Muscular development and physical activity as major determinants of femoral bone mass acquisition during growth

[EN] OBJECTIVES: To investigate to what extent bone mass accrual is determined by physical activity and changes in lean, fat, and total body mass during growth. METHODS: Twenty six physically active and 16 age matched control boys were followed up for three years. All subjects were prepubertal at the start of the survey (mean (SEM) age 9.4 (0.3) years). The weekly physical activity of the active boys included compulsory physical education sessions (80-90 minutes a week), three hours a week of extracurricular sports participation, and occasional sports competitions at weekends. The physical activity of the control group was limited to the compulsory physical education curriculum. Bone mineral content (BMC) and areal density (BMD), lean mass, and fat mass were measured by dual energy x ray absorptiometry. RESULTS: The effect of sports participation on femoral bone mass accrual was remarkable. Femoral BMC and BMD increased twice as much in the active group as in the controls over the three year period (p < 0.05). The greatest correlation was found between the increment in femoral bone mass and the increment in lean mass (BMC r = 0.67 and BMD r = 0.69, both p < 0.001). Multiple regression analysis revealed enhancement in lean mass as the best predictor of the increment in femoral bone BMC (R = 0.65) and BMD (R = 0.69). CONCLUSIONS: Long term sports participation during early adolescence results in greater accrual of bone mass. Enhancement of lean mass seems to be the best predictor of this bone mass accumulation. However, for a given muscle mass, a greater level of physical activity is associated with greater bone mass and density in peripubertal boys.

Modelo de aprendizaje exitoso en educación física y su mantenimiento. Estudio del efecto del refuerzo intermitente sobre la condición física

[ES] El propósito de este artículo es describir el proceso de la planificación de aprendizajes motores y de desarrollo de la condición física en el contexto escolar, analizando las circunstancias que rodean a este proceso, con el fin de orientar a los profesores a planificar y que garanticen cierta eficacia en la intervención.

Teaching and aligning upper level mathematics classes to Michigan high school content expectations in an alternative education setting : approaches and issues

After teaching regular education secondary mathematics for seven years, I accepted a position in an alternative education high school. Over the next four years, the State of Michigan adopted new graduation requirements phasing in a mandate for all students to complete Geometry and Algebra 2 courses. Since many of my students were already struggling in Algebra 1, getting them through Geometry and Algebra 2 seemed like a daunting task. To better instruct my students, I wanted to know how other teachers in similar situations were addressing the new High School Content Expectations (HSCEs) in upper level mathematics. This study examines how thoroughly alternative education teachers in Michigan are addressing the HSCEs in their courses, what approaches they have found most effective, and what issues are preventing teachers and schools from successfully implementing the HSCEs. Twenty-six alternative high school educators completed an online survey that included a variety of questions regarding school characteristics, curriculum alignment, implementation approaches and issues. Follow-up phone interviews were conducted with four of these participants. The survey responses were used to categorize schools as successful, unsuccessful, and neutral schools in terms of meeting the HSCEs. Responses from schools in each category were compared to identify common approaches and issues among them and to identify significant differences between school groups. Data analysis showed that successful schools taught more of the HSCEs through a variety of instructional approaches, with an emphasis on varying the ways students learned the material. Individualized instruction was frequently mentioned by successful schools and was strikingly absent from unsuccessful school responses. The main obstacle to successful implementation of the HSCEs identified in the study was gaps in student knowledge. This caused pace of instruction to also be a significant issue. School representatives were fairly united against the belief that the Algebra 2 graduation requirement was appropriate for all alternative education students. Possible implications of these findings are discussed.

The lifestyle of our kids (LOOK) project: outline of methods

This methods paper outlines the overall design of a community-based multidisciplinary longitudinal study with the intent to stimulate interest and communication from scientists and practitioners studying the role of physical activity in preventive medicine. In adults, lack of regular exercise is a major risk factor in the development of chronic degenerative diseases and is a major contributor to obesity, and now we have evidence that many of our children are not sufficiently active to prevent early symptoms of chronic disease. The lifestyle of our kids (LOOK) study investigates how early physical activity contributes to health and development, utilizing a longitudinal design and a cohort of eight hundred and thirty 7-8-year-old (grade 2) school children followed to age 11-12 years (grade 6), their average family income being very close to that of Australia. We will test two hypotheses, that (a) the quantity and quality of physical activity undertaken by primary school children will influence their psychological and physical health and development; (b) compared with existing practices in primary schools, a physical education program administered by visiting specialists will enhance health and development, and lead to a more positive perception of physical activity. To test the first hypothesis we will monitor all children longitudinally over the 4 years. To test the second we will involve an intervention group of 430 children who receive two 50min physical education classes every week from visiting specialists and a control group of 400 who continue with their usual primary school physical education with their class-room teachers. At the end of grades 2, 4, and 6 we will measure several areas of health and development including blood risk factors for chronic disease, cardiovascular structure and function, physical fitness, psychological characteristics and perceptions of physical activity, bone structure and strength, motor control, body composition, nutritional intake, influence of teachers and family, and academic performance.

Teachers' Acculturation Attitudes and their Classroom Management: an empirical study among fifth-grade primary school teachers in Switzerland

This article investigates the influence of attitudes towards acculturation of 180 primary school teachers on their classroom management. The results indicate that teachers with integrative attitudes towards immigrant students' acculturation have a high propensity to punish students for disruptive behaviour, but they also demonstrate high levels of diagnostic expertise in social areas. Teachers with assimilative attitudes are also likely to punish students for misbehaviour, but tend to have a deficiency in the ability to diagnose social tensions among students. Teachers with assimilative attitudes who report high levels of disruptive behaviour in their classroom have the strongest tendency to punish and the lowest level of diagnostic expertise in social areas.

Dynamic Activity-Related Incentives for Physical Activity.

The present studies adopted the theoretical framework of activity- and purpose-related incentives (Rheinberg, 2008) to explain the maintenance of physical activity. We hypothesized that activity-related incentives (e.g., “fun”) increase more than purpose-related incentives (e.g., “health”) between the initiation and maintenance phase of physical activity. Additionally, change in activity-related incentives was hypothesized to be a better predictor of maintenance of physical activity than change in purpose-related incentives. Two correlative field studies with rehabilitation patients (Study 1) and Nordic Walkers (Study 2) were conducted to test the hypotheses. Participants’ incentives of physical activity were measured at the beginning of exercising and two weeks (Study 1; T2) and three months (Study 2; T2) later. At T2, participants were asked for their current physical activity. Both studies showed a greater change of activity-related incentives than purpose-related incentives. Furthermore, change in activity-related incentives was more predictive of the maintenance of physical activity than change in purpose-related incentives. The results showed the important role of activity-related incentives in maintenance of physical activity. The theoretical contribution to physical activity maintenance research and practical implications for health promotion programs were discussed.

Cognitively engaging chronic physical activity, but not aerobic exercise, affects executive functions in primary school children: A group-randomized controlled trial

Although the positive effects of different kinds of physical activity (PA) on cognitive functioning have already been demonstrated in a variety of studies, the role of cognitive engagement in promoting children’s executive functions is still unclear. The aim of the present study was therefore to investigate the effects of two qualitatively different chronic PA interventions on executive functions in primary school children. 181 children aged between 10 and 12 years were assigned to either a 6-week physical education program with a high level of physical exertion and high cognitive engagement (team games), a physical education program with high physical exertion but low cognitive engagement (aerobic exercise), or to a physical education program with both low physical exertion and low cognitive engagement (control condition). Executive functions (updating, inhibition, shifting) and aerobic fitness (multistage 20-meter shuttle run test) were measured before and after the respective condition. Results revealed that both interventions (team games and aerobic exercise) have a positive impact on children’s aerobic fitness (4-5 % increase in estimated VO2max). Importantly, an improvement in shifting performance was found only in the team games and not in the aerobic exercise or control condition. Thus, the inclusion of cognitive engagement in PA seems to be the most promising type of chronic intervention to enhance executive functions in children, providing further evidence for the importance of the qualitative aspects of PA.

Understanding Impediments and Enablers to Physical Activity among African American Adults: A Systematic Review of Qualitative Studies

Objective: To systematically assess and summarize impediments and facilitating factors impacting physical activity participation among African American Adults. ^ Method: A systematic search of the literature was conducted, which included electronic databases, as well as reference list of relevant papers. Only qualitative studies which measured race and ethnicity and had African American as adult participants were included. The main themes and categories from the qualitative studies pertaining to impediments and facilitators to physical activity were identified and summarized, through descriptive meta-synthesis. ^ Result: Twenty nine qualitative studies were included. Twenty-one of the studies only focused on adult African American women, and the barriers and facilitators to physical activity as perceived by them. The biggest individual enabler towards physical activity was the positive health benefits associated with regular physical activity. Social support and easy access to parks and facilities were also identified as enablers. Barriers toward physical activity were lack of time, lack of motivation, long work hours, and physical disabilities. ^ Conclusions: The findings of this review study should be useful to those planning an intervention in African American communities. There is also a need for qualitative studies conducted only among African American men, to better understand their perspective on the facilitators and barriers to physical activity.^

The effects of ethnicity and ethnic composition of schools on physical activity and nutrition behaviors of 8th and 11th graders in Texas

With rates of obesity and overweight continuing to increase in the US, the attention of public health researchers has focused on nutrition and physical activity behaviors. However, attempts to explain the disparate rates of obesity and overweight between whites and Hispanics have often proven inadequate. Indeed, the nebulous term ‘ethnicity’ provides little important detail in addressing potential biological, behavioral, and environmental factors that may affect rates of obesity and overweight. In response to this, the present research seeks to test the explanatory powers of ethnicity by situating the nutrition and physical activity behaviors of whites and Hispanic into their broader social contexts. It is hypothesized that a student's gender and grade level, as well as the socioeconomic status and ethnic composition of their school, will have more predictive power for these behaviors than will self-reported ethnicity. ^ Analyses revealed that while ethnicity did not seem to impact nutrition behaviors among the wealthier schools and those with fewer Hispanics, ethnicity was relevant in explaining these behaviors in the poorest tertile of schools and those with the highest number of Hispanics. With respect to physical activity behaviors, the results were mixed. The variables representing regular physical activity, participation in extracurricular physical activities, and performance of strengthening and toning exercises were more likely to be determined by SES and ethnic composition than ethnicity, especially among 8th grade males. However, school sports team and physical education participation continued to vary by ethnicity, even after controlling for SES and ethnic composition of schools. In conclusion then, it is important to understand the intersecting demographic and social variables that define and surround the individual in order to understand nutrition and physical activity behaviors and thus overweight and obesity.^

Reflexiones en torno al proceso de implementación de un programa social en el campo de la actividad física en poblaciones vulnerables : Aportes para la formación del profesorado de Educación Física y la mejora de las políticas públicas

En este artículo se propone describir y analizar el proceso de implementación de un Programa social de intervención en poblaciones vulnerables a través del deporte, la actividad física y el juego recreativo que se desarrolla desde 2011 en tres espacios socio-residenciales de villa o asentamiento urbano informal del Partido de la Matanza. El programa social es analizado en diferentes aspectos claves de su proceso de implementación. Estos aspectos fueron abordados a través de una investigación cualitativa con objetivos amplios y un enfoque integral, en esta oportunidad se reflexiona sobre un avance de investigación que privilegia las percepciones y representaciones de los docentes técnicos que ejercieron el rol docente en el marco del Programa y se realizan algunos aportes para pensar la mejora en las futuras acciones y en la formación del profesorado.Se realizaron 6 grupos focales y se estima que los insumos generados serán útiles para la mejor planificación de las prácticas docentes y formación específica de los futuros profesores. Asimismo, se espera poder aportar elementos de análisis y de juicio para la gestión de políticas públicas en el campo del deporte y la actividad física como estrategia de integración social

Educación Física y deportes : las instituciones deportivas y sus actores

El trabajo aquí expuesto intenta presentar, a modo de síntesis, las características generales y algunas conclusiones del proyecto de investigación "La educación física y los deportes: las instituciones deportivas en la perspectiva de los actores", desarrollado desde el año 2003 hasta el año 2005. Desde él se buscó, a partir de la recuperación de la voz de los actores de las instituciones deportivas -padres, dirigentes, entrenadores y profesores, practicantes y jugadores-, como también desde el análisis desde los discursos y las prácticas, reconocer las ideas y conceptos que conviven en la cotidianeidad institucional; las formas de organización distintivas de esas instituciones; los modos de relación entre los diversos actores y las formas y modos sociales que sobre ellas actúan. Se indagó en las instituciones deportivas con la finalidad de rastrear los sentidos y significados que les otorgan los actores, su organización y dinámica de funcionamiento, las razones de su proceder, los principios y lógicas que las configuran. Asimismo se analizaron las articulaciones existentes con macroinstituciones externas, la autonomía o dependencia respecto de éstas, y la incidencia que tienen sobre las lógicas de las instituciones deportivas

Los Problemas de las Gimnasias

Este artículo se propone sintetizar las principales ideas de las ponencias presentadas en la Mesa de Trabajo "Los problemas de las Gimnasias" que se desarrolló en el marco del 9° Congreso Argentino y 4° Latinoamericano de Educación Física y Ciencias realizado en la Universidad Nacional de La Plata en junio de 2011. Todas ellas coinciden en pensar a la Gimnasia como parte fundamental de una Educación Corporal que se proponga transmitir aquellos saberes corporales culturalmente significativos que sirvan de herramientas para el conocimiento, el cuidado y la autogestión del propio cuerpo. A partir de estos puntos de coincidencia cada ponencia se explaya en su especificidad: ya sea desde la investigación y el análisis de los textos de divulgación y académicos, de los discursos de profesores, alumnos y practicantes; desde el análisis crítico del campo gímnico actual; desde propuestas bien concretas de trabajo de las gimnasias, en este caso la gimnasia aeróbica, la gimnasia funcional, el Método Pilates, o la gimnasia en el Profesorado en Educación Física con proyección en la gimnasia escolar

Medio ambiente social y cultural : Análisis de los enunciados de las clases de Educación Física

El análisis de las acciones verbales que tienen lugar en las clases proporciona información sobre las prácticas docentes. Los seres humanos contamos con el lenguaje como herramienta fundamental para comunicarnos y construir conocimiento. La reflexión sobre su uso, concretamente el uso que los docentes hacen de este instrumento netamente humano en sus prácticas, es esencial para acrecentar nuestro conocimiento acerca de la tarea docente.
Desde el área de la Didáctica de la Lengua y los enfoques teóricos de la Teoría de la actividad (Leontiev, 1983) y el Interaccionismo socio-discursivo (Bronckart, 1997/2004, 2007), emprendemos este trabajo que se circunscribe al material resultado de las observaciones de clases de Educación Física de nivel primario de escuelas públicas de San Carlos de Bariloche (Río Negro-Argentina). La metodología consiste en convertir los textos orales de las clases en registros escritos para estudiar su organización interna según tres niveles superpuestos, tal como Bronckart (1997/2004) plantea. El resultado es un trabajo de corte cualitativo en el que se estudian en profundidad los contenidos actitudinales presentes en las clases.
Nuestro objetivo es estudiar las interacciones docente-alumnos en el medio social áulico para determinar a través de qué actividades los docentes propiciamos el desarrollo de nuestros alumnos. Es decir, analizar cómo a través de los enunciados de los docentes, se construye el medio ambiente social y cultural (Voloshinov, 1992; Riestra, 2011) en las clases de Educación física.

Aprender a enseñar juegos motores con otros : De saber jugar a intervenir como profesor de Educación Física

Durante la formación inicial, los estudiantes del profesorado de Educación Física construyen conocimientos teóricos y prácticos alrededor de prácticas corporales ya conocidas y vivenciadas. Aprenden sobre lo aprendido. Redefinen conocimientos prácticos en un nivel mayor de complejidad y abstracción asignándoles valor educativo que fundamentará su intervención profesional. Cuando le enseñan a proponer 'juegos no juegos' (actividades o deportes que presenta como juegos aunque no todos pueden jugar) el estudiante de Educación Física dispone de elementos teóricos que fundamentan el uso del juego como un recurso pedagógico (ya sea, como contenido de otros ejes, o como estrategia metodológica para la enseñanza de deportes o habilidades motoras). Sin embargo, cuando le enseñan a proponer juegos populares para divertirse, encuentra dificultad para planificar y justificar su futura intervención. Los resultados finales de una investigación cualitativa, presentada como tesis de maestría, muestran que en Educación Física se enseñan múltiples formas de juego motor con otros pero un solo modo de jugarlos: el no lúdico. Se enseña a subordinar el modo de jugar a la forma de los juegos propuestos por el profesor. Se enseña a moverse en el marco de lo permitido por las reglas del juego, a poner el cuerpo al servicio del juego

Percepción de la educación física en docentes universitarios

El objetivo del trabajo es conocer la percepción epistemológica de docentes universitarios sobre la educación física, para contrastar esta postura contra la literatura actual y las necesidades para esta asignatura. La metodología se realizó desde una revisión sobre las reformas, normas/estándares, políticas y premisas de educación física, para la construcción de una encuesta como instrumento de medición, se encuestaron a 41 docentes que imparten clases en un programa de Licenciatura en Educación Física. Resultados: La confiabilidad del instrumento muestra un Alfa de Conbrach (.611), un 64.3 de los docentes opinan que es muy importante el dominio de habilidades motoras y formas de movimiento necesarias, para participar en una gran variedad de actividades físicas; un 54.8 considera muy importante la evaluación de los componentes de la condición física, para mejorar el rendimiento físico y la salud; un 45.2 considera muy importante la participación regular en una gran variedad de actividades físicas. Conclusiones: la percepción epistemológica de los docentes encuestados no es totalmente consistente con la postura epistemológica que se plantea a nivel internacional, por lo que se debería trabajar en la formación y actualización del docente universitario para tener una postura epistemológica adecuada hacia la educación física actual