Static Postural Control during Single-Leg Stance in Endurance, Team and Combat Athletes from the Spanish National Sport Technification Program.

In the context of pediatric physical exercise, the analysis of factors affecting postural control (PC) provides insight into the development of sport-specific motor skills. This study aims to evaluate the static PC during single-leg stance in endurance, team and combat athletes from the Spanish National Sport Technification Program. A total of 29 boys and 32 girls, aged 12 to 16 years old, were recruited. Centre of pressure (CoP) was measured on a force platform in standing position for 40 s under two sensorial and leg dominance conditions. Girls showed lower MVeloc (p < 0.001), MFreq (p > 0.001) and Sway (p < 0.001) values than boys in both sensorial conditions (open and closed eyes). The highest values in all PC variables were observed with eyes closed in both genders (p < 0.001). Sway values were lower in boys combat-athletes compared to endurance athletes in two sensorial conditions and with non-dominant leg (p < 0.05). Young athletes in their teens enrolled in a Sport Technification Program have shown differences in PC when comparing different visual conditions, sport disciplines and gender. This study opens a window to a better understanding of the determinants of PC during single-leg stance as a critical element in the sport specialization of young athletes.

The effect of a core training program on jump performance in female handball players / Efecto de un programa de entrenamiento del core en la capacidad de salto de jugadoras de balonmano / Efeito de um programa do treinamiento do Core na desempenho de saltos em jogadoras de handebol

Objectives: To analyze the effects of core strength training on jump performance in female handball players. Methods: This is a randomized controlled trial. A total of 20 female handball players [age = 19.5 (1.4) years, height = 1.65 (0.05) m, body mass= 61.7 (9.3) kg] were recruited and split in: a core training group and a control group. The core training group participated in 8 weeks in-season of a core strength program (2 times/week). Pre- and post-intervention jump height, contact time and reactive strength index were collected during bilateral and unilateral drop vertical jumps. Frontal knee projection angle was measured only at unilateral drop jumps. Statistical significant difference was set at p ˂0.05. Results: group x time interactions were statistically significant for bilateral and unilateral jump height and for FKPA (<0.05). Core training group increased the bilateral jump height by 18.8% and showed a statistically significant difference in reactive strength index from pre-intervention [0.07 (0.03)] to post-intervention [0.10 (0.04)]. The core training group also improved the unilateral jump height by 20%, but only at the non-dominant leg. This improvement was accompanied by a statistically significant decrease in the frontal knee projection angle from pre-intervention [13.8 (7.4) degrees]to post-intervention [9.3 (6.1) degrees]. Control group did not obtain significant improvements in any of the assessed variables. There were no significant differences between groups in the baseline (p>0.05). Conclusion: A core strength training increased jump performance (drop jump) in female handball players.(AU)

Objetivos: Analizar los efectos del entrenamiento de la fuerza del core sobre el rendimiento del salto en jugadoras de balonmano. Métodos: Ensayo controlado aleatorio. 20 jugadoras de balonmano [edad = 19.5 (1.4) años, altura = 1.65 (0.05) m, masa corporal = 61.7 (9.3) kg]. Dos grupos: entrenamiento del core y grupo de control. El grupo entrenamiento del core realizó 2 veces por semana (8 semanas) un programa de fortalecimiento específico del core. Fueron registradas pre-post intervención, la altura de salto, el tiempo de contacto, el índice de fuerza reactiva en saltos verticales de caída bilateral y unilateral y el ángulo de proyección frontal de rodilla en saltos con recepción unilateral (p 0.05) ˂0.05. Resultados: las interacciones grupo x tiempo fueron estadísticamente significativas para la altura de salto bilateral y unilateral y la FKPA (p<0.05). El grupo de entrenamiento del core aumentó la altura de salto bilateral en un 18.8% y mostró diferencias significativas en el índice de fuerza reactiva desde la preintervención [0.07 (0.03)] hasta la post-intervención [0.10 (0.04)]. Asimismo, mejoró la altura de salto unilateral en un 20%, en la pierna no dominante. Esta mejora se acompañó de una disminución del ángulo de proyección frontal de la rodilla entre el pre [13.8 (7.4) grados] y el post [9.3 (6.1) grados]. El grupo de control no obtuvo mejoras significativas en las variables evaluadas. No hubo diferencias significativas entre los grupos antes de la intervención (p>0.05). Conclusiones: el fortalecimiento del core ha influido positivamente en el rendimiento del salto (drop jump) en las jugadoras.(AU)

Objetivos: Analisar os efeitos do treino de força central no desempenho de saltos em jogadores de andebol feminino. Métodos: Ensaio controlado aleatorizado. 20 jogadoras de andebol [idade = 19,5 anos (1,4), altura = 1,65m (0,05), massa corporal = 61,7kg (9,3)]. Dois grupos: grupo núcleo de formação e grupo de controlo. O grupo de formação principal realizou 2 vezes por semana (8 semanas) um programa específico de reforço do núcleo. Foram registados a intervenção pré-pós, altura do salto, tempo de contacto, índice de força reativa em saltos verticais bilaterais e unilaterais, e ângulo de projeção do joelho frontal em saltos de captura unilaterais (p ˂0.05). Resultados: As interações grupo x tempo foram estatisticamente significativas para a altura de salto bilateral e unilateral, e FKPA (p<0,05). O grupo de treino principal aumentou a altura do salto bilateral em 18,8% e mostrou diferenças significativas no índice de força reativa desde a pré-intervenção [0,07 (0,03)] até à pós-intervenção [0,10 (0,04)]. Para além disso, a altura do salto unilateral melhorou em 20% na perna não dominante. Esta melhoria foi acompanhada por uma diminuição do ângulo de projecção do joelho frontal entre os pré [13,8 (7,4) graus] e os pós [9,3 (6,1) graus]. O grupo de controlo não teve uma melhoria significativa nas variáveis avaliadas. Não houve diferenças significativas entre os grupos na linha de base (p>0,05). Conclusões: O reforço do núcleo teve um efeito positivo no desempenho dos jogadores no salto de queda.(AU)

The Impact of COVID-19 on Sport in Twitter: A Quantitative and Qualitative Content Analysis.

The spread of the SARS-CoV-2 virus has transformed many aspects of people's daily life, including sports. Social networks have been flooded on these issues. The present study aims to analyze the tweets produced relating to sports and COVID-19. From the end of January to the beginning of May 2020, over 4,000,000 tweets on this subject were downloaded through the Twitter search API. Once the duplicates, replicas, and retweets were removed, 119,253 original tweets were analyzed. A quantitative-qualitative content analysis was used to study the selected tweets. Posts dynamics regarding sport and exercise evolved according to the COVID-19 pandemic and subsequent lockdown, shifting from considering sport as a healthy bastion to an activity exposed to disease like any other. Most media professional sporting events received great attention on Twitter, while grassroots and women's sport were relegated to a residual role. The analysis of the 30 topics identified focused on the social, sporting, economic and health impact of the pandemic on the sport. Sporting cancellations, leisure time and socialization disruptions, club bankruptcies, sports training and athletes' uncertain career development were the main concerns. Although general health measures appeared in the tweets analyzed, those addressed to sports practice were relatively scarce. Finally, this study shows the importance of Twitter as a means of conveying social attitudes towards sports and COVID-19 and its potential to generate alternative responses in future stages of the pandemic.

Kinanthropometric assessment of individual, collective and fight sport players from the Spanish national sport technification program / Evaluación cineantropométrica en deportistas individuales, colectivos y de lucha, del programa nacional español de tecnificación deportiva

Nowadays, the study of kinanthropometric parameters is an important tool for both early talent selection and for evaluating the efficacy of a training program. This study aimed to determine the anthropometric characteristics, body composition indicators and somatotype components of individual (athletics, swimming and triathlon), collective (handball and volleyball) and fight (karate and taekwondo) sportsmen and sportswomen from the Valencian Sports Technification Centre. This study involved a total of 62 men and 56 women, they were divided in three subgroups, including individual (athletics, swimming and triathlon), collective (handball and volleyball) and fight (karate and taekwondo) sports. The assessment was carried out according to the one established by the International Society for Advancement of Kinanthropometry (ISAK). For men, the highest value of femur breath, ectomorphy and medial calf and front thigh skinfolds are obtained for triathletes, athletics, volleyball and karate, respectively. The highest values of triceps, biceps and abdominal skinfolds, relaxed arm girth, endomorphy and body fat percentage are shown for taekwondo, while the other highest values are obtained with handball. For women, the highest value of ectomorphy is obtained for athletics. The identified kinanthropometric parameters are useful when comparing between sports and sports subgroups for the selection of subjects and to help in their performance assessment.

En la actualidad, el estudio de los parámetros cineantropométricos es una herramienta importante tanto para la selección temprana del talento como para evaluar la eficacia de un programa de capacitación. Este estudio tuvo como objetivo determinar las características antropométricas, los indicadores de composición corporal y los componentes somatotípicos de deportistas y deportistas individuales (atletismo, natación y triatlón), colectivos (balonmano y voleibol) y de lucha (karate y taekwondo) del Centro Valenciano de Tecnificación Deportiva. Este estudio involucró a un total de 62 hombres y 56 mujeres, se dividieron en tres subgrupos, que incluyen deportes individuales (atletismo, natación y triatlón), colectivos (balonmano y voleibol) y peleas (karate y taekwondo). La evaluación se realizó de acuerdo con la establecida por la Sociedad Internacional para el Avance de la Cineantropometría (ISAK). Para los hombres, el valor más alto de la respiración del fémur, la ectomorfia y los pliegues de la pantorrilla y el muslo frontal se obtienen para triatletas, atletismo, voleibol y karate, respectivamente. Los valores más altos de tríceps, bíceps y pliegues abdominales, circunferencia relajada del brazo, endomorfia y porcentaje de grasa corporal se muestran para el taekwondo, mientras que los otros valores más altos se obtienen con balonmano. Para las mujeres, el mayor valor de la ectomorfía se obtiene para el atletismo. Los parámetros cineantropométricos identificados son útiles cuando se comparan entre deportes y subgrupos deportivos para la selección de sujetos y para ayudar en su evaluación del rendimiento.

Sensory Reweighting During Bipedal Quiet Standing in Adolescents.

A cross-sectional, prospective, between-subjects design was used in this study to establish the differences in sensory reweighting of postural control among different ages during adolescence. A total of 153 adolescents (five age groups; 13-17 years old) performed bipedal standing in three sensory conditions (i.e., with visual restriction, vestibular disturbance, and proprioceptive disturbance). Center of pressure displacement signals were measured in mediolateral and anteroposterior directions to characterize reweighting in the sensory system in static postural control when sensory information is disturbed or restricted during adolescent growth. The results indicate a development of postural control, showing large differences between subjects of 13-14 years old and older adolescents. A critical change was found in sensory reweighting during bipedal stance with disturbance of proprioceptive information at 15 years old. Adolescents of 13-14 years old showed less postural control and performance than older adolescents during the disturbance of proprioceptive information. Moreover, the results demonstrated that the visual system achieves its development around 15-16 years old. In conclusion, this research suggests that a difference of sensory reweighting under this type of sensorial condition and sensory reweight systems would seem to achieve stabilization at the age of 15.

Bibliometric study of scientific production on handball / Estudo bibliométrico da produção científica em handebol / Estudio bibliométrico de la producción científica en balonmano

This study carries out a bibliometric analysis of the scientific production on handball with the following goals: (1) to characterize the publications; (2) to analyze productivity; (3) to identify topic areas and journals; and (4) to present the various co-occurrence networks. The analysis consisted of calculating basic bibliometric indicators, and co-occurrence analysis was carried out to establish the relationships between authors, between citations of scientific papers and between keywords chosen by authors. A total of 1,637 original papers and 90 reviews in 399 journals were analyzed; 4,752 authors signed papers related to handball. The main topics were 'handball' and 'ACL,' and a tendency towards increasing presence of papers from the training field was found in recent years.

O objetivo deste estudo foi realizar uma análise bibliométrica da produção científica do handebol com estes objetivos: (1) caracterizar as publicações, (2) analisar a produtividade, (3) identificar as áreas temáticas e as revistas de pesquisa e (4) apresentar as diferentes redes de co-ocorrência. A análise consistiu no cálculo de indicadores bibliométricos básicos e foi realizada uma análise de co-ocorrência para estabelecer as relações entre autores, entre citações de artigos científicos e entre palavras-chave de autores. Foram analisados 1.637 artigos originais e 90 revisões em 399 revistas. Um total de 4.752 autores assinaram artigos relacionados ao termo handebol. Os principais tópicos foram "handball" e "ACL", e encontramos uma tendência nos últimos anos em aumentar a presença de artigos da área de treinamento.

El objetivo de este estudio fue realizar un análisis bibliométrico de la producción científica sobre el balonmano con los siguientes objetivos: (1) caracterizar las publicaciones, (2) analizar la productividad, (3) identificar las áreas temáticas y las revistas y (4) presentar las diferentes redes de coocurrencia. El análisis consistió en el cálculo de indicadores bibliométricos básicos y se realizó un análisis de coocurrencia para establecer las relaciones entre autores, entre citas de artículos científicos y entre palabras clave de los autores. Se analizaron 1637 artículos originales y 90 revisiones en 399 revistas. Un total de 4752 autores firmaron trabajos relacionados con el término balonmano. Los temas principales fueron "handball" y "ACL" y, en los últimos años, hemos encontrado una tendencia de aumento en la presencia de trabajos del ámbito del entrenamiento.

An author keyword analysis for mapping Sport Sciences.

Scientific production has increased exponentially in recent years. It is necessary to find methodological strategies for understanding holistic or macro views of the major research trends developed in specific fields. Data mining is a useful technique to address this task. In particular, our study presents a global analysis of the information generated during last decades in the Sport Sciences Category (SSC) included in the Web of Science database. An analysis of the frequency of appearance and the dynamics of the Author Keywords (AKs) has been made for the last thirty years. Likewise, the network of co-occurrences established between words and the survival time of new words that have appeared since 2001 has also been analysed. One of the main findings of our research is the identification of six large thematic clusters in the SSC. There are also two major terms that coexist ('REHABILITATION' and 'EXERCISE') and show a high frequency of appearance, as well as a key behaviour in the calculated co-occurrence networks. Another significant finding is that AKs are mostly accepted in the SSC since there has been high percentage of new terms during 2001-2006, although they have a low survival period. These results support a multidisciplinary perspective within the Sport Sciences field of study and a colonization of the field by rehabilitation according to our AK analysis.

Relationship between body composition and vertical ground reaction forces in obese children when walking.

BACKGROUND: Obesity is now a serious worldwide challenge, especially in children. This condition can cause a number of different health problems, including musculoskeletal disorders, some of which are due to mechanical stress caused by excess body weight. The aim of this study was to determine the association between body composition and the vertical ground reaction force produced during walking in obese children. METHODS: Sixteen children participated in the study, six females and ten males [11.5 (1.2) years old, 69.8 (15.5) kg, 1.56 (0.09) m, and 28.36 (3.74) kg/m2 of body mass index (BMI)]. Total weight, lean mass and fat mass were measured by dual-energy X-ray absorptiometry and vertical forces while walking were obtained by a force platform. The vertical force variables analysed were impact and propulsive forces, and the rate of development of both. Multiple regression models for each vertical force parameter were calculated using the body composition variables as input. FINDINGS: The impact force regression model was found to be positively related to the weight of obese children and negatively related to lean mass. The regression model showed lean mass was positively related to the propulsive rate. Finally, regression models for impact and propulsive force showed a direct relationship with body weight. INTERPRETATION: Impact force is positively related to the weight of obese children, but lean mass helps to reduce the impact force in this population. Exercise could help obese persons to reduce their total body weight and increase their lean mass, thus reducing impact forces during sports and other activities.