Effects of a high-intensity interval training program on body composition and physical fitness in female field hockey players / Efectos de un programa de entrenamiento intervalado de alta intensidad sobre la composición corporal y condición física en jugadoras de hockey césped

SUMMARY: High-intensity interval training (HIIT) is zed by achieving similar effects to conventional physical and physiological training in a shorter time, allowing its dissemination in the sports field. The present study was aimed to analyze the effects of a HIIT program on body composition and general and specific physical fitness in Chilean female field hockey players. Experimental, repeated measures, simple blind, parallel groups, and a quantitative approach were used. The participants were randomized, and distributed into a control group (CG; n= 10) that maintained regular field hockey training and an experimental group (EG; n= 10) that also received complementary training with HIIT. Body composition (muscle mass and adipose mass), general physical fitness (jump performance with countermovement jump [CMJ] and maximum oxygen consumption [VO2max] were evaluated with the test Course-Navette), and specific physical fitness (pushing speed, dribbling speed, and shooting accuracy) were assessed with established protocols. Pre- and post-intervention comparisons were made with Student's t and Wilcoxon tests, considering p<0.05. The main results indicate that the EG presented a significant increase in muscle mass (p = 0.024; d = 0.62), CMJ (p = 0.005; d = 1.10), VO2max (p = 0.001; d = 1.58) and a significant reduction in adipose mass (p = 0.023; d = 0.36) and time in pushing speed (p = 0.028; d = 0.79). The CG did not present significant changes in any of the variables analyzed, and no significant differences were reported between the groups. In conclusion, eight weeks of HIIT significantly increases muscle mass, jump performance, and VO2max and significantly reduces adipose mass and time in pushing speed in Chilean female field hockey players.

RESUMEN: El entrenamiento intervalado de alta intensidad (EIAI) se caracteriza por conseguir en un menor tiempo efec- tos similares al entrenamiento convencional a nivel físico y fisiológico, lo que ha permitido su difusión en el ámbito deportivo. El objetivo del presente estudio fue analizar los efectos de un programa de EIAI sobre la composición corporal, condición física general y específica en mujeres chilenas que practican hockey césped. Estudio experimental, de medidas repetidas, simple ciego, grupos paralelos y enfoque cuantitativo. Las participantes fueron aleatorizadas y distribuidas en grupo control (GC; n=10) que mantuvo los entrenamientos regulares de hockey césped y grupo experimental (GE; n=10) que además recibió de complemento EIAI. Se evaluó la composición corporal (masa muscular y masa adiposa), condición física general (capacidad de salto con el salto contra movimiento [CMJ] y consumo máximo de oxígeno [VO2máx] con la prueba Course de Navette) y condición física específica (velocidad de empuje, velocidad de dribling y precisión de tiro) con protocolos establecidos. Se realizaron comparaciones pre y post intervención con las pruebas t de Student y Wilcoxon, considerando un p<0,05. Los principales resultados indican que el GE presentó un aumento significativo de la masa muscular (p=0,024; d=0,62), CMJ (p=0,005; d=1,10), VO2máx (p=0,001; d=1,58) y, una reducción significativa, de la masa adiposa (p=0,023; d=0,36) y del tiempo en la velocidad de empuje (p=0,028; d=0,79). El GC no presentó cambios significativos en ninguna de las variables analizadas, mientras que no se reportaron diferencias significativas entre los grupos. En conclusión, ocho semanas de EIAI aumentan significativamente la masa muscular, capacidad de salto y VO2máx, además de reducir significativamente la masa adiposa y el tiempo en la velocidad de empuje en mujeres chilenas que practican hockey césped.

Effects of intra-set rest on morphological variables, maximal strength and jump performance in university students / Efectos del descanso intra-serie sobre variables morfológicas, fuerza máxima y saltabilidad en estudiantes universitarios

SUMMARY: The appropriate dosage of resistance training could promote physical and physiological adaptations and decrease injuries. The aim of the study was to analyze the effects of the different intra-set rest after eight weeks of resistance training on morphological variables, maximal strength, and jump performance in physically active university students. Twenty-five students (15 men and 10 women) were randomized by sex and distributed in Control Group (CG) (n=8) with rest only at the end of the series; Experimental Group 1 (EG1) (n=9) with an intra-set rest of 30 s, and Experimental Group 2 (EG2) (n=8) with four intra-set rest of 10 s. Morphological variables [body weight, bipedal height, body mass index (BMI), fat mass and muscle mass], maximum upper body strength (bench press and military press), lower body strength [parallel squat (45°) and deadlift], as well as countermovement jump (CMJ) were measured. All three groups obtained a significant increase (p0.05); thereby, there is an equivalent increase in muscle mass, maximal strength, jump performance, and a fat mass reduction.

RESUMEN: La dosificación adecuada de ejercicios de resistencia muscular permite favorecer adaptaciones físicas y fisiológicas, y reducir lesiones. El objetivo de este estudio fue analizar los efectos de distintos tiempos de descanso intra-serie luego de ocho semanas de ejercicios de resistencia muscular sobre variables morfológicas, fuerza máxima y saltabilidad en estudiantes universitarios físicamente activos. Veinticinco estudiantes (15 hombres y 10 mujeres) fueron aleatorizados por sexo y distribuidos en: grupo control (GC) (n=8) con descanso sólo al final de la serie; grupo experimental 1 (GE1) (n=9) con un descanso intra-serie de 30 s y grupo experimental 2 (GE2) (n=8) con cuatro descansos intra-serie de 10 s. Se midieron variables morfológicas [peso corporal, estatura bípeda, índice de masa corporal (IMC), masa adiposa y masa muscular], fuerza máxima del tren superior (press de banco plano y press militar) e inferior [sentadilla paralela (45°) y peso muerto] y saltabilidad con el salto contramovimiento (CMJ). Se obtuvo un aumento significativo (p<0,01) del peso corporal e IMC y, una reducción significativa (p<0,01) de la masa adiposa en los tres grupos. La masa muscular aumentó significativamente (p<0,01) en el GC y GE1. La fuerza máxima del tren superior e inferior aumentaron significativamente (p<0,05) en los tres grupos y para todos los ejercicios, mientras que el CMJ aumentó significativamente en el GC y GE1. No existen diferencias significativas entre distintos tiempos de descanso intra-serie cuando se utiliza el mismo volumen, intensidad y descanso total durante las series de ejercicios, logrando un aumento equivalente en masa muscular, fuerza máxima, saltabilidad y reducción de la masa adiposa.

Influence of violent contexts on facial reactions elicited by angry and neutral faces.

This study focuses on determining whether violent contexts influence the perception of aggressiveness in faces analysing spontaneous corrugator supercilii activity. Participants viewed pictures of neutral and angry faces preceded by a contextual sentence describing either violent or neutral actions. They were instructed to judge each face according to whether it was aggressive or non-aggressive. Results show a higher level of perceived aggressiveness for neutral faces preceded by violent contexts, accompanied by longer reaction times, and a significant increase of corrugator activity. Angry faces preceded by neutral contexts were judged as less aggressive and elicited less corrugator activity. In conclusion, our results provide evidence that facial reactions and aggressiveness judgment for faces are context-dependent. With this work, we contribute to the view that contextual cues guide the face's emotional meaning, under top-down processing.

Muscle activation in semantic processing: An electromyography approach.

In this study, we focus on the spontaneous activity related to manual verbs to determine the extent to which semantic processing of manual verbs affects spontaneous arm muscle activity. For this purpose, we recorded the arm's electromyographic activity while participants read manual and non-manual verbs, focusing their attention on the semantic content or a specific letter. In addition, we manipulated the arm position (in front of the body or behind the back) to observe postural priming effects for spontaneous muscle activity. Our results show that when arms were placed forward and the attention was directed to the semantic content, there was an enhanced spontaneous activation. Our results suggest that spontaneous motor responses are related to the involvement of the motor system in action language comprehension as suggested by language embodiment theories.

Decreasing motion sickness by mixing different techniques.

We investigated the effectiveness of galvanic cutaneous stimulation (GCS) and auditory stimulation (AS) together and separately in mitigating motion sickness (MS). Forty-eight drivers (twenty-two men; mean age = 21.58 years) participated in a driving simulation experiment. We compared the total scores of the Simulator Sickness Questionnaire (SSQ) across four different stimulation conditions (GCS, AS, Mixed GCS-AS and no stimulation as a baseline condition). We provided evidence that mixing techniques mitigates MS owing to an improvement in body balance; furthermore, mixing techniques improves driving behavior more effectively than GCS and AS in isolation. We encourage the use of the two techniques together to decrease MS.

Variations in glenohumeral movement control when implementing an auditory feedback system: A pilot study / Variaciones en el control del movimiento glenohumeral al implementar un sistema de retroalimentación auditiva: un estudio piloto

Abstract Introduction: Human motor control requires a learning process and it can be trained by means of various sensory feedback sources. Objective: To determine variations in glenohumeral movement control by learning in young adults exposed to an auditory feedback system while they perform object translation tasks classified by difficulty level. Materials and methods: The study involved 45 volunteers of both sexes (22 women), aged between 18 and 32 years. Glenohumeral movement control was measured by means of the root mean square (RMS) of the accelerometry signal, while task execution speed (TES) was measured using an accelerometer during the execution of the task according to its difficulty (easy, moderate and hard) in four stages of randomized intervention (control, pre-exposure, exposure-with auditory feedback, and post-exposure). Results: Statistically significant differences (p<0.001) were found between the pre-exposure and exposure stages and between pre-exposure and post-exposure stages. A significant increase (p <0.001) in TES was identified between the pre-exposure and exposure stages for tasks classified as easy and hard, respectively. Conclusion: The use of an auditory feedback system in young adults without pathologies enhanced learning and glenohumeral movement control without reducing TES. This effect was maintained after the feedback, so the use of this type of feedback system in healthy individuals could result in a useful strategy for the training of motor control of the shoulder.

Resumen Introducción. El control del movimiento humano requiere de un proceso de aprendizaje y puede ser entrenado por medio de la retroalimentación proveniente de diversas fuentes sensoriales. Objetivo. Determinar variaciones en el control del movimiento glenohumeral por aprendizaje en adultos jóvenes sometidos a un sistema de retroalimentación auditiva, mientras realizan tareas de traslación de objetos clasificadas por nivel de dificultad. Materiales y métodos. Participaron 45 voluntarios de ambos sexos (22 mujeres) entre 18 y 32 años. El control del movimiento glenohumeral se midió por medio de la raíz media cuadrática de acelerometría, mientras que para la velocidad de ejecución de la tarea (VE) se usó un acelerómetro durante la ejecución de tareas según dificultad (fácil, moderado y difícil) en cuatro etapas aleatorizadas de intervención (control, pre-exposición, exposición con retroalimentación auditiva y post-exposición). Resultados. Se encontraron diferencias significativas (p<0.001) entre las etapas pre-exposición y exposición, y entre pre-exposición y postexposición. Se identificó un aumento significativo de la VE entre pre-exposición y exposición para tareas con clasificación fácil y difícil. Conclusión. El uso de un sistema de retroalimentación auditiva en adultos jóvenes sin patologías podría favorecer el aprendizaje y el control del movimiento glenohumeral sin disminuir la VE, resultado que se mantiene luego de la retroalimentación, por lo que el uso de un sistema de retroalimentación auditiva en individuos sanos podría resultar en una estrategia útil para el entrenamiento del control motriz del hombro.