Examinando por Autor "Jerez-Mayorga, Daniel"
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Ítem Age-dependent Knee Joint Isokinetic Profile in Professional Male Soccer Players(Australian International Academic Centre PTY LTD, 2022) Torres-Banduc, Maximiliano A.; Jerez-Mayorga, Daniel; Ojeda, Álvaro Huerta; Bishop, Chris; Ramirez-Campillo, RodrigoBackground: The knee-joint isokinetic profile (KJIP) injury risk factor may be modulated by chronological age, however, comparative data for elite male soccer players aged 25 years and older is lacking. Objective: To describe and compare the knee-joint isokinetic profile (KJIP) according to the chronological age of professional male soccer players. Method: In a cross-sectional study design, sixty-three soccer athletes from the first Chilean soccer division (A-series) were divided into younger and older groups (age ≤ 25 years; n = 35 and age > 25 years; n = 28, respectively). In both groups the IPKJ was assessed at 60°.s-1 in concentric mode. Results: The older group had lower extensor peak torque (p < .05). The younger group showed correlations between flexors peak torque and extensors mean power (p < .001). In the older group, flexors peak torque and flexors mean power were correlated. The flexors peak torque, total work, and mean power symmetric index (SI) exhibited values > 10 % for both groups. The extensors SI showed values > 10 % for mean power, although only in the older group. Conclusion: Several differences in the KJIP were noted between professional male soccer players aged ≤ 25 years and > 25 years. Current results offer injury prevention insights, discussed in the current manuscript. © 2022 The authors.Ítem Association Between Muscle Architecture and Muscle Quality Index in Sedentary Adults(Universidad de la Frontera, 2023) Lizama-Pérez, Rodrigo; Muñoz-Cofré, Rodrigo; Vidal-Seguel, Nicolás; Ríos, Ignacio Chirosa; Jerez-Mayorga, Daniel; Ríos, Luis ChirosaAssessment of muscl e qual i t y and architecture is important for understanding and quantifying muscle changes associated with aging and a sedentary lifestyle and provides information on the muscle's ability to generate strength, power, or function. The aims of the study were (I) to determine the association between muscle architecture parameters and muscle quality index (MQI) and (II) to determine the association between muscle architecture parameters and mean relative power in the sit-to-stand test (STS). Only muscle thickness (MT) showed a moderate association with MQI (r = 0.545). In contrast, both fascicle length (FL) and penile angle (PA) exhibited "very low" associations, which were not significant with the MQI. When examining the relationship between muscle architecture parameters and mean relative STS power, MT presented a "moderate" association (r = 0.444). However, both LF and PA showed "very low" and "low" associations, respectively, with a mean power relative to STS. In conclusion, these findings reinforce the idea that MT may be a relevant indicator of muscle quality and ability to generate power in the STS test. Specifically, an increase in MT was associated with an improvement in MQI and mean power relative to STS. © 2023, Universidad de la Frontera. All rights reserved.Ítem Comparative Analysis of Bilateral Deficits in Elbow Flexion Strength: Functional vs. Analytical Assessment(Multidisciplinary Digital Publishing Institute (MDPI), 2024-09) Pelayo-Tejo, Ignacio; Chirosa-Ríos, Luis; Escobar-Molina, Raquel; García-Ramos, Amador; del-Cuerpo, Indya; Chirosa-Ríos, Ignacio; Jerez-Mayorga, DanielBackground: this study aimed to identify the influence of postural stability on upper-limb bilateral deficit (BLD), and to compare the assessment of strength generated during elbow flexion functionally vs. analytically in the dominant and nondominant arms. Methods: Twenty men participated in two sessions to evaluate the maximum isometric strength of elbow flexion. This evaluation was performed unilaterally with the dominant arm, unilaterally with the non-dominant arm, and bilaterally, both in the sitting position (SiP) and the standing position (StP). Results: The BLD when peak force was considered was lower for StP (−6.44 ± 5.58%) compared to SiP (−10.73 ± 6.17%) (p = 0.007). Regarding peak force, statistically significant differences were observed for comparisons between dominance (p < 0.001) and Position*Dominance (p = 0.02), but mean force differences were only observed for the dominance factor (p < 0.001). Greater mean and peak forces were always produced bilaterally compared to unilaterally (p < 0.001). Conclusions: a decrease in postural stability by performing elbow flexion exercises in a standing position accentuates BLD of peak force.Ítem Comprehensive diagnosis in patients with morbid obesity; candidates for bariatric surgery and suggestions for preoperative treatment(Universidad Nacional de Colombia, 2017-07) Cofré-Lizama, Alfonso; Delgado-Floody, Pedro A.; Saldivia-Mansilla, Claudia; Jerez-Mayorga, DanielObjective The purpose of the study was to analyze and describe the psychological, metabolic, anthropometric and physical condition of obese candidates for bariatric surgery. This is in order to determine the preoperative intervention. Material and Methods The population is made up of 24 obese candidates for bariatric surgery; five men and 19 women between 21 and 60 years old. The sample type is non-probabilistic, with non-randomised subjects chosen conveniently and volunteers. Psychological, anthropometric, metabolic and physical condition variables were evaluated. Results The average age of participants corresponds to 41.0 years old. Low levels of empathic joy were observed. Anxiety symptoms presented an intermediate level: 62,5% presented minimal depression, 29,1% presented slight depression, and 8,4% presented considerable depression. Body weight averaged 99.1 kg, height 1.6 meters, Body Mass Index (BMI) 39.3, the percentage of fat mass and contour waist averaged 41.1 118.0 centimeters in that order. With regards to plasma levels (mg/dl), the following were obtained: total cholesterol 192.9, 120.0 LDL cholesterol, HDL cholesterol, 43.3, 182.3 triglycerides, glycerin to 105.9; and distance covered in 6 minutes was 511.9 meters. Conclusions The results provide information to determine best Preoperative intervention strategies; changing the lifestyles of patients, keeping the postoperative weight. © 2017, Universidad Nacional de Colombia. All rights reserved.Ítem Comprehensive eight-month intervention reduces weight and improves depression and anxiety levels in severe and morbid obesity(Universidad Nacional de Colombia, 2017) Cofre-Lizama, Alfonso; Delgado-Floody, Pedro; Angulo-Díaz, Pamela; Jerez-Mayorga, DanielIntroduction: Morbid obesity generates a considerable decrease in expectations and quality of life, which causes increased levels of depression and anxiety. Objective: The purpose of this research was to determine the effects of a comprehensive treatment program on weight loss and anxiety and depression levels of severe and morbid obese patients. Materials and methods: 4 men and 12 women with an average age of 34.0±26.0 years, and candidates for bariatric surgery were included in this study. 6 severe obese and 10 morbidly obese patients participated in a comprehensive eight-month treatment intervention. The following conditions were assessed pre- and post-intervention: weight, body mass index (BMI), waist circumference, cardiorespiratory capacity, anxiety and depression. Results: Postoperative weight and BMI decreased significantly (p< 0.001) by 12.28% and 12.30%, respectively, while waist circumference decreased by 11.67% (p< 0.001). In addition, respiratory capacity improved significantly (p< 0.001), and anxiety and depressive symptoms decreased significantly (p< 0.001). Conclusion: The comprehensive eight-month intervention had significant benefits for participants in weight loss and improved levels of anxiety and depression. For this reason, the intervention performed may be recommended for the treatment of this condition. © 2017, Universidad Nacional de Colombia. All rights reserved.Ítem Dynamometric Strength Profile of Hip Muscles in Youth Soccer Players(MDPI, 2023-01) Contreras-Díaz, Guido; Chirosa-Ríos, Luis Javier; Riego-Ruiz, Antonio; Intelangelo, Leonardo; Tuesta-Roa, Marcelo; Morales-Zúñiga, Jorge; Jerez-Mayorga, DanielBackground: Soccer is the most widely practiced sport in the world, demanding high-speed activities such as jumps, sprints and changes of direction. Therefore, having optimal levels of muscle strength improves performance and reduces the injury rate. Objectives: The objectives of our study were (i) to determine the dynamometric profile of hip muscle strength in young soccer players by position, evaluated at different isokinetic speeds, (ii) to describe the conventional and functional unilateral muscle strength ratios, (iii) to analyze the bilateral balance. Methods: Thirty-seven male soccer players (age 17.02 ± 0.92 years) participated in the study. Strength assessment was performed with a functional electromechanical dynamometer, and concentric and eccentric strength of abductors, adductors, extensors and hip flexors were measured bilaterally at 0.5 m/s and 1 m/s. Results: For eccentric right hip abduction at 0.5 m/s, defenders are significantly stronger than midfielders (p = 0.013) and stronger than forwards (p = 0.140). For eccentric right hip adduction at 0.5 m/s, defenders are significantly stronger than midfielders (p = 0.005) and stronger than forwards (p = 0.253), as for eccentric right hip adduction at 1 m/s, defenders are significantly stronger than midfielders (p = 0.014) and stronger than forwards (p = 0.084). There is a significant effect for the conventional strength ratio of left abduction/adduction at 1 m/s. The conventional strength ratio of forwards is significantly higher than that of defenders (p = 0.045) and higher than that of midfielders (p = 0.152). Conclusions: Concentric and eccentric hip strength values differ according to playing position. © 2023 by the authors.Ítem Effect of Antioxidant Supplementation on Markers of Oxidative Stress and Muscle Damage after Strength Exercise: A Systematic Review(MDPI, 2022-02) Canals-Garzón, Cristina; Guisado-Barrilao, Rafael; Martínez-García, Darío; Chirosa-Ríos, Ignacio Jesús; Jerez-Mayorga, Daniel; Guisado-Requena, Isabel MaríaBackground: The purpose of this systematic review was to determine the effect of antioxidant consumption on markers of oxidative stress and muscle damage after performing a muscle strength exercise. Methods: The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statements were followed. Four databases were used: Scopus, PubMed, WOS and SportDiscus. Methodological quality was assessed using the PEDro scale. Results: A total of 1709 articles were retrieved and following duplicate removal and application of exclusion criteria seven articles were reviewed. Supplementation with pomegranate juice alleviates oxidative stress, taurine reduces muscle damage, melatonin protects the skeletal muscles, blueberries decrease oxidation and oats mitigate muscle damage. Conclusions: Acute administration of antioxidants immediately before or during an exercise session can have beneficial effects, such as delay of fatigue and a reduction in the recovery period. Administration of antioxidant susbtances may reduce muscle damage and oxidative stress markers. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Ítem Effect of Phlebodium Decumanum on muscle damage, inflammation and cortisol during a precompetitive mesocycle in a National Volleyball Team(Federacion Espanola de Docentes de Educacion Fisica, 2023) García Verazaluce, Juan José; Guisado-Barrilao, Rafael; Figueroa, Elizabeth Llera; Hernández-Cruz, Germán; Rangel-Colmenero, Blanca R.; Ocaña-Peinado, Francisco M.; Hoyos-Flores, José Raúl; Jerez-Mayorga, Daniel; Guisado-Requena, Isabel MaríaThe severe training load of a competitive mesocycle may not be assimilated correctly by athletes, and can provoke endocrine imbalance, muscle damage and inflammation. Supplementation with antioxidants such as Phlebodium Decumanum (PHL) helps protect against such imbalances. The aim of this study is to analyse the effect of PHL on the fatigue during a precompetitive mesocycle in volleyball players. Twenty-four male volleyball players were divided into two groups (experimental and control). The experimental group was supplemented with three PHL capsules in the morning and three in the afternoon for 20 days. Blood samples were taken before training, at the end of the third week and at the end of the fourth week to evaluate creatine kinase (CK), interleukin 6 (IL-6), tumour necrosis factor-alpha (TNF-α), interleukin 10 (IL-10) and cortisol. The results show the control group, the third Cortisol were significantly increased (p < .05). In the experimental group, however, a significant increase (p < .05) was only observed in the third IL-10 value. In addition, significant differences (p < .05) were observed between the control and experimental groups in the second CK. Furthermore, there were moderate variations (effect size, ES > 0.5; 90% CI) in CK, IL-6 and TNF-α. In conclusion, PHL supplementation during a precompetitive mesocycle by volleyball players protects against the muscle damage, inflammatory modulation and cortisol response caused by fatigue. © 2023 Federacion Espanola de Docentes de Educacion Fisica. All rights reserved.Ítem Effect of sit-to-stand-based training on muscle quality in sedentary adults: a randomized controlled trial(PeerJ Inc., 2023) Lizama-Pérez, Rodrigo; Chirosa-Ríos, Luis Javier; Contreras-Díaz, Guido; Jerez-Mayorga, Daniel; Jiménez-Lupión, Daniel; Chirosa-Ríos, Ignacio JesúsThe aim of this study was to compare the effects of sit-to-stand (STS) training programs with 5 vs. 10 repetitions on muscle architecture and muscle function in sedentary adults. Sixty participants were randomly assigned into three groups: five-repetition STS (5STS), 10-repetition STS (10STS), or a control group (CG). Participants performed three sets of five or 10 repetitions of the STS exercise three times per week for 8 weeks. Before and after 8 weeks, all groups performed ultrasound measures to evaluate muscle thickness (MT), pennation angle (PA), and fascicle length (FL), and the five-repetition STS test to estimate the relative STS power and muscle quality index (MQI). After 8 weeks, both experimental groups improved MQI (40–45%), relative STS power (29–38%), and MT (8–9%) (all p < 0.001; no differences between the 5STS vs. 10STS groups). These improvements in both groups resulted in differences regarding the CG, which did not present any change. In addition, only the 5STS group improved PA (15%; p = 0.008) without differences to the 10STS and CG.This suggests that STS training is time-effective and low-cost for improving muscle function and generating adaptations in muscle architecture. Copyright 2023 Lizama-Pérez et al.Ítem Effects of different methods of strength training on indicators of muscle fatigue during and after strength training: a systematic review(Universidade Estadual Paulista - UNESP, 2020-08) Barahona-Fuentes, Guillermo D.; Ojeda, Álvaro Huerta; Jerez-Mayorga, DanielThe development of strength has shown to be beneficial to sports performance and health. However, during strength training, they also produce alterations in muscle fatigue indicators, leading to a decrease in the ability to generate strength. Despite this, there is still not enough knowledge about the levels of muscle fatigue generated by different methods of strength training and how this information can be integrated into sports planning. Review and analyze the studies existing between January 2009 and January 2019 that have used indicators of muscle fatigue established in the search terms during and after strength training as measurement variables. Evidence acquisition: The study corresponds to a systematic review of previously published studies, following the PRISMA model. Articles published between 2009 and 2019 that measured muscle fatigue indicators during and after strength training were evaluated. The electronic search was conducted through Web of Science, Scopus, Sport Discus, PubMed, and Medline. We included all articles that used a strength protocol and also measured indicators of muscle fatigue and its possible effect on physical performance. Evidence synthesis: A total of 39 articles were found, which were stratified according to the protocol used: (i) plyometric training, (ii) Bodypump® training, (iii) occlusion training, (iv) variable resistance training, (v) conventional strength training, (vi) eccentric strength training, (vii) rest times in strength training and (viii) concurrent training. Conclusion: At the end of the systematic review, it was shown that the different training methodologies for strength development generate increases in muscle fatigue indicators, and the increase generated in the different muscle fatigue indicators depends both on the methodology used and on the type of population, sex, level of training and type of sport. The most-reported indicators are [La], HR and RPE, DOM, MR variation, and ammonium.Ítem Estrategias de calentamiento y rendimiento contrarreloj en nadadores. Revisión rápida de la literatura(Retos. Volume 47, Pages 238 - 248. 2023, 2023) Enríquez-Enríquez, Diego; Mecina-Zapata, Carlos; Riveros-Cárcamo, Hernán; Jerez-Mayorga, Daniel; Ramírez-Campillo, Rodrigo; Chirosa-Ríos, Luis Javier; Guede-Rojas, FranciscoEl propósito de este estudio fue analizar la efectividad de diversas estrategias de calentamiento sobre el rendimiento en pruebas contrarreloj hasta 200-m, mediante una revisión rápida de la literatura. Utilizando directrices PRISMA, se realizó una búsqueda en la base de datos MEDLINE/Pubmed considerando estudios experimentales desde el año 2013. La calidad metodológica se evaluó mediante la escala PEDro. De 181 registros iniciales se incluyeron finalmente 16 estudios. Todos presentaron un diseño metodológico cruzado con calidad baja (tres estudios), regular (12 estudios) y buena (un estudio). Participó un total de 161 hombres y 75 mujeres con edad media de 17.96 años, compitiendo a nivel universitario, nacional o internacional. Estrategias de calentamiento activo en el agua mejoraron el tiempo de la prueba hasta en un 1.48%. La reducción de la fase de transición posterior a la realización de calentamiento activo en el agua mejoró el tiempo hasta en un 1.50%. Estrategias adicionales al calentamiento activo en el agua, mejoraron el tiempo hasta en un 2.04%. A partir de esta revisión, se concluye que no existe suficiente evidencia que sustente el uso de las diversas estrategias de calentamiento sobre el rendimiento en pruebas contrarreloj; no obstante, sus porcentajes de reducción del tiempo representan una opción interesante para nadadores y entrenadores en entornos competitivos.Ítem Exploring the mediating role of promoting school physical activity on the relationship between low socioeconomic status and academic achievement and school climate: evidence from 4,990 Chilean schools(Frontiers Media SA, 2024-06) Delgado-Floody, Pedro; Cristi-Montero, Carlos; Jerez-Mayorga, Daniel; Ruiz-Ariza, Alberto; Guzmán-Guzmán, Iris Paola; Álvarez, Cristian; Gómez-López, Manuel; Carter-Thuillier, Bastian; Caamaño-Navarrete, FelipeThere is evidence that promoting school physical activity (PSPA) benefits children and adolescents, but little is understood about how this promotion may relate to academic achievement and school climate across varying levels of socioeconomic status (SES). Hence, the study aimed to address this knowledge gap by examining two main objectives: (1) determining the association between PSPA and academic achievement and school climate according to schools’ SES and (2) exploring the potential mediating role of PSPA in the relationship between schools’ SES and academic achievement and school climate. This cross-sectional study at the school level focused on 4,990 schools (including public, subsidized, and private schools) that participated in the National Educational Study 2018 (Chile), which was applied to primary schoolchildren (4th grade, aged 8–10 years). Schools were divided into non-PSPA (n = 4,280) and PSPA (n = 710) during the year 2018. Changes in academic achievement from 2017 to 2018 and school climate were considered. PSPA was associated with improvements in maths (low-SES OR: 1.80, p < 0.001) and reading (middle-SES OR: 1.45, p = 0.029; low-SES OR: 1.47, p < 0.001). The indirect effect (IE) showed that PSPA partially mediated the relationship between SES and academic achievement in reading (IE = 1.017; SE = 0.12; 95%CI, −1.27, −0.77), maths (IE = –1.019; SE = 0.12; 95%CI, −1.25, −0.78), and school climate (IE = –0.46; SE = 0.52; 95%CI, −0.56, −0.35). In conclusion, PSPA was linked to positive changes in academic achievement, especially among low SES, and PSPA presented a potential mediating role in the relationship between SES of schools and academic achievement and school climate.Ítem Fall risk detection mechanism in the elderly, based on electromyographic signals, through the use of artificial intelligence(Universidad de Murcia, 2023) Arias-Poblete, Leónidas; Álvarez‐Arangua, Sebastián; Jerez-Mayorga, Daniel; Chamorro, Claudio; Ferrero‐Hernández, Paloma; Ferrari, Gerson; Farías‐Valenzuela, ClaudioIntroduction: The tests used to classify older adults at risk of falls are questioned in literature. Tools from the field of artificial intelligence are an alternative to classify older adults more precisely. Objective: To identify the risk of falls in the elderly through electromyographic signals of the lower limb, using tools from the field of artificial intelligence. Methods: A descriptive study design was used. The unit of analysis was made up of 32 older adults (16 with and 16 without risk of falls). The electrical activity of the lower limb muscles was recorded during the functional walking gesture. The cycles obtained were divided into training and validation sets, and then from the amplitude variable, select attributes using the Weka software. Finally, the Support Vector Machines (SVM) classifier was implemented. Results: A classifier of two classes (elderly adults with and without risk of falls) based on SVM was built, whose performance was: Kappa index 0.97 (almost perfect agreement strength), sensitivity 97%, specificity 100%. Conclusions: The SVM artificial intelligence technique applied to the analysis of lower limb electromyographic signals during walking can be considered a precision tool of diagnostic, monitoring and follow-up for older adults with and without risk of falls. © Copyright 2023: Publication Service of the University of Murcia, Murcia, Spain.Ítem Grip power test: A new valid and reliable method for assessing muscle power in healthy adolescents(Public Library of Science, 2021) Huerta Ojeda, Álvaro; Fontecilla Díaz, Blanca; Yeomans Cabrera, María Mercedes; Jerez-Mayorga, DanielThe assessment of the strength and muscle mass of the hand-finger segment are reliable indicators of health and predictors of cardiometabolic risk in the adult population. However, there are no valid and reliable tests to assess the muscle power of this segment in healthy adolescents. The objective of this study was to determine the validity and inter-day reliability of a grip power test (GripW test) in healthy adolescents. Twenty-one adolescents (15.61 ± 2.20 years old) were part of the study. All participants were instructed to perform a grip with incremental load sets from 1-10 kg as fast as possible. The validity of the GripW test was determined with the load-power curve and linear regression equation. Inter-day reliability considered the coefficient of variation (CV), intra-class correlation coefficient (ICC), and standard error of the mean (SEM). The significance level for all statistical analyses was p < 0.05. The parabola in the load-power curve for both hands showed normality for the GripW test. In addition, the analysis showed a CV = 4.63% and ICC = 1.00 for the right hand, while the left hand showed a CV = 3.23% and ICC = 1.00. The GripW test proved to be valid and reliable for assessing gripping muscle power functionally and unilaterally in healthy adolescents.Ítem Impact of Starting Knee Flexion Angle on Muscle Activity and Performance during Plyometrics without Jumping(MDPI, 2024-01) Torres-Banduc, Maximiliano; Chirosa-Ríos, Ignacio; Chirosa-Ríos, Luis; Jerez-Mayorga, DanielMost of the existing research has focused on jump plyometrics, where landing reaction forces must be dissipated among lower limb articulations. In contrast, the investigation of resisted plyometrics without jumping, devoid of such landing forces, remains relatively limited. This study aimed to (i) investigate the impact of resisted plyometrics without jumping at two knee flexion angles (60 and 90 degrees) on vastus muscle activity relative to limb dominance and (ii) assess strength, power, and work during the concentric–eccentric phases of these exercises. Thirty-one healthy participants underwent quantification of lower limb muscle amplitude, strength, power, and work during resisted plyometrics without jumping from both 60° and 90° knee flexion positions. After anthropometric evaluations, participants used a dynamometer with a load equal to 80% of body weight while wireless surface electromyography electrodes recorded data. Statistical analyses utilized paired t-tests or nonparametric equivalents and set significance at p ≤ 0.05. Results showed significantly higher muscle activity in the vastus medialis (VM) (dominant: 47.4%, p = 0.0008, rs = 0.90; nondominant: 54.8%, p = 0.047, rs = 0.88) and vastus lateralis (VL) (dominant: 46.9%, p = 0.0004, rs = 0.86; nondominant: 48.1%, p = 0.021, rs = 0.67) muscles when exercises started at 90° knee flexion, regardless of limb dominance. Substantial intermuscle differences occurred at both 60° (50.4%, p = 0.003, rs = 0.56) and 90° (54.8%, p = 0.005, rs = 0.62) knee flexion, favoring VM in the nondominant leg. Concentric and eccentric strength, power, and work metrics significantly increased when initiating exercises from a 90° position. In conclusion, commencing resisted plyometrics without jumping at a 90° knee flexion position increases VM and VL muscle activity, regardless of limb dominance. Furthermore, it enhances strength, power, and work, emphasizing the importance of knee flexion position customization for optimizing muscle engagement and functional performance.Ítem Influence of Probe Position in the Measurement of Muscle Thickness and its Association with Lean Mass: an Ultrasound Study(Universidad de la Frontera, 2023-04) Lizama-Pérez, Rodrigo; Muñoz-Cofré, Rodrigo; Vidal-Seguel, Nicolás; Chirosa Ríos, Ignacio; Jerez-Mayorga, Daniel; Intelangelo, Leonardo; Chirosa Ríos, LuisSkeletal muscles play a fundamental role in people's lives and their evaluation provides significant information on health. Different tools have been used to evaluate muscle mass, and the evaluation of muscle thickness (MT) using ultrasound has been included as an alternative, which can be performed with the probe in different positions; however, these could present differences. The objectives of this study were to determine whether there are differences in the measurement of MT in the vastus lateralis (VL) muscle using the probe in the longitudinal or transverse position, and to determine its association with the lean mass of the lower limbs. The results indicated no significant differences between MT measurements with the probe in the longitudinal and transverse positions (p =0.084). However, when associating these measurements with lower limb lean mass, it was found that transverse measurements had a strong association (r =0.547; p < 0.001), while longitudinal measurements had a moderate association (r =0.351; p =0.007). This suggests that measurements with the probe positioned transversely to measure the MT would be the best option. Therefore, it could be useful as an indicator of lower limb lean mass in the absence of tools, such as bioelectrical bioimpedance or magnetic nuclear resonance. © 2023, Universidad de la Frontera. All rights reserved.Ítem Influence of Sex and Dominant Side on the Reliability of Two Trunk Rotator Exercises(Applied Sciences (Switzerland), 2023-02) Rodríguez-Perea, Angela; Jerez-Mayorga, Daniel; Morenas-Aguilar, María Dolores; Martínez-García, Darío; Chirosa-Ríos, Ignacio Jesús; Chirosa-Ríos, Luis Javier; Reyes-Ferrada, WaleskaBackground: A method to assess the influence of sex and side testing on trunk rotator muscles has not been described. The purpose was to analyze the influence of sex and dominant and non-dominant sides (DS-NDS) on the reliability of two trunk rotator exercises and to study the relationship between the DS-NDS of two trunk rotator strength exercises. Methods: The reliability of the horizontal cable woodchop (HCW) and low cable woodchop (LWC) exercises was studied using a test-retest design with 51 physically active students. Isokinetic and isometric strength were assessed with a functional electromechanical dynamometer. Results: There were significant differences in reliability between male and female HCW and no significant differences in reliability between the average of the DS-NDS in HCW and LCW. There were no significant differences between the DS-NDS in the sex of HCW, and the strength of the two exercises showed no significant differences except for two conditions assessed. Very large to extremely large correlations were observed between sides in the strength of two exercises (r = 0.71–0.91). Conclusions: This test is handy for physical trainers or coaches to know the strength of the trunk rotators of their athletes. © 2023 by the authors.Ítem Influence of the body positions adopted for resistance training on intraocular pressure: a comparison between the supine and seated positions(Springer Science and Business Media Deutschland GmbH, 2023-07) Lara, Paula M.; Redondo, Beatriz; Jerez-Mayorga, Daniel; Martínez-García, Dario; García-Ramos, Amador; Vera, JesúsObjectives: A variety of factors are known to mediate on the intraocular pressure (IOP) response to resistance training. However, the influence of the body position adopted during resistance training on IOP remain unknown. The objective of this study was to determine the IOP response to the bench press exercise at three levels of intensity when performed in supine and seated positions. Methods: Twenty-three physically active healthy young adults (10 men and 13 women) performed 6 sets of 10 repetitions against the 10-RM (repetition maximum) load during the bench press exercise against three levels of intensity (high intensity: 10-RM load; medium intensity: 50% of the 10-RM load; and control: no external load) and while adopting two different body positions (supine and seated). A rebound tonometer was employed to measure IOP in baseline conditions (after 60 s in the corresponding body position), after each of the 10 repetitions, and after 10 s of recovery. Results: The body position adopted during the execution of the bench press exercise significantly affected the changes in IOP (p < 0.001, η p2 = 0.83), with the seated position providing lower increases in IOP levels compared to the supine position. There was an association between IOP and exercise intensity, with greater IOP values in the more physically demanding conditions (p < 0.001, η p2 = 0.80). Conclusions: The use of seated positions, instead of supine positions, for the execution of resistance training should be prioritized for maintaining more stable IOP levels. This set of findings incorporates novel insights into the mediating factors on the IOP response to resistance training. In future studies, the inclusion of glaucoma patients would allow to assess the generalizability of these findings. [Figure not available: see fulltext.] © 2023, The Author(s).Ítem Males Have a Higher Energy Expenditure than Females during Squat Training(MDPI, 2023-08) Del-Cuerpo, Indya; Jerez-Mayorga, Daniel; Chirosa-Ríos, Luis Javier; Morenas-Aguilar, María Dolores; Mariscal-Arcas, Miguel; López-Moro, Alejandro; Delgado-Floody, PedroThe main objective of this study was to determine the differences in energy expenditure (EE) according to sex during and after two different squat training protocols in a group of healthy young adults. Twenty-nine Sports Sciences students volunteered to participate in this study. They attended the laboratory on four different days and completed four sessions: two sessions with 3 sets of 12 repetitions at 75% of their one-repetition maximum (RM) and two sessions with 3 sets of 30 repetitions at 50% of their 1RM. Energy expenditure was evaluated using an indirect calorimeter. Males consistently demonstrated higher EE in all sessions and intensities. The linear regression model identified a significant association between sex, BMI, and total EE across all sessions and intensities. In conclusion, males exhibited higher EE in both protocols (50% and 75% of 1RM) throughout all sessions. Furthermore, sex and BMI were found to influence EE in healthy young adults. Therefore, coaches should consider sex when assessing EE, as the metabolic response differs between males and females. © 2023 by the authors.Ítem Muscle Quality Index in Morbidly Obesity Patients Related to Metabolic Syndrome Markers and Cardiorespiratory Fitness(MDPI, 2023-05) Caamaño-Navarrete, Felipe; Jerez-Mayorga, Daniel; Alvarez, Cristian; Del-Cuerpo, Indya; Cresp-Barría, Mauricio; Delgado-Floody, PedroBackground: Muscle quality index (MQI) is an emerging health indicator obtained by dividing handgrip strength by body mass index (BMI) that needs to be studied in morbidly obese patients (defined by BMI ≥ 35 kg/m2). Objective: To determine the association between MQI, metabolic syndrome (MetS) markers, and cardiorespiratory fitness (CRF), and as a second objective to determine the potential mediation role of MQI in the relationship between abdominal obesity and systolic blood pressure (SBP) in this sample. Methods: This cross-sectional study included 86 severely/morbidly obese patients (age = 41.1 ± 11.9 y, nine men). MQI, metabolic syndrome markers, CRF, and anthropometric parameters were measured. Two groups were developed according to MQI; High-MQI (n = 41) and Low-MQI (n = 45). Results: The Low-MQI group reported higher abdominal obesity (High-MQI: 0.7 ± 0.1 vs. Low-MQI: 0.8 ± 0.1 WC/height; p = 0.011), SBP (High-MQI: 133.0 ± 17.5 vs. Low-MQI: 140.1 ± 15.1 mmHg; p = 0.048), and lower CRF (High-MQI; 26.3 ± 5.9 vs. Low-MQI; 22.4 ± 6.1 mL/kg/min, p = 0.003) than the High-MQI group. Waist-to-height ratio (β: −0.07, p = 0.011), SBP (β: −18.47, p = 0.001), and CRF (β: 5.21, p = 0.011) were linked to MQI. In a mediation model, the indirect effect confirms that MQI is a partial mediator of the association between abdominal obesity with SBP. Conclusions: MQI in morbidly obesity patients reported an inverse association with MetS markers and a positive association with CRF (VO2max). It mediates the relationship between abdominal obesity and SBP. © 2023 by the authors.