Independent reaching of the sitting position depends on the motor performance in the 3rd month of life.

OBJECTIVE: Sitting is one of milestones in motor development. However, reaching of the sitting position must precede achieving the ability of independent sitting. Qualitative assessment of motor performance at 3 months of age, with the prospective quanti - tative assessment of the function of indepen - dent reaching of the sitting position at the age of 8 months. PATIENTS AND METHODS: 125 children, 51 girls and 74 boys (born at term n = 78; born pre - maturely n = 47) were subject to prospective assessment of motor development with qualita - tive characteristics at the age of 3 months and quantitative characteristics at the age of 8 months. In parallel, the children were subjected to neurological assessment. Risk factors that could potentially affect motor development were analyzed. RESULTS: Children who at the age of 3 months performed at least 13 /15 qualitative el - ements in the prone position and at least 13/15 qualitative elements in the supine position, at the age of 8 months reached independently the sitting position. Poor qualitative assessment at the age of 3 months and a higher prevalence of risk factors increased the risk of non-reaching the sitting position. In the prone position, the pelvis, lower limbs, the arms and shoulders showed the most expressed differences be - tween the children who reached or did not reached the independent sitting. For the supine position, the pelvis and lower limbs, as well as the extension of the spine and correct align - ment of the shoulders showed the most ex - pressed differences. CONCLUSIONS: Proper qualitative develop - ment at the age of 3 months is a good predictor of the achievement of independent reaching of the sitting position at the age of 8 months.