scenarios, experimental factors are often subject to one or more linear constraints, which pose challenges in constructing efficient designs within constrained high-dimensional experimental spaces. These challenges typically require sophisticated algorithms, which may compromise uniformity and robustness. Addressing these constraints is critical for reducing costs, improving model accuracy, and identifying global optima in optimization problems. However, existing research primarily focuses on unconstrained or minimally constrained hypercubes, leaving a gap in constructing designs tailored to arbitrary linear constraints. This study bridges this gap by extending the inverse Rosenblatt transformation framework to develop innovative methods for constructing uniform designs over arbitrary hyperplanes and hyperspheres within unit hypercubes. Explicit construction formulas for these constrained domains are derived, offering simplified calculations for practitioners and providing a practical solution applicable to a wide range of experimental scenarios. Numerical simulations demonstrate the feasibility and effectiveness of these methods, setting a new benchmark for uniform design in constrained experimental regions. Full article

Carotid artery stiffness is associated with aging and atherosclerotic disease, leading to cerebrovascular events. Shear Wave Elastography (SWE) is a novel ultrasound technique offering a direct, quantitative assessment of the arterial wall elasticity. The aim of this study is to validate the technical feasibility of SWE in measuring carotid stiffness (CS). A literature search was performed across the PubMed and Scopus databases, with keywords including “carotid stiffness”, “Shear Wave Elastography”, “atherosclerosis”, and “vascular elasticity”. The findings reveal the potential of SWE in quantifying carotid Intima–Media Complex (IMC) stiffness, with implications for the early diagnosis of vascular disease, aiding in clinical decision making and prognostic assessment. Based on the findings of the literature search, a small pilot study was conducted involving 10 participants, using the Philips EPIQ Elite system for the SWE measurements. The technical analysis revealed optimizing the region of interest (ROI) size, probe positioning, and cine-loop analysis as crucial factors for obtaining accurate results. The results of the literature review and small pilot study demonstrate the potential of SWE as a non-invasive method for assessing carotid stiffness. Certain technical adjustments, such as smaller ROIs and careful probe placement, improved the accuracy and repeatability of carotid SWE measurements. Further studies are needed to assess and standardize carotid SWE across larger patient populations. Full article

Organic matter exhibits significant heterogeneity and complexity, with varying pore structures across different types influenced by multiple interacting factors. This paper introduces a “two categories, six subcategories” classification scheme based on morphological observations using a combination of argon ion polishing and scanning electron microscopy (SEM). Organic matter is classified into two main categories: depositional organic matter and migrated organic matter, based on whether migration has occurred. Depositional organic matter is further subdivided into three types based on microscopic characteristics: bioclasts, compacted kerogen, and in situ remnants from post-hydrocarbon generation. Migrated organic matter is categorized into three types: organic matter in intragranular pores, organic matter in intergranular pores, and bitumen in microfractures. Bioclasts can be further classified into alginite, zooclasts, acritarchs, and encapsulated organic matter based on maceral type. Zooclasts, acritarchs, encapsulated organic matter, and compacted kerogen—types of depositional organic matter—have few or no pores. This is primarily related to the nature of the hydrocarbon-generating precursor materials, with compacted kerogen being influenced by low thermal maturity and diagenetic compaction. In contrast, pores are more developed in alginite, in situ remnants from post-hydrocarbon generation, and all forms of migrated organic matter, largely due to the expulsion of gaseous hydrocarbons during thermal evolution. The pores in alginite reflect both the original structural properties of the hydrocarbon-generating precursor materials and the thermal evolution process. Depositional organic matter exhibits a stronger oil-generating potential and a higher gas-generating potential, while migrated organic matter primarily possesses a stronger gas-generating capability. Specifically, organic matter enriched in alginite, in situ remnants from post-hydrocarbon generation, as well as migrated organic matter in intragranular pore and intergranular pore, exhibit a higher hydrocarbon-generation potential. Full article

Monitoring physiological parameters is vital for tracking swimmers’ progress and performance. This study examines an elite male swimmer’s nutrition during his preparation for the 2024 Paris Olympics, considering his metabolic rate and body composition. His resting energy needs (2905 ± 407.99 kcal/day) were measured using indirect Cosmed K5, calorimetry, and body composition determined through skinfold measurements. Nutrition plans were developed using software, varying with his training intensity—providing 2910 ± 379 kcal/day on rest days, and 4238 ± 562 kcal/day on intense days. The analysis of the correlations between key variables revealed strong and diverse interactions among anthropometric, metabolic data, and energy substrates. Thus, weight exhibited a very strong positive correlation with lean mass (FFM), indicating that higher weight is associated with increased lean mass. Conversely, the moderate correlation between weight and body fat percentage suggests a weaker association. The amount of skin folds accurately reflects the body fat percentage. Ensuring that a high-energy dietary intake aligned with his actual needs throughout the season was crucial for sustaining performance. Experimenting with fueling and recovery tactics during smaller competitions enabled the athlete to meet energy and nutrient demands at the elite level. Full article

(1) Background: This study aimed to examine the differences in the kinetic energy of the body’s center of mass between successful and unsuccessful attempts at transitioning from a basket to a handstand on the parallel bars. Special attention was given to the analysis of kinetic energy as a key factor in the efficient execution of this complex element. (2) Methods: The sample consisted of 10 successful and 10 unsuccessful attempts performed by an elite gymnast (a multiple-medalist in World and European Championships). All attempts and kinematic data were recorded and analyzed using high-frequency cameras (300 Hz) and the Ariel Performance 3D video system, respectively. Successful and unsuccessful performances were compared using a paired-sample t-test. (3) Results: Significant differences in kinetic energy were observed in the first part of the anti-gravitational phase of movement between successful and unsuccessful attempts. Successful attempts demonstrated a more favorable position at the beginning of this phase, allowing better utilization of accumulated kinetic energy—a higher position of the feet and hips, and a smaller shoulder joint angle at the moment the shoulder passed through the lower vertical. (4) Conclusions: Successful attempts in gymnastics are characterized by better biomechanical optimization and efficient kinetic energy use, achieved through an earlier entry into the second phase of movement with optimal body positioning, leading to greater peripheral and angular velocities crucial for performance. Full article

(1) Background: Elite sport can increase vulnerability to developing mental health pathologies. The purpose of the study is to determine the frequency at which these behavioural disorders appear in elite footballers and evaluate their relationship with other addictions. (2) Methods: A cross-sectional study was conducted between November 2020 and January 2022 on 306 participants. The variables of gambling and gaming were studied. The different groups were compared using Chi-squared tests. Probabilities exceeding 95% (p-values < 0.05) and residuals results greater than 2 or less than −2 were considered significant. (3) Results: There were significant differences between the two groups in terms of alcohol (p < 0.001), tobacco (p < 0.001), and cannabis (p = 0.016) consumption. We also found differences between those who had a history of a nervous disease (p = 0.015). 6.6% of the of football players had a probable diagnosis of a gambling disorder compared to 1% in the general population (p = 0.011). Among the pathological and non-pathological cases of gambling in the football population, significant differences were found between those with a salary of EUR 900–1500/month (p = 0.027) or a history of a nervous pathology (p = 0.021). (4) Conclusions: This study showed that professional football players were vulnerable to mental health pathologies related to gambling. Full article

This paper examines how and why Korea Soka Gakkai International (KSGI) has grown rapidly in the Korean religious market. Although Soka Gakkai was introduced to Korea as a Nichiren Shoshu lay community in the 1960s, KSGI has achieved remarkable growth without the structurally covert and organizationally authoritative control typical of traditional elite Buddhism. This fact is significant in both theory and practice, as lay movements have historically not been very successful in Korean religions. Focusing on the paradoxical affinity between secular civic movements and religious lay movements, this paper explains why and how KSGI had to combine the two movements in a socio-historical context different from that of its Japanese partner, which established a public political party, the Komeito, and formed a coalition government with other parties. As a result, this paper reveals the following findings: first, KSGI’s nonpolitical civic engagement led to a more effective growth strategy tailored to the Korean socio-historical context. Second, the Korean government’s policy of opening up to Japanese culture since the 2000s played a significant role in the growth of KSGI. Third, the spread of civil movements in Korea contributed to enhancing KSGI’s social adaptability and credibility. Full article

In the United States, small and beginning (SB) farmers depend on institutional and elite customers to increase their farm income, whereas food-insecure communities lack alternatives for accessing and utilizing healthy local foods. This study examined two middle-of-the-chain organizations attempting to break the demand- and supply-related barriers faced by food-insecure consumers and SB farmers, respectively. The study suggests that deep engagement on both sides can facilitate the creation of a viable local food pathway. One organization serves as an aggregator for SB farmers while preventing the unrealistic expectations of institutional customers. A second organization activates food-insecure consumers’ agencies to conceptualize and transform locally sourced food into acceptable forms. It provides the necessary support to ensure the utilization of healthy, nutritious foods. When the two organizations’ missions are aligned, they can use an emergent, flexible, and adaptable approach with a continuous improvement mindset to increase SB farmer livelihoods and reduce food insecurity. Middle-of-the-chain organizations collectively should have more than one way to make local foods available, accessible, and utilizable by food-insecure consumers. A nonprofit social enterprise model of organizations in the middle seems central to the viability of the community-based food system. The system is still in its early stages. Further research is needed to examine its sustained viability. Full article

Background/Objectives: Vacuum-assisted excision (VAE) is a minimally invasive technique for breast tumor treatment, offering precision, comfort, and quick recovery. It is widely used for benign breast lesions and is playing an increasingly important role in the therapeutic management of non-surgical patients or patients who refuse surgery. Optimal outcomes require an understanding of device features to tailor treatment to each lesion. The Mammotome^® Elite 10G operates in a fixed mode, while the Mammotome^® Revolve EX 8G offers multiple aspiration levels and aperture windows for greater versatility. This study analyzed the specimen features (weight and length), comparing the weight obtained from two different VAE systems to aid the appropriate selection of a device based on the clinical setting. It also determined the number of specimens needed to achieve the 4 g diagnostic threshold. Methods: The Mammotome^® Elite 10G and the Mammotome^® Revolve EX were evaluated under controlled conditions. For Mammotome^® Revolve EX, combinations of five aspiration levels and three aperture lengths (12 mm, 18 mm, and 25 mm) were tested. Twelve samples were collected from a chicken breast phantom for each setting. Specimen weights and the minimum excisions required to reach the 4 g threshold were analyzed. Results: The mean weight per sample for the Mammotome^® Elite 10G was 0.16 ± 0.04 g. For the Mammotome^® Revolve EX, the weights increased with aperture size and aspiration level, ranging from a minimum of 0.132 ± 0.028 g (a window length of 12 mm and aspiration level 1) to a maximum of 0.407 ± 0.055 g (a window length of 25 mm and aspiration level 5). The 25 mm window at aspiration level 5 achieved the 4 g threshold in as few as 10 samples. By comparison, the Mammotome^® Elite required up to 26 samples. Conclusions: Compared to the Mammotome Elite, Mammotome^® Revolve EX offers superior versatility and efficiency, reducing patient discomfort by minimizing the required samples. Its technical advantages make it a valuable tool for both diagnostic and therapeutic applications. Full article