Objective: The number of people suffering from depression and/or anxiety has increased steadily due to the coronavirus disease 2019 (COVID-19) pandemic. In this context, web-based exercise interventions have emerged as a potential treatment strategy. The objective of this study was to synthetize evidence from randomized controlled trials regarding the effects of web-based exercise interventions on patients with depressive and/or anxiety disorders. Methods: Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Six databases were searched (Cochrane Library, EBSCO, PubMed, SciELO, Scopus, and Web of Science), and eligible articles were identified according to a PICOS inclusion-exclusion approach (participants with depressive or anxiety disorders; web-based exercise interventions; active or passive control group; assessment of changes in depressive or anxiety disorders; randomized design). Primary outcomes were depressive and/or anxiety symptoms. The quality of evidence was assessed with Grading of Recommendations Assessment, Development, and Evaluation. Results: Of 7,846 search results, three studies met the inclusion criteria (172 participants between 18 and 65 years of age, 95.9% women). The web-based exercise interventions lasted 8-12 weeks and involved endurance training, yoga, or combined endurance and strength training. The comparators involved non-exercise controls or active controls. Compliance rates were low. Web-based exercise interventions were not superior to controls regarding anxiety symptoms, and only one study found benefits for depressive symptoms (p ≤ 0.05). The quality of the cumulative evidence was low. Conclusion: The available data regarding the effects of web-based exercise interventions on depression and/or anxiety symptoms is scarce, the risk of bias is high, and the quality of the cumulative results is low. Currently, no clear recommendations can be provided. Registration number: PROSPERO CRD42021225938.

Abstract: In many countries, access to universities is regulated by selection processes that use standardized tests. In Chile, for years, the University Selection Test (UST) has been used as an entry requirement and as a possible predictor of the academic performance of future students. The objective of the present study is to determine the relationship between the UST and university academic performance of their students of Pre-service Teacher Education in Physical Education who are in their first year of university. A descriptive-correlational design was used, with the participation of 315 students (22.1, dt. = 2.9). The results show that there is a weak direct correlation for both the UST (.20) and for all its components: Language and Communication UST (.17); Math UST (.13); Weighted Score (.19); Ranking (.16) and High School Grades (.16), when correlated with the Academic Performance of the first year of university. It can be concluded that the UST in Chile is not a predictive test of university academic performance in the population studied.

Resumen: En muchos países el acceso a la universidad está regulado por procesos de selección que emplean pruebas estandarizadas. En Chile durante años se empleó la Prueba de Selección Universitaria (PSU), un test estandarizado que utilizan la mayor parte de las universidades como requisito de ingreso y como posible predictor del rendimiento académico de sus futuros estudiantes. El objetivo del presente estudio es determinar la relación entre la PSU y el rendimiento académico universitario de estudiantes de Formación Inicial del Profesorado en Educación Física que cursan su primer año de universidad. Se utilizó un diseño descriptivo-correlacional, con la participación de 315 Estudiantes 22.1 (dt.=2.9). En los resultados se puede apreciar que existe una correlación directa débil tanto para la PSU (.20) como para todos sus componentes Lenguaje y Comunicación (.17); Matemáticas (.13); Puntaje Ponderado (.19); Ranking (.16) y Notas de Enseñanza Media (.16), al correlacionárseles con el rendimiento académico del primer año universitario. Se puede concluir que la PSU en Chile no es un test predictivo del rendimiento académico universitario en la población estudiada.

ABSTRACT In overload training the duration of the repetition (tempo) refers to the total time that a single repetition lasts within a set, the result being the sum between the concentric, isometric and eccentric phases of the lift (or vice versa depending on the exercise). There has been controversy in recent years regarding the duration of the repetition (and its phases) and its impact on muscle hypertrophy. The objective of this review was to analyze the effects of training programs and compare the different lifting tempos and their impact on hypertrophy. A literature search was carried out in the Pubmed electronic database, with the following inclusion criteria: i) training programs that induce volitional failure, ii) studies had been carried out under dynamic actions and with ≥4 weeks of intervention, and iii) study subjects are older than 18 years old to middle age. Of a total of 473 studies, four were included, where, 113 subjects (79 men and 34 women) participated and the tempos varied between 1.5 and 90 seconds, with lower tempos associated with a greater hypertrophic effect. A tempo between 2 and 6 seconds would be effective in inducing hypertrophic adaptations.

RESUMEN En el contexto del entrenamiento con sobrecargas, la duración de la repetición (tempo) hace referencia al tiempo total que dura una sola repetición dentro de una serie de un ejercicio, siendo el resultado de la suma entre la fase concéntrica, isométrica y excéntrica del levantamiento (o viceversa, dependiendo del ejercicio). Ha existido controversia los últimos años respecto a la duración de la repetición (y sus fases) y su impacto en la hipertrofia. El objetivo de esta revisión fue analizar los efectos de programas de entrenamiento donde se hayan comparado distintos tempos de levantamiento y su impacto en la hipertrofia. Se realizó una búsqueda de literatura en la base de datos electrónica Pubmed, con los siguientes criterios de inclusión: i) programas de entrenamiento que induzcan fallo volitivo, ii) que los estudios se hayan realizado bajo acciones dinámicas y con ≥4 semanas de intervención y iii) que los sujetos de estudio sean mayores de 18 años hasta mediana edad. De un total de 473 estudios, cuatro fueron incluidos, donde participaron 113 sujetos (79 hombres y 34 mujeres) y los tempos utilizados variaron entre 1.5 y 90 segundos, con menores tempos asociados a mayor efecto hipertrófico. Un tiempo entre 2 y 6 segundos sería efectivo para inducir adaptaciones hipertróficas.

RESUMO Introdução: O treinamento pliométrico melhora significativamente o desempenho de força, inclusive em esportes aquáticos. Objetivo: Comparar alterações da circunferência da coxa, flexibilidade dos isquiotibiais, altura do salto em agachamento e tempo de prova de natação de 200 metros depois de treinamento pliométrico em nadadores recreativos. Métodos: Dezoito nadadores recreativos do sexo masculino (idade = 18 a 20 anos) foram divididos randomicamente em um grupo de treinamento pliométrico (GP) ou controle (GC). Todos realizaram um plano de treinamento de natação em velocidade por seis semanas. Somente o GP substituiu os últimos 15 minutos de cada sessão por exercícios pliométricos. As características físicas e a circunferência da coxa foram medidas antes e depois das seis semanas de treinamento. Além disso, foram testados a flexibilidade (sentar e alcançar), o salto em agachamento e a prova de natação de 200 metros. Resultados: Um teste ANOVA de duas vias com análise post hoc revelou aumento da flexibilidade (PRÉ: 4,5 ± 5,3 cm; PÓS: 10,9 ± 5,9 cm, p < 0,01) e altura do salto (PRÉ: 24,9 ± 3,7 cm; PÓS: 28,3 ± 4,2 cm, p < 0,01), assim como diminuição do tempo de natação de 200 metros (PRÉ: 220 ± 26,5 s; PÓS: 204 ± 24,4 s, p < 0,01), apenas para o GP. Ao comparar as alterações absolutas (pré-pós) entre os grupos com o teste t de Student, o GP mostrou aumento maior da distância alcançada na flexibilidade no teste sentar e alcançar (GP: 6,34 ± 0,6 cm; GC: 2,4 ± 1,2 cm, p < 0,01) e na altura do salto em agachamento (GP: 3,4±0,7 cm; GC: 0,7±0,3 cm, p <0,01) do que o GC. Além disso, o tempo de natação de 200 metros diminuiu significativamente mais do que o GC (GP: -15,1 ± 2,4 s vs. GC: -0,8±2,7 s, p <0,01). Conclusão: O treinamento pliométrico melhora a altura do salto em agachamento, a flexibilidade e o desempenho em 200 metros de natação em nadadores adultos recreativos. Nível de evidência II; ECRC de menor qualidade.

ABSTRACT Introduction: Plyometric training significantly improves strength performance, including in aquatic sports. Objective: To compare changes in thigh girth, hamstring flexibility, squat jump height, and 200m swimming trial time induced by plyometric training in recreationally-trained swimmers. Methods: Eighteen recreationally-trained male swimmers (age=18-20 years) were randomly divided into a plyometric training group (PTG) and a control group (CG). All the swimmers completed a six-week speed swimming training plan. In the PTG only, the last ~15 min of each session was replaced with plyometric exercises. The physical characteristics and the thigh girth were measured before and after the six weeks of training. In addition, sit-and-reach flexibility and squat jump tests were conducted, as well as a 200m swimming trial. Results: Two-way ANOVA with post-hoc analysis revealed an increase in sit-and-reach flexibility (PRE: 4.5±5.3 cm; POST: 10.9±5.9 cm, p<0.01) and squat jump height (PRE: 24.9±3.7 cm; POST: 28.3±4.2 cm, p<0.01) and a decrease in 200m-swimming time (PRE: 220±26.5 sec; POST: 204±24.4 sec, p<0.01) for the PTG only. Comparing the absolute changes (post-pre) between the groups by the Student's t-test, the PTG showed a greater increase in distance reached in the sit-and-reach flexibility (PTG: 6.34±0.6 cm vs. CG: 2.4±1.2 cm, p<0.01) and squat jump height (PTG: 3.4±0.7 cm vs. CG: 0.7±0.3 cm, p<0.01) than the CG. In addition, the 200m swimming time decreased significantly more than in the CG (PTG: -15.1±2.4 sec vs. CG: -0.8±2.7 sec, p<0.01). Conclusion: Plyometric training improves jump height, flexibility, and 200m swimming performance in recreationally-trained adult swimmers. Level of Evidence II; Lesser quality RCT.

RESUMEN Introducción: El entrenamiento pliométrico mejora significativamente el desempeño de fuerza, inclusive en deportes acuáticos. Objetivo: Comparar alteraciones de la circunferencia del muslo, flexibilidad de los isquiotibiales, la altura del salto en agachamiento y tiempo de prueba de natación de 200 metros luego de entrenamiento pliométrico en nadadores recreativos. Métodos: Dieciocho nadadores recreativos del sexo masculino (edad= 18 a 20 años) fueron divididos aleatoriamente en un grupo de entrenamiento pliométrico (GP) o control (GC). Todos realizaron un plan de entrenamiento de natación en velocidad de seis semanas. Solamente el GP sustituyó los últimos 15 minutos de cada sesión con ejercicios pliométricos. Las características físicas y circunferencia de muslo se midieron antes y después de las seis semanas de entrenamiento. Además, se evaluó la flexibilidad (sentar y alcanzar), salto en agachamiento y la prueba de natación de 200 metros. Resultados: Un test ANOVA de dos vías con análisis post hoc reveló aumento de la flexibilidad (PRE: 4,5±5,3 cm; POST: 10,9±5,9 cm, p <0,01) y altura de salto (PRE: 24,9±3,7 cm; POST: 28,3±4,2 cm, p <0,01), así como disminución del tiempo de natación de 200 metros (PRE: 220±26 0,5 s POST: 204±24,4 s, p <0.01), solo para el GP. Al comparar las alteraciones absolutas (pre-post) entre los grupos con el test t de Student, el GP mostró mayor aumento de la distancia alcanzada en la flexibilidad en el test sentar y alcanzar (GP: 6,34±0,6 cm vs. GC: 2,4±1,2 cm, p <0,01) y en la altura del salto en agachamiento (GP: 3,4±0,7 cm vs. GC: 0,7±0,3 cm, p <0,01) que el GC. Además, el tiempo de natación de 200 metros disminuyó significativamente más que el GC (GP: -15,1±2,4 s vs. GC: -0,8±2,7 s, p <0,01). Conclusión: El entrenamiento pliométrico mejora la altura del salto en agachamiento, la flexibilidad y el desempeño en 200m de natación en nadadores adultos recreativos. Nivel de Evidencia II; ECRC de menor calidad.

SUMMARY: Lower-limbs appendicular muscle mass is a key body composition trait related to health and performance. Considering the relevance of lower-limbs appendicular muscle mass in soccer players, the assessment and monitoring of this variable with a low-cost tool would be of great value in order to improve performance through training and nutritional interventions. This study aimed to develop a multiple regression model in order to validate, through dual-energy X-ray absorptiometry, a novel equation to predict lower-limbs appendicular muscle mass in young soccer players using anthropometric variables. Forty-two soccer players of the Chilean National Team (age, 17.1±1.3 years; body mass, 70.0±6.8 kg; height, 175.0±6.6 cm) underwent anthropometrically and body composition assessments. Forward stepwise linear regression was used to develop the equation to estimate the lower-limb appendicular muscle mass. The estimated results were compared with measurements by dual-energy X-ray absorptiometry. The best predictor model to estimate lower-limbs appendicular muscle mass was (kg): (-21.268 + (0.087*height) - (0.853*middle thigh circumference) - (0.329*middle thigh skinfold) + (1.136*corrected middle thigh circumference) + (0.306*calf circumference)) (R2= 0.83). The lower-limbs appendicular muscle mass estimated by the equation and measured by DXA were similar (14.71±1.72 kg vs 14.76±1.89 kg, respectively), and have a good concordance according to Bland-Altman method (mean difference: 0.049 kg; 95 % IC: -1.481 to 1.578 kg) and Lin’s concordance correlation coefficient (0.91; 95 % CI: 0.85 - 0.96) methods. In conclusion, the predictive equation is a valid, easy to calculate, and a low-cost tool to predict lower-limbs appendicular muscle mass in young soccer players.

RESUMEN: La masa muscular de los miembros inferiores es un factor antropométrico clave relacionado a la salud y el rendimiento deportivo. Considerando la relevancia de este factor en jugadores de fútbol, la medición y monitoreo de esta variable a través de herramientas prácticas de bajo costo puede ser de gran utilidad para lograr objetivos relacionados a mejorar el rendimiento a través del entrenamiento e intervenciones nutricionales. El objetivo de este estudio fue desarrollar un modelo de regresión lineal con el objetivo de validar una nueva ecuación predictiva de la masa muscular de miembros inferiores en jugadores jóvenes de fútbol. Cuarenta y dos jugadores jóvenes de fútbol pertenecientes a la Selección Nacional Chilena (17,1±1,3 años; 70,0±6,8 kg; 175,0±6,6 cm) fueron sometidos a evaluaciones antropométricas y de composición corporal. La regresión lineal de pasos hacia adelante fue utilizada para desarrollar la ecuación para estimar la masa muscular de miembros inferiores. Los resultados estimados fueron comparados con medición de absorciometría de rayos X de doble energía (DEXA). El mejor modelo predictor de masa muscular de miembros inferiores (kg) fue: (-21,268 + (0,087*talla) - (0,853*circunferencia de muslo medio) - (0,329*pliegue de muslo medio) + (1,136*circunferencia de muslo medio corregida) + (0,306*circunferencia de pantorrilla)) (R2= 0,83). La masa muscular estimada por la ecuación y la medida por DEXA fue similar (14,71±1,72 kg vs 14,76±1,89 kg, respectivamente), y tuvo una buena concordancia acorde al método Bland-Altman (diferencia promedio: 0,049 kg; 95 % IC: -1,481 to 1,578 kg) y el coeficiente de correlación de concordancia de Lin (0,91; 95 % CI: 0,85 - 0,96). En conclusión, la ecuación predictiva desarrollada en este estudio es una herramienta válida, fácil de calcular y de bajo costo que permite estimar la masa muscular de miembros inferiores en futbolistas jóvenes.

Abstract Aim: The aim of this study was to assess the external load of amateur male players during 4 consecutive training microcycles (M) at the beginning of the in-season according to the training session in absolute external load demands and in relation to the competition demands. Methods: Regional-level players (n = 10; age, 20.8 ± 1.7 years; height, 175.5 ± 3.8 cm; body mass, 69.7 ± 2.9 kg; soccer experience, 13.2 ± 2.5 years) were monitored using GPS devices during training sessions and matches. The external load variables measured were: duration (min); total distance covered (TD); distance covered at high-speed (HID, 14.4-19.8 km/h); distance covered at sprinting (SPD; >19.8 km/h); and distance covered in high intensity acceleration (ACD; >2.5 m/s2) and deceleration (DECD; <-2.5 m/s2). Results: The results indicated that the external load variables (time, HID, SPD, ACD, and DECD) were similar between the four microcycles. Greater (p<0.01) time, TD, HID and SPD were observed in match day (MD)-2 compared to MD+1, MD-3, and MD-1. Aside from training duration, all external loads variables (TD, HID, SPD, ACD, and DECD) were lower during training sessions compared to official matches (p<0.05). Conclusion: Amateur soccer players present relative stable external training loads across competitive microcycles, with the peak load observed two days before the official match. Besides this, the match constitutes the highest load during a typical competitive microcycle in this cohort of players.

Abstract Aim: To examine body composition of Chilean powerlifters according to body mass and sex. Methods: Fifty-six male and female powerlifters were recruited from one national competition. Aside from the official weight categories, males were classified as the lightweight, middleweight, and heavyweight classes. Similarly, females were classified as lightweight and middle-heavyweight classes. Nineteen anthropometric measures were assessed, with lean mass as the main outcome. A one-way ANOVA was used to compare groups. Results: Male lightweight class lifted less (p<0.01) total load (417±30.9 kg) compared to heavier male classes (524±66.7 kg, middleweight; 581±131 kg, heavyweight), and female classes lifted less (p<0.01) total load (221±33.8 kg, lightweight; 254±48.3 kg, middleweight-heavyweight) compared to all male classes. Regarding lean-mass in trunk, arms and legs, total body protein, water, and mineral mass, all male groups had greater (p<0.01) values than the groups of females, while lightweight males had lower (p<0.01) values than the rest of male groups, and heavyweight males had greater (p<0.01) values than the total sample of males (except for legs lean mass, and total bone mineral content). In females, no significant differences were observed between classes, or in total load lifted or in body composition. Conclusion: Heavier male lifters had significantly greater lean mass than lighter athletes. Therefore, powerlifting performance was affected by anthropometric measures, as corroborated by 1-RM scores. However, there was a general lack of differences in body composition between female weight classes, and, as a result, a lack of differences in 1RM performance.

Introduction: The use of reliable, valid and precise skinfold calipers are key for an adequate anthropometric evaluation and corporal composition analysis. Objective: To compare five models of skinfold calipers -Prime Vision (PV); Harpenden (HP); Sanny (SN); Cescorf (CE); Lange (LA)-. Materials and methods: Thirty-five men (age = 21.5 ± 2.7 y; body mass 72.2 ± 8.0 kg; height 1.76 ± 0.06 m) were recruited and skinfolds (i.e., triceps, biceps, subscapular, pectoral, mid-axillary, suprailiac, abdominal, mid-tight, mid-calf) were measured. Four body fat predictive equations (Durnin y Wimberley; Pollock 3DC; Pollock 7DC; Petroski) were used. Normality assumption for all data was verified with the Shapiro-Wilk test. Predicted body density and fat were compared between skinfold calipers using a two-way ANOVA, with Scheffe post hoc procedures. The α level was set at p ≤ 0.05 for statistical significance. Results: No significant differences were observed between skinfold calipers for predicted body density or body fat. Conclusion: Skinfold calipers compared in this study are precise and efficient to quantify and assess body density and body fat.

Introducción: en el campo de la evaluación antropométrica, la validación y precisión de los calibres de pliegues cutáneos son fundamentales en el conocimiento efectivo de la composición corporal. Objetivo: el objetivo del estudio fue evaluar y comparar 5 modelos de calibre de pliegues cutáneos, uno de ellos digital -Prime Vision (PV), y los mecánicos Harpenden (HP), Sanny (SN), Cescorf (CE) y Lange (LA)-, a través de la densidad y grasa corporal. Material y métodos: formaron parte del estudio 35 hombres (21,5 ± 2,7 años; 72,22 ± 8,04 kg; 1,76 ± 0,06 m). Fueron medidos 9 pliegues cutáneos (tríceps, bíceps, subescapular, pectoral, axilar medio, suprailiaca iliaca, abdominal, muslo y pantorilla medial) y utilizadas 4 ecuaciones predictivas de la grasa corporal (Durnin y Womersley, Pollock de 3DC, Pollock 7DC y Petroski). Para la evaluación de los pliegues cutáneos fueron utilizados 5 modelos de calibres de pliegues cutáneos. Para verificar la distribución de la muestra fue utilizado el test de Shapiro Wilk. Para realizar la comparación de la densidad y grasa corporal en los diferentes calibres, se utilizó el test estadístico Anova dos vías con un post hoc de Scheffe. Para la comprobación estadística fue adoptado un p < 0,05. Resultados: no fue posible identificar diferencias significativas entre la densidad y la grasa corporal en los 5 calibres utilizados. Conclusión: los 5 calibres de pliegues cutáneos evaluados son precisos y eficientes para evaluar y cuantificar la DC y la grasa corporal.

In the field of competitive sport, genetics has gained a fundamental role in the study of sport performance. The aim of this study was to analyze the prevalence of polymorphisms R577X and insertion/deletion (I/D), occurring in a-actinin-3 (ACTN3) and angiotensin converting enzyme (ACE) genes, respectively, in Brazilian and Japanese gymnasts. A suitable non-probabilistic sample of 73 gymnasts (14 from Japan) was recruited and signed an informed consent. To measure ACTN3 and ECA saliva samples were obtained by means of real time polymerase chain reaction (iQ5 Thermal Cycler, BioRad). A high prevalence of RX ACTN3 genotype, R allele, ACE I/D genotype, and D allele were observed in Brazilian and Japanese gymnasts. In conclusion a high prevalence of RX ACTN3 genotype, R allele and ACE I/D genotype would allow a genetic advantage regarding muscle strength and power, possibly facilitating competitive success in gymnastics.

En el rendimiento deportivo, el estudio de la genética ha cobrado un papel fundamental al momento de estudiar el rendimiento deportivo. El objetivo del estudio fue analizar la frecuencia de genotipo y alelo de a - actinina 3 (ACTN3) R577X y enzima convertidora de angiotensina (ECA) I/D polimorfismo en un grupo de gimnastas de Brasil y Japón. Se considero una muestra de 73 gimnastas (14 de Japón y 59 de Brasil), todos los sujetos firmaron de consentimiento informado. Para la obtención de ACTN3 y ECA se recogió una muestra la saliva y analizaron los genotipos mediante el empleo de cadena de la polimerasa en tiempo real a partir del iQ5 Thermal Cycler, BioRad. Los resultados muestran una prevalencia del genotipo RX ACTN3, prevalencia del alelo R, prevalencia del genotipo DI ECA y prevalencia de alelo D en el total del grupo. Se concluye que el predominio RX del ACTN3, prevalencia del alelo R y predominio del genotipo DI en ECA pueden ofrecer una ventaja genética en cuanto a niveles de fuerza y potencia muscular, posiblemente facilitando la práctica y el éxito competitivo en gimnastas.