Language version of the article. GICID Keywords longitudinal research, children aged years, somatic and motor development of sensitive and critical periods, Research Methods, comparative analysis of methods. Issue Journal of Kinesiology and Exercise Sciences ;26 76 Abstract Aim. Two objectives were set for realization in this paper: 1. To identify the cohort dynamics of the development of selected physical fitness components in girls and boys studied longitudinally as a basis for distinguishing sensitive and critical periods proposed in sports theory.
To carry out a comparative analysis of the individual and cohort development pace of selected motor abilities, taking into account the absolute and relative ages of the subjects in order to confirm the validity of distinguishing the limits of sensitive and critical periods limits with methods used in sports practice.
Basic procedures. The research incorporated the results of an eight-year continuous study on children from Krakow. Basic somatic features and anthropometric indicators were measured. Traditional methods were used to distinguish periods of increased dynamics of motor development and of reaching puberty leaps.
The age of reaching peak body height has was determined using an original computerized method. In the distinguished fractions of biological development advancement, the individual pace of motor development of boys and girls was determined. Comparative analysis of the cohort development pace of motor skills was conducted using traditional methods in our own and comparative studies, and the individual rate of development of random children who reached puberty at different times.
Comparative analysis showed no coherence in the occurrence of dynamic development periods of motor abilities distinguished in the materials from studies on both cohort and individual cases. Differences in studying motor skill development using various methods support the lack of a basis for the use of growth dynamics as a criterion for determining sensitive and critical periods.
