Only 1 in 4 U.S. kids aged 12 to 15 meet the recommendations � an hour or more of moderate to vigorous activity every day. The results are based on about 800 kids who self-reported their activity levels and had physical exams as part of the most recent National Youth Fitness Survey. - - - Solo 1 de 4 j�venes entre las edades de 12 a 15 a�os en los E.U., cumplen con las recomendaciones - una hora de actividad f�sica moderada al d�a. Estos resultados se obtuvieron de la m�s reciente encuesta a 800 j�venes, por "National Youth Fitness".