Development of the relationship between active and passive muscle power in preterms after term age.

Fifty-eight infants were assessed with an instrument which is designed to evaluate the development of the relationship between active and passive muscle power. The purpose of this longitudinal assessment was to investigate whether preterms show a different development course than fullterms in the relationship between these two components of muscle power. Thirty-seven low-risk preterms and twenty-one healthy fullterms were followed from term until 24 weeks corrected age. It is concluded that preterms differ markedly from fullterms in the developing interrelationship between active and passive muscle power. The value of the instrument for detecting signs of early pathology is discussed.