Influences of Differing Menarche Status on Motor Capabilities of Girls, 13 To 16 Years: A Two-Year Follow-Up Study.

Puberty and the onset of menarche influences the motor performance of girls. However, the magnitude of these influences during varying maturity status, is not clear. This longitudinal study over two years aimed to investigate differences in motor fitness between early and late developing girls based on pre- and post-menarche status. A convenience sample (n = 58) of girls aged 13.51 ± 3.51, divided by means of the Status Quo method into pre (n = 13) and post-menarche (n = 45) groups, was used. Motor fitness was tested once annually by standardized protocols. Basic statistics, independent t-testing and a repeated measures ANOVA with a post hoc Bonferonni correction were used (p < 0.05 = statistical significance). Effect sizes were determined by Cohen's d-values. Only explosive upper body strength differed significantly between groups during baseline, favoring post-menarche girls. Initially, post-menarche girls showed advantages in hand-eye coordination and speed (p > 0.05) with pre-menarche girls performing better in agility and explosive leg strength (p > 0.05). At 15.51 years, no significant, between-group differences were found. Pre-menarche girls surpassed post-menarche girls in hand-eye coordination and 0-40 m speed and post-menarche girls displayed higher explosive leg and upper body strength scores (p > 0.05). Our data show that the potential to excel in sport based on motor capabilities can only be accurately estimated 1-2 years after reaching menarche.