Potential environmental factors influencing the occurrence of bottom shuffling in ordinary infants

BACKGROUND: Bottom shuffling (BS) occurs in ordinary infants without developmental disorders; however, the incidence and the related factors have been unclear. This study aimed to investigate the occurrence of BS in ordinary developing infants and the potential effects of parental intervention on the BS occurrence. METHODS: A questionnaire survey on BS was conducted among 241 parents of 0-year-old and 1-year-old children in nursery schools, randomly selected from urban and rural areas in three prefectures in Japan. RESULTS: Of the 241 infants without developmental disorders, 52 infants (21.6%) exhibited BS from 6 to 18 months of age (average: 8.3 ± 2.0 months). The ages of starting creeping, crawling, and unsupported sitting were 6.9 ± 1.8, 8.6 ± 1.8, and 7.0 ± 1.4 months of age, respectively. While the age of acquisition for creeping, crawling, or sitting did not differ due to BS, a correlation was found between BS incidence and parents' understanding of sitting development. Of the 241 parents, 110 parents responded that the timing of their infant's learning of "how to sit" should come just after their start of rolling over. In the infants with the 110 parents, a significant high frequency of the BS occurrence (27.3%, 30 out of 110) was observed. CONCLUSIONS: BS may lead to a decrease in opportunities for full-body prone activity resulting in reduced physical activity, which raises concerns about the infant's autonomy.