Evaluation of acceleration of somatic development of Lublin newborns over the period of twenty years.

The material for the present investigation includes the results of Chrzastek-Spruch's 1964-65 analysis of acceleration in 290 newborns (150 boys and 140 girls) as well as the data coming from the measurements applied to 445 newborns (225 boys and 230 girls) in 1984-85. The comparison between mean values of somatic traits of these two investigations points out to the presence of acceleration of physical development of Lublin newborns. The process involves increases in body length, lower extremity length, upper extremity length, and hip width. The width of distal femoral epiphysis is found diminished, which may attest to the process of gracilisation. Sexual dimorphism index turns out to be decreased, which is related to the fact that male and female body proportions tend to be alike. Moreover, newborns' body structures tend to become slender, which is signalled by lengthening of lower extremity and diminishing differences between shoulder width and hip width.