Relationship between biological age, habitual physical activity and morphological, physiological characteristics of 12 and 13 year old boys.
D000203:Activities of Daily Living; D000293:Adolescent; D000365:Age Determination by Skeleton; D000367:Age Factors; D000886:Anthropometry; D002648:Child; D006185:Habituation, Psychophysiologic; D006801:Humans; D008297:Male; D009426:Netherlands; D010806:Physical Education and Training; D010809:Physical Fitness; D012572:School Health Services