DEVELOPMENTAL DIFFERENCES BETWEEN BOYS AND GIRLS RESULT IN SEX-SPECIFIC PHYSICAL FITNESS CHANGES FROM FOURTH TO FIFTH GRADE

    Authors

    S. D. Flanagan; C. Dunn-Lewis; D. L. Hatfield; L. J. Distefano; M. S. Fragala; M. Shoap; M. Gotwald; J. Trail; A. L. Gomez; J. S. Volek; C. Cortis; B. A. Comstock; D. R. Hooper; T. K. Szivak; D. P. Looney; W. H. DuPont; D. M. McDermott; M. C. Gaudiose;W. J. Kraemer

    Comments

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    Abbreviated Journal Title

    J. Strength Cond. Res.

    Keywords

    physical activity; pubescence; body composition; longitudinal study; anthropometrics; body mass index; ONE-MILE RUN/WALK; GENDER-DIFFERENCES; MOTOR-PERFORMANCE; GRIP STRENGTH; CHILDREN; ADOLESCENTS; YOUTH; CHILDHOOD; TRACKING; DETERMINANTS; Sport Sciences

    Abstract

    To better understand how developmental differences impact performance on a broad selection of common physical fitness measures, we examined changes in boys and girls from fourth to fifth grade. Subjects included 273 boys (age, 9.5 +/- 0.6 years; height, 139.86 +/- 7.52 cm; mass, 38.00 +/- 9.55 kg) and 295 girls (age, 9.6 +/- 0.5 years; height, 139.30 +/- 7.19 cm; weight, 37.44 +/- 9.35 kg). We compared anthropometrics, cardiorespiratory and local muscular endurance, flexibility, power, and strength. A mixed-method analysis of variance was used to compare boys and girls at the 2 time points. Pearson correlation coefficients were used to examine relationships between anthropometric and fitness measurements. Significance was set at p < = 0.05. Weight increased significantly ( > 10%) in both sexes, and girls became significantly taller than boys after growing 4.9% by fifth grade (vs. 3.5%). Both groups improved cardiorespiratory endurance and power, although boys performed better than girls at both time points. Boys were stronger in fourth grade, but girls improved more, leading to similar fifth-grade values. Girls were more flexible in fourth grade, but their significant decreases (similar to 32.4%) coupled with large improvements in boys (similar to 105%) resulted in similar fifth-grade scores. Body mass index (BMI) was positively correlated with run time regardless of grade or sex. Power was negatively correlated with BMI and run time in fourth grade. In conclusion, sex-specific differences in physical fitness are apparent before pubescence. Furthermore, this selection of measures reveals sexually dimorphic changes, which likely reflect the onset of puberty in girls. Coaches and teachers should account these developmental differences and their effects on anthropometrics and fitness in boys and girls.

    Journal Title

    Journal of Strength and Conditioning Research

    Volume

    29

    Issue/Number

    1

    Publication Date

    1-1-2015

    Document Type

    Article

    Language

    English

    First Page

    175

    Last Page

    180

    WOS Identifier

    WOS:000347386800021

    ISSN

    1064-8011

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