The reliability of monopolar and bipolar fine-wire electromyographic measurement of muscle fatigue

This longitudinal study was designed to examine reciprocal relationships between feeding practices and infant growth over the first 6 mo of life. The following three hypotheses were tested: 1) early feeding practices predict later infant growth; 2) early infant growth predicts later feeding practices; and 3) these relationships occur after controlling for related background variables. The sample included 226 healthy, well-nourished infants born at the Queen Elizabeth Hospital, Bridgetown, Barbados. Assessments were made at birth, 7 wk, and 3 and 6 mo of age. Factor analysis of a feeding practices questionnaire for those mothers who attended all three postnatal visits yielded five uncorrelated factors. Three of these factors, preference for breast-feeding, feeding intensity and feeding difficulty, declined with infant age. Two of these factors, father helps and relatives help, increased with infant age. Several background variables, including maternal age, anthropometry and reproductive history, and reliance on outside sources of information were correlated with infant growth. Multivariate analyses confirmed all three hypotheses. The group of feeding practices (particularly the preference for breast-feeding) at 7 wk predicted increases in infant lengths at subsequent ages. Conversely, infant weights at 3 and 6 mo predicted subsequent feeding practices, especially feeding intensity. These reciprocal relationships remained even after statistically controlling for the influence of the background variables. Implications for public policy include the need for comprehensive programs advocating breast-feeding and supporting the general health of mothers and infants.