THE ORGANIZATION OF LEG MOVEMENTS IN PRETERM AND FULL-TERM INFANTS AFTER TERM AGE

In a sample of 13 full-term and 10 preterm infants, the development of kicking movements was studied at 6, 12, and 18 weeks (corrected) age. In healthy full-term infants some characteristics are strikingly stab le, such as the duration of the flexion and extension phase and the wi thin-joint organization. These parameters did not differ in preterm co mpared to full-term infatns. For other features, however, developmenta l changes and differences were observed. Full-term infants tended to d ecrease their kick frequencies slightly with age. In preterm infants m uch higher initial kick rates were found, followed by a steep decrease , which resulted in kick frequencies comparable to the full-term level s after the (corrected) age of 12 weeks. There is a tight coupling bet ween the movements in the different joints of the leg in full-term new borns. Preterm infants, in contrast, initially show much lower cross-c orrelations between hip and ankle and between knee and ankle.