Sits confidently, does not usually need arms for support and can lean forward to reach an object

Your baby has been learning to control various parts of their body for the past few months, which is now helping them to learn how to sit and reach. Their eyes can now focus more effectively, allowing them to concentrate on a person or object, which has assisted them in gaining head stability. [1] By experiencing tummy time, their neck, back and head muscles will have strengthened, and they may have thrust up onto their elbows into an elevated position, like a mini push up. All this hard work has developed the strength in their head and trunk, making them stronger and more balanced, improving their posture.  

The tripod sit 

Whilst your baby has been learning how to sit, they may well have put their arms out in front of them to help them to be stable. They were using both arms as an anchor, to keep them from falling forwards.  

Now their core has become much stronger, they are more able to sit unassisted. The trunk is now becoming more stable and their hips have the control to sit without support; your baby may be able to sit independently with a straight back. [1] The development of postural control is gradually being gained as it goes down the spine—neck, shoulders, waist, and hips. This may well be one of the first physical milestones towards being an independent being.  

As your baby explores sitting without using their arms as an anchor, you may see your baby wobble a little when they sit for a few moments on their own. This is them learning how to stabilise themselves. It is usual for babies to occasionally anchor themselves with one arm. 

Your baby may fall to one side when they turn their head, this will happen whilst they learn how to shift their weight whilst in the sitting position. Your baby's ability to sit will be becoming subconscious and the better control they have will enable them to skillfully move themselves forward and reach an object close by. 

Reaching and staying safe 

Your baby has been able to defy gravity for some time now when lifting their arms and reaching. When they start to combine sitting and reaching, they will undoubtedly make many mistakes before reaching the object successfully. It won’t take long for them to be able to reach in all directions.  

You will need to stay close to your baby when they first start to sit independently and reach for objects. They will most likely bring objects to their objects to their mouths so a little check as to what is close by wouldn’t harm. Check to see where you are placing your baby to sit, as they still might fall forwards or to the side whilst they master sitting.  

What next 

Your baby will become more stable in the seated position and will be able to sit for longer periods of time. The ability to turn and reach in all directions without falling will become well practised and they will successfully pick up objects on the first attempt. As their core strength continues to grow, you may see your baby pulling themselves up from a lying position to a sitting position independently. 

References 

[1] C.K.M.R. Formiga and M.B.M. Linhares (2015) Motor Skills: Development in Infancy and Early Childhood. Elsevier Ltd. International Encyclopedia of the Social & Behavioral Sciences, Second Edition, 2015, 971–977. Available online at: 2015CibelleeBeatrizEnciclopediaElsevier.pdf