Does load position on the trunk affect cardiopulmonary responses of the bearer during simulated front and back infant carrying methods?

Background: The position of the infant on the trunk during back and front infant carrying methods (ICMs) may be a potential factor of maternal physiological changes. Related information is necessary for the establishment of guiding principles for infant carrying tasks. Thus, this study was carried out to evaluate cardiopulmonary responses to infant-load positions on the trunk during simulated back and front ICMs. Materials and Methods: Twenty-three nulliparous females completed four trials while walking with a 6 kg simulated infant, being carried in four trunk positions (upper back, lower back, upper front, and lower front). Cardiopulmonary indices (systolic blood pressure, diastolic blood pressure, respiratory rate, and heart rate) and rating of perceived exertion were assessed pre- and post-trials. Results: All the cardiopulmonary indices did not change significantly (P > 0.05) as the infant load moved from upper to lower trunk positions during the back and front ICMs. However, marginal differences were observed. Participants perceived the lower back and upper front ICMs as less exerting than the upper back and lower front ICMs. Conclusions: Infant-load position on the trunk is not an important factor in the cardiopulmonary responses to back and front infant carrying tasks, although the lower back and upper front ICMs were perceived to be more comfortable