Miguel Rodal

This study investigated balance control during the half squat by analyzing the relationship between the center of mass (CoM) and the center of pressure (CoP) in five experienced male weightlifters performing segmented squats at five load levels (20–80% 1 RM) across four Power-Based Training (PBT) exercises. The area of the 95% confidence ellipse was quantified using the Vicon motion capture system in conjunction with AMTI force plates. Given the small sample size (n = 5), a dual inference approach was implemented—frequentist repeated-measures analysis of variance (ANOVA) complemented by a unified adaptive Bayesian hierarchical model—to mitigate Type II error in low-power scenarios. Regarding the movement phase, a marked effect on center of pressure (CoP) stability was observed, as evidenced by both statistical approaches (frequentist: F(1.65, 6.59) = 19.44, p = 0.002, ηp² = 0.829; Bayesian: P(β_phase < 0) > 0.999). Although external load did not reach statistical significance in the frequentist analysis (p = 0.177, achieved power = 0.27), the Bayesian model provided moderate evidence of a positive impact (β_load = 0.059, 95% HDI [0.005, 0.115], p = 0.981). The area of the center of mass (CoM) ellipse showed no effects of interest. Limb asymmetries were significant and consistent throughout the experiment (frequentist: 48.01 ± 30.13%; Bayesian: 69.48%, 95% HDI [55.86%, 81.44%], P(AI > 20%) = 1.000) and were not modulated by the experimental condition. CoP-CoM coupling was stronger in the mediolateral direction than in the anteroposterior direction. The findings reveal that phase is the primary factor in postural stability, exerting a modest positive influence discernible only through low-powered probabilistic inference, and that the dual framework strengthens inferential robustness in small-sample biomechanical studies. Confirmatory studies with larger samples are recommended.

Traditional biomechanical research has focused on joint mechanics and the be-havior of the center of mass (CoM); however, the dynamics of the center of pressure (CoP) and the neuromuscular strategies that support stability under load remain un-derexplored. This study examined balance control during the back half squat by ana-lyzing the relationship between the CoM and the CoP in five experienced male weightlifters performing segmented squats at five load levels (20–80% 1RM). Vicon force platforms and motion capture systems were used to quantify the area of the 95% confidence ellipse. Due to the small sample size (n = 5), a dual inferential framework was used: frequentist repeated-measures ANOVA supplemented with unified adaptive Bayesian hierarchical modeling. The phase of the motion showed a strong effect on the stability of the CoP in both frames (frequentist: F(1.65, 6.59) = 19.44, p = 0.002, ηp² = .829; Bayesian: P(β_phase2 < 0) > 0.999). The external load was not significant in the frequentist analysis (p = 0.177), but the subsequent Bayesian analysis gave moderate evidence of a positive load effect (β_load = 0.059, 95% HDI [0.005, 0.115], P=0.981). The area of the CoM ellipse did not show significant effects in either frame. Limb asym-metries were substantial and stable (frequentist: 48.01 ± 30.13%; Bayesian: 69.48%, 95% HDI [55.86%, 81.44%], P(AI > 20%) = 1.000), with no condition-dependent modulation. CoP-CoM coupling was stronger in the mediolateral than the anteroposterior direction in both frames. These results suggest that phase is the main factor influencing pressure point stability, that loading may have a moderate positive effect detectable only with low-power probabilistic techniques, and that the dual framework improves the ro-bustness of conclusions in biomechanical research with small samples. Confirmatory studies with larger sample sizes are needed.

Serotonin is a neurotransmitter that plays a crucial role in mood regulation and has several health-related functions in humans. Physical exercise (PE) has been proposed as a potential non-pharmacological strategy to modulate serotonin levels. Objective: This systematic review and meta-analysis aimed to investigate the effect of PE on circulating serotonin concentrations. Methods: Following PRISMA guidelines, a systematic search was conducted in PubMed, Web of Science, and Scopus, identifying 938 records. Randomized controlled trials with a PE intervention group and a non-PE usual care control group that meet the inclusion criteria were selected. Data were synthesized using a random-effects meta-analysis with standardized mean differences (SMD), and sensitivity analyses were performed using alternative pre–post correlation assumptions (r = 0.6–0.9). Study quality was assessed using the PEDro scale. Results: Five randomized controlled trials comprising 116 participants, all of them females, were included. The pooled analysis showed a non-significant effect of PE on circulating serotonin levels (SMD 1.48; p = 0.135; 95% CI −0.46 to 3.42), with extremely high heterogeneity (I² = 94.63%). Sensitivity analyses produced similar non-significant results and consistently high heterogeneity, indicating robustness of the original model. Methodological quality ranged from acceptable to good (PEDro scores 4–7). Conclusions: Current evidence, derived exclusively from female participants, does not support a significant effect of PE on serum or plasma serotonin levels. The substantial heterogeneity among studies and the generally moderate methodological quality limit the strength of the conclusions and generalizability of the conclusions. Further, high-quality randomized controlled trials with standardized measurement protocols are needed to clarify the influence of exercise on circulating serotonin levels.

Background: It is estimated that following acute SARS-CoV-2 infection, about 10% of people experience persistent symptoms lasting more than 3 to 4 weeks, a condition known as long COVID syndrome. Amongst its various sequelae is impairment of physical function or functional ability. Given the growing social impact of this condition, the dissemination of knowledge in this area is essential. Bibliometric analysis provides valuable information on research trends and hotspots, helping to guide future studies and inform evidence-based interventions. Aims: The aim of this study was to conduct a bibliometric analysis of research on long COVID syndrome and Physical Function. Method: A total of 213 single documents indexed in the Scopus (205) and WOS core collection (181) database were analysed using the traditional laws of bibliometrics. Results: It was found that annual publications have experienced exponential growth from 2020 to 2024, based on the data available at the time of the bibliographic search. Amongst the prolific authors, four production clusters were found, with Eleuterio A. Sánchez-Romero emerging as the most productive author. Spain and Brazil were the countries with the highest number of publications. The journals of the MDPI publishing house contributed the most papers to the object of study, especially the Journal of Clinical Medicine and the International Journal of Environmental Research and Public Health. Rehabilitation, fatigue, quality of life, and exercise were four of the main keywords used by the authors. Conclusions: The observed growth in publications suggests increasing research attention to long COVID syndrome and physical function; however, further research is still needed to establish physical function assessment protocols, patient profiles, and effective exercise-based rehabilitation programmes.

This study investigates the joint mechanical power (JMP) distribution in the half squat (HS) exercise through the Power-Based Training (PBT) framework, with the primary aim of providing preliminary methodological validation of this analytical approach and illustrating its capacity to characterize joint contributions across movement phases and load levels. Five professional weightlifters performed HS under five progressive loads (20–80% 1RM), while kinematics and kinetics were recorded with a Vicon motion capture system and force platforms. JMP at the hip, knee, and ankle was analyzed in four distinct movement phases. Results indicated that joint contributions varied with load and phase. Under light loads the knee tended to produce most power. As load increased, contributions shifted proximally: the hip increased both absorption and production, and the ankle’s relative contribution grew in the final lifting phase. The main eccentric (lowering deceleration) and concentric (lifting acceleration) phases concentrated the highest JMP values, though differences between phases diminished at higher loads, suggesting a more homogeneous effort distribution. These findings support the feasibility of the PBT framework for methodological joint-level analysis. Given the pilot scope and purposive elite sample, results are not intended for population inference but inform about methodological applications in training, rehabilitation, and injury-risk assessment.

Advances in technology and changes in the way people entertain themselves have made video games a cultural agent on a par with more traditional games, including language learning. In addition, the use of video games in education is becoming increasingly common and numerous benefits associated with their use have been discovered. The aim of this article is to analyze the search trends in studies dealing with the use of video games in language learning. To this end, a bibliometric analysis was carried out by applying the traditional laws of bibliometrics (Price’s law, Bradford’s law of concentration, Lotka’s law, Zipf’s law and h-index) to documents published in journals indexed in the Core Collection of the Web of Science (WoS). Annual publications between 2009 and 2022 show an exponential growth R2 = 86%. The journals with the most publications are Computer assisted language learning (Taylor & Francis) and Computers and Education (Elsevier). Jie Chi-Yang and Gwo Jen-Hwan were the most cited authors. The United States and Taiwan were the countries with the highest scientific output. The use of video games in language learning has been of particular interest in recent years, with benefits found for students who use them in their classes, although more research is needed to establish criteria and requirements for each video game for its intended purpose.

This study investigates the joint mechanical power (JMP) distribution in the half squat (HS) exercise through the Power-Based Training (PBT) framework, aiming to validate its methodological usability and its suitability to characterize joint contributions across movement phases and load levels. Five professional weightlifters performed HS under five progressive loads (20–80% 1RM), while kinematics and kinetics were recorded with a Vicon motion capture system and force platforms. JMP at the hip, knee, and ankle was analyzed in four distinct movement phases. Results revealed that joint contributions varied significantly with both load and phase: under light loads, the knee contributed most to power production, whereas higher loads elicited a proximal shift, with the hip showing greater power absorption and production, and the ankle gaining relative contribution in the final lifting phase. The main eccentric (lowering deceleration) and concentric (lifting acceleration) phases concentrated the highest JMP values, though differences between phases diminished at higher loads, indicating a more homogeneous effort distribution. These findings highlight the adaptive inter-joint dynamics and support the PBT framework as a rigorous, replicable tool for biomechanical analysis. The results have direct implications for designing training, rehabilitation, and injury-prevention programs based on joint-specific mechanical demands.

Muscular strength is an essential factor in sports performance and general health, especially for optimizing mechanical power, as well as for injury prevention. The present study biomechanically characterized the half squat (HS) using a systemic structural approach based on mechanical power, called Power-Based Training (PBT), through which four phases of the movement were determined (acceleration and deceleration of lowering and lifting). Five weightlifters from the Mexican national team (categories U17, U20, and U23) participated, who performed five repetitions per set of HS with progressive loads (20%, 35%, 50%, 65%, and 80% of the one repetition maximum). The behavior of the center of mass of the subject–bar system was recorded by photogrammetry, calculating position, velocity, acceleration, mechanical power, and mechanical work. The results showed a significant reduction in velocity, acceleration, and mechanical power as the load increases, as well as variations in the duration and range of displacement per phase. These findings highlight the importance of a detailed analysis to understand the neuromuscular demands of HS and to optimize its application. The PBT approach and global center of mass analysis provide a more accurate view of the mechanics of this exercise, facilitating its application in future research, as well as in performance planning and monitoring.

Muscular strength is an essential factor in sports performance and general health, especially for optimizing mechanical power, as well as for injury prevention. The present study biomechanically characterized the half squat (HS) using a systemic-structural approach based on mechanical power, called Power-Based Training (PBT), through which four phases of the movement were determined (acceleration and deceleration in descent, acceleration and deceleration in ascent). Five weightlifters from the Mexican national team (categories U17, U20 and U23) participated, who performed 5 repetitions per serie of HS with progressive loads (20%, 35%, 50%, 65% and 80% of the 1RM). The behavior of the CoM of the subject-bar system was recorded by photogrammetry, calculating position, velocity, acceleration, mechanical power and mechanical work. The results showed a significant reduction in velocity, acceleration and mechanical power as the load increases, as well as variations in the duration and range of displacement per phase. These findings evidence the importance of a detailed analysis to understand the neuromuscular demands of MS and to optimize its training. The PBT approach and global CoM analysis provide a more accurate view of the mechanics of this exercise, facilitating its application in future research, as well as in performance planning and monitoring.

Advances in technology and changes in the way people entertain themselves have made video games a cultural agent on a par with more traditional games. In addition, the use of video games in education is becoming increasingly common and numerous benefits associated with their use have been discovered. The aim of this article is to analyze the search trends in studies dealing with the use of video games in language learning. To this end, a bibliometric analysis was carried out by applying the traditional laws of bibliometrics (exponential growth law, Bradford's law of concentration, Lotka's law, Zipf's law, etc.) to documents published in journals indexed in the Core Collection of the Web of Science (WoS). Annual publications between 2009 and 2022 show an exponential growth R2=86%. The journals with the most publications are Computer assisted language learning (Taylor & Francis) and Computers and Education (Elsevier). Jie Chi-Yang and Gwo Jen-Hwan were the most cited authors. The United States and Taiwan were the countries with the highest scientific output. The use of video games in language learning has been of particular interest in recent years, with benefits found for students who use them in their classes, although more research is needed to establish criteria and requirements for each video game for its intended purpose.