BACKGROUND: Predicted maturity offset, defined as time before peak height velocity (PHV) is increasingly used as an indicator of maturity status in studies of physical activity, fitness, and sport. OBJECTIVE: To validate maturity offset prediction equations in longitudinal samples of boys and girls. METHODS: The original and modified maturity offset prediction equations were applied to serial data for 266 boys (8-17 years) and 147 girls (8-16 years) from the Cracow Growth Study. Actual age at PHV for each youngster was estimated with the SITAR protocol. In addition to maturity offset, the difference between CA at prediction and maturity offset provided an estimate of predicted age at PHV. RESULTS: Predicted maturity offset and age at PHV increased, on average, with CA at prediction. Variation in predictions was reduced compared to that in observed ages at offset and at PHV, and was more apparent with the modified equations. Relatively few predicted ages at PHV approximated observed age at PHV in early and late maturing youth of both sexes; predictions were later than observed among the former, and earlier than observed among the latter. CONCLUSION: Predicted maturity offset and ages at PHV with the original and modified equations increase with CA at prediction, have reduced variation, and have major limitations with early and late maturing boys and girls.

Department of Anatomy University School of Physical Education Cracow Poland

Department of Anthropology Faculty of Science Masaryk University Brno Czech Republic

Department of Anthropology Hirszfeld Institute of Immunology and Experimental Therapy Polish Academy of Sciences Wrocław Poland

Department of Anthropology University School of Physical Education Cracow Poland

Department of Kinesiology and Health Education University of Texas at Austin Austin Texas USA

School of Public Health and Information Sciences University of Louisville Louisville Kentucky USA

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