Search Results (52)

This study presents the development and optimisation of a standardised rheological test method based on rotational rheometry for the characterisation of cementitious mixtures designed for 3D printing. Tests were performed using a Discovery HR-20 rotational rheometer (TA Instruments, New Castle, DE, USA) equipped with a concentric-cylinder cup-and-paddle geometry. A high-early-strength Portland cement (ASTM C1157 Type HE) with a constant water-to-cement ratio (w/c) of 0.35 was employed. The methodological framework comprised five sequential stages: (i) assessment of the pre-conditioning effect; (ii) standardisation of the static shear test; (iii) optimisation of pre-conditioning parameters; (iv) standardisation of the dynamic shear test; and (v) evaluation of the influence of sample volume. Optimal conditions were determined as follows: for pre-conditioning, a shear rate of 50 s⁻¹, holding time (H_t) of 30 s, and rest period of 180 s; for the static shear test, a shear rate range of 0.05–0.10 s⁻¹ with a H_t of 60 s; for the dynamic shear test, a 30 s ramp up/down, maximum shear rate of 100 s⁻¹, and H_t of 90 s. An optimal sample volume ranging between 150 and 175 mL was established. The proposed method represents a robust and reproducible experimental protocol for evaluating, comparing, and optimising the rheological behaviour of cementitious mixtures using rotational rheometry, providing a reliable tool for the formulation of mixtures tailored to additive manufacturing or 3D printing processes. Full article

Manual wheelchair users with spinal cord injury (SCI) often experience upper-limb strain and pain due to repetitive propulsion. A detachable dual-propulsion add-on device has been developed to mitigate this issue by offering an alternative propulsion mechanism, but its user acceptability and practical benefits must be rigorously evaluated. This study will implement a structured mixed-methods usability assessment of the new device with 30 adult wheelchair users with SCI. The evaluation will combine quantitative surveys, objective task-based performance metrics, and qualitative interviews to capture a comprehensive picture of usability. We will conduct a single-arm mixed-methods protocol using a device-specific 45-item usability questionnaire and semi-structured interviews, followed by convergent triangulation to integrate quantitative scores and qualitative themes. Participants will use the dual-propulsion device in realistic scenarios and then complete a 45-item questionnaire covering effectiveness, efficiency, safety, comfort, and psychosocial satisfaction. In addition, semi-structured interviews will explore users’ experiences, perceived benefits, challenges, and suggestions. During a standardized mobility task course (doorway navigation, ramp ascent, threshold crossing, and 50 m level propulsion), objective performance indicators—including task completion time, task success/error rate, number of lever strokes, and self-selected speed—will be recorded as secondary usability outcomes. The use of both a standardized questionnaire and in-depth interviews will ensure both broad and nuanced assessment of the device’s usability. Data from the survey will be analyzed for usability scores across multiple domains, while interview transcripts will undergo thematic analysis to enrich and validate the quantitative findings. This protocol is expected to provide robust evidence of the device’s usability, inform iterative improvements in its design, and highlight the importance of structured usability evaluations for assistive technologies. Full article

Short-term bus load forecasting in distribution networks faces severe challenges of non-stationarity, high-frequency disturbances, and multi-scale coupling arising from renewable integration and emerging loads such as centralized EV charging. Conventional statistical and deep learning approaches often exhibit instability under abrupt fluctuations, whereas decomposition-based frameworks risk redundancy and information leakage. This study develops a hybrid forecasting framework that integrates variational mode decomposition (VMD), locally weighted scatterplot smoothing (LOWESS), and a multi-channel differential bidirectional long short-term memory network (Δ-BiLSTM). VMD decomposes the bus load sequence into intrinsic mode functions (IMFs), residuals are adaptively smoothed using LOWESS, and effective channels are selected through correlation-based redundancy control. The Δ-target learning strategy enhances the modeling of ramping dynamics and abrupt transitions, while Bayesian optimization and time-sequenced validation ensure reproducibility and stable training. Case studies on coastal-grid bus load data demonstrate substantial improvements in accuracy. In single-step forecasting, RMSE is reduced by 65.5% relative to ARIMA, and R² remains above 0.98 for horizons h = 1–3, with slower error growth than LSTM, RNN, and SVM. Segment-wise analysis further shows that, for $h=1$, the RMSE on the fluctuation, stable, and peak segments is reduced by 69.4%, 62.5%, and 62.4%, respectively, compared with ARIMA. The proposed Δ-BiLSTM exhibits compact error distributions and narrow interquartile ranges, confirming its robustness under peak-load and highly volatile conditions. Furthermore, the framework’s design ensures both transparency and reliable training, contributing to its robustness and practical applicability. Overall, the VMD–LOWESS–Δ-BiLSTM framework achieves superior accuracy, calibration, and robustness in complex, noisy, and non-stationary environments. Its interpretable structure and reproducible training protocol make it a reliable and practical solution for short-term bus load forecasting in modern distribution networks. Full article

Bidirectional electric vehicle (EV) charging represents an opportunity to leverage EVs as flexible energy assets within the power system. By enabling controlled power flow in both directions, bidirectional charging unlocks a wide range of grid services, thereby enhancing grid stability as the energy sector decarbonizes. This paper presents a comprehensive experimental evaluation of bidirectional charging systems (EVCS), focusing on response dynamics and controllability delays critical for grid services. A real ISO 15118–20–enabled EV and an EV emulator were used to conduct tests across configurations, utilizing the Watt & Well 22 kW bidirectional charging bay. The study compares CCS2 and CHAdeMO protocols under varying configuration conditions. Results show that modern chargers achieve sub-second responsiveness, with local communication delays typically below 0.4 s and ramping times around 0.5 s. However, power flow reversals introduce an additional delay of approximately 1 s. These updated controllability metrics are essential for validating bidirectional charging in time-critical applications such as primary frequency regulation. The findings highlight the influence of voltage level and modular configuration on dynamic performance, underscoring the need to integrate external control path delays for full-stack validation. This work provides a foundation for modeling and deploying bidirectional EVCS in fast-response grid services. Full article

Improving living conditions, public services, and social safety nets in the aging residential areas is a core component of community renewal. Age-friendly development calls for integrated improvements in accessibility, safety, comfort, and aesthetics, which are essential for meeting the mobility needs of older adults and people with disabilities. Vertical transportation upgrades, especially elevators and barrier-free design, are critical interventions, yet the lack of a systematic evaluation framework has limited a comprehensive assessment of their effectiveness. This study aims to establish a comprehensive evaluation framework that tightly integrates age-friendly development with vertical transportation improvements, providing detailed guidance to support the renewal of aging residential communities. Methods: We adopted the PRISMA 2020 systematic review methodology, performing a structured search of the Web of Science Core Collection from 2014 to 2024. After applying rigorous inclusion and exclusion criteria, 61 studies were selected for in-depth analysis. Results: The review identifies four core dimensions—accessibility, safety, comfort, and aesthetics—that directly influence vertical transportation renovation outcomes. Key factors include step-free access such as ramps and slope compliance; elevator availability and reliability; lighting and anti-slip safety; waiting and riding comfort; and clear wayfinding through signage legibility. Innovation: Based on these findings, we propose an operational framework that not only defines these dimensions but also links them to measurable evaluation indicators and provides a step-by-step usage protocol. This framework enables policymakers and practitioners to design evidence-based renewal strategies, ensure equitable mobility for vulnerable groups, and promote sustainable, inclusive communities. The findings of this study can serve as a reference for future policy formulation, design practices, and empirical research on sustainable and age-friendly community renewal. Full article

Background: High-performance tennis exposes players to repetitive high-load strokes and abrupt directional changes, which substantially increase musculoskeletal injury risk. This systematic review synthesized evidence on epidemiology, risk factors, and physiotherapy-led preventive strategies in elite adolescent and adult players. Methods: Following a PROSPERO-registered protocol, MEDLINE, Web of Science, and Scopus were searched (2011–2024) for observational studies reporting epidemiological outcomes in high-performance tennis. Methodological quality was appraised with NIH tools, and certainty of evidence was graded with GRADE. Results: Thirty-seven studies met inclusion criteria: 16 in adolescents, 18 in adults, and 3 mixed. Incidence ranged from 2.1 to 3.5 injuries/1000 h in juniors and 1.25 to 56.6/1000 h in adults. Seasonal prevalence was 46–54% in juniors and 30–54% in professionals. Lower-limb trauma (48–56%) predominated, followed by lumbar (12–39%) and shoulder overuse syndromes. Across age groups, abrupt increases in the acute-to-chronic workload ratio (≥1.3 in juniors; ≥1.5 in adults) were the strongest extrinsic predictor of injury. Intrinsic contributors included reduced glenohumeral internal rotation, scapular dyskinesis, and poor core stability. Three prevention clusters emerged: (1) External load control, four-week “ramp-up” strategies reduced injury incidence by up to 21%; (2) Kinetic-chain conditioning, core stability plus eccentric rotator-cuff training decreased overuse by 26% and preserved shoulder mobility; and (3) Technique/equipment adjustments, grip-size personalization halved lateral epicondylalgia, while serve-timing modifications reduced shoulder torque. Conclusions: Injury risk in high-performance tennis is quantifiable and preventable. Progressive load management targeted kinetic-chain conditioning, and tailored technique/equipment modifications represent the most effective evidence-based safeguards for adolescent and adult elite players. Full article

Cardiopulmonary exercise testing (CPET) is recommended as part of routine care in people with congenital heart disease. A significant difference has been observed in many CPET parameters, depending on the ergometer and exercise protocol used. The aim of this study is to investigate such differences in Fontan patients. All Fontan patients (<40 years old, NYHA class I/I–II) underwent two consecutive CPETs on different ergometers (treadmill with ramped Bruce protocol versus cycle ergometer with ramp protocol) within less than 12 months. The exclusion criterion was the presence of significant clinical/anthropometric changes between the two tests. Anthropometric, surgical, clinical, electrocardiogram (ECG) and CPET data were collected. 47 subjects were enrolled (25 males, mean age 16.4 at first test). Peak heart rate (HR) tended to be higher on the treadmill (p = 0.05 as % of predicted, p = 0.062 in absolute value). Peak oxygen consumption (VO₂) (mL/min, mL/kg/min, and % of predicted) was significantly higher on the treadmill (p < 0.01), as well the VO₂ at the ventilatory anaerobic threshold (VAT) and the peak oxygen pulse. A different kinetics of the oxygen pulse wave was observed in the same patient comparing the two testing modalities. Maximal respiratory-exchange-ratio values (>1.1) were reached more frequently on the cycle ergometer (p < 0.001). The minute ventilation–carbon dioxide output slope (VE/VCO₂ slope) was not different between the two tests (p = 0.400). Many parameters of CPET may differ depending on the ergometer used. These should be considered in clinical evaluation of Fontan patients and when exercise is to be prescribed. Full article

Laboratory-based assessment of cardiorespiratory function is a widely applied method in sports science. Most performance evaluations focus on oxygen uptake parameters. Despite the well-established concept of oxygen deficit introduced by Hill in the 1920s, relatively few studies have examined its behavior during submaximal exercise, with limited exploration of deficit dynamics. The present study aimed to analyze the behavior of oxygen deficit in young female handball players (N = 42, age: 15.4 ± 1.3 years) during graded exercise. Oxygen deficit was estimated using the American College of Sports Medicine (ACSM) algorithm, restricted to subanaerobic threshold segments of a quasi-ramp exercise protocol. Cardiorespiratory parameters were measured with the spiroergometry test on treadmills, and body composition was assessed via Dual Energy X-ray Absorptiometry (DEXA). Cluster and principal component analyzes revealed two distinct athlete profiles with statistically significant differences in both morphological and physiological traits. Cluster 2 showed significantly higher relative VO₂ peak (51.43 ± 3.70 vs. 45.70 ± 2.87 mL·kg⁻¹·min⁻¹; p < 0.001; Cohen’s d = 1.76), yet also exhibited a greater oxygen deficit per kilogram (39.03 ± 16.71 vs. 32.56 ± 14.33 mL·kg⁻¹; p = 0.018; d = 0.80). Cluster 1 had higher absolute body mass (69.67 ± 8.13 vs. 59.66 ± 6.81 kg; p < 0.001), skeletal muscle mass (p < 0.001), and fat mass (p < 0.001), indicating that body composition strongly influenced oxygen deficit values. The observed differences in oxygen deficit profiles suggest a strong influence of genetic predispositions, particularly in cardiovascular and muscular oxygen utilization capacity. Age also emerged as a critical factor in determining the potential for adaptation. Oxygen deficit during submaximal exercise appears to be a multifactorial phenomenon shaped by structural and physiological traits. While certain influencing factors can be modified through training, others especially those of genetic origin pose inherent limitations. Early development of cardiorespiratory capacity may offer the most effective strategy for long-term optimization. Full article

Background: Anderson–Fabry disease (AFD) is a progressive lysosomal storage disorder characterized by systemic glycosphingolipid accumulation. While cardiac imaging plays a central role in disease monitoring, the relationship between structural myocardial changes and exercise capacity remains incompletely defined. This study aimed to evaluate functional impairment in AFD patients using cardiopulmonary exercise testing (CPET) and to determine whether limitations are primarily cardiac or extracardiac in origin. Methods: Thirty-one patients with genetically confirmed AFD were retrospectively enrolled from two tertiary centers. All underwent baseline clinical assessment, resting transthoracic echocardiography (TTE), spirometry, and symptom-limited CPET using a cycle ergometer and a 10 W/min ramp protocol. Echocardiographic parameters included the LVEF, global longitudinal strain (GLS), E/e′ ratio, TAPSE, and PASP. CPET measurements included the peak VO₂, anaerobic threshold (AT), VE/VCO₂ slope, oxygen pulse (VO₂/HR), and VO₂/watt ratio. Results: The mean age was 48.4 ± 17.6 years, with most patients classified as NYHA I. LVEF was preserved (62.3 ± 8.6%), and diastolic indices were within normal limits (E/e′ 7.1 ± 2.4), but GLS was impaired (11.3 ± 10.5%). CPET showed reduced peak VO₂ (18.6 ± 6.1 mL/kg/min; 71.4% predicted) and early AT (40.8%), with preserved ventilatory efficiency and oxygen pulse. VO₂/watt was mildly reduced, suggesting peripheral limitations despite intact central hemodynamics. Conclusions: Functional impairment is common in AFD patients, even with mild cardiac involvement. CPET reveals early systemic limitations not captured by standard imaging, supporting its role in phenotypic characterization and therapeutic decision-making. Full article

Background: ESC sports classification in 2020, based on cardiac morphological adaptations, may not fully reflect also the variations in functional parameters of athletes. This study aims to characterize CPET-derived physiological parameters in elite athletes according to the ESC classification and evaluate whether this morphological classification also corresponds to a functional categorization. Methods: Elite athletes underwent pre-participation screening before the 2023 European Games and 2024 Olympic Games. Athletes were classified into four categories (skill, power, mixed and endurance). CPET was performed on a cycle ergometer using a ramp protocol, with measurements of VO₂ max, heart rate, power output and ventilatory efficiency. Results: We enrolled 1033 athletes (46.8% females; mean 25.6 ± 5.2 years old) engaged in skill (14.1%), power (33.2%), mixed (33.3%) and endurance (19.4%) disciplines. O₂ pulse showed an incremental significant increase (p < 0.0001) among sport categories (skill 14.9 ± 3.8 mL/beat; power 17.5 ± 4.6 mL/beat, mixed 19 ± 4.3 mL/beat and endurance 22.7 ± 5.8 mL/beat). The lowest ${\dot{\mathrm{V}}\mathrm{O}}_2$max was observed in skill disciplines (36.3 ± 7.9 mL/min/kg) whilst endurance ones showed the highest values (52.4 ± 9.7 mL/min/kg) (p < 0.0001). ${\dot{\mathrm{V}}\mathrm{O}}_2$max was higher in power compared to mixed (42 ± 7.7 mL/min/kg vs. 40.5 ± 5.8 mL/min/kg, p = 0.005) disciplines with an overlapping amount between some mixed and power disciplines. No differences were found for VE max (p = 0.075). Conclusions: Our study provided values of CPET parameters in elite athletes. Significant differences in CPET parameters were observed among different sports disciplines, with endurance athletes showing the highest absolute and relative values in all parameters. An overlap amount was noted between mixed and power categories, especially for relative maximal oxygen consumption. Full article

Visible Light Communication (VLC) has the potential to advance Intelligent Transportation Systems (ITS). This study explores the current advancements of VLC in ITS applications that may enhance traffic flow, road safety, and vehicular communication performance. The potential, benefits, and current research trends of VLC in ITS applications are discussed first. Then, the state-of-the-art VLC technologies including overall concept, IEEE communication protocols, hybrid VLC systems, and software-defined adaptive MIMO VLC systems, are discussed. We investigated different potential applications of VLC in ITS, such as signalized intersection and ramp metering control, collision warning and avoidance, vehicle localization and detection, and vehicle platooning using vehicle–vehicle (V2V), infrastructure–vehicle (I2V), and vehicle–everything (V2X) communications. Besides, VLC faces several challenges in ITS applications, and these concerns, e.g., environmental issues, communication range issues, standards and infrastructure integration issues, light conditions and integration issues are discussed. Finally, this paper discusses various advanced techniques to enhance VLC performance in ITS applications, such as machine learning-based channel estimation, adaptive beamforming, robust modulation schemes, and hybrid VLC integration. With this review, the authors aim to inform academics, engineers, and policymakers about the status and challenges of VLC in ITS. It is expected that, by applying VLC in ITS, mobility will be safer, more efficient, and sustainable. Full article

AIM: Higher exercise blood pressure in adults correlates with many cardiometabolic markers. The aim of this study was to investigate the main determinants of longitudinal variations in exercise blood pressure in young athletes. METHODS: A longitudinal retrospective study was conducted on adolescent athletes who underwent at least two sport-related pre-participation screening visits, including exercise testing with a standardized incremental ramp protocol on treadmill. Blood pressure was assessed at rest (SBP_rest), at the 3rd minute of exercise (SBP_3min), and at peak exercise (SBP_peak). Predictors of blood pressure response (i.e., respective changes vs. baseline (Δ)) were determined by multivariate regression models after adjustment for age, sex, follow-up duration, related baseline SBP values, characteristics of sport, and ΔBMI. RESULTS: A total of 351 young athletes (mean age at baseline 13 ± 2 years, 54% boys, average follow-up duration 3.4 ± 2.2 years) were enrolled. BMI increased by 1.5 ± 1.8 kg/m² (p < 0.001) during follow-up. At baseline, mean SBP_rest was 103 ± 14 mmHg, mean SBP_3min 124 ± 18 mmHg, and mean SBPpeak 154 ± 23 mmHg. A significant between-visit increase in SBP_rest (ΔSBP_rest 7.0 ± 17.4 mmHg; p < 0.001), ΔSBP_3min (4.8 ± 11 mmHg, p < 0.001), and ΔSBP_peak (11.7 ± 24 mmHg, p < 0.001) was observed. ΔSBP_3min was significantly predicted by male sex (p < 0.01), baseline BMI (p < 0.01), ΔBMI (p < 0.01), and number of practiced sports (p < 0.05), whereas ΔSBP_peak was positively predicted by male gender (p < 0.01), baseline BMI (p < 0.05), and ΔBMI (p < 0.01) and negatively by baseline resting heart rate (p < 0.01). In a logistic regression model, ΔBMI was the only independent determinant of passing from a lower to an upper quartile of SBP_3min (p < 0.001), while ΔBMI and male sex were independent determinants of moving to a higher quartile of SBP_peak (p < 0.001). CONCLUSIONS: Increase in BMI during development and male sex are independent determinants of the increase in exercise blood pressure, both at light and maximal intensity, in a population of adolescent athletes. Full article

The maximal rate of fat oxidation (MFO, in g∙min⁻¹) and the relative exercise intensity at which it occurs (FAT_max, as %V̇O_2max) are indexes of metabolic flexibility. The time-consuming, graded exercise protocol required for MFO/FAT_max determination hinders the extensive use of these indexes for individualized exercise prescription and monitoring. Purpose: validate ramp testing for MFO and FAT_max measures in postmenopausal women. Methods: Seventeen healthy women (age: 54 ± 4 years, BMI 22 ± 3 kg·m⁻², and V̇O_2max 36.4 ± 5.3 mL·min⁻¹), who were 4 ± 3 years from menopause, performed on a cycle-ergometer, a ramp, and a graded incremental test. Based on V̇O₂ and respiratory exchange ratio from the ramp and graded protocol (i.e., the 5th minute of each step), MFO and FAT_max were determined. Data from the two protocols were compared using paired t-tests, linear regression, and Bland–Altman analysis. Results: The MFO measured with a ramp protocol was not different from (0.24 ± 0.09 vs. 0.20 ± 0.08 g·min⁻¹, p = 0.10), and moderately associated with, that of the graded protocol (r² = 0.46). FAT_max occurred at similar exercise intensity for both protocols (47.8 ± 5.1 vs. 47.5 ± 4.3 %V̇O_2max, p = 0.91, r² = 0.52). The comparison of MFO and FAT_max across the protocols yields a non-significant bias but a relatively large limit of agreement (respectively, 0.05 g·min⁻¹, LOA = −0.08, and 0.19 g·min⁻¹; 0.3 %V̇O_2max, LOA = −7.8, and 10.6 %V̇O_2max). Conclusions: In postmenopausal women, ramp testing offers a valid alternative to the graded protocol for identifying MFO and FAT_max. The availability of a time- and cost-efficient approach, which can be incorporated into standard ramp incremental testing, can facilitate using these indexes of metabolic flexibility in research and medicine. Full article

The assessment of the various skills of athletes is carried out in terms of their ability to perform sport-specific tasks. The cognitive abilities of the players have significance for their effectiveness. In volleyball, a player’s ability to react quickly appears to be crucial in responding to an opponent’s dynamic play. The aim of the study was to evaluate the changes in reaction time to light signals following warm-up and physical exercise. Eighteen volleyball players (15.58 ± 2.01 years) participated in the study. Four FITLIGHT Trainer^TM discs were placed on the wall facing the participant to conduct the reaction time test. The participant’s task was to react as quickly as possible to the illuminated disc by touching it with the palm of their hand. The procedure was repeated five times: before the warm-up, after the warm-up, and after each of the three agility tests. Friedman’s ANOVA showed statistically significant differences in reaction time between the tests (Chi² ANOVA = 61.23; p < 0.001). All tests performed after the warm-up according to the RAMP protocol showed statistically significantly better results than those before the warm-up (p ≤ 0.05). At the same time, no differences were observed between the tests performed after successive agility tests. The results indicated that a well-chosen warm-up plays an important role in shortening the time of visual-motor reaction to a light stimulus (RT). Subsequent studies should be expanded to include other research groups and assess other parameters. Full article

Background: This study assessed the effects of two distinct RAMP (Raise, Activate, Mobilize, Potentiate) protocols, mobility-focused and reactiveness-focused, on change of direction speed in police students (i.e., tactical athletes). Methods: A longitudinal design with two experimental and one control group was employed. The study sample consisted of 39 police students (aged 19.2 ± 0.2 yrs) who were randomly allocated into three equal groups of 13 participants (7 females and 6 males). Experimental groups were labeled as the mobility group or reactiveness group based on the type of RAMP protocol they performed. During the tactical physical education classes, the mobility group performed four complex mobility exercises, while the reactiveness group performed four exercises for trunk reactiveness. After the specific warm-up, both groups continued with syllabus activities. The control group performed only regular activities based on the study syllabus. All participants performed the Illinois Agility test unloaded (IAT) and loaded (10 kg vest [IATL]) and Functional Movement Screening (FMS) before and after 8 weeks of the applied protocols. Results: In general, improvements were observed across all participants in the IAT (p < 0.001), IATL (p < 0.001), and FMS (p < 0.001). The mobility protocol had a more substantial impact compared to the reactiveness protocol on the IAT (d = 0.55 vs. d = 0.40), IATL (d = 0.44 vs. d = 0.38), and FMS (d = 0.88 vs. d = −0.42). Additionally, the control group, which did not follow either RAMP protocol, did not show significant improvements. Conclusions: These results underscore the importance of incorporating targeted mobility training in the limited time available for strength and conditioning programs, as it improves occupationally relevant movement qualities such as change of direction speed ability. Prioritizing mobility training in young tactical athletes may offer broader benefits compared to reactiveness training. Full article