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22 result(s) for "Jorquera-Aguilera, Carlos"
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Effects of Beta-Alanine Supplementation on Physical Performance in Aerobic–Anaerobic Transition Zones: A Systematic Review and Meta-Analysis
Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic–anaerobic transition zones is scarce and the results controversial. The aim of this systematic review and meta-analysis is to analyze the effects of BA supplementation on physical performance in aerobic–anaerobic transition zones. At the same time, the effect of different dosages and durations of BA supplementation were identified. The search was designed in accordance with the PRISMA® guidelines for systematic reviews and meta-analyses and performed in Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2010 and 2020. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the Time Trial Test (TTT) and Time to Exhaustion (TTE) tests, the latter separated into the Limited Time Test (LTT) and Limited Distance Test (LDT). The analysis was carried out with a pooled standardized mean difference (SMD) through Hedges’ g test (95% CI). Nineteen studies were included in the systematic review and meta-analysis, revealing a small effect for time in the TTT (SMD, −0.36; 95% CI, −0.87–0.16; I2 = 59%; p = 0.010), a small effect for LTT (SMD, 0.25; 95% CI, −0.01–0.51; I2 = 0%; p = 0.53), and a large effect for LDT (SMD, 4.27; 95% CI, −0.25–8.79; I2 = 94%; p = 0.00001). BA supplementation showed small effects on physical performance in aerobic–anaerobic transition zones. Evidence on acute supplementation is scarce (one study); therefore, exploration of acute supplementation with different dosages and formats on physical performance in aerobic–anaerobic transition zones is needed.
Effect of Intensity and Duration of Exercise on Gut Microbiota in Humans: A Systematic Review
(1) Background: The gut microbiota might play a part in affecting athletic performance and is of considerable importance to athletes. The aim of this study was to search the recent knowledge of the protagonist played by high-intensity and high-duration aerobic exercise on gut microbiota composition in athletes and how these effects could provide disadvantages in sports performance. (2) Methods: This systematic review follows the PRISMA guidelines. An exhaustive bibliographic search in Web of Science, PubMed, and Scopus was conducted considering the articles published in the last 5 years. The selected articles were categorized according to the type of study. The risk of bias was assessed using the Joanna Briggs Institute’s Critical Appraisal Tool for Systematic Reviews. (3) Results: Thirteen studies had negative effects of aerobic exercise on intestinal microbiota such as an upsurge in I-FABP, intestinal distress, and changes in the gut microbiota, such as an increase in Prevotella, intestinal permeability and zonulin. In contrast, seven studies observed positive effects of endurance exercise, including an increase in the level of bacteria such as increased microbial diversity and increased intestinal metabolites. (4) Conclusions: A large part of the studies found reported adverse effects on the intestinal microbiota when performing endurance exercises. In studies carried out on athletes, more negative effects on the microbiota were found than in those carried out on non-athletic subjects.
Block strength training based on age-related functional consequences in older women
Strength training is a form of healthy ageing in older women. Although recommendations currently exist, some are very broad or fail to cover the needs of aging. Therefore, the purpose of this study was to analyze the effects of blocks strength training based on age-related functional consequences on functional performance in older adult women. 82 community-dwelling older women (70.17 ± 6.04 y) were randomly assigned to either experimental (n = 40) or control (n = 42) group. Experimental group performed a Block Strength Training (BST) program based on strength, power, and muscular endurance, and different level of effort for 9 weeks, and control maintained daily routine with physical activity recommendations. Functional performance was assessed using absolute handgrip strength [AHS], timed up and go [TUG], two-minutes step test [2MST], five times stand-to-sit test [5-SST], 6-m walking speed test [6-WS] pre-post intervention. Statistical analyses were performed using two-way ANOVA (Time*Group) and effect size (partial eta-squared, ŋ P2 ) with a significance level of p  < 0.05. BST improved functional performance in the protocols of AHS (21.51 vs. 23.07-kg; + 7%), TUG (8.22 vs. 7.29-sec; + 11%), 2MST (78.76 vs. 97.18-steps; + 23%), 5-SST (12.68 vs. 9.43-sec; + 26%), and 6-WS (1.16 vs. 1.36- m·s -1 ; + 17%) compared to control (19.31 vs. 19.66-kg; 8.94 vs. 9.26-sec; 62.68 vs. 63.73-steps; 13.99 vs. 14.25-sec; 1.06 vs. 1.06-m·s -1 , respectively) in a Time*Group interaction effect ( p  < 0.01; ŋ P2   > 0.11). This BST is effective in improving overall functional performance and thus reducing the risk of physical frailty in community-dwelling older women. These findings strengthen the approach to exercise programming over recommendations, moving toward effective precision dosing for older adults.
Test-retest reliability of Latin American Group for Maturity (GDLAM) protocol in older women
Functional autonomy (FA) is a critical factor in determining the quality of life of older adults (OA), especially in the case of older women (OW), as they face a decline in FA in their later years of life. FA should be assessed early, using valid, reliable, and low-cost tests. This study evaluated the test-retest reliability of GDLAM and GDLAM autonomy index (GI) in OW. Thirty-nine OW (71.2 ± 6.50 years) participated in the study. A repeated measures design was used to compare the interday test-retest reliability of the five GDLAM tests (seconds) and the GI (points). The five tests represent activities of daily living, such as dressing or wandering around the house, while the GI provides a weighting of the results of the five tests. The analysis consisted of the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV). A CV ≤ 10% and an ICC ≥ 0.80 were considered acceptable reliability, whereas a CV ≤ 5% and an ICC ≥ 0.90 were considered high reliability. The outcome of the five tests, represented by the GI, showed high interday test-retest reliability (CV = 6.00% and ICC = 0.91). The results of this study demonstrate that the five tests of the GDLAM protocol and the GI have high interday test-retest reliability and good interday reproducibility. From a practical point of view, the GDLAM protocol allows the assessment of FA of community-dwelling OW, providing background for early diagnosis and, with it, the possibility of developing an individualized physical exercise prescription.
Effects of Non-Immersive Virtual Reality Exercise on Self-Reported Pain and Mechanical Hyperalgesia in Older Adults with Knee and Hip Osteoarthritis: A Secondary Analysis of a Randomized Controlled Trial
Background and Objectives: Osteoarthritis (OA) of the knee and hip is a major cause of pain and functional impairment. This study evaluated the effects of non-immersive virtual reality (NIVR) combined with conventional physical therapy (CPT) on pain intensity, mechanical hyperalgesia, and perceived recovery in older adults with OA. Materials and Methods: Sixty older adults with mild-to-moderate knee or hip OA were randomly assigned to a NIVR group (NIVR-G; n = 30) or a CPT group (CPT-G; n = 30). Both groups completed 30 sessions over 10 weeks (3 sessions/week). The NIVR-G performed 20 minutes of exergames integrated into CPT. Pain intensity was assessed using the Visual Analog Scale (VAS), and mechanical hyperalgesia was evaluated through pressure pain thresholds (PPTs). Secondary outcomes included the Global Rating of Change (GRoC) and the minimal clinically important difference (MCID) for the VAS. This study is a secondary analysis of a randomized controlled trial registered at ClinicalTrials.gov (ID: NCT05839262). Results: The NIVR-G demonstrated significant reductions in pain intensity after 30 sessions (p < 0.05, d = 1.50), with greater improvements compared to the CPT-G (p < 0.05, d = 1.17). The MCID for the VAS was established at 9.2 mm, with a higher proportion of responders in the NIVR-G (p < 0.05). The NIVR-G also reported superior recovery perception on the GRoC scale (p < 0.05). No significant changes in PPTs were observed in either group. However, the improvements in the NIVR-G diminished four weeks post-intervention. Conclusions: NIVR exergames combined with CPT significantly reduced pain intensity, improved perceived recovery, and resulted in a higher proportion of responders compared to CPT alone. These findings support the use of NIVR as an effective adjunct to CPT in older adults with OA; however, further research is needed to optimize its long-term benefits.
Hydration Status of Elite Youth Soccer Players: Training Versus FIFA Competition
Optimal hydration is crucial for maintaining health and athletic performance in young soccer players. This requires constant monitoring by medical and sports teams during training sessions and competitions. Objective: The purpose of this study was to examine hydration status based on variations in body weight, fluid intake, and urine specific gravity during three training sessions and a FIFA competition in elite U-17 youth soccer players, national team members. Methods: Twenty-one elite soccer players, aged 17.2 ± 0.29 years, with a body weight of 72.1 ± 6.95 kg and a height of 1.80 ± 0.05 m, participated in the study. To determine hydration status, percentage weight loss, fluid intake, and urine density were measured during three training sessions and one FIFA-level competition. Results: Differences in body weight were observed in two of the training sessions, with greater variation in the competition (3.5% of BW, p < 0.001). Significant differences were found between weight losses in training sessions vs. matches. An increase in initial weight was associated with lower urine density. Regression coefficients showed that differences in body weight can predict urine density during training and competition (p < 0.05). A decrease in final body weight could be a valid indicator as a predictor of higher urinary density.
Effect of an Intra-Sets Variable Resistance Potentiation Protocol on Throwing Speed in Elite Female Handball Players
The peak velocity of an athlete’s throws is a determining factor for sports performance. The aim of this study was to analyze the effects of a post-activation performance enhancement (PAPE) protocol with functional electro-mechanical dynamometry (FEMD) on throwing velocity. Thirteen international-level female handball players voluntarily participated in the study. The PAPE protocol considered four sets of eight repetitions controlled by FEMD (four at 30% of 1RM followed by another four at 60% of 1RM). After each series, the athletes’ throwing velocity was measured. Significant differences (p < 0.01) were found in the effect size (ES), which measures the strength of the statistical relationship between two variables by group with the repeated measures ANOVA statistic with an effect size ω2 = 0.028. The effect size analysis identified measurements that are considered null for the baseline—PAPE 1 comparison and small baseline—PAPE 2, baseline—PAPE 3, and baseline—PAPE 4. When resistance is controlled during the run as with an FEMD device, only two sets of eight repetitions (four repetitions at 30% and four repetitions at 60% of 1RM) are required for the improvement of throwing speed in elite handball players.
The Effects of Maca (Lepidium meyenii Walp) on Cellular Oxidative Stress: A Systematic Review and Meta-Analysis
Lepidium meyenii Walp (LmW) or Maca, including its bioactive components such as macamides, among others, has demonstrated antioxidant effects. However, the effect size (ES) of LmW on oxidative stress has not been qualitatively described and calculated. The primary objective of this systematic review and meta-analysis was to review and qualitatively describe the studies published up to 2023 that supplemented LmW to control cellular oxidative stress; the secondary objective was to calculate the ES of the different interventions. The search was designed following the PRISMA® guidelines for systematic reviews and meta-analyses and performed in the Web of Science, Scopus, SPORTDiscus, PubMed, and MEDLINE until 2023. The selection of studies included randomized controlled trials, with tests and post-tests, both in vitro and in vivo in animals and humans. The methodological quality and risk of bias were evaluated with the CAMARADES tool. The main variables were reduced glutathione, glutathione peroxidase, superoxide dismutase, and malondialdehyde. The analysis was conducted with a pooled standardized mean difference (SMD) through Hedges’ g test (95% CI). Eleven studies were included in the systematic review and eight in the meta-analysis. They revealed a small effect for reduced glutathione (SMD = 0.89), a large effect for glutathione peroxidase (SMD = 0.96), a moderate effect for superoxide dismutase (SMD = 0.68), and a moderate effect for malondialdehyde (SMD = −0.53). According to the results, the phytochemical compounds of LmW effectively controlled cellular oxidative stress, mainly macamides. It was also determined that a higher dose of LmW generated a greater antioxidant effect. However, information concerning humans is scarce.
Caracteristicas antropométricas de futbolistas chilenos juveniles sub 14, sub 15 y sub 16
El fútbol es el deporte más practicado a nivel mundial. Esta popularidad se debe a que prácticamente cualquier persona lo puede jugar de manera amateur, pero a medida que se va profesionalizando se requiere la valoración de un perfil antropométrico que favorezca un rol determinado dentro del campo de juego. El objetivo del estudio fue comparar las características antropométricas de futbolistas chilenos juveniles sub 14, sub 15 y sub 16 de acuerdo con la posición de juego y la categoría. Se evaluaron a 180 futbolistas juveniles de sexo masculino con edades entre los 13 y 16 años, pertenecientes a las divisiones inferiores de los clubes: Audax Italiano, Cobresal y Magallanes de la Región Metropolitana de Chile. Los datos se consideraron estadísticamente significativos con p < .05. Se encontraron diferencias significativas en el peso, talla, sumatoria de 6 pliegues, kilogramos de piel, grasa, masa ósea, masa residual y en todas las longitudes corporales entre jugadores de distintas posiciones de juego. Asimismo, se encontraron diferencias estadísticas en el peso, talla, kilogramos de piel, grasa, masa ósea, músculo, masa residual y en todas las longitudes corporales menos en la radial-estiloidea entre jugadores de distintas categorías. Los resultados muestran la importancia de dividir a los futbolistas juveniles en un mayor número de roles posicionales al momento de definir las características antropométricas ideales según su ubicación en el terreno de juego. Las diferencias encontradas en la composición corporal entre categorías sugieren prestar atención al desarrollo madurativo al momento de promover a algún jugador a una división mayor.
Combined Impact of Creatine, Caffeine, and Variable Resistance on Repeated Sprint Ability in Young Soccer Players
There is evidence that both intra-serial variable resistance (I-sVR), as pre-activation within the post-activation performance enhancement cycle (PAPE), and creatine and caffeine supplementation increase athletic performance in isolation. However, the effect of the three conditioning factors on 30 m repeated sprint ability (RSA) performance in young soccer players is unknown. This study determined the summative and isolation effect of ergogenic aids and pre-activation in half-back squats (HBSs) with I-sVR on performance in an RSA test in young soccer players. Twenty-eight young soccer players were randomly assigned to either EG1 (n = 7, creatine + caffeine + I-sVR), EG2 (n = 7, creatine + placebo2 + I-sVR), EG3 (n = 7, placebo1 + caffeine + I-sVR), or EG4 (n = 7, placebo1 + placebo2 + I-sVR), using a factorial, four-group-matched, double-blind, placebo-controlled design. Creatine supplementation included 0.3 g/kg/day for 14 days, caffeine supplementation included 0.3 mg/kg per day, and pre-activation in HBS with I-sVR (1 × 5 at 30% 1RM [1.0–1.1 m/s] + 1 × 4 at 60% 1RM [0.6–0.7 m/s]). The RSA test and HBS outcomes were evaluated. Three-way ANOVA showed non-significant differences for the RSA test and HBS outcomes (p > 0.05). At the end of this study, it was found that the three ergogenic aids, together, do not generate a summative effect on the physical performance of young soccer players. However, it is important to analyze individual responses to these specific protocols.