The study will be conducted at various city swimming pools in Warsaw. The study participants will include 20 infants participating in aquatic baby classes once a week and 20 infants not participating in any classes and their parents. The study will be conducted in a quiet and calm room, which will be prepared in advance and equipped with a smooth mat, a lounger and infant toys. The estimated time to conduct the study is about 30 minutes.

The examination will be carried out twice: before the start of the two-month course and after its completion. Each time in the presence of a parent or legal guardian, after signing a consent form for the study.

The selected methods of assessing motor development are fully non-invasive and consist of the following tests:

1. Alberta Infant Motor Scale (AIMS)-a test involving observation of motor development, in which each activity is assessed as existing or not. The sum of the scores from all trials is then placed on a centile grid, the results of which will indicate how many children of a certain age are achieving a given level of motor skills.
2. Early Motor Development Questionnaire (EMQ)-will be conducted on the basis of a ready-made form and in an anonymous manner based on parents' current knowledge of their children's development.

Inclusion Criteria:

• infants age 3-12 months

Exclusion Criteria:

• any disability that would affect motor development