Universitatea Transilvania din Brasov

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Universitatea Transilvania din Brasov Open Access Repository

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Universitatea Transilvania din Brasov

Recent Submissions

Analysis of Ankle Mobility and Dynamic Valgus Knee in Runners With and Without Patellofemoral Pain Syndrome
(WILEY, 2026-02-26) Georgian Badicu
Introduction: Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal complaints among recre-ational runners, who commonly engage in various athletic activities. Thus, there is considerable discussion surrounding its riskfactors, including dynamic knee valgus (DKV), as well as ankle dorsiflexion restriction (ADR) in a closed kinetic chain. To date,no scientific studies have investigated both ADR and DKV during the execution of the Step‐Down Lateral Test (SDLT) in femalerunners with and without PFPS.Objective: To measure ankle dorsiflexion mobility and determine differences in the magnitude and frequency of dynamic kneevalgus during the SDLT in recreational female runners with and without patellofemoral pain syndrome.Methods: This was an analytical, observational, cross‐sectional study involving 40 amateur street runners, aged between 18 and45 years, divided into a symptomatic group (SG) and asymptomatic group (AG), with allocation performed by a blindedresearcher uninvolved in data collection and video analysis. The presence of patellofemoral pain was used to define groupallocation and was assessed by an orthopedic surgeon specialized in knee disorders, based on clinical history and physicalexamination. The outcome measures included the Weight‐Bearing Lunge Test to assess ankle dorsiflexion in a closed kineticchain, as well as two‐dimensional analysis of dynamic knee valgus during the SDLT. The statistical approach was descriptiveand analytical, using the Shapiro–Wilk test, Mann–Whitney U test, or Student's t‐test, as appropriate.Results: The final sample consisted of 40 runners, with 22 participants in the AG, while the SG had a total of 18 participants,with homogeneity between groups with respect to age, sex, height and body mass index. The mean DKV in the SG was 17.23° inthe symptomatic limb, while in the asymptomatic limb it was 17.35°, from the same group; and in the group without it was16.01° in the dominant limb. The mean dorsiflexion range of motion for the symptomatic group was 4.40 cm in the symptomaticlimb, and 3.99 cm in the asymptomatic limb, while the AG demonstrated a mean of 3.78 cm in the dominant limb. Therefore, nostatistically significant differences were observed between groups or between limbs (p > 0.05), suggesting that ankle dorsiflexionmobility and dynamic knee valgus during the SDLT do not differ between recreational female runners with and without PFPS. (PDF) Analysis of Ankle Mobility and Dynamic Valgus Knee in Runners With and Without Patellofemoral Pain Syndrome. Available from: https://www.researchgate.net/publication/407176102_Analysis_of_Ankle_Mobility_and_Dynamic_Valgus_Knee_in_Runners_With_and_Without_Patellofemoral_Pain_Syndrome [accessed Jul 20 2026].
Behavioral profiles and temporal patterns of problematic smartphone use: associations with sleep hygiene and physical activity in adolescents
(2025-07-10) Georgian Badicu
Background: Problematic smartphone use (PSU) is a heterogeneous behavior, yet little is known about how dominant-use profiles relate to sleep hygiene, physical activity, and temporal usage patterns in adolescents. Objective: To categorize adolescents with PSU into predefined dominant-use profiles and examine their associations with sleep hygiene, physical activity, and temporal smartphone-use patterns. Methods: A total of 220 Tunisian middle school students (aged 14–16 years) screening positive for PSU according to validated Smartphone Addiction Scale–Short Version cutoffs underwent one month of objective monitoring via iOS/Android tracking tools. Following data validation, 180 participants were categorized into four profiles: social media (n = 52), gaming (n = 50), streaming (n = 40), and fitness (n = 38). Associations with sleep hygiene (Sleep Hygiene Index [SHI]) and physical activity (Physical Activity Questionnaire for Adolescents [PAQ-A]) were examined. Results: Distinct behavioral profiles were associated with differences in health outcomes. Gaming and streaming profiles exhibited the highest total and late-night screen time, lowest physical activity, and poorest sleep hygiene (all p < 0.001), whereas the fitness profile demonstrated the most favorable pattern. Late-night screen time was associated with additional variance in SHI scores after adjustment for profile membership and demographics (standardized β = 0.42, p < 0.001). Conclusion: Adolescent PSU manifests in distinct behavioral profiles with varying health-related associations. Nocturnal gaming and streaming are associated with poorer outcomes, potentially informing prevention efforts prioritizing usage patterns and timing over aggregate screen time. Consequently, digital well-being interventions may need to be profile-specific and time-sensitive.
Associations between generative AI use frequency, technology acceptance, attitudes toward AI, and reported learning preference patterns among students in physical education classes
(Frontiers, 2026-06-15) Alecu Stefan; Onea Gheorghe Adrian
Introduction: Physical education combines embodied practice with cognitive learning, yet generative artificial intelligence is increasingly used as an academic support tool. Limited evidence explains how this technology influences students’ motivation, learning preferences, and acceptance in authentic PE contexts. This study investigated the relationships between generative AI use, VARK learning styles, and Technology Acceptance Model beliefs among undergraduate physical education students. Methods: A cross-sectional survey was conducted with 1,084 full-time PE undergraduates (age 19–28 years). Participants completed PE-adapted instruments assessing learning preferences (VARK), technology acceptance (perceived usefulness, perceived ease of use, attitude toward using AI), and attitudes toward generative AI (interest, behavioral intention, perceived safety). Data were analyzed using descriptive statistics, reliability testing, ANOVA, and multiple regression models. Results: Students reported moderate acceptance of generative AI and generally positive attitudes toward its academic use. Kinesthetic learning remained the dominant preference, consistent with the movement-based nature of PE. However, higher AI usage frequency strongly predicted stronger visual and reading-writing preferences and lower kinesthetic orientation (β = .34–.40; β = −.39, p < .001). Significant differences emerged across learning-style groups for all TAM and AI attitude dimensions (p < .001, η² = .086–.142). Regression analysis showed that perceived usefulness, ease of use, and positive attitudes toward AI were the strongest predictors of AI usage, explaining 48% of variance. Frequent AI engagement also predicted clearer learning profile structure (β = −.62, p < .001). Conclusions: Generative AI represents a meaningful influence on learning processes in higher education physical education. While kinesthetic learning remains central, increased AI engagement aligns with shifts toward digitally mediated learning modalities. Technology acceptance beliefs strongly shape adoption behavior, suggesting that pedagogically grounded integration is needed to support diverse learners, particularly those with kinesthetic preferences.
Copper-Doped Silicate Porous Architectures for Hard Tissue Engineering
(MDPI AG, 2026-07-09) Cristea, Cristina; Puscasu, Maria Eliza; Isopencu, Gabriela Olimpia; Oprea, Ovidiu Cristian; Surdu, Vasile Adrian; Bacalum, Mihaela; Moisa, Roberta; Jinga, Sorin Ion; Busuioc, Cristina
Porous silicate scaffolds represent a promising class of grafting materials for hard tissue engineering due to their superior bioactivity, adjustable degradation rates, and ability to stimulate both osteogenesis and angiogenesis. In this work, scaffolds based on an akermanite-targeted (Ca2MgSi2O7) starting composition, including copper-doped variants, were synthesized using sol–gel and combustion routes, followed by 3D printing to achieve porous architectures with controlled pore size and interconnectivity. The powders were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermal analysis to evaluate their morphology, composition, and crystalline phases. The scaffolds were further assessed in terms of bioactivity by immersion in simulated body fluid (SBF), antibacterial activity, and in vitro cellular response. The results confirmed that copper doping enhanced antibacterial properties, while maintaining favorable biological behavior. Comparative analysis revealed differences between the two synthesis methods, with sol–gel providing more homogeneous structures and combustion leading to highly porous morphologies. These findings highlight copper-doped silicate scaffolds as promising candidates for bone tissue regeneration, combining architectural integrity with biological functionality.
Gold-Backed Cryptocurrencies, Precious Metals, and Hedging Performance: Evidence from Dynamic Dependence Structures
(2026-07-08) Yasmine Snene Manzli, Oana Panazan, Ahmed Jeribi, Catalin Gheorghe
This study compares gold-backed and conventional cryptocurrencies in terms of dependence structures and hedging effectiveness relative to precious metals. Daily data for gold, silver, cryptocurrencies, gold-backed cryptocurrencies, and USD-backed stablecoins from July 2020 to March 2026 are analyzed using a multivariate stochastic volatility framework with a grouped factor structure. Gold-backed cryptocurrencies move closely with gold and silver and provide meaningful hedging benefits. Conventional cryptocurrencies present weaker and less stable relationships with precious metals, reducing hedging potential. Important differences emerge between gold and silver, suggesting that precious metals should not be treated as a homogeneous asset class. Gold-backed cryptocurrencies appear much more closely aligned with precious metals than conventional cryptocurrencies. Additional analyses show that hedging effectiveness increases substantially during periods of elevated volatility, particularly for PAXG and XAUT, indicating stronger risk-reduction benefits under stressed market conditions. Robustness tests using SPDR Gold Shares (GLD) confirm the stability of the main findings. The findings are relevant for portfolio diversification, hedging decisions, and risk management.