Age at spermarche and comparison of growth and performance of pre- and post-spermarcheal Chinese boys.
The prevalence of first ejaculation emission (spermarche) in Chinese Han boys in 1995 was considered. The subjects were 86,744 Han boys 9 through 18 years randomly selected from 28 provinces. Median spermarcheal ages (MSAs) were 14.4 and 14.6 years for urban and rural boys, respectively, and 14.3, 14.6, and 14.7 years for the boys of 1st, 2nd, and 3rd socioeconomic classes, respectively. Two environmental factors, ecological and socioeconomic, had strong influence upon MSAs. Eight indicators of somatic growth and motor ability were compared between pre- and post-spermarcheal boys of the same age. Post-spermarcheal boys were advanced in body size, shape, and physiological function during early and middle puberty, but most of the difference disappeared by 16 years. Pre-spermarcheal boys in a given age group were more linear and had more potential for increasing leg length into late adolescence. Within an age group, post-spermarcheal boys had advanced performances in several tasks requiring endurance, strength, and power around the age of maximum growth, 13-15 years. At older ages, the groups did not differ.
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Institute of Child and Adolescent Health, Beijing Medical University, Beijing, China. hjzhuang@263.net
D000293:Adolescent / Q000502:physiology*; D000367:Age Factors; D001824:Body Constitution / Q000502:physiology; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002648:Child; D002657:Child Development / Q000502:physiology*; D002681:China; D004463:Ecology; D004542:Ejaculation / Q000502:physiology*; D006128:Growth / Q000502:physiology*; D006306:Health Surveys; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D011627:Puberty / Q000502:physiology*; D012885:Skinfold Thickness; D012959:Socioeconomic Factors; D013094:Spermatozoa / Q000502:physiology*; D011795:Surveys and Questionnaires